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Keifer J. Synaptic Mechanisms of Delay Eyeblink Classical Conditioning: AMPAR Trafficking and Gene Regulation in an In Vitro Model. Mol Neurobiol 2023; 60:7088-7103. [PMID: 37531025 DOI: 10.1007/s12035-023-03528-z] [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: 03/14/2023] [Accepted: 07/20/2023] [Indexed: 08/03/2023]
Abstract
An in vitro model of delay eyeblink classical conditioning was developed to investigate synaptic plasticity mechanisms underlying acquisition of associative learning. This was achieved by replacing real stimuli, such as an airpuff and tone, with patterned stimulation of the cranial nerves using an isolated brainstem preparation from turtle. Here, our primary findings regarding cellular and molecular mechanisms for learning acquisition using this unique approach are reviewed. The neural correlate of the in vitro eyeblink response is a replica of the actual behavior, and features of conditioned responses (CRs) resemble those observed in behavioral studies. Importantly, it was shown that acquisition of CRs did not require the intact cerebellum, but the appropriate timing did. Studies of synaptic mechanisms indicate that conditioning involves two stages of AMPA receptor (AMPAR) trafficking. Initially, GluA1-containing AMPARs are targeted to synapses followed later by replacement by GluA4 subunits that support CR expression. This two-stage process is regulated by specific signal transduction cascades involving PKA and PKC and is guided by distinct protein chaperones. The expression of the brain-derived neurotrophic factor (BDNF) protein is central to AMPAR trafficking and conditioning. BDNF gene expression is regulated by coordinated epigenetic mechanisms involving DNA methylation/demethylation and chromatin modifications that control access of promoters to transcription factors. Finally, a hypothesis is proposed that learning genes like BDNF are poised by dual chromatin features that allow rapid activation or repression in response to environmental stimuli. These in vitro studies have advanced our understanding of the cellular and molecular mechanisms that underlie associative learning.
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Affiliation(s)
- Joyce Keifer
- Neuroscience Group, Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD, 57069, USA.
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2
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Suzuki K, Shibato J, Rakwal R, Takaura M, Hotta R, Masuo Y. Biomarkers in the Rat Hippocampus and Peripheral Blood for an Early Stage of Mental Disorders Induced by Water Immersion Stress. Int J Mol Sci 2023; 24:ijms24043153. [PMID: 36834565 PMCID: PMC9960135 DOI: 10.3390/ijms24043153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/02/2023] [Accepted: 02/03/2023] [Indexed: 02/09/2023] Open
Abstract
It is difficult to evaluate the pre-symptomatic state of mental disorders and prevent its onset. Since stress could be a trigger of mental disorders, it may be helpful to identify stress-responsive biomarkers (stress markers) for the evaluation of stress levels. We have so far performed omics analyses of the rat brain and peripheral blood after various kinds of stress and have found numerous factors that respond to stress. In this study, we investigated the effects of relatively moderate stress on these factors in the rat to identify stress marker candidates. Adult male Wistar rats underwent water immersion stress for 12 h, 24 h, or 48 h. Stress caused weight loss and elevated serum corticosterone levels, and alterations regarded as anxiety and/or fear-like behaviors. Reverse-transcription PCR and Western blot analyses revealed significant alterations in the expressions of hippocampal genes and proteins by the stress for no longer than 24 h, such as mitogen-activated protein kinase phosphatase 1 (MKP-1), CCAAT/enhancer-binding protein delta (CEBPD), small ubiquitin-like modifier proteins 1/sentrin-specific peptidase 5 (SENP5), matrix metalloproteinase-8 (MMP-8), kinase suppressor of Ras 1 (KSR1), and MKP-1, MMP-8, nerve growth factor receptor (NGFR). Similar alterations were observed in three genes (MKP-1, CEBPD, MMP-8) in the peripheral blood. The present results strongly suggest that these factors may serve as stress markers. The correlation of these factors in the blood and brain may enable the evaluation of stress-induced changes in the brain by blood analysis, which will contribute to preventing the onset of mental disorders.
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Affiliation(s)
- Keisuke Suzuki
- Laboratory of Neuroscience, Department of Biology, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi 274-8510, Japan
| | - Junko Shibato
- Department of Functional Morphology, Shonan University of Medical Sciences, 16-48 Kamishinano, Totsuka-ku, Yokohama 244-0806, Japan
| | - Randeep Rakwal
- Institute of Health and Sport Sciences and Tsukuba International Academy for Sport Studies (TIAS2.0), University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8574, Japan
| | - Masahiko Takaura
- Laboratory of Neuroscience, Department of Biology, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi 274-8510, Japan
| | - Ryotaro Hotta
- Laboratory of Neuroscience, Department of Biology, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi 274-8510, Japan
| | - Yoshinori Masuo
- Laboratory of Neuroscience, Department of Biology, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi 274-8510, Japan
- Correspondence:
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3
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Ojea Ramos S, Feld M, Fustiñana MS. Contributions of extracellular-signal regulated kinase 1/2 activity to the memory trace. Front Mol Neurosci 2022; 15:988790. [PMID: 36277495 PMCID: PMC9580372 DOI: 10.3389/fnmol.2022.988790] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 09/02/2022] [Indexed: 11/15/2022] Open
Abstract
The ability to learn from experience and consequently adapt our behavior is one of the most fundamental capacities enabled by complex and plastic nervous systems. Next to cellular and systems-level changes, learning and memory formation crucially depends on molecular signaling mechanisms. In particular, the extracellular-signal regulated kinase 1/2 (ERK), historically studied in the context of tumor growth and proliferation, has been shown to affect synaptic transmission, regulation of neuronal gene expression and protein synthesis leading to structural synaptic changes. However, to what extent the effects of ERK are specifically related to memory formation and stabilization, or merely the result of general neuronal activation, remains unknown. Here, we review the signals leading to ERK activation in the nervous system, the subcellular ERK targets associated with learning-related plasticity, and how neurons with activated ERK signaling may contribute to the formation of the memory trace.
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Affiliation(s)
- Santiago Ojea Ramos
- Instituto de Fisiología, Biología Molecular y Neurociencias, Universidad de Buenos Aires-Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Mariana Feld
- Instituto de Fisiología, Biología Molecular y Neurociencias, Universidad de Buenos Aires-Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
- *Correspondence: Mariana Feld,
| | - María Sol Fustiñana
- Friedrich Miescher Institute for Biomedical Research, Basel, Switzerland
- María Sol Fustiñana,
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4
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Al-Amri AH, Armstrong P, Amici M, Ligneul C, Rouse J, El-Asrag ME, Pantiru A, Vancollie VE, Ng HW, Ogbeta JA, Goodchild K, Ellegood J, Lelliott CJ, Mullins JG, Bretman A, Al-Ali R, Beetz C, Al-Gazali L, Al Shamsi A, Lerch JP, Mellor JR, Al Sayegh A, Ali M, Inglehearn CF, Clapcote SJ. PDZD8 Disruption Causes Cognitive Impairment in Humans, Mice, and Fruit Flies. Biol Psychiatry 2022; 92:323-334. [PMID: 35227461 PMCID: PMC9302898 DOI: 10.1016/j.biopsych.2021.12.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 12/13/2021] [Accepted: 12/14/2021] [Indexed: 12/16/2022]
Abstract
BACKGROUND The discovery of coding variants in genes that confer risk of intellectual disability (ID) is an important step toward understanding the pathophysiology of this common developmental disability. METHODS Homozygosity mapping, whole-exome sequencing, and cosegregation analyses were used to identify gene variants responsible for syndromic ID with autistic features in two independent consanguineous families from the Arabian Peninsula. For in vivo functional studies of the implicated gene's function in cognition, Drosophila melanogaster and mice with targeted interference of the orthologous gene were used. Behavioral, electrophysiological, and structural magnetic resonance imaging analyses were conducted for phenotypic testing. RESULTS Homozygous premature termination codons in PDZD8, encoding an endoplasmic reticulum-anchored lipid transfer protein, showed cosegregation with syndromic ID in both families. Drosophila melanogaster with knockdown of the PDZD8 ortholog exhibited impaired long-term courtship-based memory. Mice homozygous for a premature termination codon in Pdzd8 exhibited brain structural, hippocampal spatial memory, and synaptic plasticity deficits. CONCLUSIONS These data demonstrate the involvement of homozygous loss-of-function mutations in PDZD8 in a neurodevelopmental cognitive disorder. Model organisms with manipulation of the orthologous gene replicate aspects of the human phenotype and suggest plausible pathophysiological mechanisms centered on disrupted brain development and synaptic function. These findings are thus consistent with accruing evidence that synaptic defects are a common denominator of ID and other neurodevelopmental conditions.
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Affiliation(s)
- Ahmed H. Al-Amri
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom,Leeds Institute of Medical Research, University of Leeds, Leeds, United Kingdom,National Genetic Centre, Royal Hospital, Muscat, Oman
| | - Paul Armstrong
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - Mascia Amici
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Clemence Ligneul
- Wellcome Centre for Integrative Neuroimaging, Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford, United Kingdom
| | - James Rouse
- School of Biology, University of Leeds, Leeds, United Kingdom
| | - Mohammed E. El-Asrag
- Leeds Institute of Medical Research, University of Leeds, Leeds, United Kingdom,Department of Zoology, Faculty of Science, Benha University, Benha, Egypt,Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham
| | - Andreea Pantiru
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | | | - Hannah W.Y. Ng
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - Jennifer A. Ogbeta
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - Kirstie Goodchild
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - Jacob Ellegood
- Mouse Imaging Centre, Hospital for Sick Children, Toronto, Ontario, Canada
| | | | | | - Amanda Bretman
- School of Biology, University of Leeds, Leeds, United Kingdom
| | | | | | - Lihadh Al-Gazali
- Department of Paediatrics, College of Medicine & Health Sciences, United Arab Emirates University, Al Ain, United Arab Emirates
| | - Aisha Al Shamsi
- Pediatrics Department, Tawam Hospital, Al Ain, United Arab Emirates
| | - Jason P. Lerch
- Wellcome Centre for Integrative Neuroimaging, Nuffield Department of Clinical Neuroscience, University of Oxford, Oxford, United Kingdom
| | - Jack R. Mellor
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Abeer Al Sayegh
- Genetics Department, Sultan Qaboos University Hospital, Muscat, Oman
| | - Manir Ali
- Leeds Institute of Medical Research, University of Leeds, Leeds, United Kingdom
| | - Chris F. Inglehearn
- Leeds Institute of Medical Research, University of Leeds, Leeds, United Kingdom
| | - Steven J. Clapcote
- School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom,Address correspondence to Steven J. Clapcote, Ph.D.
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5
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Luessen DJ, Conn PJ. Allosteric Modulators of Metabotropic Glutamate Receptors as Novel Therapeutics for Neuropsychiatric Disease. Pharmacol Rev 2022; 74:630-661. [PMID: 35710132 PMCID: PMC9553119 DOI: 10.1124/pharmrev.121.000540] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Metabotropic glutamate (mGlu) receptors, a family of G-protein-coupled receptors, have been identified as novel therapeutic targets based on extensive research supporting their diverse contributions to cell signaling and physiology throughout the nervous system and important roles in regulating complex behaviors, such as cognition, reward, and movement. Thus, targeting mGlu receptors may be a promising strategy for the treatment of several brain disorders. Ongoing advances in the discovery of subtype-selective allosteric modulators for mGlu receptors has provided an unprecedented opportunity for highly specific modulation of signaling by individual mGlu receptor subtypes in the brain by targeting sites distinct from orthosteric or endogenous ligand binding sites on mGlu receptors. These pharmacological agents provide the unparalleled opportunity to selectively regulate neuronal excitability, synaptic transmission, and subsequent behavioral output pertinent to many brain disorders. Here, we review preclinical and clinical evidence supporting the utility of mGlu receptor allosteric modulators as novel therapeutic approaches to treat neuropsychiatric diseases, such as schizophrenia, substance use disorders, and stress-related disorders.
