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Deng QQ, Sheng WL, Zhang G, Weng SJ, Yang XL, Zhong YM. Signalling mechanism for somatostatin receptor 5-mediated suppression of AMPA responses in rat retinal ganglion cells. Neuropharmacology 2016; 107:215-226. [DOI: 10.1016/j.neuropharm.2016.03.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 01/25/2016] [Accepted: 03/02/2016] [Indexed: 01/21/2023]
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202
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Han J, Zhang H, Wang S, Zhou J, Luo Y, Long LH, Hu ZL, Wang F, Chen JG, Wu PF. Potentiation of Surface Stability of AMPA Receptors by Sulfhydryl Compounds: A Redox-Independent Effect by Disrupting Palmitoylation. Neurochem Res 2016; 41:2890-2903. [PMID: 27426946 DOI: 10.1007/s11064-016-2006-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 07/04/2016] [Accepted: 07/12/2016] [Indexed: 02/07/2023]
Abstract
Sulfhydryl compounds such as dithiothreitol (DTT) and β-mercaptoethanol (β-ME) are widely used as redox agents. Previous studies in our group and other laboratory have reported the effect of sulfhydryl compounds on the function of glutamate receptor, including plasticity. Most of these findings have focused on the N-methyl-D-aspartic acid receptor, in contrast, very little is known about the effect of sulfhydryl compounds on α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor (AMPAR). Here, we observed that DTT (100 μM), β-ME (200 μM) and L-cysteine (200 μM) significantly elevated the surface expression of AMPARs via reducing their palmitoylation in rat hippocampal slices in vitro. Increased surface stability of AMPARs was not be correlated with the altered redox status, because the chemical entities containing mercapto group such as penicillamine (200 μM) and 2-mercapto-1-methylimidazole (200 μM) exhibited little effects on the surface expression of AMPARs. Computing results of Asp-His-His-Cys (DHHC) 3, the main enzyme for palmitoylation of AMPARs, indicated that only the alkyl mercaptans with chain-like configuration, such as DTT and β-ME, can enter the pocket of DHHC3 and disrupt the catalytic activity via inhibiting DHHC3 auto-palmitoylation. Collectively, our findings indicate a novel redox-independent mechanism underlay the multiple effects of thiol reductants on synaptic function.
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Affiliation(s)
- Jun Han
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, Hubei, China
| | - Hai Zhang
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, Hubei, China
| | - Sheng Wang
- School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, 430074, China
| | - Jun Zhou
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, Hubei, China
| | - Yi Luo
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, Hubei, China
| | - Li-Hong Long
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, Hubei, China.,Key Laboratory of Neurological Diseases (HUST), Ministry of Education of China, Wuhan, 430030, Hubei, China.,The Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province, Wuhan, 430030, Hubei, China.,Laboratory of Neuropsychiatric Diseases, The Institute of Brain Research, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China
| | - Zhuang-Li Hu
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, Hubei, China.,Key Laboratory of Neurological Diseases (HUST), Ministry of Education of China, Wuhan, 430030, Hubei, China.,The Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province, Wuhan, 430030, Hubei, China.,Laboratory of Neuropsychiatric Diseases, The Institute of Brain Research, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China
| | - Fang Wang
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, Hubei, China.,Key Laboratory of Neurological Diseases (HUST), Ministry of Education of China, Wuhan, 430030, Hubei, China.,The Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province, Wuhan, 430030, Hubei, China.,Laboratory of Neuropsychiatric Diseases, The Institute of Brain Research, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China
| | - Jian-Guo Chen
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, Hubei, China.,Key Laboratory of Neurological Diseases (HUST), Ministry of Education of China, Wuhan, 430030, Hubei, China.,The Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province, Wuhan, 430030, Hubei, China.,Laboratory of Neuropsychiatric Diseases, The Institute of Brain Research, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China
| | - Peng-Fei Wu
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, 13 Hangkong Road, Wuhan, 430030, Hubei, China. .,Key Laboratory of Neurological Diseases (HUST), Ministry of Education of China, Wuhan, 430030, Hubei, China. .,The Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province, Wuhan, 430030, Hubei, China. .,Laboratory of Neuropsychiatric Diseases, The Institute of Brain Research, Huazhong University of Science and Technology, Wuhan, 430030, Hubei, China.
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203
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Kim S, Pick JE, Abera S, Khatri L, Ferreira DDP, Sathler MF, Morison SL, Hofmann F, Ziff EB. Brain region-specific effects of cGMP-dependent kinase II knockout on AMPA receptor trafficking and animal behavior. ACTA ACUST UNITED AC 2016; 23:435-41. [PMID: 27421896 PMCID: PMC4947234 DOI: 10.1101/lm.042960.116] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Accepted: 05/27/2016] [Indexed: 12/25/2022]
Abstract
Phosphorylation of GluA1, a subunit of AMPA receptors (AMPARs), is critical for AMPAR synaptic trafficking and control of synaptic transmission. cGMP-dependent protein kinase II (cGKII) mediates this phosphorylation, and cGKII knockout (KO) affects GluA1 phosphorylation and alters animal behavior. Notably, GluA1 phosphorylation in the KO hippocampus is increased as a functional compensation for gene deletion, while such compensation is absent in the prefrontal cortex. Thus, there are brain region-specific effects of cGKII KO on AMPAR trafficking, which could affect animal behavior. Here, we show that GluA1 phosphorylation levels differ in various brain regions, and specific behaviors are altered according to region-specific changes in GluA1 phosphorylation. Moreover, we identified distinct regulations of phosphatases in different brain regions, leading to regional heterogeneity of GluA1 phosphorylation in the KO brain. Our work demonstrates region-specific changes in GluA1 phosphorylation in cGKII KO mice and corresponding effects on cognitive performance. We also reveal distinct regulation of phosphatases in different brain region in which region-specific effects of kinase gene KO arise and can selectively alter animal behavior.
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Affiliation(s)
- Seonil Kim
- Department of Biochemistry and Molecular Pharmacology, New York University Langone Medical Center, New York 10016, New York, USA
| | - Joseph E Pick
- Department of Biochemistry and Molecular Pharmacology, New York University Langone Medical Center, New York 10016, New York, USA
| | - Sinedu Abera
- Department of Biochemistry and Molecular Pharmacology, New York University Langone Medical Center, New York 10016, New York, USA
| | - Latika Khatri
- Department of Biochemistry and Molecular Pharmacology, New York University Langone Medical Center, New York 10016, New York, USA
| | - Danielle D P Ferreira
- Department of Biochemistry and Molecular Pharmacology, New York University Langone Medical Center, New York 10016, New York, USA Department of Pharmacology and Physiology, Fluminense Federal University, Niteroi 24210-130, Brazil
| | - Matheus F Sathler
- Department of Biochemistry and Molecular Pharmacology, New York University Langone Medical Center, New York 10016, New York, USA Department of Pharmacology and Physiology, Fluminense Federal University, Niteroi 24210-130, Brazil
| | - Sage L Morison
- Department of Biochemistry and Molecular Pharmacology, New York University Langone Medical Center, New York 10016, New York, USA Center for Neural Science, New York University, New York 10012, USA
| | - Franz Hofmann
- Technical University of Munich, Munich 80802, Germany
| | - Edward B Ziff
- Department of Biochemistry and Molecular Pharmacology, New York University Langone Medical Center, New York 10016, New York, USA
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204
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Itoh N, Enomoto A, Nagai T, Takahashi M, Yamada K. Molecular mechanism linking BDNF/TrkB signaling with the NMDA receptor in memory: the role of Girdin in the CNS. Rev Neurosci 2016; 27:481-90. [DOI: 10.1515/revneuro-2015-0072] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 01/14/2016] [Indexed: 12/21/2022]
Abstract
AbstractIt is well known that synaptic plasticity is the cellular mechanism underlying learning and memory. Activity-dependent synaptic changes in electrical properties and morphology, including synaptogenesis, lead to alterations of synaptic strength, which is associated with long-term potentiation (LTP). Brain-derived neurotrophic factor (BDNF)/tropomyosin-related kinase B (TrkB) signaling is involved in learning and memory formation by regulating synaptic plasticity. The phosphatidylinositol 3-kinase (PI3-K)/Akt pathway is one of the key signaling cascades downstream BDNF/TrkB and is believed to modulate N-methyl-d-aspartate (NMDA) receptor-mediated synaptic plasticity. However, the molecular mechanism underlying the connection between these two key players in synaptic plasticity remains largely unknown. Girders of actin filament (Girdin), an Akt substrate that directly binds to actin filaments, has been shown to play a role in neuronal migration and neuronal development. Recently, we identified Girdin as a key molecule involved in regulating long-term memory. It was demonstrated that phosphorylation of Girdin by Akt contributed to the maintenance of LTP by linking the BDNF/TrkB signaling pathway with NMDA receptor activity. These findings indicate that Girdin plays a pivotal role in a variety of processes in the CNS. Here, we review recent advances in our understanding about the roles of Girdin in the CNS and focus particularly on neuronal migration and memory.
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Affiliation(s)
| | | | - Taku Nagai
- 1Department of Neuropsychopharmacology and Hospital Pharmacy, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi 466-8560, Japan
| | - Masahide Takahashi
- 2Department of Pathology, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa, Nagoya, Aichi 466-8550, Japan
| | - Kiyofumi Yamada
- 1Department of Neuropsychopharmacology and Hospital Pharmacy, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi 466-8560, Japan
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205
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Ge YX, Tian XZ, Lin YY, Liu XY. Chronic treatment with levetiracetam reverses deficits in hippocampal LTP in vivo in experimental temporal lobe epilepsy rats. Neurosci Lett 2016; 628:194-200. [PMID: 27345386 DOI: 10.1016/j.neulet.2016.06.043] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Revised: 06/10/2016] [Accepted: 06/21/2016] [Indexed: 12/21/2022]
Abstract
Temporal lobe epilepsy (TLE), the common form of epilepsy in adults, often displays complex partial seizures and cognitive deficits. The underlying mechanisms of such deficits are not yet well understood. Many contributing factors, such as initial epileptogenic lesion, seizure type, age of onset, and treatment side effects have been proposed. Levetiracetam (LEV) is a novel anti-epileptic drug (AED) used to treat partial seizures and idiopathic generalized epilepsy. It has been suggested that LEV exerts antiepileptic properties by modulation of synaptic release of neurotransmitters. However, its neuroprotective effects on learning and memory are not yet well demonstrated. Here we showed the impairment of spatial memory in the pilocarpine-induced experimental TLE rats, which can be improved by LEV. Furthermore, we found chronic LEV treatment partially reversed the SE-induced synaptic dysfunction in hippocampal LTP induction in vivo. In addition, LEV treatment can alleviate the SE-induced abnormal GluR1 phosphorylation at Ser(831) site, which may contribute to the rescue of synaptic transmission. These results indicate the neuroprotective role for LEV while it exhibits an antiseizure effect on experimental epileptic models.
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Affiliation(s)
- Yu-Xing Ge
- Department of Neurology, Tongji University Affiliated Tenth People's Hospital, 200072 Shanghai, PR China
| | - Xiang-Zhu Tian
- Department of Neurology, Tongji University Affiliated Tenth People's Hospital, 200072 Shanghai, PR China
| | - Ying-Ying Lin
- Department of Neurology, Tongji University Affiliated Tenth People's Hospital, 200072 Shanghai, PR China
| | - Xue-Yuan Liu
- Department of Neurology, Tongji University Affiliated Tenth People's Hospital, 200072 Shanghai, PR China.
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206
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Korte M, Schmitz D. Cellular and System Biology of Memory: Timing, Molecules, and Beyond. Physiol Rev 2016; 96:647-93. [PMID: 26960344 DOI: 10.1152/physrev.00010.2015] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The storage of information in the mammalian nervous systems is dependent on a delicate balance between change and stability of neuronal networks. The induction and maintenance of processes that lead to changes in synaptic strength to a multistep process which can lead to long-lasting changes, which starts and ends with a highly choreographed and perfectly timed dance of molecules in different cell types of the central nervous system. This is accompanied by synchronization of specific networks, resulting in the generation of characteristic "macroscopic" rhythmic electrical fields, whose characteristic frequencies correspond to certain activity and information-processing states of the brain. Molecular events and macroscopic fields influence each other reciprocally. We review here cellular processes of synaptic plasticity, particularly functional and structural changes, and focus on timing events that are important for the initial memory acquisition, as well as mechanisms of short- and long-term memory storage. Then, we cover the importance of epigenetic events on the long-time range. Furthermore, we consider how brain rhythms at the network level participate in processes of information storage and by what means they participating in it. Finally, we examine memory consolidation at the system level during processes of sleep.
