151
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Bjørn-Yoshimoto WE, Underhill SM. The importance of the excitatory amino acid transporter 3 (EAAT3). Neurochem Int 2016; 98:4-18. [PMID: 27233497 DOI: 10.1016/j.neuint.2016.05.007] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 05/09/2016] [Accepted: 05/17/2016] [Indexed: 12/21/2022]
Abstract
The neuronal excitatory amino acid transporter 3 (EAAT3) is fairly ubiquitously expressed in the brain, though it does not necessarily maintain the same function everywhere. It is important in maintaining low local concentrations of glutamate, where its predominant post-synaptic localization can buffer nearby glutamate receptors and modulate excitatory neurotransmission and synaptic plasticity. It is also the main neuronal cysteine uptake system acting as the rate-limiting factor for the synthesis of glutathione, a potent antioxidant, in EAAT3 expressing neurons, while on GABAergic neurons, it is important in supplying glutamate as a precursor for GABA synthesis. Several diseases implicate EAAT3, and modulation of this transporter could prove a useful therapeutic approach. Regulation of EAAT3 could be targeted at several points for functional modulation, including the level of transcription, trafficking and direct pharmacological modulation, and indeed, compounds and experimental treatments have been identified that regulate EAAT3 function at different stages, which together with observations of EAAT3 regulation in patients is giving us insight into the endogenous function of this transporter, as well as the consequences of altered function. This review summarizes work done on elucidating the role and regulation of EAAT3.
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Affiliation(s)
- Walden E Bjørn-Yoshimoto
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, 2100 København Ø, Denmark
| | - Suzanne M Underhill
- National Institute of Mental Health, National Institutes of Health, 35 Convent Drive Room 3A: 210 MSC3742, Bethesda, MD 20892-3742, USA.
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152
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The calcium sensor Copine-6 regulates spine structural plasticity and learning and memory. Nat Commun 2016; 7:11613. [PMID: 27194588 PMCID: PMC4874034 DOI: 10.1038/ncomms11613] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 04/13/2016] [Indexed: 02/07/2023] Open
Abstract
Hippocampal long-term potentiation (LTP) represents the cellular response of excitatory synapses to specific patterns of high neuronal activity and is required for learning and memory. Here we identify a mechanism that requires the calcium-binding protein Copine-6 to translate the initial calcium signals into changes in spine structure. We show that Copine-6 is recruited from the cytosol of dendrites to postsynaptic spine membranes by calcium transients that precede LTP. Cpne6 knockout mice are deficient in hippocampal LTP, learning and memory. Hippocampal neurons from Cpne6 knockouts lack spine structural plasticity as do wild-type neurons that express a Copine-6 calcium mutant. The function of Copine-6 is based on its binding, activating and recruiting the Rho GTPase Rac1 to cell membranes. Consistent with this function, the LTP deficit of Cpne6 knockout mice is rescued by the actin stabilizer jasplakinolide. These data show that Copine-6 links activity-triggered calcium signals to spine structural plasticity necessary for learning and memory.
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153
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Lei W, Omotade OF, Myers KR, Zheng JQ. Actin cytoskeleton in dendritic spine development and plasticity. Curr Opin Neurobiol 2016; 39:86-92. [PMID: 27138585 DOI: 10.1016/j.conb.2016.04.010] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 04/15/2016] [Accepted: 04/15/2016] [Indexed: 01/20/2023]
Abstract
Synapses are the basic unit of neuronal communication and their disruption is associated with many neurological disorders. Significant progress has been made towards understanding the molecular and genetic regulation of synapse formation, modulation, and dysfunction, but the underlying cellular mechanisms remain incomplete. The actin cytoskeleton not only provides the structural foundation for synapses, but also regulates a diverse array of cellular activities underlying synaptic function. Here we will discuss the regulation of the actin cytoskeleton in dendritic spines, the postsynaptic compartment of excitatory synapses. We will focus on a select number of actin regulatory processes, highlighting recent advances, the complexity of crosstalk between different pathways, and the challenges of understanding their precise impact on the structure and function of synapses.
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Affiliation(s)
- Wenliang Lei
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, United States
| | - Omotola F Omotade
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, United States
| | - Kenneth R Myers
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, United States
| | - James Q Zheng
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, United States; Center for Neurodegenerative Diseases, Emory University School of Medicine, Atlanta, GA 30322, United States.
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154
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Regulation of the Postsynaptic Compartment of Excitatory Synapses by the Actin Cytoskeleton in Health and Its Disruption in Disease. Neural Plast 2016; 2016:2371970. [PMID: 27127658 PMCID: PMC4835652 DOI: 10.1155/2016/2371970] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 03/09/2016] [Indexed: 02/07/2023] Open
Abstract
Disruption of synaptic function at excitatory synapses is one of the earliest pathological changes seen in wide range of neurological diseases. The proper control of the segregation of neurotransmitter receptors at these synapses is directly correlated with the intact regulation of the postsynaptic cytoskeleton. In this review, we are discussing key factors that regulate the structure and dynamics of the actin cytoskeleton, the major cytoskeletal building block that supports the postsynaptic compartment. Special attention is given to the complex interplay of actin-associated proteins that are found in the synaptic specialization. We then discuss our current understanding of how disruption of these cytoskeletal elements may contribute to the pathological events observed in the nervous system under disease conditions with a particular focus on Alzheimer's disease pathology.
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155
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Matsuura K, Otani M, Takano M, Kadoyama K, Matsuyama S. The influence of chronic nicotine treatment on proteins expressed in the mouse hippocampus and cortex. Eur J Pharmacol 2016; 780:16-25. [PMID: 26988295 DOI: 10.1016/j.ejphar.2016.03.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 03/10/2016] [Accepted: 03/11/2016] [Indexed: 12/21/2022]
Abstract
Chronic treatment with nicotine, the primary psychoactive substance in tobacco smoke, affects central nervous system functions, such as synaptic plasticity. Here, to clarify the effects of chronic nicotine treatment on the higher brain functions, proteomic analysis of the hippocampus and cortex of mice treated for 6 months with nicotine was performed using two-dimensional gel electrophoresis (2-DE) followed by mass spectrometry. There was significant change in the expression of 16 proteins and one phosphoprotein in the hippocampus (increased tubulin β-5, atp5b, MDH1, cytochrome b-c1 complex subunit 1, Hsc70, dynamin, profilin-2, 4-aminobutyrate aminotransferase, mitochondrial isoform 1 precursor, calpain small subunit 1, and vacuolar adenosine triphosphatase subunit B and decreased γ-actin, α-tubulin isotype M-α-2, putative β-actin, tubulin β-2A, NDUFA10, and G6PD) and 24 proteins and two phosphoproteins in the cortex (increased spectrin α chain, non-erythrocytic 1 isoform 1, tubulin β-5, γ-actin, creatine kinase B-type, LDH-B, secernin-1, UCH-L1, 14-3-3 γ, type II peroxiredoxin 1, PEBP-1, and unnamed protein product and decreased tubulin α-1C, α-internexin, γ-enolase, PDHE1-B, DPYL2, vacuolar adenosine triphosphatase subunit A, vacuolar adenosine triphosphatase subunit B, TCTP, NADH dehydrogenase Fe-S protein 1, protein disulfide-isomerase A3, hnRNP H2, γ-actin, atp5b, and unnamed protein product). Additionally, Western blotting validated the changes in dynamin, Hsc70, MDH1, NDUFA10, α-internexin, tubulin β-5 chain, and secernin-1. Thus, these findings indicate that chronic nicotine treatment changes the expression of proteins and phosphoproteins in the hippocampus and cortex. We propose that effect of smoking on higher brain functions could be mediated by alterations in expression levels of these proteins.
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Affiliation(s)
- Kenji Matsuura
- Department of Pharmaceutical Health Care, Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, 7-2-1 Kamiohno, Himeji 670-8524, Japan
| | - Mieko Otani
- Department of Life Sciences Pharmacy, School of Pharmaceutical Sciences, Kobe Gakuin University, Kobe 650-8586, Japan
| | - Masaoki Takano
- Department of Life Sciences Pharmacy, School of Pharmaceutical Sciences, Kobe Gakuin University, Kobe 650-8586, Japan
| | - Keiichi Kadoyama
- Department of Pharmaceutical Health Care, Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, 7-2-1 Kamiohno, Himeji 670-8524, Japan
| | - Shogo Matsuyama
- Department of Pharmaceutical Health Care, Faculty of Pharmaceutical Sciences, Himeji Dokkyo University, 7-2-1 Kamiohno, Himeji 670-8524, Japan.
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156
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van der Kooij MA, Masana M, Rust MB, Müller MB. The stressed cytoskeleton: How actin dynamics can shape stress-related consequences on synaptic plasticity and complex behavior. Neurosci Biobehav Rev 2016; 62:69-75. [DOI: 10.1016/j.neubiorev.2015.12.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 12/01/2015] [Accepted: 12/07/2015] [Indexed: 01/06/2023]
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157
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Bamburg JR, Bernstein BW. Actin dynamics and cofilin-actin rods in alzheimer disease. Cytoskeleton (Hoboken) 2016; 73:477-97. [PMID: 26873625 DOI: 10.1002/cm.21282] [Citation(s) in RCA: 118] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 02/04/2016] [Accepted: 02/05/2016] [Indexed: 12/18/2022]
Abstract
Cytoskeletal abnormalities and synaptic loss, typical of both familial and sporadic Alzheimer disease (AD), are induced by diverse stresses such as neuroinflammation, oxidative stress, and energetic stress, each of which may be initiated or enhanced by proinflammatory cytokines or amyloid-β (Aβ) peptides. Extracellular Aβ-containing plaques and intracellular phospho-tau-containing neurofibrillary tangles are postmortem pathologies required to confirm AD and have been the focus of most studies. However, AD brain, but not normal brain, also have increased levels of cytoplasmic rod-shaped bundles of filaments composed of ADF/cofilin-actin in a 1:1 complex (rods). Cofilin, the major ADF/cofilin isoform in mammalian neurons, severs actin filaments at low cofilin/actin ratios and stabilizes filaments at high cofilin/actin ratios. It binds cooperatively to ADP-actin subunits in F-actin. Cofilin is activated by dephosphorylation and may be oxidized in stressed neurons to form disulfide-linked dimers, required for bundling cofilin-actin filaments into stable rods. Rods form within neurites causing synaptic dysfunction by sequestering cofilin, disrupting normal actin dynamics, blocking transport, and exacerbating mitochondrial membrane potential loss. Aβ and proinflammatory cytokines induce rods through a cellular prion protein-dependent activation of NADPH oxidase and production of reactive oxygen species. Here we review recent advances in our understanding of cofilin biochemistry, rod formation, and the development of cognitive deficits. We will then discuss rod formation as a molecular pathway for synapse loss that may be common between all three prominent current AD hypotheses, thus making rods an attractive therapeutic target. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- James R Bamburg
- Department of Biochemistry and Molecular Biology and the Molecular, Cellular and Integrative Neuroscience Program, Colorado State University, Fort Collins, CO.
| | - Barbara W Bernstein
- Department of Biochemistry and Molecular Biology and the Molecular, Cellular and Integrative Neuroscience Program, Colorado State University, Fort Collins, CO
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158
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Control of Dendritic Spine Morphological and Functional Plasticity by Small GTPases. Neural Plast 2016; 2016:3025948. [PMID: 26989514 PMCID: PMC4775798 DOI: 10.1155/2016/3025948] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 01/06/2016] [Accepted: 01/19/2016] [Indexed: 11/18/2022] Open
Abstract
Structural plasticity of excitatory synapses is a vital component of neuronal development, synaptic plasticity, and behaviour. Abnormal development or regulation of excitatory synapses has also been strongly implicated in many neurodevelopmental, psychiatric, and neurodegenerative disorders. In the mammalian forebrain, the majority of excitatory synapses are located on dendritic spines, specialized dendritic protrusions that are enriched in actin. Research over recent years has begun to unravel the complexities involved in the regulation of dendritic spine structure. The small GTPase family of proteins have emerged as key regulators of structural plasticity, linking extracellular signals with the modulation of dendritic spines, which potentially underlies their ability to influence cognition. Here we review a number of studies that examine how small GTPases are activated and regulated in neurons and furthermore how they can impact actin dynamics, and thus dendritic spine morphology. Elucidating this signalling process is critical for furthering our understanding of the basic mechanisms by which information is encoded in neural circuits but may also provide insight into novel targets for the development of effective therapies to treat cognitive dysfunction seen in a range of neurological disorders.