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6
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Miningou Zobon NT, Jędrzejewska-Szmek J, Blackwell KT. Temporal pattern and synergy influence activity of ERK signaling pathways during L-LTP induction. eLife 2021; 10:e64644. [PMID: 34374340 PMCID: PMC8363267 DOI: 10.7554/elife.64644] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 08/03/2021] [Indexed: 01/21/2023] Open
Abstract
Long-lasting long-term potentiation (L-LTP) is a cellular mechanism of learning and memory storage. Studies have demonstrated a requirement for extracellular signal-regulated kinase (ERK) activation in L-LTP produced by a diversity of temporal stimulation patterns. Multiple signaling pathways converge to activate ERK, with different pathways being required for different stimulation patterns. To answer whether and how different temporal patterns select different signaling pathways for ERK activation, we developed a computational model of five signaling pathways (including two novel pathways) leading to ERK activation during L-LTP induction. We show that calcium and cAMP work synergistically to activate ERK and that stimuli given with large intertrial intervals activate more ERK than shorter intervals. Furthermore, these pathways contribute to different dynamics of ERK activation. These results suggest that signaling pathways with different temporal sensitivities facilitate ERK activation to diversity of temporal patterns.
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Affiliation(s)
| | - Joanna Jędrzejewska-Szmek
- Laboratory of Neuroinformatic, Nencki Institute of Experimental Biology of Polish Academy of SciencesWarsawPoland
| | - Kim T Blackwell
- Interdisciplinary Program in Neuroscience, Bioengineering Department, George Mason UniversityFairfaxUnited States
- Krasnow Institute for Advanced Study, George Mason UniversityFairfaxUnited States
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7
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Liu A, Ji H, Ren Q, Meng Y, Zhang H, Collingride G, Xie W, Jia Z. The Requirement of the C-Terminal Domain of GluA1 in Different Forms of Long-Term Potentiation in the Hippocampus Is Age-Dependent. Front Synaptic Neurosci 2020; 12:588785. [PMID: 33192442 PMCID: PMC7661473 DOI: 10.3389/fnsyn.2020.588785] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 09/25/2020] [Indexed: 11/13/2022] Open
Abstract
Long-term potentiation (LTP) at glutamatergic synapses is an extensively studied form of long-lasting synaptic plasticity widely regarded as the cellular basis for learning and memory. At the CA1 synapse, there are multiple forms of LTP with distinct properties. Although AMPA glutamate receptors (AMPARs) are a key target of LTP expression, whether they are required in all forms of LTP remains unclear. To address this question, we have used our recently developed mouse line, GluA1C2KI, where the c-terminal domain (CTD) of the endogenous GluA1 is replaced by that of GluA2. Unlike traditional GluA1 global or conditional KO mice, GluA1C2KI mice have no changes in basal AMPAR properties or synaptic transmission allowing a better assessment of GluA1 in synaptic plasticity. We previously showed that these mice are impaired in LTP induced by high-frequency stimulation (HFS-LTP), but whether other forms of LTP are also affected in these mice is unknown. In this study, we compared various forms of LTP at CA1 synapses between GluA1C2KI and wild-type littermates by using several induction protocols. We show that HFS-LTP is impaired in both juvenile and adult GluA1C2KI mice. The LTP induced by theta-burst stimulation (TBS-LTP) is also abolished in juvenile GluA1C2KI mice. Interestingly, TBS-LTP can still be induced in adult GluA1C2KI mice, but its mechanisms are altered becoming more sensitive to protein synthesis and the extracellular signal-regulated kinase (ERK) inhibitors compared to wild type (WT) control. The GluA1C2KI mice are also differentially altered in several forms of LTP induced under whole-cell recording paradigms. These results indicate that the CTD of GluA1 is differentially involved in different forms of LTP at CA1 synapse highlighting the complexity and adaptative potential of LTP expression mechanisms in the hippocampus.
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Affiliation(s)
- An Liu
- The Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, School of Life Science and Technology, Jiangsu Co-Innovation Center of Neuroregeneration, Southeast University, Nanjing, China
| | - Hong Ji
- The Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, School of Life Science and Technology, Jiangsu Co-Innovation Center of Neuroregeneration, Southeast University, Nanjing, China
| | - Qiaoyun Ren
- The Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, School of Life Science and Technology, Jiangsu Co-Innovation Center of Neuroregeneration, Southeast University, Nanjing, China
| | - Yanghong Meng
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Haiwang Zhang
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
| | - Graham Collingride
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Wei Xie
- The Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, School of Life Science and Technology, Jiangsu Co-Innovation Center of Neuroregeneration, Southeast University, Nanjing, China
| | - Zhengping Jia
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.,Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
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8
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Dominant-Negative Attenuation of cAMP-Selective Phosphodiesterase PDE4D Action Affects Learning and Behavior. Int J Mol Sci 2020; 21:ijms21165704. [PMID: 32784895 PMCID: PMC7460819 DOI: 10.3390/ijms21165704] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 07/26/2020] [Accepted: 08/06/2020] [Indexed: 12/22/2022] Open
Abstract
PDE4 cyclic nucleotide phosphodiesterases reduce 3′, 5′ cAMP levels in the CNS and thereby regulate PKA activity and the phosphorylation of CREB, fundamental to depression, cognition, and learning and memory. The PDE4 isoform PDE4D5 interacts with the signaling proteins β-arrestin2 and RACK1, regulators of β2-adrenergic and other signal transduction pathways. Mutations in PDE4D in humans predispose to acrodysostosis, associated with cognitive and behavioral deficits. To target PDE4D5, we developed mice that express a PDE4D5-D556A dominant-negative transgene in the brain. Male transgenic mice demonstrated significant deficits in hippocampus-dependent spatial learning, as assayed in the Morris water maze. In contrast, associative learning, as assayed in a fear conditioning assay, appeared to be unaffected. Male transgenic mice showed augmented activity in prolonged (2 h) open field testing, while female transgenic mice showed reduced activity in the same assay. Transgenic mice showed no demonstrable abnormalities in prepulse inhibition. There was also no detectable difference in anxiety-like behavior, as measured in the elevated plus-maze. These data support the use of a dominant-negative approach to the study of PDE4D5 function in the CNS and specifically in learning and memory.
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9
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Miningou N, Blackwell KT. The road to ERK activation: Do neurons take alternate routes? Cell Signal 2020; 68:109541. [PMID: 31945453 DOI: 10.1016/j.cellsig.2020.109541] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 01/11/2020] [Accepted: 01/12/2020] [Indexed: 01/29/2023]
Abstract
The ERK cascade is a central signaling pathway that regulates a wide variety of cellular processes including proliferation, differentiation, learning and memory, development, and synaptic plasticity. A wide range of inputs travel from the membrane through different signaling pathway routes to reach activation of one set of output kinases, ERK1&2. The classical ERK activation pathway beings with growth factor activation of receptor tyrosine kinases. Numerous G-protein coupled receptors and ionotropic receptors also lead to ERK through increases in the second messengers calcium and cAMP. Though both types of pathways are present in diverse cell types, a key difference is that most stimuli to neurons, e.g. synaptic inputs, are transient, on the order of milliseconds to seconds, whereas many stimuli acting on non-neural tissue, e.g. growth factors, are longer duration. The ability to consolidate these inputs to regulate the activation of ERK in response to diverse signals raises the question of which factors influence the difference in ERK activation pathways. This review presents both experimental studies and computational models aimed at understanding the control of ERK activation and whether there are fundamental differences between neurons and other cells. Our main conclusion is that differences between cell types are quite subtle, often related to differences in expression pattern and quantity of some molecules such as Raf isoforms. In addition, the spatial location of ERK is critical, with regulation by scaffolding proteins producing differences due to colocalization of upstream molecules that may differ between neurons and other cells.
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Affiliation(s)
- Nadiatou Miningou
- Department of Chemistry and Biochemistry, George Mason University, Fairfax, VA 22030, United States of America
| | - Kim T Blackwell
- Interdisciplinary Program in Neuroscience and Bioengineering Department, George Mason University, Fairfax, VA 22030, United States of America.
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10
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Xiang Z, Lv X, Maksymetz J, Stansley BJ, Ghoshal A, Gogliotti RG, Niswender CM, Lindsley CW, Conn PJ. mGlu 5 Positive Allosteric Modulators Facilitate Long-Term Potentiation via Disinhibition Mediated by mGlu 5-Endocannabinoid Signaling. ACS Pharmacol Transl Sci 2019; 2:198-209. [PMID: 31259318 PMCID: PMC6591772 DOI: 10.1021/acsptsci.9b00017] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Indexed: 11/29/2022]
Abstract
Metabotropic glutamate (mGlu) receptor type 5 (mGlu5) positive allosteric modulators (PAMs) enhance hippocampal long-term potentiation (LTP) and have cognition-enhancing effects in animal models. These effects were initially thought to be mediated by potentiation of mGlu5 modulation of N-methyl-d-aspartate receptor (NMDAR) currents. However, a biased mGlu5 PAM that potentiates Gαq-dependent mGlu5 signaling, but not mGlu5 modulation of NMDAR currents, retains cognition-enhancing effects in animal models, suggesting that potentiation of NMDAR currents is not required for these in vivo effects of mGlu5 PAMs. However, it is not clear whether the potentiation of NMDAR currents is critical for the ability of mGlu5 PAMs to enhance hippocampal LTP. We now report the characterization of effects of two structurally distinct mGlu5 PAMs, VU-29 and VU0092273, on NMDAR currents and hippocampal LTP. As with other mGlu5 PAMs that do not display observable bias for potentiation of NMDAR currents, VU0092273 enhanced both mGlu5 modulation of NMDAR currents and induction of LTP at the hippocampal Schaffer collateral (SC)-CA1 synapse. In contrast, VU-29 did not potentiate mGlu5 modulation of NMDAR currents but induced robust potentiation of hippocampal LTP. Interestingly, both VU-29 and VU0092273 suppressed evoked inhibitory postsynaptic currents (eIPSCs) in CA1 pyramidal cells, and this effect was blocked by the cannabinoid receptor type 1 (CB1) antagonist AM251. Furthermore, AM251 blocked the ability of both mGlu5 PAMs to enhance LTP. Finally, both PAMs failed to enhance LTP in mice with the restricted genetic deletion of mGlu5 in CA1 pyramidal cells. Taken together with previous findings, these results suggest that enhancement of LTP by mGlu5 PAMs does not depend on mGlu5 modulation of NMDAR currents but is mediated by a previously established mechanism in which mGlu5 in CA1 pyramidal cells induces endocannabinoid release and CB1-dependent disinhibition.