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Affiliation(s)
- Martin Korte
- Zoological Institute, Division of Cellular Neurobiology, Braunschweig, Germany; Helmholtz Centre for Infection Research, AG NIND, Braunschweig, Germany; and Neuroscience Research Centre, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Dietmar Schmitz
- Zoological Institute, Division of Cellular Neurobiology, Braunschweig, Germany; Helmholtz Centre for Infection Research, AG NIND, Braunschweig, Germany; and Neuroscience Research Centre, Charité Universitätsmedizin Berlin, Berlin, Germany
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207
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Yan R, Fan Q, Zhou J, Vassar R. Inhibiting BACE1 to reverse synaptic dysfunctions in Alzheimer's disease. Neurosci Biobehav Rev 2016; 65:326-40. [PMID: 27044452 PMCID: PMC4856578 DOI: 10.1016/j.neubiorev.2016.03.025] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 03/25/2016] [Accepted: 03/29/2016] [Indexed: 12/21/2022]
Abstract
Over the past two decades, many studies have identified significant contributions of toxic β-amyloid peptides (Aβ) to the etiology of Alzheimer's disease (AD), which is the most common age-dependent neurodegenerative disease. AD is also recognized as a disease of synaptic failure. Aβ, generated by sequential proteolytic cleavages of amyloid precursor protein (APP) by BACE1 and γ-secretase, is one of major culprits that cause this failure. In this review, we summarize current findings on how BACE1-cleaved APP products impact learning and memory through proteins localized on glutamatergic, GABAergic, and dopaminergic synapses. Considering the broad effects of Aβ on all three types of synapses, BACE1 inhibition emerges as a practical approach for ameliorating Aβ-mediated synaptic dysfunctions. Since BACE1 inhibitory drugs are currently in clinical trials, this review also discusses potential complications arising from BACE1 inhibition. We emphasize that the benefits of BACE1 inhibitory drugs will outweigh the concerns.
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Affiliation(s)
- Riqiang Yan
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.
| | - Qingyuan Fan
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - John Zhou
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Robert Vassar
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA.
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208
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He ZY, Hu WY, Zhang M, Yang ZZ, Zhu HM, Xing D, Ma QH, Xiao ZC. Wip1 phosphatase modulates both long-term potentiation and long-term depression through the dephosphorylation of CaMKII. Cell Adh Migr 2016; 10:237-47. [PMID: 27158969 DOI: 10.4161/19336918.2014.994916] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Synaptic plasticity is an important mechanism that underlies learning and cognition. Protein phosphorylation by kinases and dephosphorylation by phosphatases play critical roles in the activity-dependent alteration of synaptic plasticity. In this study, we report that Wip1, a protein phosphatase, is essential for long-term potentiation (LTP) and long-term depression (LTD) processes. Wip1-deletion suppresses LTP and enhances LTD in the hippocampus CA1 area. Wip1 deficiency-induced aberrant elevation of CaMKII T286/287 and T305 phosphorylation underlies these dysfunctions. Moreover, we showed that Wip1 modulates CaMKII dephosphorylation. Wip1(-/-) mice exhibit abnormal GluR1 membrane expression, which could be reversed by the application of a CaMKII inhibitor, indicating that Wip1/CaMKII signaling is crucial for synaptic plasticity. Together, our results demonstrate that Wip1 phosphatase plays a vital role in regulating hippocampal synaptic plasticity by modulating the phosphorylation of CaMKII.
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Affiliation(s)
- Zhi-Yong He
- a MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University , Guangzhou , China.,b The Key Laboratory of Stem Cell and Regenerative Medicine, Institute of Molecular and Clinical Medicine, Kunming Medical University , Kunming , China.,c Department of Anatomy and Developmental Biology , Monash University , Clayton , Melbourne , Australia
| | - Wei-Yan Hu
- b The Key Laboratory of Stem Cell and Regenerative Medicine, Institute of Molecular and Clinical Medicine, Kunming Medical University , Kunming , China.,c Department of Anatomy and Developmental Biology , Monash University , Clayton , Melbourne , Australia.,e School of Pharmaceutical Science & Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University , Kunming , China
| | - Ming Zhang
- b The Key Laboratory of Stem Cell and Regenerative Medicine, Institute of Molecular and Clinical Medicine, Kunming Medical University , Kunming , China
| | - Zara Zhuyun Yang
- b The Key Laboratory of Stem Cell and Regenerative Medicine, Institute of Molecular and Clinical Medicine, Kunming Medical University , Kunming , China.,c Department of Anatomy and Developmental Biology , Monash University , Clayton , Melbourne , Australia
| | - Hong-Mei Zhu
- b The Key Laboratory of Stem Cell and Regenerative Medicine, Institute of Molecular and Clinical Medicine, Kunming Medical University , Kunming , China.,c Department of Anatomy and Developmental Biology , Monash University , Clayton , Melbourne , Australia
| | - Da Xing
- a MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University , Guangzhou , China
| | - Quan-Hong Ma
- a MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science, College of Biophotonics, South China Normal University , Guangzhou , China.,d Institute of Neuroscience, Suzhou University , Soochow , China
| | - Zhi-Cheng Xiao
- b The Key Laboratory of Stem Cell and Regenerative Medicine, Institute of Molecular and Clinical Medicine, Kunming Medical University , Kunming , China.,c Department of Anatomy and Developmental Biology , Monash University , Clayton , Melbourne , Australia
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209
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α/β-Hydrolase domain-containing 6 (ABHD6) negatively regulates the surface delivery and synaptic function of AMPA receptors. Proc Natl Acad Sci U S A 2016; 113:E2695-704. [PMID: 27114538 DOI: 10.1073/pnas.1524589113] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
In the brain, AMPA-type glutamate receptors are major postsynaptic receptors at excitatory synapses that mediate fast neurotransmission and synaptic plasticity. α/β-Hydrolase domain-containing 6 (ABHD6), a monoacylglycerol lipase, was previously found to be a component of AMPA receptor macromolecular complexes, but its physiological significance in the function of AMPA receptors (AMPARs) has remained unclear. The present study shows that overexpression of ABHD6 in neurons drastically reduced excitatory neurotransmission mediated by AMPA but not by NMDA receptors at excitatory synapses. Inactivation of ABHD6 expression in neurons by either CRISPR/Cas9 or shRNA knockdown methods significantly increased excitatory neurotransmission at excitatory synapses. Interestingly, overexpression of ABHD6 reduced glutamate-induced currents and the surface expression of GluA1 in HEK293T cells expressing GluA1 and stargazin, suggesting a direct functional interaction between these two proteins. The C-terminal tail of GluA1 was required for the binding between of ABHD6 and GluA1. Mutagenesis analysis revealed a GFCLIPQ sequence in the GluA1 C terminus that was essential for the inhibitory effect of ABHD6. The hydrolase activity of ABHD6 was not required for the effects of ABHD6 on AMPAR function in either neurons or transfected HEK293T cells. Thus, these findings reveal a novel and unexpected mechanism governing AMPAR trafficking at synapses through ABHD6.
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210
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Rueda CB, Llorente-Folch I, Traba J, Amigo I, Gonzalez-Sanchez P, Contreras L, Juaristi I, Martinez-Valero P, Pardo B, Del Arco A, Satrustegui J. Glutamate excitotoxicity and Ca2+-regulation of respiration: Role of the Ca2+ activated mitochondrial transporters (CaMCs). BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1158-1166. [PMID: 27060251 DOI: 10.1016/j.bbabio.2016.04.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Revised: 04/05/2016] [Accepted: 04/05/2016] [Indexed: 12/21/2022]
Abstract
Glutamate elicits Ca(2+) signals and workloads that regulate neuronal fate both in physiological and pathological circumstances. Oxidative phosphorylation is required in order to respond to the metabolic challenge caused by glutamate. In response to physiological glutamate signals, cytosolic Ca(2+) activates respiration by stimulation of the NADH malate-aspartate shuttle through Ca(2+)-binding to the mitochondrial aspartate/glutamate carrier (Aralar/AGC1/Slc25a12), and by stimulation of adenine nucleotide uptake through Ca(2+) binding to the mitochondrial ATP-Mg/Pi carrier (SCaMC-3/Slc25a23). In addition, after Ca(2+) entry into the matrix through the mitochondrial Ca(2+) uniporter (MCU), it activates mitochondrial dehydrogenases. In response to pathological glutamate stimulation during excitotoxicity, Ca(2+) overload, reactive oxygen species (ROS), mitochondrial dysfunction and delayed Ca(2+) deregulation (DCD) lead to neuronal death. Glutamate-induced respiratory stimulation is rapidly inactivated through a mechanism involving Poly (ADP-ribose) Polymerase-1 (PARP-1) activation, consumption of cytosolic NAD(+), a decrease in matrix ATP and restricted substrate supply. Glutamate-induced Ca(2+)-activation of SCaMC-3 imports adenine nucleotides into mitochondria, counteracting the depletion of matrix ATP and the impaired respiration, while Aralar-dependent lactate metabolism prevents substrate exhaustion. A second mechanism induced by excitotoxic glutamate is permeability transition pore (PTP) opening, which critically depends on ROS production and matrix Ca(2+) entry through the MCU. By increasing matrix content of adenine nucleotides, SCaMC-3 activity protects against glutamate-induced PTP opening and lowers matrix free Ca(2+), resulting in protracted appearance of DCD and protection against excitotoxicity in vitro and in vivo, while the lack of lactate protection during in vivo excitotoxicity explains increased vulnerability to kainite-induced toxicity in Aralar +/- mice. This article is part of a Special Issue entitled 'EBEC 2016: 19th European Bioenergetics Conference, Riva del Garda, Italy, July 2-6, 2016', edited by Prof. Paolo Bernardi.
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Affiliation(s)
- Carlos B Rueda
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Spain
| | - Irene Llorente-Folch
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Spain
| | - Javier Traba
- Cardiovascular and Pulmonary Branch, NHLBI, NIH, 20892 Bethesda, MD, USA
| | - Ignacio Amigo
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, 13560-970 São Paulo, Brazil
| | - Paloma Gonzalez-Sanchez
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Spain
| | - Laura Contreras
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Spain
| | - Inés Juaristi
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Spain
| | - Paula Martinez-Valero
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Spain
| | - Beatriz Pardo
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Spain
| | - Araceli Del Arco
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Spain; Facultad de Ciencias Ambientales y Bioquímica, Universidad de Castilla la Mancha, Toledo 45071, Spain
| | - Jorgina Satrustegui
- Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, Universidad Autónoma de Madrid-Consejo Superior de Investigaciones Científicas, 28049 Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), Spain; Instituto de Investigaciones Sanitarias Fundación Jiménez Díaz (IIS-FJD), Spain
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Abstract
The immediate early gene c-fos has long been known as a molecular marker of neural activity. The neuron's activity is transformed into intracellular calcium influx through NMDA receptors and L-type voltage sensitive calcium channels. For the transcription of c-fos, neural activity should be strong enough to activate mitogen-activated protein kinase (MAPK) signaling pathway which shows low calcium sensitivity. Upon translation, the auto-inhibition by Fos protein regulates basal Fos expression. The pattern of external stimuli and the valence of the stimulus to the animal change Fos signal, thus the signal reflects learning and memory aspects. Understanding the features of multiple components regulating Fos signaling is necessary for the optimal generation and interpretation of Fos signal.
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Affiliation(s)
- Leeyup Chung
- Dept. of Neurobiology, Duke University School of Medicine, Durham, NC, USA
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212
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Babiec WE, Guglietta R, O'Dell TJ. Basal levels of AMPA receptor GluA1 subunit phosphorylation at threonine 840 and serine 845 in hippocampal neurons. ACTA ACUST UNITED AC 2016; 23:127-33. [PMID: 26980779 PMCID: PMC4793196 DOI: 10.1101/lm.040675.115] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 01/12/2016] [Indexed: 01/19/2023]
Abstract
Dephosphorylation of AMPA receptor (AMPAR) GluA1 subunits at two sites, serine 845 (S845) and threonine 840 (T840), is thought to be involved in NMDA receptor-dependent forms of long-term depression (LTD). Importantly, the notion that dephosphorylation of these sites contributes to LTD assumes that a significant fraction of GluA1 subunits are basally phosphorylated at these sites. To examine this question, we used immunoprecipitation/depletion assays to estimate the proportion of GluA1 subunits basally phosphorylated at S845 and T840. Although dephosphorylation of S845 is thought to have a key role in LTD, our results indicate that few GluA1 subunits in hippocampal neurons are phosphorylated at this site. In contrast, ∼50% of GluA1 subunits are basally phosphorylated at T840, suggesting that dephosphorylation of this site can contribute to the down-regulation of AMPAR-mediated synaptic transmission in LTD.