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159
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Kellner Y, Fricke S, Kramer S, Iobbi C, Wierenga CJ, Schwab ME, Korte M, Zagrebelsky M. Nogo-A controls structural plasticity at dendritic spines by rapidly modulating actin dynamics. Hippocampus 2016; 26:816-31. [DOI: 10.1002/hipo.22565] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/28/2015] [Indexed: 11/08/2022]
Affiliation(s)
- Yves Kellner
- Division of Cellular Neurobiology; Zoological Institute; Braunschweig Germany
| | - Steffen Fricke
- Division of Cellular Neurobiology; Zoological Institute; Braunschweig Germany
| | - Stella Kramer
- Brain Research Institute, University of Zurich; Zurich Switzerland
- Department of Health Sciences and Technology; ETH Zurich; Zurich Switzerland
| | - Cristina Iobbi
- Division of Cellular Neurobiology; Zoological Institute; Braunschweig Germany
| | - Corette J. Wierenga
- Division of Cell Biology, Faculty of Science; Utrecht University Utrecht; Netherlands
| | - Martin E. Schwab
- Brain Research Institute, University of Zurich; Zurich Switzerland
- Department of Health Sciences and Technology; ETH Zurich; Zurich Switzerland
| | - Martin Korte
- Division of Cellular Neurobiology; Zoological Institute; Braunschweig Germany
- Helmholtz Centre for Infection Research, AG NIND; Braunschweig Germany
| | - Marta Zagrebelsky
- Division of Cellular Neurobiology; Zoological Institute; Braunschweig Germany
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160
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Hippocampal Dendritic Spines Are Segregated Depending on Their Actin Polymerization. Neural Plast 2016; 2016:2819107. [PMID: 26881098 PMCID: PMC4736993 DOI: 10.1155/2016/2819107] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 09/21/2015] [Accepted: 10/01/2015] [Indexed: 01/28/2023] Open
Abstract
Dendritic spines are mushroom-shaped protrusions of the postsynaptic membrane. Spines receive the majority of glutamatergic synaptic inputs. Their morphology, dynamics, and density have been related to synaptic plasticity and learning. The main determinant of spine shape is filamentous actin. Using FRAP, we have reexamined the actin dynamics of individual spines from pyramidal hippocampal neurons, both in cultures and in hippocampal organotypic slices. Our results indicate that, in cultures, the actin mobile fraction is independently regulated at the individual spine level, and mobile fraction values do not correlate with either age or distance from the soma. The most significant factor regulating actin mobile fraction was the presence of astrocytes in the culture substrate. Spines from neurons growing in the virtual absence of astrocytes have a more stable actin cytoskeleton, while spines from neurons growing in close contact with astrocytes show a more dynamic cytoskeleton. According to their recovery time, spines were distributed into two populations with slower and faster recovery times, while spines from slice cultures were grouped into one population. Finally, employing fast lineal acquisition protocols, we confirmed the existence of loci with high polymerization rates within the spine.
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161
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Cofilin as a Promising Therapeutic Target for Ischemic and Hemorrhagic Stroke. Transl Stroke Res 2015; 7:33-41. [PMID: 26670926 DOI: 10.1007/s12975-015-0438-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 12/01/2015] [Accepted: 12/03/2015] [Indexed: 01/22/2023]
Abstract
Neurovascular unit (NVU) is considered as a conceptual framework for investigating the mechanisms as well as developing therapeutic targets for ischemic and hemorrhagic stroke. From a molecular perspective, oxidative stress, excitotoxicity, inflammation, and disruption of the blood brain barrier are broad pathophysiological frameworks on the basis on which potential therapeutic candidates for ischemic and hemorrhagic stroke could be discussed. Cofilin is a potent actin-binding protein that severs and depolymerizes actin filaments in order to generate the dynamics of the actin cytoskeleton. Although studies of the molecular mechanisms of cofilin-induced reorganization of the actin cytoskeleton have been ongoing for decades, the multicellular functions of cofilin and its regulation in different molecular pathways are expanding beyond its primary role in actin cytoskeleton. This review focuses on the role of cofilin in oxidative stress, excitotoxicity, inflammation, and disruption of the blood brain barrier in the context of NVU as well as how and why cofilin could be studied further as a potential target for ischemic and hemorrhagic stroke.
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162
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Rust MB. Novel functions for ADF/cofilin in excitatory synapses - lessons from gene-targeted mice. Commun Integr Biol 2015; 8:e1114194. [PMID: 27066177 PMCID: PMC4802768 DOI: 10.1080/19420889.2015.1114194] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 10/23/2015] [Accepted: 10/23/2015] [Indexed: 10/27/2022] Open
Abstract
Actin filaments (F-actin) are the major structural component of excitatory synapses. In excitatory synapses, F-actin is enriched in presynaptic terminals and in postsynaptic dendritic spines, and actin dynamics - the spatiotemporally controlled assembly and disassembly of F-actin - have been implicated in pre- and postsynaptic physiology, additionally to their function in synapse morphology. Hence, actin binding proteins that control actin dynamics have moved into the focus as regulators of synapse morphology and physiology. Actin depolymerizing proteins of the ADF/cofilin family are important regulators of actin dynamics, and several recent studies highlighted the relevance of cofilin 1 for dendritic spine morphology, trafficking of postsynaptic glutamate receptors, and synaptic plasticity. Conversely, almost nothing was known about the synaptic function of ADF, a second ADF/cofilin family member present at excitatory synapses, and it remained unknown whether ADF/cofilin is relevant for presynaptic physiology. To comprehensively characterize the synaptic function of ADF/cofilin we made use of mutant mice lacking either ADF or cofilin 1 or both proteins. Our analysis revealed presynaptic defects (altered distribution and enhanced exocytosis of synaptic vesicles) and behavioral abnormalities reminiscent of attention deficit-hyperactivity disorder in double mutants that were not present in single mutants. Hence, by exploiting gene-targeted mice, we demonstrated the relevance of ADF for excitatory synapses, and we unraveled novel functions for ADF/cofilin in presynaptic physiology and behavior.
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Affiliation(s)
- Marco B Rust
- Molecular Neurobiology Group; Institute of Physiological Chemistry; University of Marburg ; Marburg, Germany
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163
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Chevy Q, Heubl M, Goutierre M, Backer S, Moutkine I, Eugène E, Bloch-Gallego E, Lévi S, Poncer JC. KCC2 Gates Activity-Driven AMPA Receptor Traffic through Cofilin Phosphorylation. J Neurosci 2015; 35:15772-86. [PMID: 26631461 PMCID: PMC6605455 DOI: 10.1523/jneurosci.1735-15.2015] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Revised: 09/01/2015] [Accepted: 09/26/2015] [Indexed: 12/31/2022] Open
Abstract
Expression of the neuronal K/Cl transporter KCC2 is tightly regulated throughout development and by both normal and pathological neuronal activity. Changes in KCC2 expression have often been associated with altered chloride homeostasis and GABA signaling. However, recent evidence supports a role of KCC2 in the development and function of glutamatergic synapses through mechanisms that remain poorly understood. Here we show that suppressing KCC2 expression in rat hippocampal neurons precludes long-term potentiation of glutamatergic synapses specifically by preventing activity-driven membrane delivery of AMPA receptors. This effect is independent of KCC2 transporter function and can be accounted for by increased Rac1/PAK- and LIMK-dependent cofilin phosphorylation and actin polymerization in dendritic spines. Our results demonstrate that KCC2 plays a critical role in the regulation of spine actin cytoskeleton and gates long-term plasticity at excitatory synapses in cortical neurons.
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Affiliation(s)
- Quentin Chevy
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche-S 839, F-75005, Paris, France, Sorbonne Universités, Université Pierre et Marie Curie Université Paris 06, Unité Mixte de Recherche-S 839, F-75005, Paris, France, Institut du Fer a Moulin, F-75005, Paris, France, and
| | - Martin Heubl
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche-S 839, F-75005, Paris, France, Sorbonne Universités, Université Pierre et Marie Curie Université Paris 06, Unité Mixte de Recherche-S 839, F-75005, Paris, France, Institut du Fer a Moulin, F-75005, Paris, France, and
| | - Marie Goutierre
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche-S 839, F-75005, Paris, France, Sorbonne Universités, Université Pierre et Marie Curie Université Paris 06, Unité Mixte de Recherche-S 839, F-75005, Paris, France, Institut du Fer a Moulin, F-75005, Paris, France, and
| | - Stéphanie Backer
- Institut Cochin, Institut National de la Santé et de la Recherche Médicale, U 1016, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8104, Université Paris Descartes, F-75014, Paris, France
| | - Imane Moutkine
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche-S 839, F-75005, Paris, France, Sorbonne Universités, Université Pierre et Marie Curie Université Paris 06, Unité Mixte de Recherche-S 839, F-75005, Paris, France, Institut du Fer a Moulin, F-75005, Paris, France, and
| | - Emmanuel Eugène
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche-S 839, F-75005, Paris, France, Sorbonne Universités, Université Pierre et Marie Curie Université Paris 06, Unité Mixte de Recherche-S 839, F-75005, Paris, France, Institut du Fer a Moulin, F-75005, Paris, France, and
| | - Evelyne Bloch-Gallego
- Institut Cochin, Institut National de la Santé et de la Recherche Médicale, U 1016, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 8104, Université Paris Descartes, F-75014, Paris, France
| | - Sabine Lévi
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche-S 839, F-75005, Paris, France, Sorbonne Universités, Université Pierre et Marie Curie Université Paris 06, Unité Mixte de Recherche-S 839, F-75005, Paris, France, Institut du Fer a Moulin, F-75005, Paris, France, and
| | - Jean Christophe Poncer
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche-S 839, F-75005, Paris, France, Sorbonne Universités, Université Pierre et Marie Curie Université Paris 06, Unité Mixte de Recherche-S 839, F-75005, Paris, France, Institut du Fer a Moulin, F-75005, Paris, France, and
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164
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Sturgeon M, Davis D, Albers A, Beatty D, Austin R, Ferguson M, Tounsel B, Liebl FLW. The Notch ligand E3 ligase, Mind Bomb1, regulates glutamate receptor localization in Drosophila. Mol Cell Neurosci 2015; 70:11-21. [PMID: 26596173 DOI: 10.1016/j.mcn.2015.11.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Revised: 11/09/2015] [Accepted: 11/16/2015] [Indexed: 12/29/2022] Open
Abstract
The postsynaptic density (PSD) is a protein-rich network important for the localization of postsynaptic glutamate receptors (GluRs) and for signaling downstream of these receptors. Although hundreds of PSD proteins have been identified, many are functionally uncharacterized. We conducted a reverse genetic screen for mutations that affected GluR localization using Drosophila genes that encode homologs of mammalian PSD proteins. 42.8% of the mutants analyzed exhibited a significant change in GluR localization at the third instar larval neuromuscular junction (NMJ), a model synapse that expresses homologs of AMPA receptors. We identified the E3 ubiquitin ligase, Mib1, which promotes Notch signaling, as a regulator of synaptic GluR localization. Mib1 positively regulates the localization of the GluR subunits GluRIIA, GluRIIB, and GluRIIC. Mutations in mib1 and ubiquitous expression of Mib1 that lacks its ubiquitin ligase activity result in the loss of synaptic GluRIIA-containing receptors. In contrast, overexpression of Mib1 in all tissues increases postsynaptic levels of GluRIIA. Cellular levels of Mib1 are also important for the structure of the presynaptic motor neuron. While deficient Mib1 signaling leads to overgrowth of the NMJ, ubiquitous overexpression of Mib1 results in a reduction in the number of presynaptic motor neuron boutons and branches. These synaptic changes may be secondary to attenuated glutamate release from the presynaptic motor neuron in mib1 mutants as mib1 mutants exhibit significant reductions in the vesicle-associated protein cysteine string protein and in the frequency of spontaneous neurotransmission.