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Affiliation(s)
- Zixiu Xiang
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery,Department of Chemistry, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Xiaohui Lv
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery,Department of Chemistry, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - James Maksymetz
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery,Department of Chemistry, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Branden J Stansley
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery,Department of Chemistry, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Ayan Ghoshal
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery,Department of Chemistry, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Rocco G Gogliotti
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery,Department of Chemistry, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Colleen M Niswender
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery,Department of Chemistry, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Craig W Lindsley
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery,Department of Chemistry, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - P Jeffrey Conn
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery,Department of Chemistry, Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
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11
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From membrane receptors to protein synthesis and actin cytoskeleton: Mechanisms underlying long lasting forms of synaptic plasticity. Semin Cell Dev Biol 2019; 95:120-129. [PMID: 30634048 DOI: 10.1016/j.semcdb.2019.01.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Revised: 01/07/2019] [Accepted: 01/08/2019] [Indexed: 12/13/2022]
Abstract
Synaptic plasticity, the activity dependent change in synaptic strength, forms the molecular foundation of learning and memory. Synaptic plasticity includes structural changes, with spines changing their size to accomodate insertion and removal of postynaptic receptors, which are correlated with functional changes. Of particular relevance for memory storage are the long lasting forms of synaptic plasticity which are protein synthesis dependent. Due to the importance of spine structural plasticity and protein synthesis, this review focuses on the signaling pathways that connect synaptic stimulation with regulation of protein synthesis and remodeling of the actin cytoskeleton. We also review computational models that implement novel aspects of molecular signaling in synaptic plasticity, such as the role of neuromodulators and spatial microdomains, as well as highlight the need for computational models that connect activation of memory kinases with spine actin dynamics.
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12
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Blackwell KT, Salinas AG, Tewatia P, English B, Hellgren Kotaleski J, Lovinger DM. Molecular mechanisms underlying striatal synaptic plasticity: relevance to chronic alcohol consumption and seeking. Eur J Neurosci 2018; 49:768-783. [PMID: 29602186 DOI: 10.1111/ejn.13919] [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: 12/06/2017] [Revised: 03/19/2018] [Accepted: 03/20/2018] [Indexed: 01/02/2023]
Abstract
The striatum, the input structure of the basal ganglia, is a major site of learning and memory for goal-directed actions and habit formation. Spiny projection neurons of the striatum integrate cortical, thalamic, and nigral inputs to learn associations, with cortico-striatal synaptic plasticity as a learning mechanism. Signaling molecules implicated in synaptic plasticity are altered in alcohol withdrawal, which may contribute to overly strong learning and increased alcohol seeking and consumption. To understand how interactions among signaling molecules produce synaptic plasticity, we implemented a mechanistic model of signaling pathways activated by dopamine D1 receptors, acetylcholine receptors, and glutamate. We use our novel, computationally efficient simulator, NeuroRD, to simulate stochastic interactions both within and between dendritic spines. Dopamine release during theta burst and 20-Hz stimulation was extrapolated from fast-scan cyclic voltammetry data collected in mouse striatal slices. Our results show that the combined activity of several key plasticity molecules correctly predicts the occurrence of either LTP, LTD, or no plasticity for numerous experimental protocols. To investigate spatial interactions, we stimulate two spines, either adjacent or separated on a 20-μm dendritic segment. Our results show that molecules underlying LTP exhibit spatial specificity, whereas 2-arachidonoylglycerol exhibits a spatially diffuse elevation. We also implement changes in NMDA receptors, adenylyl cyclase, and G protein signaling that have been measured following chronic alcohol treatment. Simulations under these conditions suggest that the molecular changes can predict changes in synaptic plasticity, thereby accounting for some aspects of alcohol use disorder.
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Affiliation(s)
- Kim T Blackwell
- The Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA, USA.,Department of Bioengineering, George Mason University, Fairfax, VA, USA
| | - Armando G Salinas
- The Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA, USA.,National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, USA
| | - Parul Tewatia
- Science for Life Laboratory, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Brad English
- The Krasnow Institute for Advanced Study, George Mason University, Fairfax, VA, USA
| | - Jeanette Hellgren Kotaleski
- Science for Life Laboratory, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm, Sweden
| | - David M Lovinger
- National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, USA
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13
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Germino EA, Miller JP, Diehl L, Swanson CJ, Durinck S, Modrusan Z, Miner JH, Shaw AS. Homozygous KSR1 deletion attenuates morbidity but does not prevent tumor development in a mouse model of RAS-driven pancreatic cancer. PLoS One 2018; 13:e0194998. [PMID: 29596465 PMCID: PMC5875795 DOI: 10.1371/journal.pone.0194998] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 03/14/2018] [Indexed: 01/04/2023] Open
Abstract
Given the frequency with which MAP kinase signaling is dysregulated in cancer, much effort has been focused on inhibiting RAS signaling for therapeutic benefit. KSR1, a pseudokinase that interacts with RAF, is a potential target; it was originally cloned in screens for suppressors of constitutively active RAS, and its deletion prevents RAS-mediated transformation of mouse embryonic fibroblasts. In this work, we used a genetically engineered mouse model of pancreatic cancer to assess whether KSR1 deletion would influence tumor development in the setting of oncogenic RAS. We found that Ksr1-/- mice on this background had a modest but significant improvement in all-cause morbidity compared to Ksr1+/+ and Ksr1+/- cohorts. Ksr1-/- mice, however, still developed tumors, and precursor pancreatic intraepithelial neoplastic (PanIN) lesions were detected within a similar timeframe compared to Ksr1+/+ mice. No significant differences in pERK expression or in proliferation were noted. RNA sequencing also did not reveal any unique genetic signature in Ksr1-/- tumors. Further studies will be needed to determine whether and in what settings KSR inhibition may be clinically useful.
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Affiliation(s)
- Elizabeth A. Germino
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Research Biology, Genentech, South San Francisco, California, United States of America
| | - Joseph P. Miller
- Division of Nephrology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Lauri Diehl
- Department of Pathology, Genentech, South San Francisco, California, United States of America
| | - Carter J. Swanson
- Department of Research Biology, Genentech, South San Francisco, California, United States of America
| | - Steffen Durinck
- Department of Bioinformatics and Computational Biology, Genentech, South San Francisco, California, United States of America
- Department of Molecular Biology, Genentech, South San Francisco, California, United States of America
| | - Zora Modrusan
- Department of Molecular Biology, Genentech, South San Francisco, California, United States of America
| | - Jeffrey H. Miner
- Division of Nephrology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Andrey S. Shaw
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Research Biology, Genentech, South San Francisco, California, United States of America
- * E-mail:
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14
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Abstract
The c-Jun N-terminal kinase (JNK) signal transduction pathway is implicated in learning and memory. Here, we examined the role of JNK activation mediated by the JNK-interacting protein 1 (JIP1) scaffold protein. We compared male wild-type mice with a mouse model harboring a point mutation in the Jip1 gene that selectively blocks JIP1-mediated JNK activation. These male mutant mice exhibited increased NMDAR currents, increased NMDAR-mediated gene expression, and a lower threshold for induction of hippocampal long-term potentiation. The JIP1 mutant mice also displayed improved hippocampus-dependent spatial memory and enhanced associative fear conditioning. These results were confirmed using a second JIP1 mutant mouse model that suppresses JNK activity. Together, these observations establish that JIP1-mediated JNK activation contributes to the regulation of hippocampus-dependent, NMDAR-mediated synaptic plasticity and learning.SIGNIFICANCE STATEMENT The results of this study demonstrate that c-Jun N-terminal kinase (JNK) activation induced by the JNK-interacting protein 1 (JIP1) scaffold protein negatively regulates the threshold for induction of long-term synaptic plasticity through the NMDA-type glutamate receptor. This change in plasticity threshold influences learning. Indeed, mice with defects in JIP1-mediated JNK activation display enhanced memory in hippocampus-dependent tasks, such as contextual fear conditioning and Morris water maze, indicating that JIP1-JNK constrains spatial memory. This study identifies JIP1-mediated JNK activation as a novel molecular pathway that negatively regulates NMDAR-dependent synaptic plasticity and memory.
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15
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Campbell SL, van Groen T, Kadish I, Smoot LHM, Bolger GB. Altered phosphorylation, electrophysiology, and behavior on attenuation of PDE4B action in hippocampus. BMC Neurosci 2017; 18:77. [PMID: 29197324 PMCID: PMC5712142 DOI: 10.1186/s12868-017-0396-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Accepted: 11/28/2017] [Indexed: 01/19/2023] Open
Abstract
Background PDE4 cyclic nucleotide phosphodiesterases regulate 3′, 5′ cAMP abundance in the CNS and thereby regulate PKA activity and phosphorylation of CREB, which has been implicated in learning and memory, depression and other functions. The PDE4 isoform PDE4B1 also interacts with the DISC1 protein, implicated in neural development and behavioral disorders. The cellular functions of PDE4B1 have been investigated extensively, but its function(s) in the intact organism remained unexplored. Results To specifically disrupt PDE4B1, we developed mice that express a PDE4B1-D564A transgene in the hippocampus and forebrain. The transgenic mice showed enhanced phosphorylation of CREB and ERK1/2 in hippocampus. Hippocampal neurogenesis was increased in the transgenic mice. Hippocampal electrophysiological studies showed increased baseline synaptic transmission and enhanced LTP in male transgenic mice. Behaviorally, male transgenic mice showed increased activity in prolonged open field testing, but neither male nor female transgenic mice showed detectable anxiety-like behavior or antidepressant effects in the elevated plus-maze, tail-suspension or forced-swim tests. Neither sex showed any significant differences in associative fear conditioning or showed any demonstrable abnormalities in pre-pulse inhibition. Conclusions These data support the use of an isoform-selective approach to the study of PDE4B1 function in the CNS and suggest a probable role of PDE4B1 in synaptic plasticity and behavior. They also provide additional rationale and a refined approach to the development of small-molecule PDE4B1-selective inhibitors, which have potential functions in disorders of cognition, memory, mood and affect.
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Affiliation(s)
- Susan L Campbell
- Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.,Center for Glial Biology in Health, Disease, and Cancer, Virginia Tech Carilion Research Institute, 2 Riverside Circle, Roanoke, VA, 24016, USA
| | - Thomas van Groen
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Inga Kadish
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Lisa High Mitchell Smoot
- Department of Medicine, University of Alabama at Birmingham, NP 2501, 1720 2nd Ave S, Birmingham, AL, 35294-3300, USA
| | - Graeme B Bolger
- Department of Pharmacology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA. .,Department of Medicine, University of Alabama at Birmingham, NP 2501, 1720 2nd Ave S, Birmingham, AL, 35294-3300, USA. .,Center for Glial Biology in Health, Disease, and Cancer, Virginia Tech Carilion Research Institute, 2 Riverside Circle, Roanoke, VA, 24016, USA.
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16
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Deciphering the RAS/ERK pathway in vivo. Biochem Soc Trans 2017; 45:27-36. [PMID: 28202657 DOI: 10.1042/bst20160135] [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: 05/27/2016] [Revised: 11/03/2016] [Accepted: 11/07/2016] [Indexed: 12/19/2022]
Abstract
The RAS/ERK pathway has been intensely studied for about three decades, not least because of its role in human pathologies. ERK activation is observed in the majority of human cancers; in about one-third of them, it is driven by mutational activation of pathway components. The pathway is arguably one of the best targets for molecule-based pharmacological intervention, and several small-molecule inhibitors are in clinical use. Genetically engineered mouse models have greatly contributed to our understanding of signaling pathways in development, tissue homeostasis, and disease. In the specific case of the RAS/ERK pathway, they have revealed unique biological roles of structurally and functionally similar proteins, new kinase-independent effectors, and unsuspected relationships with other cascades. This short review summarizes the contribution of mouse models to our current understanding of the pathway.