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Affiliation(s)
- Walter E Babiec
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095, USA
| | - Ryan Guglietta
- Interdepartmental Ph.D. Program for Neuroscience at UCLA, Los Angeles, California 90095, USA
| | - Thomas J O'Dell
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, California 90095, USA UCLA Integrative Center for Learning and Memory, Brain Research Institute, Los Angeles, California 90095, USA
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213
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Shisa6 traps AMPA receptors at postsynaptic sites and prevents their desensitization during synaptic activity. Nat Commun 2016; 7:10682. [PMID: 26931375 PMCID: PMC4778035 DOI: 10.1038/ncomms10682] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Accepted: 01/11/2016] [Indexed: 11/08/2022] Open
Abstract
Trafficking and biophysical properties of AMPA receptors (AMPARs) in the brain depend on interactions with associated proteins. We identify Shisa6, a single transmembrane protein, as a stable and directly interacting bona fide AMPAR auxiliary subunit. Shisa6 is enriched at hippocampal postsynaptic membranes and co-localizes with AMPARs. The Shisa6 C-terminus harbours a PDZ domain ligand that binds to PSD-95, constraining mobility of AMPARs in the plasma membrane and confining them to postsynaptic densities. Shisa6 expressed in HEK293 cells alters GluA1- and GluA2-mediated currents by prolonging decay times and decreasing the extent of AMPAR desensitization, while slowing the rate of recovery from desensitization. Using gene deletion, we show that Shisa6 increases rise and decay times of hippocampal CA1 miniature excitatory postsynaptic currents (mEPSCs). Shisa6-containing AMPARs show prominent sustained currents, indicating protection from full desensitization. Accordingly, Shisa6 prevents synaptically trapped AMPARs from depression at high-frequency synaptic transmission. Auxiliary AMPA receptor subunits can affect gating and surface mobility. Here the authors show that Shisa6 traps AMPA receptors at postsynaptic sites via PSD-95, and keeps them in an activated state in the presence of glutamate, preventing full desensitization and consequently synaptic depression.
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214
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Insular Cortex is Critical for the Perception, Modulation, and Chronification of Pain. Neurosci Bull 2016; 32:191-201. [PMID: 26898298 DOI: 10.1007/s12264-016-0016-y] [Citation(s) in RCA: 155] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 12/22/2015] [Indexed: 12/20/2022] Open
Abstract
An increasing body of neuroimaging and electrophysiological studies of the brain suggest that the insular cortex (IC) integrates multimodal salient information ranging from sensation to cognitive-affective events to create conscious interoception. Especially with regard to pain experience, the IC has been supposed to participate in both sensory-discriminative and affective-motivational aspects of pain. In this review, we discuss the latest data proposing that subregions of the IC are involved in isolated pain networks: the posterior sensory circuit and the anterior emotional network. Due to abundant connections with other brain areas, the IC is likely to serve as an interface where cross-modal shaping of pain occurs. In chronic pain, however, this mode of emotional awareness and the modulation of pain are disrupted. We highlight some of the molecular mechanisms underlying the changes of the pain modulation system that contribute to the transition from acute to chronic pain in the IC.
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215
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Abstract
A cardinal feature of early stages of human brain development centers on the sensory, cognitive, and emotional experiences that shape neuronal-circuit formation and refinement. Consequently, alterations in these processes account for many psychiatric and neurodevelopmental disorders. Neurodevelopment disorders affect 3-4% of the world population. The impact of these disorders presents a major challenge to clinicians, geneticists, and neuroscientists. Mutations that cause neurodevelopmental disorders are commonly found in genes encoding proteins that regulate synaptic function. Investigation of the underlying mechanisms using gain or loss of function approaches has revealed alterations in dendritic spine structure, function, and plasticity, consequently modulating the neuronal circuit formation and thereby raising the possibility of neurodevelopmental disorders resulting from synaptopathies. One such gene, SYNGAP1 (Synaptic Ras-GTPase-activating protein) has been shown to cause Intellectual Disability (ID) with comorbid Autism Spectrum Disorder (ASD) and epilepsy in children. SYNGAP1 is a negative regulator of Ras, Rap and of AMPA receptor trafficking to the postsynaptic membrane, thereby regulating not only synaptic plasticity, but also neuronal homeostasis. Recent studies on the neurophysiology of SYNGAP1, using Syngap1 mouse models, have provided deeper insights into how downstream signaling proteins and synaptic plasticity are regulated by SYNGAP1. This knowledge has led to a better understanding of the function of SYNGAP1 and suggests a potential target during critical period of development when the brain is more susceptible to therapeutic intervention.
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Affiliation(s)
- Nallathambi Jeyabalan
- Narayana Nethralaya Post-Graduate Institute of Ophthalmology, Narayana Nethralaya Foundation, Narayana Health City Bangalore, India
| | - James P Clement
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research Bangalore, India
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216
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Caudal D, Rame M, Jay TM, Godsil BP. Dynamic Regulation of AMPAR Phosphorylation In Vivo Following Acute Behavioral Stress. Cell Mol Neurobiol 2016; 36:1331-1342. [PMID: 26814839 DOI: 10.1007/s10571-016-0332-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 07/31/2015] [Indexed: 12/20/2022]
Abstract
The tuning of glutamatergic transmission is an essential mechanism for neuronal communication. α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) are ionotropic glutamate receptors that mediate fast synaptic transmission. The phosphorylation states of specific serine residues on the GluA1 and GluA2 AMPAR subunits are considered critical post-translational modifications that regulate AMPAR activity and subcellular trafficking. While behavioral stress, via stress hormones, exerts specific alterations on such glutamatergic processes, there have been conflicting data concerning the influence of stress on AMPAR phosphorylation in different brain regions, and the post-stress signaling mechanisms mediating these processes are not well delineated. Here, we examined the dynamics of phosphorylation at three AMPAR serine residues (ser831-GluA1, ser845-GluA1, and ser880-GluA2) in four brain regions [amygdala, medial prefrontal cortex (mPFC), dorsal hippocampus, and ventral hippocampus] of the rat during the hour following behavioral stress. We also tested the impact of post-stress corticosteroid receptor blockade on AMPAR phosphorylation. Both GluA1 subunit residues exhibited elevated phosphorylation after stress, yet post-stress administration of corticosteroid receptor antagonists curtailed these effects only at ser831-GluA1. In contrast, ser880-GluA2 displayed a time-dependent tendency for early decreased phosphorylation (that was selectively augmented by mifepristone treatment in the amygdala and mPFC of stressed animals) followed by increased phosphorylation later on. These findings show that the in vivo regulation of AMPAR phosphorylation after stress is a dynamic and subunit-specific process, and they provide support for the hypothesis that corticosteroid receptors have an ongoing role in the regulation of ser831-GluA1 phosphorylation during the post-stress interval.
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Affiliation(s)
- Dorian Caudal
- Physiopathologie des Maladies Psychiatriques, UMR_S 894 Inserm, Centre de Psychiatrie et Neurosciences, 2ter rue d'Alesia, 75014, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Marion Rame
- Physiopathologie des Maladies Psychiatriques, UMR_S 894 Inserm, Centre de Psychiatrie et Neurosciences, 2ter rue d'Alesia, 75014, Paris, France
| | - Thérèse M Jay
- Physiopathologie des Maladies Psychiatriques, UMR_S 894 Inserm, Centre de Psychiatrie et Neurosciences, 2ter rue d'Alesia, 75014, Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Bill P Godsil
- Physiopathologie des Maladies Psychiatriques, UMR_S 894 Inserm, Centre de Psychiatrie et Neurosciences, 2ter rue d'Alesia, 75014, Paris, France. .,Université Paris Descartes, Sorbonne Paris Cité, Paris, France.
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217
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Hilgenstock R, Weiss T, Huonker R, Witte OW. Behavioural and neurofunctional impact of transcranial direct current stimulation on somatosensory learning. Hum Brain Mapp 2016; 37:1277-95. [PMID: 26757368 DOI: 10.1002/hbm.23101] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 12/08/2015] [Accepted: 12/13/2015] [Indexed: 11/12/2022] Open
Abstract
We investigated the effect of repeated delivery of anodal transcranial direct current stimulation (tDCS) on somatosensory performance and long-term learning. Over the course of five days, tDCS was applied to the primary somatosensory cortex (S1) by means of neuronavigation employing magnetencephalography (MEG). Compared to its sham application, tDCS promoted tactile learning by reducing the two-point discrimination threshold assessed by the grating orientation task (GOT) primarily by affecting intersessional changes in performance. These results were accompanied by alterations in the neurofunctional organization of the brain, as revealed by functional magnetic resonance imaging conducted prior to the study, at the fifth day of tDCS delivery and four weeks after the last application of tDCS. A decrease in activation at the primary site of anodal tDCS delivery in the left S1 along retention of superior tactile acuity was observed at follow-up four weeks after the application of tDCS. Thus, we demonstrate long-term effects that repeated tDCS imposes on somatosensory functioning. This is the first study to provide insight into the mode of operation of tDCS on the brain's response to long-term perceptual learning, adding an important piece of evidence from the domain of non-invasive brain stimulation to show that functional changes detectable by fMRI in primary sensory cortices participate in perceptual learning.
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Affiliation(s)
- Raphael Hilgenstock
- Hans Berger Department of Neurology, Jena University Hospital, Friedrich Schiller University, Jena, Germany.,Department of Pediatrics, HELIOS Children's Hospital Wuppertal, Witten/Herdecke University, Wuppertal, Germany
| | - Thomas Weiss
- Department of Biological and Clinical Psychology, Friedrich Schiller University, Jena, Germany
| | - Ralph Huonker
- Brain Imaging Center, Hans Berger Department of Neurology, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Otto W Witte
- Hans Berger Department of Neurology, Jena University Hospital, Friedrich Schiller University, Jena, Germany.,Center for Sepsis Control and Care, Jena University Hospital, Friedrich Schiller University, Jena, Germany
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218
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Zhang Q, Liu W, Niu Q, Wang Y, Zhao H, Zhang H, Song J, Tsuda S, Saito N. Effects of perfluorooctane sulfonate and its alternatives on long-term potentiation in the hippocampus CA1 region of adult rats in vivo. Toxicol Res (Camb) 2016; 5:539-546. [PMID: 30090368 DOI: 10.1039/c5tx00184f] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 01/05/2016] [Indexed: 11/21/2022] Open
Abstract
With the limited but ongoing usage of perfluorooctane sulfonate (PFOS), the health effects of both PFOS and its alternatives are far from being understood. Long-term potentiation (LTP) was evaluated in rats after exposure to PFOS and its alternatives, aiming to provide some evidence about their potential to affect cognitive ability. Different dosages of PFOS and alternative chemicals, including perfluorohexane sulfonate (PFHxS), perfluorobutane sulfonate (PFBS) and chlorinated polyfluorinated ether sulfonate (Cl-PFAES), were given to rats via acute intracerebroventricular injection. The field excitatory postsynaptic potential (fEPSP) amplitude of the input/output functions, paired-pulse facilitations, and LTP in vivo were recorded. PFOS and its alternatives inhibited LTP in varying degrees, without significant effects on the normal synaptic transmission. In addition, PFHxS and Cl-PFAES exhibited comparable potential to PFOS in disturbing LTP. The results suggested that acute exposure to PFOS and its alternatives impaired the synaptic plasticity by a postsynaptic rather than a presynaptic mechanism. Besides, the fEPSP amplitude of the baseline was reduced by Cl-PFAES but not by other compounds, indicating that Cl-PFAES might act in a different mode. Providing some electrophysiological evidence and the potential mechanism of the neurotoxicity induced by PFOS and its alternatives, the present study addresses further evaluation of their safety and health risks.