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Affiliation(s)
- Morgan Sturgeon
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, United States
| | - Dustin Davis
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, United States
| | - Amanda Albers
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, United States
| | - Derek Beatty
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, United States
| | - Rik Austin
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, United States
| | - Matt Ferguson
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, United States
| | - Brittany Tounsel
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, United States
| | - Faith L W Liebl
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, IL 62026, United States.
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165
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Cuberos H, Vallée B, Vourc'h P, Tastet J, Andres CR, Bénédetti H. Roles of LIM kinases in central nervous system function and dysfunction. FEBS Lett 2015; 589:3795-806. [PMID: 26545494 DOI: 10.1016/j.febslet.2015.10.032] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 10/21/2015] [Accepted: 10/28/2015] [Indexed: 12/30/2022]
Abstract
LIM kinase 1 (LIMK1) and LIM kinase 2 (LIMK2) regulate actin dynamics by phosphorylating cofilin. In this review, we outline studies that have shown an involvement of LIMKs in neuronal function and we detail some of the pathways and molecular mechanisms involving LIMKs in neurodevelopment and synaptic plasticity. We also review the involvement of LIMKs in neuronal diseases and emphasize the differences in the regulation of LIMKs expression and mode of action. We finally present the existence of a cofilin-independent pathway also involved in neuronal function. A better understanding of the differences between both LIMKs and of the precise molecular mechanisms involved in their mode of action and regulation is now required to improve our understanding of the physiopathology of the neuronal diseases associated with LIMKs.
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Affiliation(s)
- H Cuberos
- CNRS UPR 4301, CBM, Orléans, France; UMR INSERM U930, Université François-Rabelais, Tours, France
| | - B Vallée
- CNRS UPR 4301, CBM, Orléans, France
| | - P Vourc'h
- UMR INSERM U930, Université François-Rabelais, Tours, France; CHRU de Tours, Service de Biochimie et de Biologie Moléculaire, Tours, France
| | - J Tastet
- University Medical Center Utrecht, Brain Center Rudolf Magnus, Utrecht, Netherlands
| | - C R Andres
- UMR INSERM U930, Université François-Rabelais, Tours, France; CHRU de Tours, Service de Biochimie et de Biologie Moléculaire, Tours, France
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166
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Jitsuki S, Nakajima W, Takemoto K, Sano A, Tada H, Takahashi-Jitsuki A, Takahashi T. Nogo Receptor Signaling Restricts Adult Neural Plasticity by Limiting Synaptic AMPA Receptor Delivery. Cereb Cortex 2015; 26:427-439. [PMID: 26472557 PMCID: PMC4677985 DOI: 10.1093/cercor/bhv232] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Experience-dependent plasticity is limited in the adult brain, and its molecular and cellular mechanisms are poorly understood. Removal of the myelin-inhibiting signaling protein, Nogo receptor (NgR1), restores adult neural plasticity. Here we found that, in NgR1-deficient mice, whisker experience-driven synaptic α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR) insertion in the barrel cortex, which is normally complete by 2 weeks after birth, lasts into adulthood. In vivo live imaging by two-photon microscopy revealed more AMPAR on the surface of spines in the adult barrel cortex of NgR1-deficient than on those of wild-type (WT) mice. Furthermore, we observed that whisker stimulation produced new spines in the adult barrel cortex of mutant but not WT mice, and that the newly synthesized spines contained surface AMPAR. These results suggest that Nogo signaling limits plasticity by restricting synaptic AMPAR delivery in coordination with anatomical plasticity.
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Affiliation(s)
- Susumu Jitsuki
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Waki Nakajima
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Kiwamu Takemoto
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan.,JST, PRESTO, Saitama 332-0012, Japan
| | - Akane Sano
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Hirobumi Tada
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Aoi Takahashi-Jitsuki
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Takuya Takahashi
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
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167
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Abstract
The small size of dendritic spines belies the elaborate role they play in excitatory synaptic transmission and ultimately complex behaviors. The cytoskeletal architecture of the spine is predominately composed of actin filaments. These filaments, which at first glance might appear simple, are also surprisingly complex. They dynamically assemble into different structures and serve as a platform for orchestrating the elaborate responses of the spine during spinogenesis and experience-dependent plasticity. Multiple mutations associated with human neurodevelopmental and psychiatric disorders involve genes that encode regulators of the synaptic cytoskeleton. A major, unresolved question is how the disruption of specific actin filament structures leads to the onset and progression of complex synaptic and behavioral phenotypes. This review will cover established and emerging mechanisms of actin cytoskeletal remodeling and how this influences specific aspects of spine biology that are implicated in disease.
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Affiliation(s)
| | - Scott H Soderling
- From the Departments of Cell Biology and Neurobiology, Duke University, School of Medicine, Durham, North Carolina 27710
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168
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Abstract
The structural plasticity of dendritic spines is considered to be essential for various forms of synaptic plasticity, learning, and memory. The process is mediated by a complex signaling network consisting of numerous species of molecules. Furthermore, the spatiotemporal dynamics of the biochemical signaling are regulated in a complicated manner because of geometrical restrictions from the unique morphology of the dendritic branches and spines. Recent advances in optical techniques have enabled the exploration of the spatiotemporal aspects of the signal regulations in spines and dendrites and have provided many insights into the principle of the biochemical computation that underlies spine structural plasticity.
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Affiliation(s)
- Jun Nishiyama
- Max Planck Florida Institute for Neuroscience, One Max Planck Way, Jupiter, FL 33458, USA
| | - Ryohei Yasuda
- Max Planck Florida Institute for Neuroscience, One Max Planck Way, Jupiter, FL 33458, USA.
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169
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Bu Y, Wang N, Wang S, Sheng T, Tian T, Chen L, Pan W, Zhu M, Luo J, Lu W. Myosin IIb-dependent Regulation of Actin Dynamics Is Required for N-Methyl-D-aspartate Receptor Trafficking during Synaptic Plasticity. J Biol Chem 2015; 290:25395-410. [PMID: 26330558 DOI: 10.1074/jbc.m115.644229] [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: 02/10/2015] [Indexed: 12/21/2022] Open
Abstract
N-Methyl-d-aspartate receptor (NMDAR) synaptic incorporation changes the number of NMDARs at synapses and is thus critical to various NMDAR-dependent brain functions. To date, the molecules involved in NMDAR trafficking and the underlying mechanisms are poorly understood. Here, we report that myosin IIb is an essential molecule in NMDAR synaptic incorporation during PKC- or θ burst stimulation-induced synaptic plasticity. Moreover, we demonstrate that myosin light chain kinase (MLCK)-dependent actin reorganization contributes to NMDAR trafficking. The findings from additional mutual occlusion experiments demonstrate that PKC and MLCK share a common signaling pathway in NMDAR-mediated synaptic regulation. Because myosin IIb is the primary substrate of MLCK and can regulate actin dynamics during synaptic plasticity, we propose that the MLCK- and myosin IIb-dependent regulation of actin dynamics is required for NMDAR trafficking during synaptic plasticity. This study provides important insights into a mechanical framework for understanding NMDAR trafficking associated with synaptic plasticity.
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Affiliation(s)
- Yunfei Bu
- From the Department of Neurobiology, Nanjing Medical University, Nanjing, Jiangsu Province 210029, China
| | - Ning Wang
- From the Department of Neurobiology, Nanjing Medical University, Nanjing, Jiangsu Province 210029, China, the Key Laboratory of Developmental Genes and Human Disease of the Ministry of Education of China, Institute of Life Sciences, Southeast University, Nanjing, Jiangsu Province 210096, China
| | - Shaoli Wang
- From the Department of Neurobiology, Nanjing Medical University, Nanjing, Jiangsu Province 210029, China, the Key Laboratory of Developmental Genes and Human Disease of the Ministry of Education of China, Institute of Life Sciences, Southeast University, Nanjing, Jiangsu Province 210096, China
| | - Tao Sheng
- From the Department of Neurobiology, Nanjing Medical University, Nanjing, Jiangsu Province 210029, China, the Key Laboratory of Developmental Genes and Human Disease of the Ministry of Education of China, Institute of Life Sciences, Southeast University, Nanjing, Jiangsu Province 210096, China
| | - Tian Tian
- From the Department of Neurobiology, Nanjing Medical University, Nanjing, Jiangsu Province 210029, China
| | - Linlin Chen
- From the Department of Neurobiology, Nanjing Medical University, Nanjing, Jiangsu Province 210029, China
| | - Weiwei Pan
- From the Department of Neurobiology, Nanjing Medical University, Nanjing, Jiangsu Province 210029, China
| | - Minsheng Zhu
- the Key Laboratory of Model Animal for Disease Study of the Ministry of Education of China, Model Animal Research Center, Nanjing University, Nanjing, Jiangsu Province 210063, China, and
| | - Jianhong Luo
- the Department of Neurobiology, Key Laboratory of Medical Neurobiology of the Ministry of Health of China, Zhejiang Province Key Laboratory of Neurobiology, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province 310058, China
| | - Wei Lu
- From the Department of Neurobiology, Nanjing Medical University, Nanjing, Jiangsu Province 210029, China, the Key Laboratory of Developmental Genes and Human Disease of the Ministry of Education of China, Institute of Life Sciences, Southeast University, Nanjing, Jiangsu Province 210096, China, the Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province 226001, China,
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170
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Rust MB. ADF/cofilin: a crucial regulator of synapse physiology and behavior. Cell Mol Life Sci 2015; 72:3521-9. [PMID: 26037722 PMCID: PMC11113150 DOI: 10.1007/s00018-015-1941-z] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Revised: 05/21/2015] [Accepted: 05/26/2015] [Indexed: 12/19/2022]
Abstract
Actin filaments (F-actin) are the major structural component of excitatory synapses, being present in presynaptic terminals and in postsynaptic dendritic spines. In the last decade, it has been appreciated that actin dynamics, the assembly and disassembly of F-actin, is crucial not only for the structure of excitatory synapses, but also for pre- and postsynaptic physiology. Hence, regulators of actin dynamics take a central role in mediating neurotransmitter release, synaptic plasticity, and ultimately behavior. Actin depolymerizing proteins of the ADF/cofilin family are essential regulators of actin dynamics, and a number of recent studies highlighted their crucial functions in excitatory synapses. In dendritic spines, ADF/cofilin activity is required for spine enlargement during initial long-term potentiation (LTP), but needs to be switched off during spine stabilization and LTP consolidation. Conversely, active ADF/cofilin is needed for spine pruning during long-term depression (LTD). Moreover, ADF/cofilin controls activity-induced synaptic availability of glutamate receptors, and exocytosis of synaptic vesicles. These data show that the activity of ADF/cofilin in synapses needs to be spatially and temporally tightly controlled through several upstream regulatory pathways, which have been identified recently. Hence, ADF/cofilin-controlled actin dynamics emerged as a critical and central regulator of synapse physiology. In this review, I will summarize and discuss our current knowledge on the roles of ADF/cofilin in synapse physiology and behavior, by focusing on excitatory synapses of the mammalian central nervous system.