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17
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Tang S, Yasuda R. Imaging ERK and PKA Activation in Single Dendritic Spines during Structural Plasticity. Neuron 2017; 93:1315-1324.e3. [PMID: 28285819 DOI: 10.1016/j.neuron.2017.02.032] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 11/10/2016] [Accepted: 02/16/2017] [Indexed: 01/12/2023]
Abstract
Extracellular signal-regulated kinase (ERK) and protein kinase A (PKA) play important roles in LTP and spine structural plasticity. While fluorescence resonance energy transfer (FRET)-based sensors for these kinases had previously been developed, they did not provide sufficient sensitivity for imaging small neuronal compartments, such as single dendritic spines in brain slices. Here we improved the sensitivity of FRET-based kinase sensors for monitoring kinase activity under two-photon fluorescence lifetime imaging microscopy (2pFLIM). Using these improved sensors, we succeeded in imaging ERK and PKA activation in single dendritic spines during structural long-term potentiation (sLTP) in hippocampal CA1 pyramidal neurons, revealing that the activation of these kinases spreads widely with length constants of more than 10 μm. The strategy for improvement of sensors used here should be applicable for developing highly sensitive biosensors for various protein kinases. VIDEO ABSTRACT.
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Affiliation(s)
- Shen Tang
- Max Planck Florida Institute for Neuroscience, 1 Max Planck Way, Jupiter, FL 33458, USA
| | - Ryohei Yasuda
- Max Planck Florida Institute for Neuroscience, 1 Max Planck Way, Jupiter, FL 33458, USA.
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18
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Haiying G, Mingjie H, Lingyu Z, Qingxiang W, Haisong W, Bingxi Z. Anesthetics inhibit extracellular signal-regulated Kinase1/2 phosphorylation via NMDA receptor, phospholipase C and protein kinase C in mouse hippocampal slices. Neurochem Int 2017; 103:36-44. [DOI: 10.1016/j.neuint.2016.12.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 12/25/2016] [Accepted: 12/29/2016] [Indexed: 11/16/2022]
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19
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Senter RK, Ghoshal A, Walker AG, Xiang Z, Niswender CM, Conn PJ. The Role of mGlu Receptors in Hippocampal Plasticity Deficits in Neurological and Psychiatric Disorders: Implications for Allosteric Modulators as Novel Therapeutic Strategies. Curr Neuropharmacol 2017; 14:455-73. [PMID: 27296640 PMCID: PMC4983746 DOI: 10.2174/1570159x13666150421003225] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 03/18/2015] [Accepted: 04/09/2015] [Indexed: 11/22/2022] Open
Abstract
Long-term potentiation (LTP) and long-term depression (LTD) are two distinct forms of synaptic plasticity that have been extensively characterized at the Schaffer collateral-CA1 (SCCA1) synapse and the mossy fiber (MF)-CA3 synapse within the hippocampus, and are postulated to be the molecular underpinning for several cognitive functions. Deficits in LTP and LTD have been implicated in the pathophysiology of several neurological and psychiatric disorders. Therefore, there has been a large effort focused on developing an understanding of the mechanisms underlying these forms of plasticity and novel therapeutic strategies that improve or rescue these plasticity deficits. Among many other targets, the metabotropic glutamate (mGlu) receptors show promise as novel therapeutic candidates for the treatment of these disorders. Among the eight distinct mGlu receptor subtypes (mGlu1-8), the mGlu1,2,3,5,7 subtypes are expressed throughout the hippocampus and have been shown to play important roles in the regulation of synaptic plasticity in this brain area. However, development of therapeutic agents that target these mGlu receptors has been hampered by a lack of subtype-selective compounds. Recently, discovery of allosteric modulators of mGlu receptors has provided novel ligands that are highly selective for individual mGlu receptor subtypes. The mGlu receptors modulate the multiple forms of synaptic plasticity at both SC-CA1 and MF synapses and allosteric modulators of mGlu receptors have emerged as potential therapeutic agents that may rescue plasticity deficits and improve cognitive function in patients suffering from multiple neurological and psychiatric disorders.
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Affiliation(s)
| | | | | | | | | | - P Jeffrey Conn
- Department of Pharmacology, Faculty of Vanderbilt University Medical Center, 1205 Light Hall, Nashville, TN 37232, USA.
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20
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Lake D, Corrêa SAL, Müller J. Negative feedback regulation of the ERK1/2 MAPK pathway. Cell Mol Life Sci 2016; 73:4397-4413. [PMID: 27342992 PMCID: PMC5075022 DOI: 10.1007/s00018-016-2297-8] [Citation(s) in RCA: 342] [Impact Index Per Article: 42.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 06/16/2016] [Accepted: 06/17/2016] [Indexed: 01/04/2023]
Abstract
The extracellular signal-regulated kinase 1/2 (ERK1/2) mitogen-activated protein kinase (MAPK) signalling pathway regulates many cellular functions, including proliferation, differentiation, and transformation. To reliably convert external stimuli into specific cellular responses and to adapt to environmental circumstances, the pathway must be integrated into the overall signalling activity of the cell. Multiple mechanisms have evolved to perform this role. In this review, we will focus on negative feedback mechanisms and examine how they shape ERK1/2 MAPK signalling. We will first discuss the extensive number of negative feedback loops targeting the different components of the ERK1/2 MAPK cascade, specifically the direct posttranslational modification of pathway components by downstream protein kinases and the induction of de novo gene synthesis of specific pathway inhibitors. We will then evaluate how negative feedback modulates the spatiotemporal signalling dynamics of the ERK1/2 pathway regarding signalling amplitude and duration as well as subcellular localisation. Aberrant ERK1/2 activation results in deregulated proliferation and malignant transformation in model systems and is commonly observed in human tumours. Inhibition of the ERK1/2 pathway thus represents an attractive target for the treatment of malignant tumours with increased ERK1/2 activity. We will, therefore, discuss the effect of ERK1/2 MAPK feedback regulation on cancer treatment and how it contributes to reduced clinical efficacy of therapeutic agents and the development of drug resistance.
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Affiliation(s)
- David Lake
- Warwick Medical School, University of Warwick, Coventry, UK
| | - Sonia A L Corrêa
- School of Life Sciences, University of Warwick, Coventry, UK
- Faculty of Life Sciences, University of Bradford, Bradford, UK
| | - Jürgen Müller
- Warwick Medical School, University of Warwick, Coventry, UK.
- Aston Medical Research Institute, Aston Medical School, Aston University, Birmingham, B4 7ET, UK.
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21
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Mirisis AA, Alexandrescu A, Carew TJ, Kopec AM. The Contribution of Spatial and Temporal Molecular Networks in the Induction of Long-term Memory and Its Underlying Synaptic Plasticity. AIMS Neurosci 2016; 3:356-384. [PMID: 27819030 PMCID: PMC5096789 DOI: 10.3934/neuroscience.2016.3.356] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The ability to form long-lasting memories is critical to survival and thus is highly conserved across the animal kingdom. By virtue of its complexity, this same ability is vulnerable to disruption by a wide variety of neuronal traumas and pathologies. To identify effective therapies with which to treat memory disorders, it is critical to have a clear understanding of the cellular and molecular mechanisms which subserve normal learning and memory. A significant challenge to achieving this level of understanding is posed by the wide range of distinct temporal and spatial profiles of molecular signaling induced by learning-related stimuli. In this review we propose that a useful framework within which to address this challenge is to view the molecular foundation of long-lasting plasticity as composed of unique spatial and temporal molecular networks that mediate signaling both within neurons (such as via kinase signaling) as well as between neurons (such as via growth factor signaling). We propose that evaluating how cells integrate and interpret these concurrent and interacting molecular networks has the potential to significantly advance our understanding of the mechanisms underlying learning and memory formation.
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Affiliation(s)
- Anastasios A. Mirisis
- Center for Neural Science, New York University, New York, NY, USA
- Department of Biology, New York University, New York, NY, USA
| | - Anamaria Alexandrescu
- Center for Neural Science, New York University, New York, NY, USA
- Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY, USA
| | - Thomas J. Carew
- Center for Neural Science, New York University, New York, NY, USA
| | - Ashley M. Kopec
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
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22
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Li L, Qiao C, Chen G, Qian H, Hou Y, Li T, Liu X. Ifenprodil attenuates the acquisition and expression of methamphetamine-induced behavioral sensitization and activation of Ras-ERK1/2 cascade in the caudate putamen. Neuroscience 2016; 335:20-9. [DOI: 10.1016/j.neuroscience.2016.08.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 08/08/2016] [Accepted: 08/09/2016] [Indexed: 02/06/2023]
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23
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Rinaldi L, Delle Donne R, Sepe M, Porpora M, Garbi C, Chiuso F, Gallo A, Parisi S, Russo L, Bachmann V, Huber RG, Stefan E, Russo T, Feliciello A. praja2 regulates KSR1 stability and mitogenic signaling. Cell Death Dis 2016; 7:e2230. [PMID: 27195677 PMCID: PMC4917648 DOI: 10.1038/cddis.2016.109] [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: 02/09/2016] [Revised: 03/25/2016] [Accepted: 03/31/2016] [Indexed: 12/17/2022]
Abstract
The kinase suppressor of Ras 1 (KSR1) has a fundamental role in mitogenic signaling by scaffolding components of the Ras/MAP kinase pathway. In response to Ras activation, KSR1 assembles a tripartite kinase complex that optimally transfers signals generated at the cell membrane to activate ERK. We describe a novel mechanism of ERK attenuation based on ubiquitin-dependent proteolysis of KSR1. Stimulation of membrane receptors by hormones or growth factors induced KSR1 polyubiquitination, which paralleled a decline of ERK1/2 signaling. We identified praja2 as the E3 ligase that ubiquitylates KSR1. We showed that praja2-dependent regulation of KSR1 is involved in the growth of cancer cells and in the maintenance of undifferentiated pluripotent state in mouse embryonic stem cells. The dynamic interplay between the ubiquitin system and the kinase scaffold of the Ras pathway shapes the activation profile of the mitogenic cascade. By controlling KSR1 levels, praja2 directly affects compartmentalized ERK activities, impacting on physiological events required for cell proliferation and maintenance of embryonic stem cell pluripotency.
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Affiliation(s)
- L Rinaldi
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, IEOS-CNR, CEINGE University Federico II, Naples 80131, Italy
| | - R Delle Donne
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, IEOS-CNR, CEINGE University Federico II, Naples 80131, Italy
| | - M Sepe
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, IEOS-CNR, CEINGE University Federico II, Naples 80131, Italy
| | - M Porpora
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, IEOS-CNR, CEINGE University Federico II, Naples 80131, Italy
| | - C Garbi
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, IEOS-CNR, CEINGE University Federico II, Naples 80131, Italy
| | - F Chiuso
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, IEOS-CNR, CEINGE University Federico II, Naples 80131, Italy
| | - A Gallo
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, IEOS-CNR, CEINGE University Federico II, Naples 80131, Italy
| | - S Parisi
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, IEOS-CNR, CEINGE University Federico II, Naples 80131, Italy
| | - L Russo
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, IEOS-CNR, CEINGE University Federico II, Naples 80131, Italy
| | - V Bachmann
- Institute of Biochemistry and Center for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria.,Bioinformatics Institute (BII), Agency for Science Technology and Research (A*STAR), Singapore 138671, Singapore
| | - R G Huber
- Institute of Biochemistry and Center for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria.,Bioinformatics Institute (BII), Agency for Science Technology and Research (A*STAR), Singapore 138671, Singapore
| | - E Stefan
- Institute of Biochemistry and Center for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria.,Bioinformatics Institute (BII), Agency for Science Technology and Research (A*STAR), Singapore 138671, Singapore
| | - T Russo
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, IEOS-CNR, CEINGE University Federico II, Naples 80131, Italy
| | - A Feliciello
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, IEOS-CNR, CEINGE University Federico II, Naples 80131, Italy
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24
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Quantitative proteomics reveals protein kinases and phosphatases in the individual phases of contextual fear conditioning in the C57BL/6J mouse. Behav Brain Res 2016; 303:208-17. [DOI: 10.1016/j.bbr.2015.12.033] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 12/14/2015] [Accepted: 12/18/2015] [Indexed: 12/20/2022]
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25
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Shan LL, Guo H, Song NN, Jia ZP, Hu XT, Huang JF, Ding YQ, Richter-Levin G, Richter-Levine G, Zhou QX, Xu L. Light exposure before learning improves memory consolidation at night. Sci Rep 2015; 5:15578. [PMID: 26493375 PMCID: PMC4616152 DOI: 10.1038/srep15578] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 09/28/2015] [Indexed: 01/12/2023] Open
Abstract
Light is recently recognized as a modulator able to activate the hippocampus and modulate memory processing, but little is known about the molecular mechanisms. Here, we report that in mice, a short pulse of white light before learning dramatically improves consolidation of contextual fear memory during the night. The light exposure increases hippocampal active p21-activated kinase 1 (PAK1) and CA1 long-term potentiation (LTP). These light effects are abolished in PAK1 knockout and dominant-negative transgenic mice, but preserved by expression of constitutively active PAK1 in the hippocampus. Our results indicate that light can act as a switch of PAK1 activity that modulate CA1 LTP and thereby memory consolidation without affecting learning and short-term memory.