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Affiliation(s)
- Qian Zhang
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE) , School of Environmental Science and Technology , Dalian University of Technology , Dalian 116024 , China . ; ; , +86-411-84706263
| | - Wei Liu
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE) , School of Environmental Science and Technology , Dalian University of Technology , Dalian 116024 , China . ; ; , +86-411-84706263
| | - Qiao Niu
- Department of Occupational Health , Shanxi Medical University , Taiyuan 030001 , Shanxi , China
| | - Yu Wang
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE) , School of Environmental Science and Technology , Dalian University of Technology , Dalian 116024 , China . ; ; , +86-411-84706263
| | - Huimin Zhao
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE) , School of Environmental Science and Technology , Dalian University of Technology , Dalian 116024 , China . ; ; , +86-411-84706263
| | - Huifang Zhang
- Department of Occupational Health , Shanxi Medical University , Taiyuan 030001 , Shanxi , China
| | - Jing Song
- Department of Occupational Health , Shanxi Medical University , Taiyuan 030001 , Shanxi , China
| | - Shuji Tsuda
- Research Institute for Environmental Sciences and Public Health of Iwate Prefecture , Morioka , Iwate , Japan
| | - Norimitsu Saito
- Research Institute for Environmental Sciences and Public Health of Iwate Prefecture , Morioka , Iwate , Japan
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219
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Grillo CA, Piroli GG, Lawrence RC, Wrighten SA, Green AJ, Wilson SP, Sakai RR, Kelly SJ, Wilson MA, Mott DD, Reagan LP. Hippocampal Insulin Resistance Impairs Spatial Learning and Synaptic Plasticity. Diabetes 2015; 64. [PMID: 26216852 PMCID: PMC4613975 DOI: 10.2337/db15-0596] [Citation(s) in RCA: 211] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Insulin receptors (IRs) are expressed in discrete neuronal populations in the central nervous system, including the hippocampus. To elucidate the functional role of hippocampal IRs independent of metabolic function, we generated a model of hippocampal-specific insulin resistance using a lentiviral vector expressing an IR antisense sequence (LV-IRAS). LV-IRAS effectively downregulates IR expression in the rat hippocampus without affecting body weight, adiposity, or peripheral glucose homeostasis. Nevertheless, hippocampal neuroplasticity was impaired in LV-IRAS-treated rats. High-frequency stimulation, which evoked robust long-term potentiation (LTP) in brain slices from LV control rats, failed to evoke LTP in LV-IRAS-treated rats. GluN2B subunit levels, as well as the basal level of phosphorylation of GluA1, were reduced in the hippocampus of LV-IRAS rats. Moreover, these deficits in synaptic transmission were associated with impairments in spatial learning. We suggest that alterations in the expression and phosphorylation of glutamate receptor subunits underlie the alterations in LTP and that these changes are responsible for the impairment in hippocampal-dependent learning. Importantly, these learning deficits are strikingly similar to the impairments in complex task performance observed in patients with diabetes, which strengthens the hypothesis that hippocampal insulin resistance is a key mediator of cognitive deficits independent of glycemic control.
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Affiliation(s)
- Claudia A Grillo
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC
| | - Gerardo G Piroli
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC
| | - Robert C Lawrence
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC Department of Psychology, University of South Carolina, Columbia, SC
| | - Shayna A Wrighten
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC
| | - Adrienne J Green
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC
| | - Steven P Wilson
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC
| | - Randall R Sakai
- Department of Psychiatry, University of Cincinnati Medical Center, Cincinnati, OH
| | - Sandra J Kelly
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC Department of Psychology, University of South Carolina, Columbia, SC
| | - Marlene A Wilson
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC William Jennings Bryan Dorn Veterans Affairs Medical Center, Columbia, SC
| | - David D Mott
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC
| | - Lawrence P Reagan
- Department of Pharmacology, Physiology & Neuroscience, University of South Carolina School of Medicine, Columbia, SC William Jennings Bryan Dorn Veterans Affairs Medical Center, Columbia, SC
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220
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Beshara S, Beston BR, Pinto JGA, Murphy KM. Effects of Fluoxetine and Visual Experience on Glutamatergic and GABAergic Synaptic Proteins in Adult Rat Visual Cortex. eNeuro 2015; 2:ENEURO.0126-15.2015. [PMID: 26730408 PMCID: PMC4698542 DOI: 10.1523/eneuro.0126-15.2015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 12/04/2015] [Accepted: 12/08/2015] [Indexed: 01/12/2023] Open
Abstract
Fluoxetine has emerged as a novel treatment for persistent amblyopia because in adult animals it reinstates critical period-like ocular dominance plasticity and promotes recovery of visual acuity. Translation of these results from animal models to the clinic, however, has been challenging because of the lack of understanding of how this selective serotonin reuptake inhibitor affects glutamatergic and GABAergic synaptic mechanisms that are essential for experience-dependent plasticity. An appealing hypothesis is that fluoxetine recreates a critical period (CP)-like state by shifting synaptic mechanisms to be more juvenile. To test this we studied the effect of fluoxetine treatment in adult rats, alone or in combination with visual deprivation [monocular deprivation (MD)], on a set of highly conserved presynaptic and postsynaptic proteins (synapsin, synaptophysin, VGLUT1, VGAT, PSD-95, gephyrin, GluN1, GluA2, GluN2B, GluN2A, GABAAα1, GABAAα3). We did not find evidence that fluoxetine shifted the protein amounts or balances to a CP-like state. Instead, it drove the balances in favor of the more mature subunits (GluN2A, GABAAα1). In addition, when fluoxetine was paired with MD it created a neuroprotective-like environment by normalizing the glutamatergic gain found in adult MDs. Together, our results suggest that fluoxetine treatment creates a novel synaptic environment dominated by GluN2A- and GABAAα1-dependent plasticity.
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Affiliation(s)
- Simon Beshara
- McMaster Integrative Neuroscience Discovery and Study (MiNDS) Program, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | - Brett R. Beston
- McMaster Integrative Neuroscience Discovery and Study (MiNDS) Program, McMaster University, Hamilton, Ontario L8S 4K1, Canada
- Department of Psychology, Neuroscience & Behavior, McMaster University, Hamilton, Ontario L8S 4K1, Canada
- Department of Psychology, University of Toronto Mississauga, Mississauga, L5L 1C6, ON
| | - Joshua G. A. Pinto
- McMaster Integrative Neuroscience Discovery and Study (MiNDS) Program, McMaster University, Hamilton, Ontario L8S 4K1, Canada
- Health Care Investment Banking, Credit Suisse AG, San Francisco, CA 94108
| | - Kathryn M. Murphy
- McMaster Integrative Neuroscience Discovery and Study (MiNDS) Program, McMaster University, Hamilton, Ontario L8S 4K1, Canada
- Department of Psychology, Neuroscience & Behavior, McMaster University, Hamilton, Ontario L8S 4K1, Canada
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221
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Tian Y, Tang FL, Sun X, Wen L, Mei L, Tang BS, Xiong WC. VPS35-deficiency results in an impaired AMPA receptor trafficking and decreased dendritic spine maturation. Mol Brain 2015; 8:70. [PMID: 26521016 PMCID: PMC4628247 DOI: 10.1186/s13041-015-0156-4] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 10/09/2015] [Indexed: 11/10/2022] Open
Abstract
Background Vacuolar protein sorting 35 (VPS35), a key component of retromer, plays an important role in endosome-to-Golgi retrieval of membrane proteins. Dysfunction of VPS35/retromer is a risk factor for neurodegenerative disorders, including AD (Alzheimer’s disease) and PD (Parkinson’s disease). However, exactly how VPS35-deficiency contributes to AD or PD pathogenesis remains poorly understood. Results We found that VPS35-deficiency impaired dendritic spine maturation and decreased glutamatergic transmission. AMPA receptors, GluA1 and GluA2, are significantly reduced in purified synaptosomal and PSD fractions from VPS35-deficient brain. The surface levels of AMPA receptors are also decreased in VPS35-deficient neurons. Additionally, VPS35 interacted with AMPA-type receptors, GluA1 and GluA2. Overexpression of GluA2, but not GluA1, could partially restore the spine maturation deficit in VPS35-deficient neurons. Conclusions These results provide evidence for VPS35’s function in promoting spine maturation, which is likely through increasing AMPA receptor targeting to the postsynaptic membrane. Perturbation of such a VPS35/retromer function may contribute to the impaired glutamatergic transmission and pathogenesis of neurodegenerative disorders, such as AD and PD. Electronic supplementary material The online version of this article (doi:10.1186/s13041-015-0156-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yun Tian
- Department of Geriatrics and Department of Neurology, Xiangya Hospital, Central South University, ChangSha, 410008, China.,Department of Neuroscience & Regenerative Medicine and Department of Neurology, Medical College of Georgia, Augusta, GA, 30912, USA
| | - Fu-Lei Tang
- Department of Neuroscience & Regenerative Medicine and Department of Neurology, Medical College of Georgia, Augusta, GA, 30912, USA.,Charlie Norwood VA Medical Center, Augusta, GA, 30912, USA
| | - XiangDong Sun
- Department of Neuroscience & Regenerative Medicine and Department of Neurology, Medical College of Georgia, Augusta, GA, 30912, USA
| | - Lei Wen
- Department of Neuroscience & Regenerative Medicine and Department of Neurology, Medical College of Georgia, Augusta, GA, 30912, USA.,Department of Traditional Chinese Medicine, Xia-Men University, Xia-Men, China
| | - Lin Mei
- Department of Neuroscience & Regenerative Medicine and Department of Neurology, Medical College of Georgia, Augusta, GA, 30912, USA.,Charlie Norwood VA Medical Center, Augusta, GA, 30912, USA
| | - Bei-Sha Tang
- Department of Geriatrics and Department of Neurology, Xiangya Hospital, Central South University, ChangSha, 410008, China.
| | - Wen-Cheng Xiong
- Department of Neuroscience & Regenerative Medicine and Department of Neurology, Medical College of Georgia, Augusta, GA, 30912, USA. .,Charlie Norwood VA Medical Center, Augusta, GA, 30912, USA.
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222
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Brosch T, Neumann H, Roelfsema PR. Reinforcement Learning of Linking and Tracing Contours in Recurrent Neural Networks. PLoS Comput Biol 2015; 11:e1004489. [PMID: 26496502 PMCID: PMC4619762 DOI: 10.1371/journal.pcbi.1004489] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 08/05/2015] [Indexed: 11/30/2022] Open
Abstract
The processing of a visual stimulus can be subdivided into a number of stages. Upon stimulus presentation there is an early phase of feedforward processing where the visual information is propagated from lower to higher visual areas for the extraction of basic and complex stimulus features. This is followed by a later phase where horizontal connections within areas and feedback connections from higher areas back to lower areas come into play. In this later phase, image elements that are behaviorally relevant are grouped by Gestalt grouping rules and are labeled in the cortex with enhanced neuronal activity (object-based attention in psychology). Recent neurophysiological studies revealed that reward-based learning influences these recurrent grouping processes, but it is not well understood how rewards train recurrent circuits for perceptual organization. This paper examines the mechanisms for reward-based learning of new grouping rules. We derive a learning rule that can explain how rewards influence the information flow through feedforward, horizontal and feedback connections. We illustrate the efficiency with two tasks that have been used to study the neuronal correlates of perceptual organization in early visual cortex. The first task is called contour-integration and demands the integration of collinear contour elements into an elongated curve. We show how reward-based learning causes an enhancement of the representation of the to-be-grouped elements at early levels of a recurrent neural network, just as is observed in the visual cortex of monkeys. The second task is curve-tracing where the aim is to determine the endpoint of an elongated curve composed of connected image elements. If trained with the new learning rule, neural networks learn to propagate enhanced activity over the curve, in accordance with neurophysiological data. We close the paper with a number of model predictions that can be tested in future neurophysiological and computational studies. Our experience with the visual world allows us to group image elements that belong to the same perceptual object and to segregate them from other objects and the background. If subjects learn to group contour elements, this experience influences neuronal activity in early visual cortical areas, including the primary visual cortex (V1). Learning presumably depends on alterations in the pattern of connections within and between areas of the visual cortex. However, the processes that control changes in connectivity are not well understood. Here we present the first computational model that can train a neural network to integrate collinear contour elements into elongated curves and to trace a curve through the visual field. The new learning algorithm trains fully recurrent neural networks, provided the connectivity causes the networks to reach a stable state. The model reproduces the behavioral performance of monkeys trained in these tasks and explains the patterns of neuronal activity in the visual cortex that emerge during learning, which is remarkable because the only feedback for the model is a reward for successful trials. We discuss a number of the model predictions that can be tested in future neuroscientific work.