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Affiliation(s)
- Marco B Rust
- Molecular Neurobiology Group, Institute of Physiological Chemistry, University of Marburg, 35032, Marburg, Germany,
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171
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Kaminskaya AN, Nikitina EA, Medvedeva AV, Gerasimenko MS, Chernikova DA, Savvateeva-Popova EV. The influence of the limk1 gene polymorphism on learning acquisition and memory formation, pCREB distribution and aggregate formation in neuromuscular junctions in Drosophila melanogaster. RUSS J GENET+ 2015. [DOI: 10.1134/s1022795415060071] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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172
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Estrous Cycle-Dependent Phasic Changes in the Stoichiometry of Hippocampal Synaptic AMPA Receptors in Rats. PLoS One 2015; 10:e0131359. [PMID: 26121335 PMCID: PMC4486186 DOI: 10.1371/journal.pone.0131359] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 06/01/2015] [Indexed: 11/26/2022] Open
Abstract
Cognitive function can be affected by the estrous cycle. However, the effect of the estrous cycle on synaptic functions is poorly understood. Here we show that in female rats, inhibitory-avoidance (IA) task (hippocampus-dependent contextual fear-learning task) drives GluA2-lacking Ca2+-permeable AMPA receptors (CP-AMPARs) into the hippocampal CA3-CA1 synapses during all periods of the estrous cycle except the proestrous period, when estrogen levels are high. In addition, IA task failed to drive CP-AMPARs into the CA3-CA1 synapses of ovariectomized rats only when estrogen was present. Thus, changes in the stoichiometry of AMPA receptors during learning depend on estrogen levels. Furthermore, the induction of long-term potentiation (LTP) after IA task was prevented during the proestrous period, while intact LTP is still expressed after IA task during other period of the estrous cycle. Consistent with this finding, rats conditioned by IA training failed to acquire hippocampus-dependent Y-maze task during the proestrous period. On the other hand, during other estrous period, rats were able to learn Y-maze task after IA conditioning. These results suggest that high estrogen levels prevent the IA learning-induced delivery of CP-AMPARs into hippocampal CA3-CA1 synapses and limit synaptic plasticity after IA task, thus preventing the acquisition of additional learning.
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173
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Abstract
Membrane trafficking of AMPA receptors (AMPARs) is critical for neuronal function and plasticity. Although rapid forms of AMPAR internalization during long-term depression (LTD) require clathrin and dynamin, the mechanisms governing constitutive AMPAR turnover and internalization of AMPARs during slow homeostatic forms of synaptic plasticity remain unexplored. Here, we show that, in contrast to LTD, constitutive AMPAR internalization and homeostatic AMPAR downscaling in rat neurons do not require dynamin or clathrin function. Instead, constitutive AMPAR trafficking is blocked by a Rac1 inhibitor and is regulated by a dynamic nonstructural pool of F-actin. Our findings reveal a novel role for neuronal clathrin-independent endocytosis controlled by actin dynamics and suggest that the interplay between different modes of receptor endocytosis provides for segregation between distinct modes of neuronal plasticity.
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174
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Two-Photon Correlation Spectroscopy in Single Dendritic Spines Reveals Fast Actin Filament Reorganization during Activity-Dependent Growth. PLoS One 2015; 10:e0128241. [PMID: 26020927 PMCID: PMC4447372 DOI: 10.1371/journal.pone.0128241] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 04/24/2015] [Indexed: 11/19/2022] Open
Abstract
Two-photon fluorescence correlation spectroscopy (2P-FCS) within single dendritic spines of living hippocampal pyramidal neurons was used to resolve various subpopulations of mobile F-actin during activity-dependent structural changes such as potentiation induced spine head growth. Two major classes of mobile F-actin were discovered: very dynamic and about a hundred times less dynamic F-actin. Spine head enlargement upon application of Tetraethylammonium (TEA), a protocol previously used for the chemical induction of long-term potentiation (cLTP) strictly correlated to changes in the dynamics and filament numbers in the different actin filament fractions. Our observations suggest that spine enlargement is governed by a mechanism in which longer filaments are first cut into smaller filaments that cooperate with the second, increasingly dynamic shorter actin filament population to quickly reorganize and expand the actin cytoskeleton within the spine head. This process would allow a fast and efficient spine head enlargement using a major fraction of the actin filament population that was already present before spine head growth.
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175
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Podgorniak T, Milan M, Pujolar JM, Maes GE, Bargelloni L, De Oliveira E, Pierron F, Daverat F. Differences in brain gene transcription profiles advocate for an important role of cognitive function in upstream migration and water obstacles crossing in European eel. BMC Genomics 2015; 16:378. [PMID: 25962588 PMCID: PMC4427925 DOI: 10.1186/s12864-015-1589-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 04/27/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND European eel is a panmictic species, whose decline has been recorded since the last 20 years. Among human-induced environmental factors of decline, the impact of water dams during species migration is questioned. The main issue of this study was to pinpoint phenotypic traits that predisposed glass eels to successful passage by water barriers. The approach of the study was individual-centred and without any a priori hypothesis on traits involved in the putative obstacles selective pressure. We analyzed the transcription level of 14,913 genes. RESULTS Transcriptome analysis of three tissues (brain, liver and muscle) from individuals sampled on three successive forebays separated by water obstacles indicated different gene transcription profiles in brain between the two upstream forebays. No differences in gene transcription levels were observed in liver and muscle samples among segments. A total of 26 genes were differentially transcribed in brain. These genes encode for, among others, keratins, cytokeratins, calcium binding proteins (S100 family), cofilin, calmodulin, claudin and thy-1 membrane glycoprotein. The functional analysis of these genes highlighted a putative role of cytoskeletal dynamics and synaptic plasticity in fish upstream migration. CONCLUSION Synaptic connections in brain are solicited while eels are climbing the obstacles with poorly designed fishways. Successful passage by such barriers can be related to spatial learning and spatial orientation abilities when fish is out of the water.
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Affiliation(s)
- Tomasz Podgorniak
- Irstea Bordeaux, UR EABX, HYNES (Irstea - EDF R&D), 50 avenue de Verdun, Cestas, 33612, Cedex, France.
| | - Massimo Milan
- University of Padova, Viale dell'Università 16, Legnaro, 35020, PD, Italy.
| | - Jose Marti Pujolar
- University of Padova, Viale dell'Università 16, Legnaro, 35020, PD, Italy. .,Department of Bioscience, Aarhus University, Ny Munkegade 114, Aarhus C, DK-8000, Denmark.
| | - Gregory E Maes
- Centre for Sustainable Tropical Fisheries and Aquaculture, Comparative Genomics Centre, College of Marine and Environmental Sciences, James Cook University, Townsville, Qld 4811, Australia. .,Laboratory of Biodiversity and Evolutionary Genomics, University of Leuven (KU Leuven), Leuven, B-3000, Belgium.
| | - Luca Bargelloni
- University of Padova, Viale dell'Università 16, Legnaro, 35020, PD, Italy.
| | - Eric De Oliveira
- EDF R&D LNHE, HYNES (Irstea-EDF R&D), 6, quai Watier, Bat Q, Chatou, 78400, France.
| | - Fabien Pierron
- Univ. Bordeaux, EPOC, UMR 5805, Talence, F-33400, France. .,CNRS, EPOC, UMR 5805, Talence, F-33400, France.
| | - Francoise Daverat
- Irstea Bordeaux, UR EABX, HYNES (Irstea - EDF R&D), 50 avenue de Verdun, Cestas, 33612, Cedex, France.
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176
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Barone E, Mosser S, Fraering PC. Inactivation of brain Cofilin-1 by age, Alzheimer's disease and γ-secretase. Biochim Biophys Acta Mol Basis Dis 2015; 1842:2500-9. [PMID: 25315299 DOI: 10.1016/j.bbadis.2014.10.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 09/21/2014] [Accepted: 10/06/2014] [Indexed: 11/19/2022]
Abstract
Rapid remodeling of the actin cytoskeleton in the pre- and/or post-synaptic compartments is responsible for the regulation of neuronal plasticity,which is an important process for learning and memory. Cofilin1 plays an essential role in these processes and a dysregulation of its activity was associated with the cognitive decline observed during normal aging and Alzheimer's disease (AD). To understand the mechanism(s) regulating Cofilin1 activity we evaluated changes occurring with regard to Cofilin1 and its up-stream regulators Lim kinase-1 (LIMK1) and Slingshot phosphatase-1 (SSH1) in (i) human AD brain, (ii) 1-, 4-, and 10-months old APP/PS1 mice, (iii) wildtype 3-, 8-, 12-, 18- and 26-months old mice, as well as in cellular models including (iv) mouse primary cortical neurons (PCNs, cultured for 5, 10, 15 and 20 days in vitro) and (v) mouse embryonic fibroblasts (MEF). Interestingly,we found an increased Cofilin1 phosphorylation/inactivation with age and AD pathology, both in vivo and in vitro. These changes were associated with a major inactivation of SSH1. Interestingly, inhibition of ã-secretase activity with Compound-E (10 ìM) prevented Cofilin1 phosphorylation/inactivation through an increase of SSH1 activity in PCNs. Similarly, MEF cells double knock-out for ã-secretase catalytic subunits presenilin-1 and -2(MEFDKO) showed a strong decrease of both Cofilin1 and SSH1 phosphorylation,which were rescued by the over expression of human ã-secretase. Together, these results shed new light in understanding the molecular mechanisms promoting Cofilin1 dysregulation, both during aging and AD. They further have the potential to impact the development of therapies to safely treat AD.