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Affiliation(s)
- Li-Li Shan
- Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, the Chinese Academy of Science, Kunming 650223, China.,KIZ-SU Joint Laboratory of Animal Models and Drug Development, College of Pharmaceutical Sciences, Soochow University, Suzhou 215123, China.,Laboratory of Learning and Memory, Kunming Institute of Zoology, the Chinese Academy of Science, Kunming 650223, China.,University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Hao Guo
- Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, the Chinese Academy of Science, Kunming 650223, China.,Laboratory of Learning and Memory, Kunming Institute of Zoology, the Chinese Academy of Science, Kunming 650223, China.,University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Ning-Ning Song
- Collaborative Innovation Center for Brain Science, Department of Anatomy and Neurobiology, Tongji University School of Medicine, 1239 Siping Road, Shanghai 200092, China
| | - Zheng-Ping Jia
- Neurosciences &Mental Health, The Hospital for Sick Children, Department of Physiology, Faculty of Medicine, University of Toronto, 555 University Ave., Toronto, Ontario 5MS 3H2, Canada
| | - Xin-Tian Hu
- Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, the Chinese Academy of Science, Kunming 650223, China.,CAS Center for Excellence in Brain Science, 320 Yue Yang Road, Shanghai, 200031, China
| | - Jing-Fei Huang
- KIZ-SU Joint Laboratory of Animal Models and Drug Development, College of Pharmaceutical Sciences, Soochow University, Suzhou 215123, China.,State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming 650223, China
| | - Yu-Qiang Ding
- Collaborative Innovation Center for Brain Science, Department of Anatomy and Neurobiology, Tongji University School of Medicine, 1239 Siping Road, Shanghai 200092, China
| | | | - Gal Richter-Levine
- The Institute for the Study of Affective Neuroscience, and Sagol Department of Neurobiology and Department of Psychology, University of Haifa, Haifa, Israel
| | - Qi-Xin Zhou
- Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, the Chinese Academy of Science, Kunming 650223, China.,KIZ-SU Joint Laboratory of Animal Models and Drug Development, College of Pharmaceutical Sciences, Soochow University, Suzhou 215123, China.,Laboratory of Learning and Memory, Kunming Institute of Zoology, the Chinese Academy of Science, Kunming 650223, China
| | - Lin Xu
- Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, the Chinese Academy of Science, Kunming 650223, China.,KIZ-SU Joint Laboratory of Animal Models and Drug Development, College of Pharmaceutical Sciences, Soochow University, Suzhou 215123, China.,Laboratory of Learning and Memory, Kunming Institute of Zoology, the Chinese Academy of Science, Kunming 650223, China.,University of the Chinese Academy of Sciences, Beijing 100049, China.,CAS Center for Excellence in Brain Science, 320 Yue Yang Road, Shanghai, 200031, China
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26
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Abstract
This review covers the spatial and temporal rules governing induction of hippocampal long-term potentiation (LTP) by theta-burst stimulation. Induction of LTP in field CA1 by high frequency stimulation bursts that resemble the burst discharges (complex-spikes) of hippocampal pyramidal neurons involves a multiple-step mechanism. A single burst is insufficient for LTP induction because it evokes both excitatory and inhibitory currents that partially cancel and limit postsynaptic depolarization. Bursts repeated at the frequency (~5 Hz) of the endogenous theta rhythm induce maximal LTP, primarily because this frequency disables feed-forward inhibition and allows sufficient postsynaptic depolarization to activate voltage-sensitive NMDA receptors. The disinhibitory process, referred to as "priming", involves presynaptic GABA autoreceptors that inhibit GABA release. Activation of NMDA receptors allows a calcium flux into dendritic spines that serves as the proximal trigger for LTP. We include new data showing that theta-burst stimulation is more efficient than other forms of stimulation for LTP induction. In addition, we demonstrate that associative interactions between synapses activated during theta-bursts are limited to major dendritic domains since such interactions occur within apical or basal dendritic trees but not between them. We review evidence that recordings of electrophysiological responses during theta burst stimulation can help to determine if experimental manipulations that affect LTP do so by affecting events antecedent to the induction process, such as NMDA receptor activation, or downstream signaling cascades that result from postsynaptic calcium fluxes. Finally, we argue that theta-burst LTP represents a minimal model for stable, non-decremental LTP that is more sensitive to a variety of experimental manipulations than is LTP induced by other stimulation paradigms. This article is part of a Special Issue entitled SI: Brain and Memory.
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Affiliation(s)
- John Larson
- Psychiatric Institute, Department of Psychiatry, University of Illinois College of Medicine, Chicago, IL 60612, United States.
| | - Erin Munkácsy
- Barshop Institute for Longevity and Aging Studies, Department of Cell and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78245, United States
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Shifting towards a model of mGluR5 dysregulation in schizophrenia: Consequences for future schizophrenia treatment. Neuropharmacology 2015; 115:73-91. [PMID: 26349010 DOI: 10.1016/j.neuropharm.2015.08.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 08/02/2015] [Accepted: 08/03/2015] [Indexed: 12/22/2022]
Abstract
Metabotropic glutamate receptor subtype 5 (mGluR5), encoded by the GRM5 gene, represents a compelling novel drug target for the treatment of schizophrenia. mGluR5 is a postsynaptic G-protein coupled glutamate receptor strongly linked with several critical cellular processes that are reported to be disrupted in schizophrenia. Accordingly, mGluR5 positive allosteric modulators show encouraging therapeutic potential in preclinical schizophrenia models, particularly for the treatment of cognitive dysfunctions against which currently available therapeutics are largely ineffective. More work is required to support the progression of mGluR5-targeting drugs into the clinic for schizophrenia treatment, although some obstacles may be overcome by comprehensively understanding how mGluR5 itself is involved in the neurobiology of the disorder. Several processes that are necessary for the regulation of mGluR5 activity have been identified, but not examined, in the context of schizophrenia. These processes include protein-protein interactions, dimerisation, subcellular trafficking, the impact of genetic variability or mutations on protein function, as well as epigenetic, post-transcriptional and post-translational processes. It is essential to understand these aspects of mGluR5 to determine whether they are affected in schizophrenia pathology, and to assess the consequences of mGluR5 dysfunction for the future use of mGluR5-based drugs. Here, we summarise the known processes that regulate mGluR5 and those that have already been studied in schizophrenia, and discuss the consequences of this dysregulation for current mGluR5 pharmacological strategies. This article is part of the Special Issue entitled 'Metabotropic Glutamate Receptors, 5 years on'.
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Hitchcock LN, Lattal KM. Histone-mediated epigenetics in addiction. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 128:51-87. [PMID: 25410541 DOI: 10.1016/b978-0-12-800977-2.00003-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Many of the brain regions, neurotransmitter systems, and behavioral changes that occur after occasional drug use in healthy subjects and after chronic drug abuse in addicted patients are well characterized. An emerging literature suggests that epigenetic processes, those processes that regulate the accessibility of DNA to regulatory proteins within the nucleus, are keys to how addiction develops and how it may be treated. Investigations of the regulation of chromatin, the organizational system of DNA, by histone modification are leading to a new understanding of the cellular and behavioral alterations that occur after drug use. We will describe how, when, and where histone tails are modified and how some of the most recognized histone regulation patterns are involved in the cycle of addiction, including initial and chronic drug intake, withdrawal, abstinence, and relapse. Finally, we consider how an approach that targets histone modifications may promote successful treatment.
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Affiliation(s)
- Leah N Hitchcock
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon, USA
| | - K Matthew Lattal
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon, USA
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Different patterns of electrical activity lead to long-term potentiation by activating different intracellular pathways. J Neurosci 2015; 35:621-33. [PMID: 25589756 DOI: 10.1523/jneurosci.2193-14.2015] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Deciphering and storing information coded in different firing patterns are important properties of neuronal networks, as they allow organisms to respond and adapt to external and internal events. Here we report that hippocampal CA1 pyramidal neurons respond to brief bursts of high-frequency stimulation (HFS) and θ burst stimulation (TBS) with long-lasting enhanced responses (long-term potentiation [LTP]), albeit by engaging different signaling pathways. TBS induces LTP through calpain-1-mediated suprachiasmatic nucleus circadian oscillatory protein degradation, ERK activation, and actin polymerization, whereas HFS requires adenosine A2 receptors, PKA, and actin polymerization. TBS- but not HFS-induced LTP is impaired in calpain-1 knock-out mice. However, TBS-induced LTP and learning impairment in knock-out mice are restored by activating the HFS pathway. Thus, different patterns of rhythmic activities trigger potentiation by activating different pathways, and cross talks between these can be used to restore LTP and learning when elements of the pathways are impaired.
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Abstract
Calcium signaling is involved in a multitude of physiological and pathophysiological mechanisms. Over the last decade, it has been increasingly recognized as an important factor in epileptogenesis, and it is becoming obvious that the excess synchronization of neurons that is characteristic for seizures can be linked to various calcium signaling pathways. These include immediate effects on membrane excitability by calcium influx through ion channels as well as delayed mechanisms that act through G-protein coupled pathways. Calcium signaling is able to cause hyperexcitability either by direct modulation of neuronal activity or indirectly through calcium-dependent gliotransmission. Furthermore, feedback mechanisms between mitochondrial calcium signaling and reactive oxygen species are able to cause neuronal cell death and seizures. Unravelling the complexity of calcium signaling in epileptogenesis is a daunting task, but it includes the promise to uncover formerly unknown targets for the development of new antiepileptic drugs.