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Affiliation(s)
- Tobias Brosch
- University of Ulm, Institute of Neural Information Processing, Ulm, Germany
| | - Heiko Neumann
- University of Ulm, Institute of Neural Information Processing, Ulm, Germany
- * E-mail:
| | - Pieter R. Roelfsema
- Department of Vision & Cognition, Netherlands Institute for Neuroscience (KNAW), Amsterdam, The Netherlands
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, VU University, Amsterdam, The Netherlands
- Psychiatry Department, Academic Medical Center, Amsterdam, The Netherlands
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223
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Kim S, Violette CJ, Ziff EB. Reduction of increased calcineurin activity rescues impaired homeostatic synaptic plasticity in presenilin 1 M146V mutant. Neurobiol Aging 2015; 36:3239-3246. [PMID: 26455952 DOI: 10.1016/j.neurobiolaging.2015.09.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 09/09/2015] [Accepted: 09/10/2015] [Indexed: 02/01/2023]
Abstract
Alzheimer's disease (AD) is one of the most common neurodegenerative diseases characterized by memory loss and cognitive impairment. Whereas most AD cases are sporadic, some are caused by mutations in early-onset familial AD (FAD) genes. One FAD gene encodes presenilin 1 (PS1), and a PS1 mutation in methionine 146 impairs homeostatic synaptic plasticity (HSP). We have previously shown that Ca(2+) and calcineurin activity are critical regulators of HSP. Here, we confirm that endoplasmic reticulum-mediated Ca(2+) signals are increased in mutant PS1 neurons. We further show that calcineurin activity is abnormally elevated in the mutant and that inhibition of increased calcineurin activity stabilizes GluA1 phosphorylation, promoting synaptic trafficking of Ca(2+)-permeable α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, contributing to the recovery of impaired HSP found in the mutant. Because HSP is suggested to have roles during learning and memory formation, increased calcineurin activity-induced impairment of HSP can cause cognitive decline in FAD. Thus, reducing abnormally increased calcineurin activity in AD brain may be beneficial for improving AD-related cognitive decline.
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Affiliation(s)
- Seonil Kim
- Department of Biochemistry and Molecular Pharmacology, New York University Langone Medical Center, New York, NY, USA.
| | | | - Edward B Ziff
- Department of Biochemistry and Molecular Pharmacology, New York University Langone Medical Center, New York, NY, USA.
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224
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Duan JJ, Lozada AF, Gou CY, Xu J, Chen Y, Berg DK. Nicotine recruits glutamate receptors to postsynaptic sites. Mol Cell Neurosci 2015; 68:340-9. [PMID: 26365992 DOI: 10.1016/j.mcn.2015.09.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 08/04/2015] [Accepted: 09/07/2015] [Indexed: 01/20/2023] Open
Abstract
Cholinergic neurons project throughout the nervous system and activate nicotinic receptors to modulate synaptic function in ways that shape higher order brain function. The acute effects of nicotinic signaling on long-term synaptic plasticity have been well-characterized. Less well understood is how chronic exposure to low levels of nicotine, such as those encountered by habitual smokers, can alter neural connections to promote addiction and other lasting behavioral effects. We show here that chronic exposure of hippocampal neurons in culture to low levels of nicotine recruits AMPA and NMDA receptors to the cell surface and sequesters them at postsynaptic sites. The receptors include GluA2-containing AMPA receptors, which are responsible for most of the excitatory postsynaptic current mediated by AMPA receptors on the neurons, and include NMDA receptors containing GluN1 and GluN2B subunits. Moreover, we find that the nicotine treatment also increases expression of the presynaptic component synapsin 1 and arranges it in puncta juxtaposed to the additional AMPA and NMDA receptor puncta, suggestive of increases in synaptic contacts. Consistent with increased synaptic input, we find that the nicotine treatment leads to an increase in the excitatory postsynaptic currents mediated by AMPA and NMDA receptors. Further, the increases skew the ratio of excitatory-to-inhibitory input that the cell receives, and this holds both for pyramidal neurons and inhibitory neurons in the hippocampal CA1 region. The GluN2B-containing NMDA receptor redistribution at synapses is associated with a significant increase in GluN2B phosphorylation at Tyr1472, a site known to prevent GluN2B endocytosis. These results suggest that chronic exposure to low levels of nicotine not only alters functional connections but also is likely to change excitability levels across networks. Further, it may increase the propensity for synaptic plasticity, given the increase in synaptic NMDA receptors.
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Affiliation(s)
- Jing-Jing Duan
- Department of Anatomy and Neurobiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Neurobiology Section, Division of Biological Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0357, United States
| | - Adrian F Lozada
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0357, United States
| | - Chen-Yu Gou
- Department of Anatomy and Neurobiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Jing Xu
- Pain Research Center and Department of Physiology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510080, China
| | - Yuan Chen
- Department of Anatomy and Neurobiology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China.
| | - Darwin K Berg
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0357, United States.
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225
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Szewczyk B, Pochwat B, Rafało A, Palucha-Poniewiera A, Domin H, Nowak G. Activation of mTOR dependent signaling pathway is a necessary mechanism of antidepressant-like activity of zinc. Neuropharmacology 2015; 99:517-26. [PMID: 26297535 DOI: 10.1016/j.neuropharm.2015.08.026] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 07/23/2015] [Accepted: 08/16/2015] [Indexed: 12/13/2022]
Abstract
The rapid antidepressant response to the N-methyl-D-aspartate (NMDA) receptor antagonists is mediated by activation of the mammalian target of the rapamycin (mTOR) signaling pathway, an increase in the synthesis of synaptic proteins and formation of new synapses in the prefrontal cortex (PFC) of rats. Zinc (Zn), which is a potent NMDA receptor antagonist, exerts antidepressant-like effects in screening tests and models of depression. We focused these studies in investigating whether activation of the mTOR signaling pathway is also a necessary mechanism of the antidepressant-like activity of Zn. We observed that a single injection of Zn (5 mg/kg) induced an increase in the phosphorylation of mTOR and p70S6K 30 min and 3 h after Zn treatment at time points when Zn produced also an antidepressant-like effect in the forced swim test (FST). Furthermore, Zn administered 3 h before the decapitation increased the level of brain derived neurotrophic factor (BDNF), GluA1 and synapsin I. An elevated level of GluA1 and synapsin I was still observed 24 h after the Zn treatment, although Zn did not produce any effects in the FST at that time point. We also observed that pretreatment with rapamycin (mTORC1 inhibitor), LY294002 (PI3K inhibitor), H-89 (PKA inhibitor) and GF109203X (PKC inhibitor) blocked the antidepressant-like effect of Zn in FST in rats and blocks Zn-induced activation of mTOR signaling proteins (analyzed 30 min after Zn administration). These studies indicated that the antidepressant-like activity of Zn depends on the activation of mTOR signaling and other signaling pathways related to neuroplasticity, which can indirectly modulate mTOR function.
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Affiliation(s)
- Bernadeta Szewczyk
- Department of Neurobiology, Institute of Pharmacology, Polish Academy of Sciences, Smetna 12, 31-343 Krakow, Poland.
| | - Bartłomiej Pochwat
- Department of Neurobiology, Institute of Pharmacology, Polish Academy of Sciences, Smetna 12, 31-343 Krakow, Poland
| | - Anna Rafało
- Department of Neurobiology, Institute of Pharmacology, Polish Academy of Sciences, Smetna 12, 31-343 Krakow, Poland
| | - Agnieszka Palucha-Poniewiera
- Department of Neurobiology, Institute of Pharmacology, Polish Academy of Sciences, Smetna 12, 31-343 Krakow, Poland
| | - Helena Domin
- Department of Neurobiology, Institute of Pharmacology, Polish Academy of Sciences, Smetna 12, 31-343 Krakow, Poland
| | - Gabriel Nowak
- Department of Neurobiology, Institute of Pharmacology, Polish Academy of Sciences, Smetna 12, 31-343 Krakow, Poland; Department of Pharmacobiology, Jagiellonian University Medical College, Medyczna 9, 30-688 Kraków, Poland
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226
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Duman CH, Duman RS. Spine synapse remodeling in the pathophysiology and treatment of depression. Neurosci Lett 2015; 601:20-9. [PMID: 25582786 PMCID: PMC4497940 DOI: 10.1016/j.neulet.2015.01.022] [Citation(s) in RCA: 187] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 01/07/2015] [Accepted: 01/08/2015] [Indexed: 12/21/2022]
Abstract
Clinical brain imaging and postmortem studies provide evidence of structural and functional abnormalities of key limbic and cortical structures in depressed patients, suggesting that spine synapse connectivity is altered in depression. Characterization of the cellular determinants underlying these changes in patients are limited, but studies in rodent models demonstrate alterations of dendrite complexity and spine density and function that could contribute to the morphological and functional alterations observed in humans. Rodent studies demonstrate region specific effects in chronic stress models of depression, including reductions in dendrite complexity and spine density in the hippocampus and prefrontal cortex (PFC) but increases in the basolateral amygdala and nucleus accumbens. Alterations of spine synapse connectivity in these regions are thought to contribute to the behavioral symptoms of depression, including disruption of cognition, mood, emotion, motivation, and reward. Studies of the mechanisms underlying these effects demonstrate a role for altered brain derived neurotrophic factor (BDNF) signaling that regulates synaptic protein synthesis. In contrast, there is evidence that chronic antidepressant treatment can block or reverse the spine synapse alterations caused by stress. Notably, the new fast acting antidepressant ketamine, which produces rapid therapeutic actions in treatment resistant MDD patients, rapidly increases spine synapse number in the PFC of rodents and reverses the effects of chronic stress. The rapid synaptic and behavioral actions of ketamine occur via increased BDNF regulation of synaptic protein synthesis. Together these studies provide evidence for a neurotophic and synaptogenic hypothesis of depression and treatment response and indicate that spine synapse connectivity in key cortical and limbic brain regions is critical for control of mood and emotion.
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Affiliation(s)
- Catharine H Duman
- Laboratory of Molecular Psychiatry, Department of Psychiatry, Yale University School of Medicine, 34 Park Street, New Haven, CT 06508, USA
| | - Ronald S Duman
- Laboratory of Molecular Psychiatry, Department of Psychiatry, Yale University School of Medicine, 34 Park Street, New Haven, CT 06508, USA.
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227
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Abstract
Synthesizing, localizing, and stabilizing new protein copies at synapses are crucial factors in maintaining the synaptic changes required for storing long-term memories. PKMζ recently emerged as a molecule putatively responsible for maintaining encoded memories over time because its presence correlates with late LTP and because its inhibition disrupts LTP in vitro and long-term memory storage in vivo. Here we investigated PKMζ stability in rat neurons to better understand its role during information encoding and storage. We used TimeSTAMP reporters to track the synthesis and degradation of PKMζ as well as a related atypical PKC, PKCλ. These reporters revealed that both PKMζ and PKCλ were upregulated after chemical LTP induction; however, these new PKMζ copies exhibited more rapid turnover than basally produced PKMζ, particularly in dendritic spines. In contrast to PKMζ, new PKCλ copies exhibited elevated stability. Stable information storage over long periods of time is more challenging the shorter the metabolic lifetime of the candidate molecules.
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228
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Region-specific alterations of AMPA receptor phosphorylation and signaling pathways in the pilocarpine model of epilepsy. Neurochem Int 2015; 87:22-33. [DOI: 10.1016/j.neuint.2015.05.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 05/06/2015] [Accepted: 05/07/2015] [Indexed: 01/27/2023]
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229
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Abstract
Cyclin Y (CCNY) is a member of the cyclin protein family, known to regulate cell division in proliferating cells. Interestingly, CCNY is expressed in neurons that do not undergo cell division. Here, we report that CCNY negatively regulates long-term potentiation (LTP) of synaptic strength through inhibition of AMPA receptor trafficking. CCNY is enriched in postsynaptic fractions from rat forebrain and is localized adjacent to postsynaptic sites in dendritic spines in rat hippocampal neurons. Using live-cell imaging of a pH-sensitive AMPA receptor, we found that during LTP-inducing stimulation, CCNY inhibits AMPA receptor exocytosis in dendritic spines. Furthermore, CCNY abolishes LTP in hippocampal slices. Taken together, our findings demonstrate that CCNY inhibits plasticity-induced AMPA receptor delivery to synapses and thereby blocks LTP, identifying a novel function for CCNY in post-mitotic cells.