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177
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George J, Soares C, Montersino A, Beique JC, Thomas GM. Palmitoylation of LIM Kinase-1 ensures spine-specific actin polymerization and morphological plasticity. eLife 2015; 4:e06327. [PMID: 25884247 PMCID: PMC4429338 DOI: 10.7554/elife.06327] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2015] [Accepted: 04/16/2015] [Indexed: 12/04/2022] Open
Abstract
Precise regulation of the dendritic spine actin cytoskeleton is critical for neurodevelopment and neuronal plasticity, but how neurons spatially control actin dynamics is not well defined. Here, we identify direct palmitoylation of the actin regulator LIM kinase-1 (LIMK1) as a novel mechanism to control spine-specific actin dynamics. A conserved palmitoyl-motif is necessary and sufficient to target LIMK1 to spines and to anchor LIMK1 in spines. ShRNA knockdown/rescue experiments reveal that LIMK1 palmitoylation is essential for normal spine actin polymerization, for spine-specific structural plasticity and for long-term spine stability. Palmitoylation is critical for LIMK1 function because this modification not only controls LIMK1 targeting, but is also essential for LIMK1 activation by its membrane-localized upstream activator PAK. These novel roles for palmitoylation in the spatial control of actin dynamics and kinase signaling provide new insights into structural plasticity mechanisms and strengthen links between dendritic spine impairments and neuropathological conditions. DOI:http://dx.doi.org/10.7554/eLife.06327.001 Neurons transmit information from one cell to the next by passing signals across junctions called synapses. For the neurons that receive these signals, these junctions are found on fine branch-like structures called dendrites that stick out of the cell. Dendrites themselves are decorated with smaller structures called dendritic spines, which typically receive information from one other neuron via a single synapse. Dendritic spines form in response to the signaling activity of the neuron, and problems with forming these spines have been linked to conditions such as autism and schizophrenia. Dendritic spines are created by the cell's cytoskeleton—a network of proteins that creates a constantly changing internal scaffold that shapes cells. One cytoskeleton protein called actin exists as thin filaments that can be extended or broken up by other proteins. It is not fully understood how actin is regulated in the dendritic spines. However, some researchers thought that the proteins that control the formation of the actin filaments would need to be localized to the dendritic spines to ensure that the spines form correctly. Some proteins can be made to localize to cell membranes by attaching a molecule called palmitic acid to them. Previous research has suggested that this ‘palmitoylation’ process is particularly important in neurons. Through a combination of experimental techniques, George et al. now show that palmitoylation is required to localize a protein called LIMK1, which regulates the construction of actin filaments, to the tips of dendritic spines. Further experiments showed that blocking the palmitoylation of LIMK1 alters how actin filaments form, makes spines unstable and causes synapses to be lost. George et al. also discovered that palmitoylation is necessary for LIMK1 to be activated by another protein that is found at dendritic spine membranes. This ‘dual-control’ mechanism makes it possible to precisely control where actin filaments form within dendritic spines. In addition to LIMK1, several other enzymes are also modified by palmitoylation. It will therefore be interesting to determine whether this dual control mechanism is broadly used by neurons to precisely regulate the structure and function of individual spines and synapses. DOI:http://dx.doi.org/10.7554/eLife.06327.002
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Affiliation(s)
- Joju George
- Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, United States
| | - Cary Soares
- Heart and Stroke Partnership for Stroke Recovery, University of Ottawa, Ottawa, Canada
| | - Audrey Montersino
- Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, United States
| | - Jean-Claude Beique
- Heart and Stroke Partnership for Stroke Recovery, University of Ottawa, Ottawa, Canada
| | - Gareth M Thomas
- Shriners Hospitals Pediatric Research Center, Temple University School of Medicine, Philadelphia, United States
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178
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PKC enhances the capacity for secretion by rapidly recruiting covert voltage-gated Ca2+ channels to the membrane. J Neurosci 2015; 35:2747-65. [PMID: 25673863 DOI: 10.1523/jneurosci.3581-14.2015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
It is unknown whether neurons can dynamically control the capacity for secretion by promptly changing the number of plasma membrane voltage-gated Ca(2+) channels. To address this, we studied peptide release from the bag cell neurons of Aplysia californica, which initiate reproduction by secreting hormone during an afterdischarge. This burst engages protein kinase C (PKC) to trigger the insertion of a covert Ca(2+) channel, Apl Cav2, alongside a basal channel, Apl Cav1. The significance of Apl Cav2 recruitment to secretion remains undetermined; therefore, we used capacitance tracking to assay secretion, along with Ca(2+) imaging and Ca(2+) current measurements, from cultured bag cell neurons under whole-cell voltage-clamp. Activating PKC with the phorbol ester, PMA, enhanced Ca(2+) entry, and potentiated stimulus-evoked secretion. This relied on channel insertion, as it was occluded by preventing Apl Cav2 engagement with prior whole-cell dialysis or the cytoskeletal toxin, latrunculin B. Channel insertion reduced the stimulus duration and/or frequency required to initiate secretion and strengthened excitation-secretion coupling, indicating that Apl Cav2 accesses peptide release more readily than Apl Cav1. The coupling of Apl Cav2 to secretion also changed with behavioral state, as Apl Cav2 failed to evoke secretion in silent neurons from reproductively inactive animals. Finally, PKC also acted secondarily to enhance prolonged exocytosis triggered by mitochondrial Ca(2+) release. Collectively, our results suggest that bag cell neurons dynamically elevate Ca(2+) channel abundance in the membrane to ensure adequate secretion during the afterdischarge.
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179
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Woo JA, Boggess T, Uhlar C, Wang X, Khan H, Cappos G, Joly-Amado A, De Narvaez E, Majid S, Minamide LS, Bamburg JR, Morgan D, Weeber E, Kang DE. RanBP9 at the intersection between cofilin and Aβ pathologies: rescue of neurodegenerative changes by RanBP9 reduction. Cell Death Dis 2015; 6:1676. [PMID: 25741591 PMCID: PMC4385917 DOI: 10.1038/cddis.2015.37] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2014] [Revised: 01/05/2015] [Accepted: 01/19/2015] [Indexed: 12/21/2022]
Abstract
Molecular pathways underlying the neurotoxicity and production of amyloid β protein (Aβ) represent potentially promising therapeutic targets for Alzheimer's disease (AD). We recently found that overexpression of the scaffolding protein RanBP9 increases Aβ production in cell lines and in transgenic mice while promoting cofilin activation and mitochondrial dysfunction. Translocation of cofilin to mitochondria and induction of cofilin–actin pathology require the activation/dephosphorylation of cofilin by Slingshot homolog 1 (SSH1) and cysteine oxidation of cofilin. In this study, we found that endogenous RanBP9 positively regulates SSH1 levels and mediates Aβ-induced translocation of cofilin to mitochondria and induction of cofilin–actin pathology in cultured cells, primary neurons, and in vivo. Endogenous level of RanBP9 was also required for Aβ-induced collapse of growth cones in immature neurons (days in vitro 9 (DIV9)) and depletion of synaptic proteins in mature neurons (DIV21). In vivo, amyloid precursor protein (APP)/presenilin-1 (PS1) mice exhibited 3.5-fold increased RanBP9 levels, and RanBP9 reduction protected against cofilin–actin pathology, synaptic damage, gliosis, and Aβ accumulation associated with APP/PS1 mice. Brains slices derived from APP/PS1 mice showed significantly impaired long-term potentiation (LTP), and RanBP9 reduction significantly enhanced paired pulse facilitation and LTP, as well as partially rescued contextual memory deficits associated with APP/PS1 mice. Therefore, these results underscore the critical importance of endogenous RanBP9 not only in Aβ accumulation but also in mediating the neurotoxic actions of Aβ at the level of synaptic plasticity, mitochondria, and cofilin–actin pathology via control of the SSH1-cofilin pathway in vivo.
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Affiliation(s)
- J A Woo
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Institute, Tampa, FL, USA
| | - T Boggess
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Institute, Tampa, FL, USA
| | - C Uhlar
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Institute, Tampa, FL, USA
| | - X Wang
- Department of Molecular Pharmacology and Physiology, USF Health Byrd Alzheimer's Institute, Tampa, FL, USA
| | - H Khan
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Institute, Tampa, FL, USA
| | - G Cappos
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Institute, Tampa, FL, USA
| | - A Joly-Amado
- Department of Molecular Pharmacology and Physiology, USF Health Byrd Alzheimer's Institute, Tampa, FL, USA
| | - E De Narvaez
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Institute, Tampa, FL, USA
| | - S Majid
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Institute, Tampa, FL, USA
| | - L S Minamide
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA
| | - J R Bamburg
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO, USA
| | - D Morgan
- Department of Molecular Pharmacology and Physiology, USF Health Byrd Alzheimer's Institute, Tampa, FL, USA
| | - E Weeber
- Department of Molecular Pharmacology and Physiology, USF Health Byrd Alzheimer's Institute, Tampa, FL, USA
| | - D E Kang
- Department of Molecular Medicine, USF Health Byrd Alzheimer's Institute, Tampa, FL, USA
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180
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Tsubota T, Okubo-Suzuki R, Ohashi Y, Tamura K, Ogata K, Yaguchi M, Matsuyama M, Inokuchi K, Miyashita Y. Cofilin1 controls transcolumnar plasticity in dendritic spines in adult barrel cortex. PLoS Biol 2015; 13:e1002070. [PMID: 25723479 PMCID: PMC4344332 DOI: 10.1371/journal.pbio.1002070] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 01/08/2015] [Indexed: 12/20/2022] Open
Abstract
During sensory deprivation, the barrel cortex undergoes expansion of a functional column representing spared inputs (spared column), into the neighboring deprived columns (representing deprived inputs) which are in turn shrunk. As a result, the neurons in a deprived column simultaneously increase and decrease their responses to spared and deprived inputs, respectively. Previous studies revealed that dendritic spines are remodeled during this barrel map plasticity. Because cofilin1, a predominant regulator of actin filament turnover, governs both the expansion and shrinkage of the dendritic spine structure in vitro, it hypothetically regulates both responses in barrel map plasticity. However, this hypothesis remains untested. Using lentiviral vectors, we knocked down cofilin1 locally within layer 2/3 neurons in a deprived column. Cofilin1-knocked-down neurons were optogenetically labeled using channelrhodopsin-2, and electrophysiological recordings were targeted to these knocked-down neurons. We showed that cofilin1 knockdown impaired response increases to spared inputs but preserved response decreases to deprived inputs, indicating that cofilin1 dependency is dissociated in these two types of barrel map plasticity. To explore the structural basis of this dissociation, we then analyzed spine densities on deprived column dendritic branches, which were supposed to receive dense horizontal transcolumnar projections from the spared column. We found that spine number increased in a cofilin1-dependent manner selectively in the distal part of the supragranular layer, where most of the transcolumnar projections existed. Our findings suggest that cofilin1-mediated actin dynamics regulate functional map plasticity in an input-specific manner through the dendritic spine remodeling that occurs in the horizontal transcolumnar circuits. These new mechanistic insights into transcolumnar plasticity in adult rats may have a general significance for understanding reorganization of neocortical circuits that have more sophisticated columnar organization than the rodent neocortex, such as the primate neocortex. In vivo measurement of the electrophysiology and shape of neurons reveals that cofilin1 is needed for remodeling dendritic spines in circuits that connect mouse whisker barrels, so aiding experience-dependent plasticity in the neocortex. Plasticity in the adult neocortex is the basis of our learning and memory. However, its molecular mechanisms are still unclear. In the sensory barrel cortex of rodents, a well-characterized model for neocortical plasticity, neurons directly code for whisker displacement—neurons within a given barrel will fire when the whisker that that barrel represents is moved. Strikingly, the deprivation of all but a single whisker alters the original representations—cortical columns representing the deprived inputs shrink and that representing the spared inputs expands, intruding into the surrounding deprived columns. Because single-neuron-level structural changes are suggested to be involved in this plasticity, here we focused on cofilin1, a protein that is known to modulate the cytoskeleton and to regulate the structure of dendritic spines. We induced experience-dependent plasticity in the D1 column by sparing only the D1 whisker, and knocked down the expression of cofilin1 in the D2 column. Cofilin1 knockdown differentially affected plasticity, such that experience-dependent increases in spared input representation were impaired, whereas decreases in deprived input representation were intact. We then found that during these plastic changes, the density of dendritic spines increased in a cofilin1-dependent manner around the connections between the D1 and D2 columns. Cofilin1-dependent density increase was observed only in the most superficial part of the cortex but not in deeper parts, consistent with the distribution patterns of axons that transmit spared and deprived information, respectively. These results suggest that cofilin1 regulates neocortical functional plasticity through the remodeling of dendritic spines within circuits that connect columns.