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Zheng Z, Keifer J. Sequential delivery of synaptic GluA1- and GluA4-containing AMPA receptors (AMPARs) by SAP97 anchored protein complexes in classical conditioning. J Biol Chem 2014; 289:10540-10550. [PMID: 24567325 DOI: 10.1074/jbc.m113.535179] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Multiple signaling pathways are involved in AMPAR trafficking to synapses during synaptic plasticity and learning. The mechanisms for how these pathways are coordinated in parallel but maintain their functional specificity involves subcellular compartmentalization of kinase function by scaffolding proteins, but how this is accomplished is not well understood. Here, we focused on characterizing the molecular machinery that functions in the sequential synaptic delivery of GluA1- and GluA4-containing AMPARs using an in vitro model of eyeblink classical conditioning. We show that conditioning induces the interaction of selective protein complexes with the key structural protein SAP97, which tightly regulates the synaptic delivery of GluA1 and GluA4 AMPAR subunits. The results demonstrate that in the early stages of conditioning the initial activation of PKA stimulates the formation of a SAP97-AKAP/PKA-GluA1 protein complex leading to synaptic delivery of GluA1-containing AMPARs through a SAP97-PSD95 interaction. This is followed shortly thereafter by generation of a SAP97-KSR1/PKC-GluA4 complex for GluA4 AMPAR subunit delivery again through a SAP97-PSD95 interaction. These data suggest that SAP97 forms the molecular backbone of a protein scaffold critical for delivery of AMPARs to the PSD during conditioning. Together, the findings reveal a cooperative interaction of multiple scaffolding proteins for appropriately timed delivery of subunit-specific AMPARs to synapses and support a sequential two-stage model of AMPAR synaptic delivery during classical conditioning.
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Affiliation(s)
- Zhaoqing Zheng
- Neuroscience Group, Division of Basic Biomedical Sciences University of South Dakota Sanford School of Medicine, Vermillion, South Dakota 57010
| | - Joyce Keifer
- Neuroscience Group, Division of Basic Biomedical Sciences University of South Dakota Sanford School of Medicine, Vermillion, South Dakota 57010.
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Blackwell KT. Approaches and tools for modeling signaling pathways and calcium dynamics in neurons. J Neurosci Methods 2013; 220:131-40. [PMID: 23743449 PMCID: PMC3830683 DOI: 10.1016/j.jneumeth.2013.05.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Revised: 05/15/2013] [Accepted: 05/16/2013] [Indexed: 01/25/2023]
Abstract
Signaling pathways are cascades of intracellular biochemical reactions that are activated by transmembrane receptors, and ultimately lead to transcription in the nucleus. In neurons, both calcium permeable synaptic and ionic channels as well as G protein coupled receptors initiate activation of signaling pathway molecules that interact with electrical activity at multiple spatial and time scales. At small temporal and spatial scales, calcium modifies the properties of ionic channels, whereas at larger temporal and spatial scales, various kinases and phosphatases modify the properties of ionic channels, producing phenomena such as synaptic plasticity and homeostatic plasticity. The elongated structure of neuronal dendrites and the organization of multi-protein complexes by anchoring proteins imply that the spatial dimension must be explicit. Therefore, modeling signaling pathways in neurons utilizes algorithms for both diffusion and reactions. The small size of spines coupled with small concentrations of some molecules implies that some reactions occur stochastically. The need for stochastic simulation of many reaction and diffusion events coupled with the multiple temporal and spatial scales makes modeling of signaling pathways a difficult problem. Several different software programs have achieved different aspects of these capabilities. This review explains some of the mathematical formulas used for modeling reactions and diffusion. In addition, it briefly presents the simulators used for modeling reaction-diffusion systems in neurons, together with scientific problems addressed.
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Affiliation(s)
- K T Blackwell
- George Mason University, The Krasnow Institute for Advanced Studies, MS 2A1, Fairfax, VA 22030-444, USA.
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Pearce L, Atanassova N, Banton M, Bottomley B, van der Klaauw A, Revelli JP, Hendricks A, Keogh J, Henning E, Doree D, Jeter-Jones S, Garg S, Bochukova E, Bounds R, Ashford S, Gayton E, Hindmarsh P, Shield J, Crowne E, Barford D, Wareham N, O’Rahilly S, Murphy M, Powell D, Barroso I, Farooqi I. KSR2 mutations are associated with obesity, insulin resistance, and impaired cellular fuel oxidation. Cell 2013; 155:765-77. [PMID: 24209692 PMCID: PMC3898740 DOI: 10.1016/j.cell.2013.09.058] [Citation(s) in RCA: 129] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 07/31/2013] [Accepted: 09/20/2013] [Indexed: 02/02/2023]
Abstract
Kinase suppressor of Ras 2 (KSR2) is an intracellular scaffolding protein involved in multiple signaling pathways. Targeted deletion of Ksr2 leads to obesity in mice, suggesting a role in energy homeostasis. We explored the role of KSR2 in humans by sequencing 2,101 individuals with severe early-onset obesity and 1,536 controls. We identified multiple rare variants in KSR2 that disrupt signaling through the Raf-MEKERK pathway and impair cellular fatty acid oxidation and glucose oxidation in transfected cells; effects that can be ameliorated by the commonly prescribed antidiabetic drug, metformin. Mutation carriers exhibit hyperphagia in childhood, low heart rate, reduced basal metabolic rate and severe insulin resistance. These data establish KSR2 as an important regulator of energy intake, energy expenditure, and substrate utilization in humans. Modulation of KSR2-mediated effects may represent a novel therapeutic strategy for obesity and type 2 diabetes.
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Affiliation(s)
- Laura R. Pearce
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge CB2 0QQ, UK
| | - Neli Atanassova
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge CB2 0QQ, UK
| | - Matthew C. Banton
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge CB2 0QQ, UK
| | - Bill Bottomley
- Wellcome Trust Sanger Institute, Cambridge, CB10 1SA, UK
| | - Agatha A. van der Klaauw
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge CB2 0QQ, UK
| | | | | | - Julia M. Keogh
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge CB2 0QQ, UK
| | - Elana Henning
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge CB2 0QQ, UK
| | - Deon Doree
- Lexicon Pharmaceuticals, The Woodlands, TX 77381, USA
| | | | - Sumedha Garg
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge CB2 0QQ, UK
| | - Elena G. Bochukova
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge CB2 0QQ, UK
| | - Rebecca Bounds
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge CB2 0QQ, UK
| | - Sofie Ashford
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge CB2 0QQ, UK
| | - Emma Gayton
- Wellcome Trust Sanger Institute, Cambridge, CB10 1SA, UK
| | - Peter C. Hindmarsh
- Institute of Child Health, University College London, London WC1E 6BT, UK
| | - Julian P.H. Shield
- University of Bristol and Bristol Royal Hospital for Children, Bristol BS2 8BJ, UK
| | - Elizabeth Crowne
- University of Bristol and Bristol Royal Hospital for Children, Bristol BS2 8BJ, UK
| | - David Barford
- Institute of Cancer Research, Chester Beatty Laboratories, London SW3 6JB, UK
| | - Nick J. Wareham
- MRC Epidemiology Unit, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge CB2 0QQ, UK
| | | | - Stephen O’Rahilly
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge CB2 0QQ, UK
| | - Michael P. Murphy
- MRC Mitochondrial Biology Unit, Wellcome Trust/MRC Building, Hills Road, Cambridge CB2 0XY, UK
| | | | - Ines Barroso
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge CB2 0QQ, UK
- Wellcome Trust Sanger Institute, Cambridge, CB10 1SA, UK
| | - I. Sadaf Farooqi
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge CB2 0QQ, UK
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34
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Blackwell KT, Jedrzejewska-Szmek J. Molecular mechanisms underlying neuronal synaptic plasticity: systems biology meets computational neuroscience in the wilds of synaptic plasticity. WILEY INTERDISCIPLINARY REVIEWS. SYSTEMS BIOLOGY AND MEDICINE 2013; 5:717-31. [PMID: 24019266 PMCID: PMC3947422 DOI: 10.1002/wsbm.1240] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 07/25/2013] [Accepted: 07/29/2013] [Indexed: 12/29/2022]
Abstract
Interactions among signaling pathways that are activated by transmembrane receptors produce complex networks and emergent dynamical behaviors that are implicated in synaptic plasticity. Temporal dynamics and spatial aspects are critical determinants of cell responses such as synaptic plasticity, although the mapping between spatiotemporal activity pattern and direction of synaptic plasticity is not completely understood. Computational modeling of neuronal signaling pathways has significantly contributed to understanding signaling pathways underlying synaptic plasticity. Spatial models of signaling pathways in hippocampal neurons have revealed mechanisms underlying the spatial distribution of extracellular signal-related kinase (ERK) activation in hippocampal neurons. Other spatial models have demonstrated that the major role of anchoring proteins in striatal and hippocampal synaptic plasticity is to place molecules near their activators. Simulations of yet other models have revealed that the spatial distribution of synaptic plasticity may differ for potentiation versus depression. In general, the most significant advances have been made by interactive modeling and experiments; thus, an interdisciplinary approach should be applied to investigate critical issues in neuronal signaling pathways. These issues include identifying which transmembrane receptors are key for activating ERK in neurons, and the crucial targets of kinases that produce long-lasting synaptic plasticity. Although the number of computer programs for computationally efficient simulation of large reaction-diffusion networks is increasing, parameter estimation and sensitivity analysis in these spatial models remain more difficult than in single compartment models. Advances in live cell imaging coupled with further software development will continue to accelerate the development of spatial models of synaptic plasticity.
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Affiliation(s)
- KT Blackwell
- Molecular Neuroscience Department, The Krasnow Institute for Advanced Studies George Mason University, Fairfax, VA 22030-444, USA
| | - J Jedrzejewska-Szmek
- Molecular Neuroscience Department, The Krasnow Institute for Advanced Studies George Mason University, Fairfax, VA 22030-444, USA
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35
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Kopec AM, Carew TJ. Growth factor signaling and memory formation: temporal and spatial integration of a molecular network. Learn Mem 2013; 20:531-9. [PMID: 24042849 PMCID: PMC3768197 DOI: 10.1101/lm.031377.113] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Growth factor (GF) signaling is critically important for developmental plasticity. It also plays a crucial role in adult plasticity, such as that required for memory formation. Although different GFs interact with receptors containing distinct types of kinase domains, they typically signal through converging intracellular cascades (e.g., Ras–MEK–MAPK) to mediate overlapping functional endpoints. Several GFs have been implicated in memory formation, but due to a high level of convergent signaling, the unique contributions of individual GFs as well as the interactions between GF signaling cascades during the induction of memory is not well known. In this review, we highlight the unique roles of specific GFs in dendritic plasticity, and discuss the spatial and temporal profiles of different GFs during memory formation. Collectively, the data suggest that the roles of GF signaling in long-lasting behavioral and structural plasticity may be best viewed as interactive components in a complex molecular network.
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Affiliation(s)
- Ashley M Kopec
- Center for Neural Science, New York University, New York, New York 10003, USA
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36
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Vetterkind S, Poythress RH, Lin QQ, Morgan KG. Hierarchical scaffolding of an ERK1/2 activation pathway. Cell Commun Signal 2013; 11:65. [PMID: 23987506 PMCID: PMC3846746 DOI: 10.1186/1478-811x-11-65] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 08/27/2013] [Indexed: 12/30/2022] Open
Abstract
Background Scaffold proteins modulate cellular signaling by facilitating assembly of specific signaling pathways. However, there is at present little information if and how scaffold proteins functionally interact with each other. Results Here, we show that two scaffold proteins, caveolin-1 and IQGAP1, are required for phosphorylation of the actin associated pool of extracellular signal regulated kinase 1 and 2 (ERK1/2) in response to protein kinase C activation. We show by immunofluorescence and proximity ligation assays, that IQGAP1 tethers ERK1/2 to actin filaments. Moreover, siRNA experiments demonstrate that IQGAP1 is required for activation of actin-bound ERK1/2. Caveolin-1 is also necessary for phosphorylation of actin-bound ERK1/2 in response to protein kinase C, but is dispensible for ERK1/2 association with actin. Simultaneous knock down of caveolin-1 and IQGAP1 decreases total phorbol ester-induced ERK1/2 phosphorylation to the same degree as single knock down of either caveolin-1 or IQGAP1, indicating that caveolin-1 and IQGAP1 operate in the same ERK activation pathway. We further show that caveolin-1 knock down, but not IQGAP1 knock down, reduces C-Raf phosphorylation in response to phorbol ester stimulation. Conclusions Based on our data, we suggest that caveolin-1 and IQGAP1 assemble distinct signaling modules, which are then linked in a hierarchical arrangement to generate a functional ERK1/2 activation pathway.