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230
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Ip FCF, Fu WY, Cheng EYL, Tong EPS, Lok KC, Liang Y, Ye WC, Ip NY. Anemoside A3 Enhances Cognition through the Regulation of Synaptic Function and Neuroprotection. Neuropsychopharmacology 2015; 40:1877-87. [PMID: 25649278 PMCID: PMC4839511 DOI: 10.1038/npp.2015.37] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 01/16/2015] [Accepted: 01/21/2015] [Indexed: 01/22/2023]
Abstract
Compounds that have the ability to both strengthen synaptic function and facilitate neuroprotection are valuable cognitive enhancers that may improve health and quality of life, as well as retard age-related cognitive deterioration. Medicinal plants are an abundant source of potential cognitive enhancers. Here we report that anemoside A3 (AA3) isolated from Pulsatilla chinensis modulates synaptic connectivity in circuits central to memory enhancement. AA3 specifically modulates the function of AMPA-type glutamate receptors (AMPARs) by increasing serine phosphorylation within the GluA1 subunit, which is a modification required for the trafficking of GluA1-containing AMPARs to synapses. Furthermore, AA3 administration activates several synaptic signaling molecules and increases protein expressions of the neurotrophin brain-derived neurotrophic factor and monoamine neurotransmitters in the mouse hippocampus. In addition to acting through AMPARs, AA3 also acts as a non-competitive NMDA receptor (NMDAR) modulator with a neuroprotective capacity against ischemic brain injury and overexcitation in rats. These findings collectively suggest that AA3 possesses a unique ability to modulate the functions of both AMPARs and NMDARs. Concordantly, behavioral studies indicate that AA3 not only facilitates hippocampal long-term potentiation but also enhances spatial reference memory formation in mice. These multifaceted roles suggest that AA3 is an attractive candidate for further development as a cognitive enhancer capable of alleviating memory dysfunctions associated with aging and neurodegenerative diseases.
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Affiliation(s)
- Fanny CF Ip
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong, China,Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Hong Kong, China,State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China,HKUST–Jinan Joint Laboratory of Innovative Drug Discovery, Jinan University, Guangzhou, China
| | - Wing-Yu Fu
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong, China,Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Hong Kong, China,State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Elaine YL Cheng
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong, China,Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Hong Kong, China,State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Estella PS Tong
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong, China,Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Hong Kong, China,State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Ka-Chun Lok
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong, China,Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Hong Kong, China,State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Yan Liang
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong, China,Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Hong Kong, China,State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Wen-Cai Ye
- HKUST–Jinan Joint Laboratory of Innovative Drug Discovery, Jinan University, Guangzhou, China,Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, Guangzhou, China,Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine and New Drugs Research, Jinan University, Guangzhou, China,Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, Guangzhou, China, Tel: +8620 8522 0936, Fax: 8620-8522-1559, E-mail:
| | - Nancy Y Ip
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong, China,Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Hong Kong, China,State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China,HKUST–Jinan Joint Laboratory of Innovative Drug Discovery, Jinan University, Guangzhou, China,Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong 000, China, Tel: +852 2358 7269, Fax: +852 2358 1464, E-mail:
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231
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Cheng N, Hu X, Tian T, Lu W. PKMζ knockdown disrupts post-ischemic long-term potentiation via inhibiting postsynaptic expression of aminomethyl phosphonic acid receptors. J Biomed Res 2015; 29:241-9. [PMID: 26060448 PMCID: PMC4449492 DOI: 10.7555/jbr.28.20140033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 03/11/2014] [Accepted: 05/07/2014] [Indexed: 11/12/2022] Open
Abstract
Post-ischemic long-term potentiation (i-LTP) is a pathological form of plasticity that was observed in glutamate receptor-mediated neurotransmission after stroke and may exert a detrimental effect via facilitating excitotoxic damage. The mechanism underlying i-LTP, however, remains less understood. By employing electrophysiological recording and immunofluorescence assay on hippocampal slices and cultured neurons, we found that protein kinase Mζ (PKMζ), an atypical protein kinase C isoform, was involved in enhancing aminomethyl phosphonic acid (AMPA) receptor (AMPAR) expression after i-LTP induction. PKMζ knockdown attenuated postsynaptic expression of AMPA receptors and disrupted i-LTP. Consistently, we observed less neuronal death of cultured hippocampal cells with PKMζ knockdown. Meanwhile, these findings indicate that PKMζ plays an important role in i-LTP by regulating postsynaptic expression of AMPA receptors. This work adds new knowledge to the mechanism of i-LTP, and thus is helpful to find the potential target for clinical therapy of ischemic stroke.
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Affiliation(s)
- Nan Cheng
- Department of Neurobiology, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Xiaoqiao Hu
- Department of Neurobiology, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Tian Tian
- Department of Neurobiology, Nanjing Medical University, Nanjing, Jiangsu 210029, China
| | - Wei Lu
- Department of Neurobiology, Nanjing Medical University, Nanjing, Jiangsu 210029, China
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232
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Intracellular oligomeric amyloid-beta rapidly regulates GluA1 subunit of AMPA receptor in the hippocampus. Sci Rep 2015; 5:10934. [PMID: 26055072 PMCID: PMC4460729 DOI: 10.1038/srep10934] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Accepted: 05/08/2015] [Indexed: 01/08/2023] Open
Abstract
The acute neurotoxicity of oligomeric forms of amyloid-β 1-42 (Aβ) is implicated in the pathogenesis of Alzheimer’s disease (AD). However, how these oligomers might first impair neuronal function at the onset of pathology is poorly understood. Here we have examined the underlying toxic effects caused by an increase in levels of intracellular Aβ, an event that could be important during the early stages of the disease. We show that oligomerised Aβ induces a rapid enhancement of AMPA receptor-mediated synaptic transmission (EPSCA) when applied intracellularly. This effect is dependent on postsynaptic Ca2+ and PKA. Knockdown of GluA1, but not GluA2, prevents the effect, as does expression of a S845-phosphomutant of GluA1. Significantly, an inhibitor of Ca2+-permeable AMPARs (CP-AMPARs), IEM 1460, reverses the increase in the amplitude of EPSCA. These results suggest that a primary neuronal response to intracellular Aβ oligomers is the rapid synaptic insertion of CP-AMPARs.
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233
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Ghafari M, Keihan Falsafi S, Höger H, Bennett KL, Lubec G. Identification of new phosphorylation sites of AMPA receptors in the rat hippocampus--A resource for neuroscience research. Proteomics Clin Appl 2015; 9:808-16. [PMID: 25656447 DOI: 10.1002/prca.201400057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 10/16/2014] [Accepted: 02/03/2015] [Indexed: 12/14/2022]
Abstract
PURPOSE AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) receptors (AMPARs) are glutamate-gated ion channels that mediate the majority of fast excitatory synaptic transmissions in the mammalian brain. A series of phosphorylation sites have been predicted or identified and knowledge on phosphorylations is mandatory for understanding receptor biology and functions. EXPERIMENTAL DESIGN Immunoprecipitation from extracted hippocampal rat proteins was carried out using an antibody against the AMPAR GluA1 subunit, followed by identification of GluA1 and binding partners by MS. Bands from SDS-PAGE were picked, peptides were generated by trypsin and chymotrypsin digestion and identified by MS/MS (LTQ Orbitrap Velos). RESULTS Using Mascot as a search engine, phosphorylation sites S506, S645, S720, S849, S863, S895, T858, Y228, Y419, and T734 were found on GluA1; S357, S513, S656, S727, T243, T420, T741, Y 143, Y301,Y426 on GluA2; S301, S516, S657, S732, T222, and T746 were observed on GluA3; and S514, S653 was phosphorylated on GluA4. CONCLUSIONS AND CLINICAL RELEVANCE A series of additional protein modifications were observed and in particular, tyrosine and tryptophan nitrations on GluA1 were detected that may raise questions on additional regulation mechanisms for AMPARs in addition to phosphorylations. The findings are relevant for interpretation of previous work and design of future studies using AMPAR serving as a resource for neuroscience research and indeed, phosphorylations and PTMs per se would have to be respected when neuropathological and neurological disorders are being studied.
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Affiliation(s)
- Maryam Ghafari
- Department of Pediatrics, Medical University of Vienna, Vienna, Austria
| | | | - Harald Höger
- Core Unit of Biomedical Research, Division of Laboratory Animal Science and Genetics, Medical University of Vienna, Himberg, Austria
| | - Keiryn L Bennett
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Gert Lubec
- Department of Pediatrics, Medical University of Vienna, Vienna, Austria
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234
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Gu W, Fukuda T, Isaji T, Hang Q, Lee HH, Sakai S, Morise J, Mitoma J, Higashi H, Taniguchi N, Yawo H, Oka S, Gu J. Loss of α1,6-Fucosyltransferase Decreases Hippocampal Long Term Potentiation: IMPLICATIONS FOR CORE FUCOSYLATION IN THE REGULATION OF AMPA RECEPTOR HETEROMERIZATION AND CELLULAR SIGNALING. J Biol Chem 2015; 290:17566-75. [PMID: 25979332 DOI: 10.1074/jbc.m114.579938] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Indexed: 01/01/2023] Open
Abstract
Core fucosylation is catalyzed by α1,6-fucosyltransferase (FUT8), which transfers a fucose residue to the innermost GlcNAc residue via α1,6-linkage on N-glycans in mammals. We previously reported that Fut8-knock-out (Fut8(-/-)) mice showed a schizophrenia-like phenotype and a decrease in working memory. To understand the underlying molecular mechanism, we analyzed early form long term potentiation (E-LTP), which is closely related to learning and memory in the hippocampus. The scale of E-LTP induced by high frequency stimulation was significantly decreased in Fut8(-/-) mice. Tetraethylammonium-induced LTP showed no significant differences, suggesting that the decline in E-LTP was caused by postsynaptic events. Unexpectedly, the phosphorylation levels of calcium/calmodulin-dependent protein kinase II (CaMKII), an important mediator of learning and memory in postsynapses, were greatly increased in Fut8(-/-) mice. The expression levels of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionate receptors (AMPARs) in the postsynaptic density were enhanced in Fut8(-/-) mice, although there were no significant differences in the total expression levels, implicating that AMPARs without core fucosylation might exist in an active state. The activation of AMPARs was further confirmed by Fura-2 calcium imaging using primary cultured neurons. Taken together, loss of core fucosylation on AMPARs enhanced their heteromerization, which increase sensitivity for postsynaptic depolarization and persistently activate N-methyl-d-aspartate receptors as well as Ca(2+) influx and CaMKII and then impair LTP.
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Affiliation(s)
- Wei Gu
- From the Division of Regulatory Glycobiology and
| | | | - Tomoya Isaji
- From the Division of Regulatory Glycobiology and
| | - Qinglei Hang
- From the Division of Regulatory Glycobiology and
| | - Ho-hsun Lee
- From the Division of Regulatory Glycobiology and
| | - Seiichiro Sakai
- the Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, 980-8577
| | - Jyoji Morise
- the Department of Biological Chemistry, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, and
| | - Junya Mitoma
- the Division of Glyco-Signal Research, Tohoku Pharmaceutical University, Sendai, Miyagi, 981-8558
| | - Hideyoshi Higashi
- the Division of Glyco-Signal Research, Tohoku Pharmaceutical University, Sendai, Miyagi, 981-8558
| | | | - Hiromu Yawo
- the Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi, 980-8577
| | - Shogo Oka
- the Department of Biological Chemistry, Human Health Sciences, Graduate School of Medicine, Kyoto University, Kyoto, 606-8507, and
| | - Jianguo Gu
- From the Division of Regulatory Glycobiology and
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235
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Ohi Y, Kato D, Mizuno M, Sato T, Ueki Y, Borlongan CV, Ojika K, Haji A, Matsukawa N. Enhancement of long-term potentiation via muscarinic modulation in the hippocampus of HCNP precursor transgenic mice. Neurosci Lett 2015; 597:1-6. [PMID: 25899776 DOI: 10.1016/j.neulet.2015.04.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 03/26/2015] [Accepted: 04/15/2015] [Indexed: 10/23/2022]
Abstract
Hippocampal cholinergic neurostimulating peptide (HCNP) regulates acetylcholine synthesis in the septal hippocampus through the quantitative increase of choline acetyltransferase levels in the septal nucleus both in vitro and in vivo. Additionally, HCNP-precursor protein transgenic (HCNP-pp Tg) mice display depressive behavior. To examine the physiological function of HCNP and/or HCNP-pp on hippocampal neural activity, we investigated whether overexpression of HCNP-pp strengthened the efficiency of neural activity in the hippocampus. Long-term potentiation (LTP) of excitatory synaptic transmission was induced by a tetanic stimulation of the Schaffer collateral-commissural fibers (SCs) in mouse hippocampal slices. LTP in HCNP-pp Tg mice was significantly enhanced when compared with wild-type littermate (WT) mice. This facilitation of LTP in HCNP-pp Tg mice was blocked by atropine or pirenzepine, but not by mecamylamine. In contrast, LTP in WT mice was not affected by atropine, but enhanced by carbachol. However, neither difference in the input-output relationship of field excitatory postsynaptic potentials nor in the facilitation ratio in paired-pulse stimulation of the SCs was observed between HCNP-pp Tg and WT mice, indicating that presynaptic glutamate release in HCNP-pp Tg mice is similar to that of WT mice. These results suggest that muscarinic (M1) modulation of glutamatergic postsynaptic function may be involved in strengthening LTP in HCNP-pp Tg mice.