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Affiliation(s)
- Tadashi Tsubota
- Department of Physiology, The University of Tokyo School of Medicine, Tokyo, Japan
| | - Reiko Okubo-Suzuki
- Department of Biochemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Saitama, Japan
| | - Yohei Ohashi
- Department of Physiology, The University of Tokyo School of Medicine, Tokyo, Japan
| | - Keita Tamura
- Department of Physiology, The University of Tokyo School of Medicine, Tokyo, Japan
| | - Koshin Ogata
- Department of Physiology, The University of Tokyo School of Medicine, Tokyo, Japan
| | - Masae Yaguchi
- Department of Physiology, The University of Tokyo School of Medicine, Tokyo, Japan
| | - Makoto Matsuyama
- Department of Physiology, The University of Tokyo School of Medicine, Tokyo, Japan
| | - Kaoru Inokuchi
- Department of Biochemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Saitama, Japan
| | - Yasushi Miyashita
- Department of Physiology, The University of Tokyo School of Medicine, Tokyo, Japan
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Saitama, Japan
- * E-mail:
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181
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Slingshot-Cofilin activation mediates mitochondrial and synaptic dysfunction via Aβ ligation to β1-integrin conformers. Cell Death Differ 2015; 22:921-34. [PMID: 25698445 PMCID: PMC4423195 DOI: 10.1038/cdd.2015.5] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 11/19/2014] [Accepted: 12/16/2014] [Indexed: 02/08/2023] Open
Abstract
The accumulation of amyloid-β protein (Aβ) is an early event associated with synaptic and mitochondrial damage in Alzheimer's disease (AD). Recent studies have implicated the filamentous actin (F-actin) severing protein, Cofilin, in synaptic remodeling, mitochondrial dysfunction, and AD pathogenesis. However, whether Cofilin is an essential component of the AD pathogenic process and how Aβ impinges its signals to Cofilin from the neuronal surface are unknown. In this study, we found that Aβ42 oligomers (Aβ42O, amyloid-β protein 1–42 oligomers) bind with high affinity to low or intermediate activation conformers of β1-integrin, resulting in the loss of surface β1-integrin and activation of Cofilin via Slingshot homology-1 (SSH1) activation. Specifically, conditional loss of β1-integrin prevented Aβ42O-induced Cofilin activation, and allosteric modulation or activation of β1-integrin significantly reduced Aβ42O binding to neurons while blocking Aβ42O-induced reactive oxygen species (ROS) production, mitochondrial dysfunction, depletion of F-actin/focal Vinculin, and apoptosis. Cofilin, in turn, was required for Aβ42O-induced loss of cell surface β1-integrin, disruption of F-actin/focal Talin–Vinculin, and depletion of F-actin-associated postsynaptic proteins. SSH1 reduction, which mitigated Cofilin activation, prevented Aβ42O-induced mitochondrial Cofilin translocation and apoptosis, while AD brain mitochondria contained significantly increased activated/oxidized Cofilin. In mechanistic support in vivo, AD mouse model (APP (amyloid precursor protein)/PS1) brains contained increased SSH1/Cofilin and decreased SSH1/14-3-3 complexes, indicative of SSH1–Cofilin activation via release of SSH1 from 14-3-3. Finally, genetic reduction in Cofilin rescued APP/Aβ-induced synaptic protein loss and gliosis in vivo as well as deficits in long-term potentiation (LTP) and contextual memory in APP/PS1 mice. These novel findings therefore implicate the essential involvement of the β1-integrin–SSH1–Cofilin pathway in mitochondrial and synaptic dysfunction in AD.
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182
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Li G, Zhou J, Budhraja A, Hu X, Chen Y, Cheng Q, Liu L, Zhou T, Li P, Liu E, Gao N. Mitochondrial translocation and interaction of cofilin and Drp1 are required for erucin-induced mitochondrial fission and apoptosis. Oncotarget 2015; 6:1834-49. [PMID: 25595902 PMCID: PMC4359335 DOI: 10.18632/oncotarget.2795] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 11/20/2014] [Indexed: 01/12/2023] Open
Abstract
Cofilin is a member of the actin-depolymerizing factor (ADF) family protein, which plays an essential role in regulation of the mitochondrial apoptosis. It remains unclear how cofilin regulates the mitochondrial apoptosis. Here, we report for the first time that natural compound 4-methylthiobutyl isothiocyanate (erucin) found in consumable cruciferous vegetables induces mitochondrial fission and apoptosis in human breast cancer cells through the mitochondrial translocation of cofilin. Importantly, cofilin regulates erucin-induced mitochondrial fission by interacting with dynamin-related protein (Drp1). Knockdown of cofilin or Drp1 markedly reduced erucin-mediated mitochondrial translocation and interaction of cofilin and Drp1, mitochondrial fission, and apoptosis. Only dephosphorylated cofilin (Ser 3) and Drp1 (Ser 637) are translocated to the mitochondria. Cofilin S3E and Drp1 S637D mutants, which mimick the phosphorylated forms, suppressed mitochondrial translocation, fission, and apoptosis. Moreover, both dephosphorylation and mitochondrial translocation of cofilin and Drp1 are dependent on ROCK1 activation. In vivo findings confirmed that erucin-mediated inhibition of tumor growth in a breast cancer cell xenograft mouse model is associated with the mitochondrial translocation of cofilin and Drp1, fission and apoptosis. Our study reveals a novel role of cofilin in regulation of mitochondrial fission and suggests erucin as a potential drug for treatment of breast cancer.
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Affiliation(s)
- Guobing Li
- 1 College of Pharmacy, 3rd Military Medical University, Chongqing 400038, China
| | - Jing Zhou
- 1 College of Pharmacy, 3rd Military Medical University, Chongqing 400038, China
| | - Amit Budhraja
- 3 Cell & Molecular Biology, St. Jude Children's Research Hospital, Memphis TN 38105, USA
| | - Xiaoye Hu
- 1 College of Pharmacy, 3rd Military Medical University, Chongqing 400038, China
| | - Yibiao Chen
- 1 College of Pharmacy, 3rd Military Medical University, Chongqing 400038, China
| | - Qi Cheng
- 1 College of Pharmacy, 3rd Military Medical University, Chongqing 400038, China
| | - Lei Liu
- 1 College of Pharmacy, 3rd Military Medical University, Chongqing 400038, China
| | - Ting Zhou
- 1 College of Pharmacy, 3rd Military Medical University, Chongqing 400038, China
| | - Ping Li
- 2 State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, China
| | - Ehu Liu
- 2 State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing 210009, China
| | - Ning Gao
- 1 College of Pharmacy, 3rd Military Medical University, Chongqing 400038, China
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183
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Hall BS, Moda RN, Liston C. Glucocorticoid Mechanisms of Functional Connectivity Changes in Stress-Related Neuropsychiatric Disorders. Neurobiol Stress 2015; 1:174-183. [PMID: 25729760 PMCID: PMC4340078 DOI: 10.1016/j.ynstr.2014.10.008] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Stress—especially chronic, uncontrollable stress—is an important risk factor for many neuropsychiatric disorders. The underlying mechanisms are complex and multifactorial, but they involve correlated changes in structural and functional measures of neuronal connectivity within cortical microcircuits and across neuroanatomically distributed brain networks. Here, we review evidence from animal models and human neuroimaging studies implicating stress-associated changes in functional connectivity in the pathogenesis of PTSD, depression, and other neuropsychiatric conditions. Changes in fMRI measures of corticocortical connectivity across distributed networks may be caused by specific structural alterations that have been observed in the prefrontal cortex, hippocampus, and other vulnerable brain regions. These effects are mediated in part by glucocorticoids, which are released from the adrenal gland in response to a stressor and also oscillate in synchrony with diurnal rhythms. Recent work indicates that circadian glucocorticoid oscillations act to balance synapse formation and pruning after learning and during development, and chronic stress disrupts this balance. We conclude by considering how disrupted glucocorticoid oscillations may contribute to the pathophysiology of depression and PTSD in vulnerable individuals, and how circadian rhythm disturbances may affect non-psychiatric populations, including frequent travelers, shift workers, and patients undergoing treatment for autoimmune disorders.
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Affiliation(s)
- Baila S Hall
- Brain and Mind Research Institute and Program in Neuroscience, Weill Cornell Medical College, 413 East 69 Street, Box 240, New York, NY 10021
| | - Rachel N Moda
- Brain and Mind Research Institute and Program in Neuroscience, Weill Cornell Medical College, 413 East 69 Street, Box 240, New York, NY 10021
| | - Conor Liston
- Brain and Mind Research Institute and Program in Neuroscience, Weill Cornell Medical College, 413 East 69 Street, Box 240, New York, NY 10021 ; Sackler Institute for Developmental Psychobiology, Weill Cornell Medical College, 413 East 69 Street, Box 240, New York, NY 10021 ; Department of Psychiatry, Weill Cornell Medical College, 413 East 69 Street, Box 240, New York, NY 10021
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184
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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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185
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Molecular regulation of synaptogenesis during associative learning and memory. Brain Res 2014; 1621:239-51. [PMID: 25485772 DOI: 10.1016/j.brainres.2014.11.054] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 11/24/2014] [Accepted: 11/25/2014] [Indexed: 01/06/2023]
Abstract
Synaptogenesis plays a central role in associative learning and memory. The biochemical pathways that underlie synaptogenesis are complex and incompletely understood. Nevertheless, research has so far identified three conceptually distinct routes to synaptogenesis: cell-cell contact mediated by adhesion proteins, cell-cell biochemical signaling from astrocytes and other cells, and neuronal signaling through classical ion channels and cell surface receptors. The cell adhesion pathways provide the physical substrate to the new synaptic connection, while cell-cell signaling may provide a global or regional signal, and the activity-dependent pathways provide the neuronal specificity that is required for the new synapses to produce functional neuronal networks capable of storing associative memories. These three aspects of synaptogenesis require activation of a variety of interacting biochemical pathways that converge on the actin cytoskeleton and strengthen the synapse in an information-dependent manner. This article is part of a Special Issue titled SI: Brain and Memory.