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Affiliation(s)
- Susanne Vetterkind
- Department of Health Sciences, Boston University, Boston, MA 02215, USA.
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37
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Tronson NC, Taylor JR. Addiction: a drug-induced disorder of memory reconsolidation. Curr Opin Neurobiol 2013; 23:573-80. [PMID: 23415831 PMCID: PMC3677957 DOI: 10.1016/j.conb.2013.01.022] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2012] [Revised: 01/15/2013] [Accepted: 01/16/2013] [Indexed: 12/15/2022]
Abstract
Persistent maladaptive memories that maintain drug seeking and are resistant to extinction are a hallmark of addiction. As such, disruption of memory reconsolidation after retrieval has received attention for its therapeutic potential. Unrestrained reconsolidation may have the opposite effect, leading to reiterative and cumulative strengthening of memory over long periods of time. Here we review the molecular mechanisms underlying reconsolidation of appetitive and drug-rewarded memories, and discuss how these findings contribute to our understanding of the nature of this process. Finally, we suggest that drug-induced alterations to signal transduction might lead to dysregulation of reconsolidation, causing enhancements of drug-related memory after retrieval, and significantly contribute to the compulsive drug seeking that is a core component of addiction.
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Affiliation(s)
- Natalie C Tronson
- Department of Psychology, University of Michigan, Ann Arbor, MI 48109,
| | - Jane R. Taylor
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06508
- Department of Psychology, Yale University, New Haven, CT 06508,
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Baudry M, Bi X. Learning and memory: an emergent property of cell motility. Neurobiol Learn Mem 2013; 104:64-72. [PMID: 23707799 DOI: 10.1016/j.nlm.2013.04.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 04/29/2013] [Accepted: 04/30/2013] [Indexed: 01/24/2023]
Abstract
In this review, we develop the argument that the molecular/cellular mechanisms underlying learning and memory are an adaptation of the mechanisms used by all cells to regulate cell motility. Neuronal plasticity and more specifically synaptic plasticity are widely recognized as the processes by which information is stored in neuronal networks engaged during the acquisition of information. Evidence accumulated over the last 25 years regarding the molecular events underlying synaptic plasticity at excitatory synapses has shown the remarkable convergence between those events and those taking place in cells undergoing migration in response to extracellular signals. We further develop the thesis that the calcium-dependent protease, calpain, which we postulated over 25 years ago to play a critical role in learning and memory, plays a central role in the regulation of both cell motility and synaptic plasticity. The findings discussed in this review illustrate the general principle that fundamental cell biological processes are used for a wide range of functions at the level of organisms.
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Affiliation(s)
- Michel Baudry
- Graduate College of Biomedical Sciences, Western University of Health Sciences, Pomona, CA 91766, USA.
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39
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Sweatt JD. Pitt-Hopkins Syndrome: intellectual disability due to loss of TCF4-regulated gene transcription. Exp Mol Med 2013; 45:e21. [PMID: 23640545 PMCID: PMC3674405 DOI: 10.1038/emm.2013.32] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 02/03/2013] [Indexed: 01/22/2023] Open
Abstract
TCF4 (transcription factor 4; E2-2, ITF2) is a transcription factor that when haplo-insufficient causes Pitt-Hopkins Syndrome (PTHS), an autism-spectrum disorder that is associated with pervasive developmental delay and severe intellectual disability. The TCF4 gene is also a risk factor with highly significant linkage to schizophrenia, presumably via overexpression of the TCF4 gene product in the central nervous system. This review will present an overview of the clinical manifestations of PTHS and relate those clinical attributes to the underlying molecular genetics of TCF4. In order to provide a molecular biological context for the loss of function of TCF4 in PTHS, the review will also present a brief overview of the basic biochemistry of TCF4-mediated regulation of cellular and neuronal gene expression. In the final section of this review, I will discuss and speculate upon possible roles for the TCF4 transcription factor in neuronal function and comment upon how understanding these roles may give new insights into the molecular neurobiology of human cognition.
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Affiliation(s)
- J David Sweatt
- Department of Neurobiology and Evelyn F. McKnight Brain Institute, Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL 35294-2182, USA.
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40
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Meister M, Tomasovic A, Banning A, Tikkanen R. Mitogen-Activated Protein (MAP) Kinase Scaffolding Proteins: A Recount. Int J Mol Sci 2013; 14:4854-84. [PMID: 23455463 PMCID: PMC3634400 DOI: 10.3390/ijms14034854] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 02/17/2013] [Accepted: 02/21/2013] [Indexed: 12/20/2022] Open
Abstract
The mitogen-activated protein kinase (MAPK) pathway is the canonical signaling pathway for many receptor tyrosine kinases, such as the Epidermal Growth Factor Receptor. Downstream of the receptors, this pathway involves the activation of a kinase cascade that culminates in a transcriptional response and affects processes, such as cell migration and adhesion. In addition, the strength and duration of the upstream signal also influence the mode of the cellular response that is switched on. Thus, the same components can in principle coordinate opposite responses, such as proliferation and differentiation. In recent years, it has become evident that MAPK signaling is regulated and fine-tuned by proteins that can bind to several MAPK signaling proteins simultaneously and, thereby, affect their function. These so-called MAPK scaffolding proteins are, thus, important coordinators of the signaling response in cells. In this review, we summarize the recent advances in the research on MAPK/extracellular signal-regulated kinase (ERK) pathway scaffolders. We will not only review the well-known members of the family, such as kinase suppressor of Ras (KSR), but also put a special focus on the function of the recently identified or less studied scaffolders, such as fibroblast growth factor receptor substrate 2, flotillin-1 and mitogen-activated protein kinase organizer 1.
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Affiliation(s)
- Melanie Meister
- Institute of Biochemistry, Medical Faculty, University of Giessen, Friedrichstrasse 24, 35392 Giessen, Germany; E-Mails: (M.M.); (A.B.)
| | - Ana Tomasovic
- Department of Molecular Hematology, University of Frankfurt, Medical School, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany; E-Mail:
| | - Antje Banning
- Institute of Biochemistry, Medical Faculty, University of Giessen, Friedrichstrasse 24, 35392 Giessen, Germany; E-Mails: (M.M.); (A.B.)
| | - Ritva Tikkanen
- Institute of Biochemistry, Medical Faculty, University of Giessen, Friedrichstrasse 24, 35392 Giessen, Germany; E-Mails: (M.M.); (A.B.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +49-641-9947-420; Fax: +49-641-9947-429
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Abstract
One of the most exciting discoveries in the learning and memory field in the past two decades is the observation that active regulation of gene expression is necessary for experience to trigger lasting functional and behavioral change, in a wide variety of species, including humans. Thus, as opposed to the traditional view of 'nature' (genes) being separate from 'nurture' (environment and experience), it is now clear that experience actively drives alterations in central nervous system (CNS) gene expression in an ongoing fashion, and that the resulting transcriptional changes are necessary for experience to trigger altered long-term behavior. In parallel over the past decade, epigenetic mechanisms, including regulation of chromatin structure and DNA methylation, have been shown to be potent regulators of gene transcription in the CNS. In this review, we describe data supporting the hypothesis that epigenetic molecular mechanisms, especially DNA methylation and demethylation, drive long-term behavioral change through active regulation of gene transcription in the CNS. Specifically, we propose that epigenetic molecular mechanisms underlie the formation and stabilization of context- and cue-triggered fear conditioning based in the hippocampus and amygdala, a conclusion reached in a wide variety of studies using laboratory animals. Given the relevance of cued and contextual fear conditioning to post-traumatic stress, by extension we propose that these mechanisms may contribute to post-traumatic stress disorder (PTSD) in humans. Moreover, we speculate that epigenetically based pharmacotherapy may provide a new avenue of drug treatment for PTSD-related cognitive and behavioral function.
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Affiliation(s)
- Iva B Zovkic
- Department of Neurobiology, Evelyn F. McKnight Brain Institute, University of Alabama, Birmingham, AL, USA
| | - J David Sweatt
- Department of Neurobiology, Evelyn F. McKnight Brain Institute, University of Alabama, Birmingham, AL, USA,Department of Neurobiology, Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, 1010 Shelby Building, 1825 University Boulevard, Birmingham, AL 35294-2182, USA, Tel: +205 975 5196, Fax: +205 934 6571, E-mail:
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Local synaptic integration of mitogen-activated protein kinase and protein kinase A signaling mediates intermediate-term synaptic facilitation in Aplysia. Proc Natl Acad Sci U S A 2012; 109:18162-7. [PMID: 23071303 DOI: 10.1073/pnas.1209956109] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
It is widely appreciated that memory processing engages a wide range of molecular signaling cascades in neurons, but how these cascades are temporally and spatially integrated is not well understood. To explore this important question, we used Aplysia californica as a model system. We simultaneously examined the timing and subcellular location of two signaling molecules, MAPK (ERK1/2) and protein kinase A (PKA), both of which are critical for the formation of enduring memory for sensitization. We also explored their interaction during the formation of enduring synaptic facilitation, a cellular correlate of memory, at tail sensory-to-motor neuron synapses. We find that repeated tail nerve shock (TNS, an analog of sensitizing training) immediately and persistently activates MAPK in both sensory neuron somata and synaptic neuropil. In contrast, we observe immediate PKA activation only in the synaptic neuropil. It is followed by PKA activation in both compartments 1 h after TNS. Interestingly, blocking MAPK activation during, but not after, TNS impairs PKA activation in synaptic neuropil without affecting the delayed PKA activation in sensory neuron somata. Finally, by applying inhibitors restricted to the synaptic compartment, we show that synaptic MAPK activation during TNS is required for the induction of intermediate-term synaptic facilitation, which leads to the persistent synaptic PKA activation required to maintain this facilitation. Collectively, our results elucidate how MAPK and PKA signaling cascades are spatiotemporally integrated in a single neuron to support synaptic plasticity underlying memory formation.
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DeAndrade MP, Zhang L, Doroodchi A, Yokoi F, Cheetham CC, Chen HX, Roper SN, Sweatt JD, Li Y. Enhanced hippocampal long-term potentiation and fear memory in Btbd9 mutant mice. PLoS One 2012; 7:e35518. [PMID: 22536397 PMCID: PMC3334925 DOI: 10.1371/journal.pone.0035518] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Accepted: 03/17/2012] [Indexed: 01/01/2023] Open
Abstract
Polymorphisms in BTBD9 have recently been associated with higher risk of restless legs syndrome (RLS), a neurological disorder characterized by uncomfortable sensations in the legs at rest that are relieved by movement. The BTBD9 protein contains a BTB/POZ domain and a BACK domain, but its function is unknown. To elucidate its function and potential role in the pathophysiology of RLS, we generated a line of mutant Btbd9 mice derived from a commercial gene-trap embryonic stem cell clone. Btbd9 is the mouse homolog of the human BTBD9. Proteins that contain a BTB/POZ domain have been reported to be associated with synaptic transmission and plasticity. We found that Btbd9 is naturally expressed in the hippocampus of our mutant mice, a region critical for learning and memory. As electrophysiological characteristics of CA3-CA1 synapses of the hippocampus are well characterized, we performed electrophysiological recordings in this region. The mutant mice showed normal input-output relationship, a significant impairment in pre-synaptic activity, and an enhanced long-term potentiation. We further performed an analysis of fear memory and found the mutant mice had an enhanced cued and contextual fear memory. To elucidate a possible molecular basis for these enhancements, we analyzed proteins that have been associated with synaptic plasticity. We found an elevated level of dynamin 1, an enzyme associated with endocytosis, in the mutant mice. These results suggest the first identified function of Btbd9 as being involved in regulating synaptic plasticity and memory. Recent studies have suggested that enhanced synaptic plasticity, analogous to what we have observed, in other regions of the brain could enhance sensory perception similar to what is seen in RLS patients. Further analyses of the mutant mice will help shine light on the function of BTBD9 and its role in RLS.