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Affiliation(s)
- Yoshiaki Ohi
- Laboratory of Neuropharmacology, School of Pharmacy, Aichi Gakuin University, 1-100 Kusumoto, Chikusa-ku, Nagoya 464-8650, Japan
| | - Daisuke Kato
- Department of Neurology, School of Medicine, Nagoya City University, 1 Kawasumi, Mizuho-ku, Nagoya 467-8602, Japan
| | - Masayuki Mizuno
- Department of Neurology, School of Medicine, Nagoya City University, 1 Kawasumi, Mizuho-ku, Nagoya 467-8602, Japan
| | - Toyohiro Sato
- Department of Neurology, School of Medicine, Nagoya City University, 1 Kawasumi, Mizuho-ku, Nagoya 467-8602, Japan
| | - Yoshino Ueki
- Department of Neurology, School of Medicine, Nagoya City University, 1 Kawasumi, Mizuho-ku, Nagoya 467-8602, Japan
| | - Cesario V Borlongan
- Center of Excellence for Aging and Brain Repair, Department of Neurosurgery and Repair, University of South Florida, Tampa, Florida, USA
| | - Kosei Ojika
- Department of Neurology, School of Medicine, Nagoya City University, 1 Kawasumi, Mizuho-ku, Nagoya 467-8602, Japan
| | - Akira Haji
- Laboratory of Neuropharmacology, School of Pharmacy, Aichi Gakuin University, 1-100 Kusumoto, Chikusa-ku, Nagoya 464-8650, Japan
| | - Noriyuki Matsukawa
- Department of Neurology, School of Medicine, Nagoya City University, 1 Kawasumi, Mizuho-ku, Nagoya 467-8602, Japan.
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236
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Episodic sucrose intake during food restriction increases synaptic abundance of AMPA receptors in nucleus accumbens and augments intake of sucrose following restoration of ad libitum feeding. Neuroscience 2015; 295:58-71. [PMID: 25800309 DOI: 10.1016/j.neuroscience.2015.03.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 02/22/2015] [Accepted: 03/12/2015] [Indexed: 01/07/2023]
Abstract
Weight-loss dieting often leads to loss of control, rebound weight gain, and is a risk factor for binge pathology. Based on findings that food restriction (FR) upregulates sucrose-induced trafficking of glutamatergic AMPA receptors to the nucleus accumbens (NAc) postsynaptic density (PSD), this study was an initial test of the hypothesis that episodic "breakthrough" intake of forbidden food during dieting interacts with upregulated mechanisms of synaptic plasticity to increase reward-driven feeding. Ad libitum (AL) fed and FR subjects consumed a limited amount of 10% sucrose, or had access to water, every other day for 10 occasions. Beginning three weeks after return of FR rats to AL feeding, when 24-h chow intake and rate of body weight gain had normalized, subjects with a history of sucrose intake during FR consumed more sucrose during a four week intermittent access protocol than the two AL groups and the group that had access to water during FR. In an experiment that substituted noncontingent administration of d-amphetamine for sucrose, FR subjects displayed an enhanced locomotor response during active FR but a blunted response, relative to AL subjects, during recovery from FR. This result suggests that the enduring increase in sucrose consumption is unlikely to be explained by residual enhancing effects of FR on dopamine signaling. In a biochemical experiment which paralleled the sucrose behavioral experiment, rats with a history of sucrose intake during FR displayed increased abundance of pSer845-GluA1, GluA2, and GluA3 in the NAc PSD relative to rats with a history of FR without sucrose access and rats that had been AL throughout, whether they had a history of episodic sucrose intake or not. A history of FR, with or without a history of sucrose intake, was associated with increased abundance of GluA1. A terminal 15-min bout of sucrose intake produced a further increase in pSer845-GluA1 and GluA2 in subjects with a history of sucrose intake during FR. Generally, neither a history of sucrose intake nor a terminal bout of sucrose intake affected AMPA receptor abundance in the NAc PSD of AL subjects. Together, these results are consistent with the hypothesis, but the functional contribution of increased synaptic incorporation of AMPA receptors remains to be established.
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237
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An iGlu Receptor Antagonist and Its Simultaneous Use with an Anticancer Drug for Cancer Therapy. Chemistry 2015; 21:6123-31. [DOI: 10.1002/chem.201406527] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Indexed: 12/31/2022]
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238
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Yang YJ, Chen HB, Wei B, Wang W, Zhou PL, Zhan JQ, Hu MR, Yan K, Hu B, Yu B. Cognitive decline is associated with reduced surface GluR1 expression in the hippocampus of aged rats. Neurosci Lett 2015; 591:176-181. [DOI: 10.1016/j.neulet.2015.02.030] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 01/27/2015] [Accepted: 02/13/2015] [Indexed: 10/24/2022]
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239
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Network compensation of cyclic GMP-dependent protein kinase II knockout in the hippocampus by Ca2+-permeable AMPA receptors. Proc Natl Acad Sci U S A 2015; 112:3122-7. [PMID: 25713349 DOI: 10.1073/pnas.1417498112] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Gene knockout (KO) does not always result in phenotypic changes, possibly due to mechanisms of functional compensation. We have studied mice lacking cGMP-dependent kinase II (cGKII), which phosphorylates GluA1, a subunit of AMPA receptors (AMPARs), and promotes hippocampal long-term potentiation (LTP) through AMPAR trafficking. Acute cGKII inhibition significantly reduces LTP, whereas cGKII KO mice show no LTP impairment. Significantly, the closely related kinase, cGKI, does not compensate for cGKII KO. Here, we describe a previously unidentified pathway in the KO hippocampus that provides functional compensation for the LTP impairment observed when cGKII is acutely inhibited. We found that in cultured cGKII KO hippocampal neurons, cGKII-dependent phosphorylation of inositol 1,4,5-trisphosphate receptors was decreased, reducing cytoplasmic Ca(2+) signals. This led to a reduction of calcineurin activity, thereby stabilizing GluA1 phosphorylation and promoting synaptic expression of Ca(2+)-permeable AMPARs, which in turn induced a previously unidentified form of LTP as a compensatory response in the KO hippocampus. Calcineurin-dependent Ca(2+)-permeable AMPAR expression observed here is also used during activity-dependent homeostatic synaptic plasticity. Thus, a homeostatic mechanism used during activity reduction provides functional compensation for gene KO in the cGKII KO hippocampus.
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240
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Chen HT, Chen JC. Role of the ventral tegmental area in methamphetamine extinction: AMPA receptor-mediated neuroplasticity. Learn Mem 2015; 22:149-58. [PMID: 25691515 PMCID: PMC4340131 DOI: 10.1101/lm.037721.114] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
The molecular mechanisms underlying drug extinction remain largely unknown, although a role for medial prefrontal cortex (mPFC) glutamate neurons has been suggested. Considering that the mPFC sends glutamate efferents to the ventral tegmental area (VTA), we tested whether the VTA is involved in methamphetamine (METH) extinction via conditioned place preference (CPP). Among various METH-CPP stages, we found that the amount of phospho-GluR1/Ser845 increased in the VTA at behavioral extinction, but not the acquisition or withdrawal stage. Via surface biotinylation, we found that levels of membrane GluR1 were significantly increased during METH-CPP extinction, while no change was observed at the acquisition stage. Specifically, the number of dendritic spines in the VTA was increased at behavioral extinction, but not during acquisition. To validate the role of the mPFC in METH-CPP extinction, we lesioned the mPFC. Ibotenic acid lesioning of the mPFC did not affect METH-CPP acquisition, however, it abolished the extinction stage and reversed the enhanced phospho-GluR1/Ser845 levels as well as increases in VTA dendritic spines during METH-CPP extinction. Overall, this study demonstrates that the mPFC plays a critical role in METH-CPP extinction and identifies the VTA as an alternative target in mediating the extinction of drug conditioning.
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Affiliation(s)
- Han-Ting Chen
- Department of Physiology and Pharmacology, Institute of Biomedical Sciences, School of Medicine, Chang-Gung University, Tao-Yuan 333, Taiwan
| | - Jin-Chung Chen
- Department of Physiology and Pharmacology, Institute of Biomedical Sciences, School of Medicine, Chang-Gung University, Tao-Yuan 333, Taiwan Healthy Ageing Research Center, Chang-Gung University, Tao-Yuan 333, Taiwan Neuroscience Research Center, Chang-Gung Memorial Hospital, Tao-Yuan 333, Taiwan
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241
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KIS: synaptic plasticity's missing molecular link? J Neurosci 2015; 35:2839-41. [PMID: 25698723 DOI: 10.1523/jneurosci.5082-14.2015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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242
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Pelletier SJ, Cicchetti F. Cellular and molecular mechanisms of action of transcranial direct current stimulation: evidence from in vitro and in vivo models. Int J Neuropsychopharmacol 2015; 18:pyu047. [PMID: 25522391 PMCID: PMC4368894 DOI: 10.1093/ijnp/pyu047] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Transcranial direct current stimulation is a noninvasive technique that has been experimentally tested for a number of psychiatric and neurological conditions. Preliminary observations suggest that this approach can indeed influence a number of cellular and molecular pathways that may be disease relevant. However, the mechanisms of action underlying its beneficial effects are largely unknown and need to be better understood to allow this therapy to be used optimally. In this review, we summarize the physiological responses observed in vitro and in vivo, with a particular emphasis on cellular and molecular cascades associated with inflammation, angiogenesis, neurogenesis, and neuroplasticity recruited by direct current stimulation, a topic that has been largely neglected in the literature. A better understanding of the neural responses to transcranial direct current stimulation is critical if this therapy is to be used in large-scale clinical trials with a view of being routinely offered to patients suffering from various conditions affecting the central nervous system.
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Affiliation(s)
| | - Francesca Cicchetti
- Centre Hospitalier Universitaire de Québec, Axe Neuroscience, Québec, QC, Canada (Mr Pelletier and Dr Cicchetti); Département de Psychiatrie et Neurosciences, Université Laval, Québec, QC, Canada (Mr Pelletier and Dr Cicchetti).
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243
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Reimers JM, Loweth JA, Wolf ME. BDNF contributes to both rapid and homeostatic alterations in AMPA receptor surface expression in nucleus accumbens medium spiny neurons. Eur J Neurosci 2014; 39:1159-69. [PMID: 24712995 DOI: 10.1111/ejn.12422] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 09/30/2013] [Accepted: 10/12/2013] [Indexed: 12/15/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) plays a critical role in plasticity at glutamate synapses and in the effects of repeated cocaine exposure. We recently showed that intracranial injection of BDNF into the rat nucleus accumbens (NAc), a key region for cocaine addiction, rapidly increases α-amino-3-hyroxy-5-methyl-4-isoxazole-propionic acid receptor (AMPAR) surface expression. To further characterize BDNF's role in both rapid AMPAR trafficking and slower, homeostatic changes in AMPAR surface expression, we investigated the effects of acute (30 min) and long-term (24 h) treatment with BDNF on AMPAR distribution in NAc medium spiny neurons from postnatal rats co-cultured with mouse prefrontal cortex neurons to restore excitatory inputs. Immunocytochemical studies showed that acute BDNF treatment increased cell surface GluA1 and GluA2 levels, as well as their co-localization, on NAc neurons. This effect of BDNF, confirmed using a protein crosslinking assay, was dependent on ERK but not AKT signaling. In contrast, long-term BDNF treatment decreased AMPAR surface expression on NAc neurons. Based on this latter result, we tested the hypothesis that BDNF plays a role in AMPAR 'scaling down' in response to a prolonged increase in neuronal activity produced by bicuculline (24 h). Supporting this hypothesis, decreasing BDNF signaling with the extracellular BDNF scavenger TrkB-Fc prevented the scaling down of GluA1 and GluA2 surface levels in NAc neurons normally produced by bicuculline. In conclusion, BDNF exerts bidirectional effects on NAc AMPAR surface expression, depending on duration of exposure. Furthermore, BDNF's involvement in synaptic scaling in the NAc differs from its previously described role in the visual cortex.