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186
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Hanley JG. Actin-dependent mechanisms in AMPA receptor trafficking. Front Cell Neurosci 2014; 8:381. [PMID: 25429259 PMCID: PMC4228833 DOI: 10.3389/fncel.2014.00381] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 10/24/2014] [Indexed: 11/22/2022] Open
Abstract
The precise regulation of AMPA receptor (AMPAR) number and subtype at the synapse is crucial for the regulation of excitatory neurotransmission, synaptic plasticity and the consequent formation of appropriate neural circuits for learning and memory. AMPAR trafficking involves the dynamic processes of exocytosis, endocytosis and endosomal recycling, all of which involve the actin cytoskeleton. The actin cytoskeleton is highly dynamic and highly regulated by an abundance of actin-binding proteins and upstream signaling pathways that modulate actin polymerization and depolymerization. Actin dynamics generate forces that manipulate membranes in the process of vesicle biogenesis, and also for propelling vesicles through the cytoplasm to reach their destination. In addition, trafficking mechanisms exploit more stable aspects of the actin cytoskeleton by using actin-based motor proteins to traffic vesicular cargo along actin filaments. Numerous studies have shown that actin dynamics are critical for AMPAR localization and function. The identification of actin-binding proteins that physically interact with AMPAR subunits, and research into their mode of action is starting to shed light on the mechanisms involved. Such proteins either regulate actin dynamics to modulate mechanical forces exerted on AMPAR-containing membranes, or associate with actin filaments to target or transport AMPAR-containing vesicles to specific subcellular regions. In addition, actin-regulatory proteins that do not physically interact with AMPARs may influence AMPAR trafficking by regulating the local actin environment in the dendritic spine.
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187
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Li M, Zhang X, Wu A, Wang Z, Li J, Yue Y. Propofol-induced age-different hypocampal long-term potentiation is associated with F-actin polymerization in rats. Cell Biochem Biophys 2014; 71:1059-66. [PMID: 25344646 DOI: 10.1007/s12013-014-0309-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Elderly patients may experience a decline in cognition after a surgery performed under anesthesia. Propofol (2,6-diisopropylphenol), a common intravenous anesthetic agent, has been reported to mediate the long-term potentiation (LTP), a major form of synaptic plasticity. The present study was conducted to investigate the underlying mechanisms in young (3-month-old) and elderly (20-month-old) male rats. A decline of theta-burst stimulation (TBS)-induced LTP in the hippocampal CA1 area was found in the young rats at 72 h post-anesthesia, and this alteration almost disappeared after 2-week-recovery as compared with their age-matched control rats. On the other hand, the propofol-induced CA1 LTP reduction was persistent in the aged rats during the whole experimental process. Moreover, TBS-induced increases in CA 1 filamentous-actin (F-actin) polymerization and phospho-cofilin expression were enhanced at 72 h post-anesthesia in young rats, and this change was significantly attenuated after 2 weeks. However, in anesthetic elderly rats, the alterations in F-actin and phospho-cofilin of the CA1 region were still presented at the end of the experiments. Taken together, our results indicate that the discrepant responses between young and aged rats to propofol anesthesia may be associated with the differential polymerization of F-actin.
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Affiliation(s)
- Mingying Li
- Department of Anaesthesiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, 100020, China
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188
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Guven K, Gunning P, Fath T. TPM3 and TPM4 gene products segregate to the postsynaptic region of central nervous system synapses. BIOARCHITECTURE 2014; 1:284-289. [PMID: 22545181 PMCID: PMC3337131 DOI: 10.4161/bioa.1.6.19336] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Synaptic function in the central nervous system (CNS) is highly dependent on a dynamic actin cytoskeleton in both the pre- and the postsynaptic compartment. Remodelling of the actin cytoskeleton is controlled by tropomyosins, a family of actin-associated proteins which define distinct actin filament populations. Here we show that TPM3 and TPM4 gene products localize to the postsynaptic region in mouse hippocampal neurons. Furthermore our data confirm previous findings of isoform segregation to the pre- and postsynaptic compartments at CNS synapses. These data provide fundamental insights in the formation of functionally distinct actin filament populations at the pre- and post-synapse.
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189
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Chazeau A, Mehidi A, Nair D, Gautier JJ, Leduc C, Chamma I, Kage F, Kechkar A, Thoumine O, Rottner K, Choquet D, Gautreau A, Sibarita JB, Giannone G. Nanoscale segregation of actin nucleation and elongation factors determines dendritic spine protrusion. EMBO J 2014; 33:2745-64. [PMID: 25293574 DOI: 10.15252/embj.201488837] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Actin dynamics drive morphological remodeling of neuronal dendritic spines and changes in synaptic transmission. Yet, the spatiotemporal coordination of actin regulators in spines is unknown. Using single protein tracking and super-resolution imaging, we revealed the nanoscale organization and dynamics of branched F-actin regulators in spines. Branched F-actin nucleation occurs at the PSD vicinity, while elongation occurs at the tip of finger-like protrusions. This spatial segregation differs from lamellipodia where both branched F-actin nucleation and elongation occur at protrusion tips. The PSD is a persistent confinement zone for IRSp53 and the WAVE complex, an activator of the Arp2/3 complex. In contrast, filament elongators like VASP and formin-like protein-2 move outwards from the PSD with protrusion tips. Accordingly, Arp2/3 complexes associated with F-actin are immobile and surround the PSD. Arp2/3 and Rac1 GTPase converge to the PSD, respectively, by cytosolic and free-diffusion on the membrane. Enhanced Rac1 activation and Shank3 over-expression, both associated with spine enlargement, induce delocalization of the WAVE complex from the PSD. Thus, the specific localization of branched F-actin regulators in spines might be reorganized during spine morphological remodeling often associated with synaptic plasticity.
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Affiliation(s)
- Anaël Chazeau
- Interdisciplinary Institute for Neuroscience, University Bordeaux UMR 5297, Bordeaux, France CNRS, Interdisciplinary Institute for Neuroscience UMR 5297, Bordeaux, France
| | - Amine Mehidi
- Interdisciplinary Institute for Neuroscience, University Bordeaux UMR 5297, Bordeaux, France CNRS, Interdisciplinary Institute for Neuroscience UMR 5297, Bordeaux, France
| | - Deepak Nair
- Interdisciplinary Institute for Neuroscience, University Bordeaux UMR 5297, Bordeaux, France CNRS, Interdisciplinary Institute for Neuroscience UMR 5297, Bordeaux, France
| | - Jérémie J Gautier
- CNRS UPR3082, Laboratoire d'Enzymologie et Biochimie Structurales, Gif-sur-Yvette Cedex, France
| | - Cécile Leduc
- University Bordeaux, LP2N, Talence, France CNRS & Institut d'Optique, LP2N, Talence, France
| | - Ingrid Chamma
- Interdisciplinary Institute for Neuroscience, University Bordeaux UMR 5297, Bordeaux, France CNRS, Interdisciplinary Institute for Neuroscience UMR 5297, Bordeaux, France
| | - Frieda Kage
- Division of Molecular Cell Biology, Zoological Institute, Technical University Braunschweig, Braunschweig, Germany
| | - Adel Kechkar
- Interdisciplinary Institute for Neuroscience, University Bordeaux UMR 5297, Bordeaux, France CNRS, Interdisciplinary Institute for Neuroscience UMR 5297, Bordeaux, France
| | - Olivier Thoumine
- Interdisciplinary Institute for Neuroscience, University Bordeaux UMR 5297, Bordeaux, France CNRS, Interdisciplinary Institute for Neuroscience UMR 5297, Bordeaux, France
| | - Klemens Rottner
- Division of Molecular Cell Biology, Zoological Institute, Technical University Braunschweig, Braunschweig, Germany Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Daniel Choquet
- Interdisciplinary Institute for Neuroscience, University Bordeaux UMR 5297, Bordeaux, France CNRS, Interdisciplinary Institute for Neuroscience UMR 5297, Bordeaux, France
| | - Alexis Gautreau
- CNRS UPR3082, Laboratoire d'Enzymologie et Biochimie Structurales, Gif-sur-Yvette Cedex, France
| | - Jean-Baptiste Sibarita
- Interdisciplinary Institute for Neuroscience, University Bordeaux UMR 5297, Bordeaux, France CNRS, Interdisciplinary Institute for Neuroscience UMR 5297, Bordeaux, France
| | - Grégory Giannone
- Interdisciplinary Institute for Neuroscience, University Bordeaux UMR 5297, Bordeaux, France CNRS, Interdisciplinary Institute for Neuroscience UMR 5297, Bordeaux, France
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190
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Ohsawa M, Otake S, Murakami T, Yamamoto S, Makino T, Ono H. Gabapentin prevents oxaliplatin-induced mechanical hyperalgesia in mice. J Pharmacol Sci 2014; 125:292-9. [PMID: 24990115 DOI: 10.1254/jphs.14058fp] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Oxaliplatin, a platinum-based chemotherapy drug, frequently causes acute and chronic peripheral neuropathies including mechanical hyperalgesia. These adverse effects hinder anticancer therapy with the drug. In this study, we examined several drugs that might prevent oxaliplatin-induced peripheral neuropathy. Single intraperitoneal (i.p.) injection of oxaliplatin (10 mg/kg) induced cold allodynia (acetone test) and mechanical hyperalgesia (von Frey test). Gabapentin, but not simvastatin and atorvastatin, prevented oxaliplatin-induced mechanical hyperalgesia without affecting cold allodynia. Moreover, oxaliplatin caused phosphorylation of cofilin protein in the spinal cord, which has been shown to be involved in the neuropathic hyperalgesia. This increased phosphorylation of cofilin was also attenuated by gabapentin treatment. These results suggest that gabapentin is useful for relieving oxaliplatin-induced mechanical hyperalgesia and that the pathogenic mechanisms of cold allodynia and mechanical hyperalgesia differ.
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Affiliation(s)
- Masahiro Ohsawa
- Laboratory of CNS Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Japan
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191
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Ueda Y. The Role of Phosphoinositides in Synapse Function. Mol Neurobiol 2014; 50:821-38. [DOI: 10.1007/s12035-014-8768-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Accepted: 06/01/2014] [Indexed: 11/30/2022]
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192
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Nikitina EA, Kaminskaya AN, Molotkov DA, Popov AV, Savvateeva-Popova EV. Effect of heat shock on courtship behavior, sound production, and learning in comparison with the brain content of LIMK1 in Drosophila melanogaster males with altered structure of the limk1 gene. J EVOL BIOCHEM PHYS+ 2014. [DOI: 10.1134/s0022093014020082] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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193
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Bosch M, Castro J, Saneyoshi T, Matsuno H, Sur M, Hayashi Y. Structural and molecular remodeling of dendritic spine substructures during long-term potentiation. Neuron 2014; 82:444-59. [PMID: 24742465 DOI: 10.1016/j.neuron.2014.03.021] [Citation(s) in RCA: 408] [Impact Index Per Article: 40.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/06/2014] [Indexed: 11/13/2022]
Abstract
Synapses store information by long-lasting modifications of their structure and molecular composition, but the precise chronology of these changes has not been studied at single-synapse resolution in real time. Here we describe the spatiotemporal reorganization of postsynaptic substructures during long-term potentiation (LTP) at individual dendritic spines. Proteins translocated to the spine in four distinct patterns through three sequential phases. In the initial phase, the actin cytoskeleton was rapidly remodeled while active cofilin was massively transported to the spine. In the stabilization phase, cofilin formed a stable complex with F-actin, was persistently retained at the spine, and consolidated spine expansion. In contrast, the postsynaptic density (PSD) was independently remodeled, as PSD scaffolding proteins did not change their amount and localization until a late protein synthesis-dependent third phase. Our findings show how and when spine substructures are remodeled during LTP and explain why synaptic plasticity rules change over time.