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Affiliation(s)
- Mark P. DeAndrade
- Interdisciplinary Program in Biomedical Sciences, College of Medicine, University of Florida, Gainesville, Florida, United States of America
- Department of Neurology, College of Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Li Zhang
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Atbin Doroodchi
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Fumiaki Yokoi
- Department of Neurology, College of Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Chad C. Cheetham
- Center for Neurodegeneration and Experimental Therapeutics, Department of Neurology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Huan-Xin Chen
- Department of Neurosurgery, College of Medicine, University of Florida, Gainesville, Florida, United States of America
| | - Steven N. Roper
- Department of Neurosurgery, College of Medicine, University of Florida, Gainesville, Florida, United States of America
| | - J. David Sweatt
- Department of Neurobiology, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Yuqing Li
- Department of Neurology, College of Medicine, University of Florida, Gainesville, Florida, United States of America
- * E-mail:
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Vinson PN, Conn PJ. Metabotropic glutamate receptors as therapeutic targets for schizophrenia. Neuropharmacology 2012; 62:1461-72. [PMID: 21620876 PMCID: PMC3189289 DOI: 10.1016/j.neuropharm.2011.05.005] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 05/02/2011] [Accepted: 05/08/2011] [Indexed: 01/13/2023]
Abstract
Treatment options for schizophrenia that address all symptom categories (positive, negative, and cognitive) are lacking in current therapies for this disorder. Compounds targeting the metabotropic glutamate (mGlu) receptors hold promise as a more comprehensive therapeutic alternative to typical and atypical antipsychotics and may avoid the occurrence of extrapyramidal side effects that accompany these treatments. Activation of the group II mGlu receptors (mGlu(2) and mGlu(3)) and the group I mGlu(5) are hypothesized to normalize the disruption of thalamocortical glutamatergic circuitry that results in abnormal glutamaterigic signaling in the prefrontal cortex (PFC). Agonists of mGlu(2) and mGlu(3) have demonstrated efficacy for the positive symptom group in both animal models and clinical trials with mGlu(2) being the subtype most likely responsible for the therapeutic effect. Limitations in the chemical space tolerated by the orthosteric site of the mGlu receptors has led to the pursuit of compounds that potentiate the receptor's response to glutamate by acting at less highly conserved allosteric sites. Several series of selective positive allosteric modulators (PAMs) for mGlu(2) and mGlu(5) have demonstrated efficacy in animal models used for the evaluation of antipsychotic agents. In addition, evidence from animal studies indicates that mGlu(5) PAMs hold promise for the treatment of cognitive deficits that occur in schizophrenia. Hopefully, further optimization of allosteric modulators of mGlu receptors will yield clinical candidates that will allow full evaluation of the potential efficacy of these compounds in the treatment of multiple symptom domains in schizophrenia patients in the near future.
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Affiliation(s)
- Paige N. Vinson
- Vanderbilt University Medical Center, Department of Pharmacology and Vanderbilt Center for Neuroscience Drug Discovery, Nashville, TN 37202
| | - P. Jeffrey Conn
- Vanderbilt University Medical Center, Department of Pharmacology and Vanderbilt Center for Neuroscience Drug Discovery, Nashville, TN 37202
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Hu JF, Niu F, Ning N, Duan WZ, Chu SF, Xue W, Yuan YH, Chen NH, Zhang JT. Activation of ERK1/2-CREB pathway during potentiating synaptic transmission of (-)clausenamide in rat dentate gyrus. JOURNAL OF ASIAN NATURAL PRODUCTS RESEARCH 2012; 14:256-262. [PMID: 22332773 DOI: 10.1080/10286020.2011.650885] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
To investigate the signal mechanism of (-)clausenamide ((-)-3-hydroxy-5-(hydroxy-phenyl-methyl)-1-methyl-4-phenyl-pyrrolidin-2-one, 1) and for understanding its effect on synaptic transmission, electrophysiological recording was done for basal synaptic transmission determination. Western blot analysis was employed to examine the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) and cAMP responsive element-binding protein (CREB). Immunohistochemistry and tissue in situ hybridization were applied to detect the expression of Zif268. The results showed that (-)clausenamide (1) increased the population spike of hippocampal dentate gyrus. The phosphorylation of ERK1/2 in hippocampus and cortex was increased and reached the maximum at 5 min and 30 min, respectively. (-)Clausenamide (1) promoted the phosphorylation of CREB, the downstream protein of ERK1/2. The expression of Zif268 protein and mRNA increased in both hippocampal dentate gyrus and cortex. Therefore, (-)clausenamide (1) activated the ERK1/2-CREB pathway, which may provide an explanation for its effect on potentiating synaptic transmission and improving learning and memory.
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Affiliation(s)
- Jin-Feng Hu
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Department of Pharmacology, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
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Abstract
Protein scaffolds control the intensity and duration of signaling and dictate the specificity of signaling through MAP kinase pathways. KSR1 is a molecular scaffold of the Raf/MEK/ERK MAP kinase cascade that regulates the intensity and duration of ERK activation. Relative to wild-type mice, ksr1-/- mice are modestly glucose intolerant, but show a normal response to exogenous insulin. However, ksr1-/- mice also demonstrate a three-fold increase in serum insulin levels in response to a glucose challenge, suggesting a role for KSR1 in insulin secretion. The kinase MARK2 is closely related to C-TAK1, a known regulator of KSR1. Mice lacking MARK2 have an increased rate of glucose disposal in response to exogenous insulin, increased glucose tolerance, and are resistant to diet-induced obesity. mark2-/-ksr1-/- (DKO) mice were compared to wild type, mark2-/-, and ksr1-/- mice for their ability to regulate glucose homeostasis. Here we show that disruption of KSR1 in mark2-/- mice reverses the increased sensitivity to exogenous insulin resulting from MARK2 deletion. DKO mice respond to exogenous insulin similarly to wild type and ksr1-/- mice. These data suggest a model whereby MARK2 negatively regulates insulin sensitivity in peripheral tissue through inhibition of KSR1. Consistent with this model, we found that MARK2 binds and phosphorylates KSR1 on Ser392. Phosphorylation of Ser392 is a critical regulator of KSR1 stability, subcellular location, and ERK activation. These data reveal an unexpected role for the molecular scaffold KSR1 in insulin-regulated glucose metabolism.
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Osborne JK, Zaganjor E, Cobb MH. Signal control through Raf: in sickness and in health. Cell Res 2011; 22:14-22. [PMID: 22143568 DOI: 10.1038/cr.2011.193] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The extracellular signal-regulated kinase 1/2 (ERK1/2) cascade is the prototype mammalian mitogen-activated protein kinase (MAPK) signaling cascade that regulates a number of processes, including proliferation, differentiation, survival, migration, stress responses and apoptosis. How this seemingly linear cascade is modulated to achieve a specific cellular function has been a main focus of the field. In this review, we describe new as well as old findings in the regulation of the ERK1/2 pathway in normal and disease states via MAP3Ks.
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Affiliation(s)
- Jihan K Osborne
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-9041, USA
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Martín ED, Sánchez-Perez A, Trejo JL, Martin-Aldana JA, Cano Jaimez M, Pons S, Acosta Umanzor C, Menes L, White MF, Burks DJ. IRS-2 Deficiency impairs NMDA receptor-dependent long-term potentiation. ACTA ACUST UNITED AC 2011; 22:1717-27. [PMID: 21955917 PMCID: PMC3388895 DOI: 10.1093/cercor/bhr216] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The beneficial effects of insulin and insulin-like growth factor I on cognition have been documented in humans and animal models. Conversely, obesity, hyperinsulinemia, and diabetes increase the risk for neurodegenerative disorders including Alzheimer's disease (AD). However, the mechanisms by which insulin regulates synaptic plasticity are not well understood. Here, we report that complete disruption of insulin receptor substrate 2 (Irs2) in mice impairs long-term potentiation (LTP) of synaptic transmission in the hippocampus. Basal synaptic transmission and paired-pulse facilitation were similar between the 2 groups of mice. Induction of LTP by high-frequency conditioning tetanus did not activate postsynaptic N-methyl-D-aspartate (NMDA) receptors in hippocampus slices from Irs2(-/-) mice, although the expression of NR2A, NR2B, and PSD95 was equivalent to wild-type controls. Activation of Fyn, AKT, and MAPK in response to tetanus stimulation was defective in Irs2(-/-) mice. Interestingly, IRS2 was phosphorylated during induction of LTP in control mice, revealing a potential new component of the signaling machinery which modulates synaptic plasticity. Given that IRS2 expression is diminished in Type 2 diabetics as well as in AD patients, these data may reveal an explanation for the prevalence of cognitive decline in humans with metabolic disorders by providing a mechanistic link between insulin resistance and impaired synaptic transmission.
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Affiliation(s)
- Eduardo D Martín
- Laboratory of Neurophysiology and Synaptic Plasticity, Albacete Science and Technology Park, PCYTA, Institute for Research in Neurological Disabilities, University of Castilla-La Mancha, 02071 Albacete, Spain
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Abstract
General or brain-region-specific decreases in spine number or morphology accompany major neuropsychiatric disorders. It is unclear, however, whether changes in spine density are specific for an individual mental process or disorder and, if so, which molecules confer such specificity. Here we identify the scaffolding protein IQGAP1 as a key regulator of dendritic spine number with a specific role in cognitive but not emotional or motivational processes. We show that IQGAP1 is an important component of NMDAR multiprotein complexes and functionally interacts with the NR2A subunits and the extracellular signal-regulated kinase 1 (ERK1) and ERK2 signaling pathway. Mice lacking the IQGAP1 gene exhibited significantly lower levels of surface NR2A and impaired ERK activity compared to their wild-type littermates. Accordingly, primary hippocampal cultures of IQGAP1(-/-) neurons exhibited reduced surface expression of NR2A and disrupted ERK signaling in response to NR2A-dependent NMDAR stimulation. These molecular changes were accompanied by region-specific reductions of dendritic spine density in key brain areas involved in cognition, emotion, and motivation. IQGAP1 knock-outs exhibited marked long-term memory deficits accompanied by impaired hippocampal long-term potentiation (LTP) in a weak cellular learning model; in contrast, LTP was unaffected when induced with stronger stimulation paradigms. Anxiety- and depression-like behavior remained intact. On the basis of these findings, we propose that a dysfunctional IQGAP1 gene contributes to the cognitive deficits in brain disorders characterized by fewer dendritic spines.
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Differential effect of the mGlu5 receptor positive allosteric modulator ADX-47273 on early and late hippocampal LTP. Neuropharmacology 2011; 61:707-14. [DOI: 10.1016/j.neuropharm.2011.05.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Revised: 02/28/2011] [Accepted: 05/17/2011] [Indexed: 11/23/2022]
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