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Affiliation(s)
- Jeremy M Reimers
- Department of Neuroscience, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL, 60064-3095, USA
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244
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Hosokawa T, Mitsushima D, Kaneko R, Hayashi Y. Stoichiometry and phosphoisotypes of hippocampal AMPA-type glutamate receptor phosphorylation. Neuron 2014; 85:60-67. [PMID: 25533481 DOI: 10.1016/j.neuron.2014.11.026] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/13/2014] [Indexed: 01/18/2023]
Abstract
It has been proposed that the AMPAR phosphorylation regulates trafficking and channel activity, thereby playing an important role in synaptic plasticity. However, the actual stoichiometry of phosphorylation, information critical to understand the role of phosphorylation, is not known because of the lack of appropriate techniques for measurement. Here, using Phos-tag SDS-PAGE, we estimated the proportion of phosphorylated AMPAR subunit GluA1. The level of phosphorylated GluA1 at S831 and S845, two major sites implicated in AMPAR regulation, is almost negligible. Less than 1% of GluA1 is phosphorylated at S831 and less than 0.1% at S845. Considering the number of AMPAR at each synapse, the majority of synapses do not contain any phosphorylated AMPAR. Also, we did not see evidence of GluA1 dually phosphorylated at S831 and S845. Neuronal stimulation and learning increased phosphorylation, but the proportion was still low. Our results impel us to reconsider the mechanisms underlying synaptic plasticity.
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Affiliation(s)
| | - Dai Mitsushima
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa 236-0004, Japan; Department of Systems Neuroscience, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan
| | - Rina Kaneko
- Brain Science Institute, RIKEN, Wako, Saitama 351-0198, Japan
| | - Yasunori Hayashi
- Brain Science Institute, RIKEN, Wako, Saitama 351-0198, Japan; Saitama University Brain Science Institute, Saitama University, Saitama 338-8570, Japan.
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245
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Lian H, Yang L, Cole A, Sun L, Chiang ACA, Fowler SW, Shim DJ, Rodriguez-Rivera J, Taglialatela G, Jankowsky JL, Lu HC, Zheng H. NFκB-activated astroglial release of complement C3 compromises neuronal morphology and function associated with Alzheimer's disease. Neuron 2014; 85:101-115. [PMID: 25533482 DOI: 10.1016/j.neuron.2014.11.018] [Citation(s) in RCA: 423] [Impact Index Per Article: 42.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2014] [Indexed: 11/26/2022]
Abstract
Abnormal NFκB activation has been implicated in Alzheimer's disease (AD). However, the signaling pathways governing NFκB regulation and function in the brain are poorly understood. We identify complement protein C3 as an astroglial target of NFκB and show that C3 release acts through neuronal C3aR to disrupt dendritic morphology and network function. Exposure to Aβ activates astroglial NFκB and C3 release, consistent with the high levels of C3 expression in brain tissue from AD patients and APP transgenic mice, where C3aR antagonist treatment rescues cognitive impairment. Therefore, dysregulation of neuron-glia interaction through NFκB/C3/C3aR signaling may contribute to synaptic dysfunction in AD, and C3aR antagonists may be therapeutically beneficial.
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Affiliation(s)
- Hong Lian
- Huffington Center on Aging, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Houston, TX 77030, USA
| | - Li Yang
- Huffington Center on Aging, Houston, TX 77030, USA
| | - Allysa Cole
- Huffington Center on Aging, Houston, TX 77030, USA
| | - Lu Sun
- Huffington Center on Aging, Houston, TX 77030, USA
| | - Angie C-A Chiang
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Stephanie W Fowler
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - David J Shim
- Huffington Center on Aging, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | | | - Giulio Taglialatela
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Joanna L Jankowsky
- Huffington Center on Aging, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hui-Chen Lu
- Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Department of Pediatrics, Baylor College of Medicine and the Cain Foundation Laboratories, Jan and Dan Duncan Neurological Research Institute at Texas Children's Hospital, Houston, TX 77030, USA
| | - Hui Zheng
- Huffington Center on Aging, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA.
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246
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Rudy JW. Variation in the persistence of memory: An interplay between actin dynamics and AMPA receptors. Brain Res 2014; 1621:29-37. [PMID: 25511990 DOI: 10.1016/j.brainres.2014.12.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 12/02/2014] [Accepted: 12/03/2014] [Indexed: 10/24/2022]
Abstract
William James noted that memories could persist from minutes to weeks. This essay attempts to explain this variation by situating the explanation in the biochemistry of dendritic spines. Two outcomes are critical to generate the synaptic basis of memory: (1) the actin cytoskeleton in the spine must be degraded to permit (2) additional AMPA receptors (GluA1s) to enter new "hot spots" in the postsynaptic density. These initial outcomes can support short-lasting memories. The threshold for these events is low but the underlying synaptic changes cannot resist the endocytic processes that remove the added AMPA receptors. For the memory to persist the degraded actin cytoskeleton must be rebuilt and the vacated "hot spots" refilled with GluA2 receptors. A primary claim is that it is the stabilization of an enlarged actin cytoskeleton that is the target outcome that consolidates the synaptic basis of memory (see Lynch et al., 2007). The stabilized actin cytoskeleton has properties that enable it to garner the synaptic proteins it needs to self sustain the potentiated state and to benefit from activation of memory modulation systems. This article is part of a Special Issue entitled Brain and Memory.
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Affiliation(s)
- Jerry W Rudy
- Department of Psychology and Neuroscience University of Colorado, Boulder, CO 80309, United States.
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247
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Rudy JW. Actin dynamics and the evolution of the memory trace. Brain Res 2014; 1621:17-28. [PMID: 25498985 DOI: 10.1016/j.brainres.2014.12.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 12/02/2014] [Accepted: 12/03/2014] [Indexed: 12/24/2022]
Abstract
The goal of this essay is to link the regulation of actin dynamics to the idea that the synaptic changes that support long-term potentiation and memory evolve in temporally overlapping stages-generation, stabilization, and consolidation. Different cellular/molecular processes operate at each stage to change the spine cytoarchitecture and, in doing so, alter its function. Calcium-dependent processes that degrade the actin cytoskeleton network promote a rapid insertion of AMPA receptors into the post synaptic density, which increases a spine's capacity to express a potentiated response to glutamate. Other post-translation events then begin to stabilize and expand the actin cytoskeleton by increasing the filament actin content of the spine and reorganizing it to be resistant to depolymerizing events. Disrupting actin polymerization during this stabilization period is a terminal event-the actin cytoskeleton shrinks and potentiated synapses de-potentiate and memories are lost. Late-arriving, new proteins may consolidate changes in the actin cytoskeleton. However, to do so requires a stabilized actin cytoskeleton. The now enlarged spine has properties that enable it to capture other newly transcribed mRNAs or their protein products and thus enable the synaptic changes that support LTP and memory to be consolidated and maintained. This article is part of a Special Issue entitled SI: Brain and Memory.
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Affiliation(s)
- Jerry W Rudy
- Department of Psychology and Neuroscience, University of Colorado, 345 UCB, Boulder, CO 80309, USA.
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248
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Bell ME, Bourne JN, Chirillo MA, Mendenhall JM, Kuwajima M, Harris KM. Dynamics of nascent and active zone ultrastructure as synapses enlarge during long-term potentiation in mature hippocampus. J Comp Neurol 2014; 522:3861-84. [PMID: 25043676 PMCID: PMC4167938 DOI: 10.1002/cne.23646] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 06/23/2014] [Accepted: 06/30/2014] [Indexed: 11/08/2022]
Abstract
Nascent zones and active zones are adjacent synaptic regions that share a postsynaptic density, but nascent zones lack the presynaptic vesicles found at active zones. Here dendritic spine synapses were reconstructed through serial section electron microscopy (3DEM) and EM tomography to investigate nascent zone dynamics during long-term potentiation (LTP) in mature rat hippocampus. LTP was induced with theta-burst stimulation, and comparisons were made with control stimulation in the same hippocampal slices at 5 minutes, 30 minutes, and 2 hours post-induction and to perfusion-fixed hippocampus in vivo. Nascent zones were present at the edges of ∼35% of synapses in perfusion-fixed hippocampus and as many as ∼50% of synapses in some hippocampal slice conditions. By 5 minutes, small dense-core vesicles known to transport active zone proteins moved into more presynaptic boutons. By 30 minutes, nascent zone area decreased, without significant change in synapse area, suggesting that presynaptic vesicles were recruited to preexisting nascent zones. By 2 hours, both nascent and active zones were enlarged. Immunogold labeling revealed glutamate receptors in nascent zones; however, average distances from nascent zones to docked presynaptic vesicles ranged from 170 ± 5 nm in perfusion-fixed hippocampus to 251 ± 4 nm at enlarged synapses by 2 hours during LTP. Prior stochastic modeling suggests that decrease in glutamate concentration reduces the probability of glutamate receptor activation from 0.4 at the center of release to 0.1 just 200 nm away. Thus, conversion of nascent zones to functional active zones likely requires the recruitment of presynaptic vesicles during LTP.
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Affiliation(s)
- Maria Elizabeth Bell
- Center for Learning and Memory, Department of Neuroscience, Institute for Neuroscience, University of Texas, Austin, TX 78712
| | - Jennifer N. Bourne
- Center for Learning and Memory, Department of Neuroscience, Institute for Neuroscience, University of Texas, Austin, TX 78712
| | - Michael A. Chirillo
- Center for Learning and Memory, Department of Neuroscience, Institute for Neuroscience, University of Texas, Austin, TX 78712
- The University of Texas Medical School, Houston, TX 77030
| | - John M. Mendenhall
- Center for Learning and Memory, Department of Neuroscience, Institute for Neuroscience, University of Texas, Austin, TX 78712
| | - Masaaki Kuwajima
- Center for Learning and Memory, Department of Neuroscience, Institute for Neuroscience, University of Texas, Austin, TX 78712
| | - Kristen M. Harris
- Center for Learning and Memory, Department of Neuroscience, Institute for Neuroscience, University of Texas, Austin, TX 78712
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249
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Li X, Wolf ME. Multiple faces of BDNF in cocaine addiction. Behav Brain Res 2014; 279:240-54. [PMID: 25449839 DOI: 10.1016/j.bbr.2014.11.018] [Citation(s) in RCA: 134] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 11/04/2014] [Accepted: 11/08/2014] [Indexed: 01/04/2023]
Abstract
Brain-derived neurotrophic factor (BDNF) has been found to play roles in many types of plasticity including drug addiction. Here, we focus on rodent studies over the past two decades that have demonstrated diverse roles of BDNF in models of cocaine addiction. First, we will provide an overview of studies showing that cocaine exposure alters (and generally increases) BDNF levels in reward-related regions including the ventral tegmental area, nucleus accumbens, prefrontal cortex, and amygdala. Then we will review evidence that BDNF contributes to behavioral changes in animal models of cocaine addiction, focusing on conditioned place preference, behavioral sensitization, maintenance and reinstatement of self-administration, and incubation of cocaine craving. Last, we will review the role of BDNF in synaptic plasticity, particularly as it relates to plasticity of AMPA receptor transmission after cocaine exposure. We conclude that BDNF regulates cocaine-induced behaviors in a highly complex manner that varies depending on the brain region (and even among different cell types within the same brain region), the nature of cocaine exposure, and the "addiction phase" examined (e.g., acquisition vs maintenance; early vs late withdrawal). These complexities make BDNF a daunting therapeutic target for treating cocaine addiction. However, recent clinical evidence suggests that the serum BDNF level may serve as a biomarker in cocaine addicts to predict future relapse, providing an alternative direction for exploring BDNF's potential relevance to treating cocaine addiction.
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Affiliation(s)
- Xuan Li
- Behavioral Neuroscience Research Branch, Intramural Research Program, NIDA/NIH/DHHS, Baltimore, MD, USA.
| | - Marina E Wolf
- Department of Neuroscience, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA
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250
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Min MY, Yang HW, Yen CT, Chen CC, Cheng SJ. ERK, synaptic plasticity and acid-induced-muscle pain. Commun Integr Biol 2014. [DOI: 10.4161/cib.15694] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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