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Affiliation(s)
- Miquel Bosch
- RIKEN-MIT Neuroscience Research Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
| | - Jorge Castro
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Takeo Saneyoshi
- Brain Science Institute, RIKEN, Wako, Saitama 351-0198, Japan
| | - Hitomi Matsuno
- Brain Science Institute, RIKEN, Wako, Saitama 351-0198, Japan
| | - Mriganka Sur
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Yasunori Hayashi
- RIKEN-MIT Neuroscience Research Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Brain Science Institute, RIKEN, Wako, Saitama 351-0198, Japan; Saitama University Brain Science Institute, Saitama University, Saitama 338-8570, Japan.
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194
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Lamprecht R. The actin cytoskeleton in memory formation. Prog Neurobiol 2014; 117:1-19. [DOI: 10.1016/j.pneurobio.2014.02.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 02/02/2014] [Accepted: 02/03/2014] [Indexed: 01/21/2023]
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195
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Tan H, Cao J, Zhang J, Zuo Z. Critical role of inflammatory cytokines in impairing biochemical processes for learning and memory after surgery in rats. J Neuroinflammation 2014; 11:93. [PMID: 24884762 PMCID: PMC4046437 DOI: 10.1186/1742-2094-11-93] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Accepted: 05/01/2014] [Indexed: 11/16/2022] Open
Abstract
Background Patients with postoperative cognitive dysfunction have poor outcomes. Neuroinflammation may be the underlying pathophysiology for this dysfunction. We determined whether proinflammatory cytokines affect the trafficking of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors to the plasma membrane, a fundamental biochemical process for learning and memory. Methods Four-month-old male Fischer 344 rats were subjected to right carotid exposure under isoflurane anesthesia. Some rats received intravenous lidocaine infusion during anesthesia. Rats were tested two weeks later by Barnes maze. The hippocampus was harvested six hours after the surgery for western blotting of interleukin (IL)-1β or IL-6. Hippocampal slices were prepared from control rats or rats subjected to surgery two weeks previously. They were incubated with tetraethylammonium, an agent that can induce long term potentiation, for determining the trafficking of GluR1, an α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor subunit. Results Surgery or anesthesia increased the time to identify the target box during the Barnes maze test training sessions and one day after the training sessions. Surgery also prolonged the time to identify the target box eight days after the training sessions. Surgery increased IL-1β and IL-6 in the hippocampus. The tetraethylammonium–induced GluR1 phosphorylation and trafficking were abolished in the hippocampal slices of rats after surgery. These surgical effects were partly inhibited by lidocaine. The incubation of control hippocampal slices with IL-1β and IL-6 abolished tetraethylammonium–induced GluR1 trafficking and phosphorylation. Lidocaine minimally affected the effects of IL-1β on GluR1 trafficking. Conclusions Our results suggest that surgery increases proinflammatory cytokines that then inhibit GluR1 trafficking, leading to learning and memory impairment.
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Affiliation(s)
| | | | | | - Zhiyi Zuo
- Department of Anesthesiology, University of Virginia, 1 Hospital Drive, PO Box 800710, Charlottesville, VA 22908-0710, USA.
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196
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Wolf M, Zimmermann AM, Görlich A, Gurniak CB, Sassoè-Pognetto M, Friauf E, Witke W, Rust MB. ADF/Cofilin Controls Synaptic Actin Dynamics and Regulates Synaptic Vesicle Mobilization and Exocytosis. Cereb Cortex 2014; 25:2863-75. [PMID: 24770705 DOI: 10.1093/cercor/bhu081] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Actin is a regulator of synaptic vesicle mobilization and exocytosis, but little is known about the mechanisms that regulate actin at presynaptic terminals. Genetic data on LIMK1, a negative regulator of actin-depolymerizing proteins of the ADF/cofilin family, suggest a role for ADF/cofilin in presynaptic function. However, synapse physiology is fully preserved upon genetic ablation of ADF in mice, and n-cofilin mutant mice display defects in postsynaptic plasticity, but not in presynaptic function. One explanation for this phenomenon is overlapping functions of ADF and n-cofilin in presynaptic physiology. Here, we tested this hypothesis and genetically removed ADF together with n-cofilin from synapses. In double mutants for ADF and n-cofilin, synaptic actin dynamics was impaired and more severely affected than in single mutants. The resulting cytoskeletal defects heavily affected the organization, mobilization, and exocytosis of synaptic vesicles in hippocampal CA3-CA1 synapses. Our data for the first time identify overlapping functions for ADF and n-cofilin in presynaptic physiology and vesicle trafficking. We conclude that n-cofilin is a limiting factor in postsynaptic plasticity, a function which cannot be substituted by ADF. On the presynaptic side, the presence of either ADF or n-cofilin is sufficient to control actin remodeling during vesicle release.
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Affiliation(s)
- Michael Wolf
- Department of Biology, Neurobiology/Neurophysiology Group, University of Kaiserslautern, Kaiserslautern 67663, Germany
| | - Anika-Maria Zimmermann
- Department of Biology, Neurobiology/Neurophysiology Group, University of Kaiserslautern, Kaiserslautern 67663, Germany
| | - Andreas Görlich
- Department of Biology, Neurobiology/Neurophysiology Group, University of Kaiserslautern, Kaiserslautern 67663, Germany Current address: Rockefeller University, 1230 York Avenue, New York, NY 10065, USA
| | | | - Marco Sassoè-Pognetto
- Department of Anatomy, Pharmacology and Forensic Medicine and National Institute of Neuroscience-Italy, University of Turin, Turin 10126, Italy
| | - Eckhard Friauf
- Animal Physiology Group, University of Kaiserslautern, Kaiserslautern 67663, Germany
| | - Walter Witke
- Institute of Genetics, University of Bonn, Bonn 53115, Germany
| | - Marco B Rust
- Department of Biology, Neurobiology/Neurophysiology Group, University of Kaiserslautern, Kaiserslautern 67663, Germany Institute of Physiological Chemistry, University of Marburg, 35043 Marburg, Germany
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197
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Walsh KP, Minamide LS, Kane SJ, Shaw AE, Brown DR, Pulford B, Zabel MD, Lambeth JD, Kuhn TB, Bamburg JR. Amyloid-β and proinflammatory cytokines utilize a prion protein-dependent pathway to activate NADPH oxidase and induce cofilin-actin rods in hippocampal neurons. PLoS One 2014; 9:e95995. [PMID: 24760020 PMCID: PMC3997518 DOI: 10.1371/journal.pone.0095995] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 04/02/2014] [Indexed: 11/18/2022] Open
Abstract
Neurites of neurons under acute or chronic stress form bundles of filaments (rods) containing 1∶1 cofilin∶actin, which impair transport and synaptic function. Rods contain disulfide cross-linked cofilin and are induced by treatments resulting in oxidative stress. Rods form rapidly (5-30 min) in >80% of cultured hippocampal or cortical neurons treated with excitotoxic levels of glutamate or energy depleted (hypoxia/ischemia or mitochondrial inhibitors). In contrast, slow rod formation (50% of maximum response in ∼6 h) occurs in a subpopulation (∼20%) of hippocampal neurons upon exposure to soluble human amyloid-β dimer/trimer (Aβd/t) at subnanomolar concentrations. Here we show that proinflammatory cytokines (TNFα, IL-1β, IL-6) also induce rods at the same rate and within the same neuronal population as Aβd/t. Neurons from prion (PrP(C))-null mice form rods in response to glutamate or antimycin A, but not in response to proinflammatory cytokines or Aβd/t. Two pathways inducing rod formation were confirmed by demonstrating that NADPH-oxidase (NOX) activity is required for prion-dependent rod formation, but not for rods induced by glutamate or energy depletion. Surprisingly, overexpression of PrP(C) is by itself sufficient to induce rods in over 40% of hippocampal neurons through the NOX-dependent pathway. Persistence of PrP(C)-dependent rods requires the continuous activity of NOX. Removing inducers or inhibiting NOX activity in cells containing PrP(C)-dependent rods causes rod disappearance with a half-life of about 36 min. Cofilin-actin rods provide a mechanism for synapse loss bridging the amyloid and cytokine hypotheses for Alzheimer disease, and may explain how functionally diverse Aβ-binding membrane proteins induce synaptic dysfunction.
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Affiliation(s)
- Keifer P. Walsh
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Laurie S. Minamide
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Sarah J. Kane
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, United States of America
- Molecular, Cellular and Integrative Neuroscience Program, Colorado State University, Fort Collins, Colorado, United States of America
| | - Alisa E. Shaw
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, United States of America
| | - David R. Brown
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Bruce Pulford
- Prion Research Center, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - Mark D. Zabel
- Molecular, Cellular and Integrative Neuroscience Program, Colorado State University, Fort Collins, Colorado, United States of America
- Prion Research Center, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
| | - J. David Lambeth
- Department of Pathology, Emory University School of Medicine, Atlanta, Georgia, United States of America
| | - Thomas B. Kuhn
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, United States of America
- Department of Chemistry and Biochemistry, University of Alaska, Fairbanks, Alaska, United States of America
| | - James R. Bamburg
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado, United States of America
- Molecular, Cellular and Integrative Neuroscience Program, Colorado State University, Fort Collins, Colorado, United States of America
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198
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Calabrese B, Saffin JM, Halpain S. Activity-dependent dendritic spine shrinkage and growth involve downregulation of cofilin via distinct mechanisms. PLoS One 2014; 9:e94787. [PMID: 24740405 PMCID: PMC3989342 DOI: 10.1371/journal.pone.0094787] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 03/19/2014] [Indexed: 01/09/2023] Open
Abstract
A current model posits that cofilin-dependent actin severing negatively impacts dendritic spine volume. Studies suggested that increased cofilin activity underlies activity-dependent spine shrinkage, and that reduced cofilin activity induces activity-dependent spine growth. We suggest instead that both types of structural plasticity correlate with decreased cofilin activity. However, the mechanism of inhibition determines the outcome for spine morphology. RNAi in rat hippocampal cultures demonstrates that cofilin is essential for normal spine maintenance. Cofilin-F-actin binding and filament barbed-end production decrease during the early phase of activity-dependent spine shrinkage; cofilin concentration also decreases. Inhibition of the cathepsin B/L family of proteases prevents both cofilin loss and spine shrinkage. Conversely, during activity-dependent spine growth, LIM kinase stimulates cofilin phosphorylation, which activates phospholipase D-1 to promote actin polymerization. These results implicate novel molecular mechanisms and prompt a revision of the current model for how cofilin functions in activity-dependent structural plasticity.
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Affiliation(s)
- Barbara Calabrese
- Division of Biological Sciences, and Sanford Consortium for Regenerative Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Jean-Michel Saffin
- Division of Biological Sciences, and Sanford Consortium for Regenerative Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Shelley Halpain
- Division of Biological Sciences, and Sanford Consortium for Regenerative Medicine, University of California San Diego, La Jolla, California, United States of America
- * E-mail:
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199
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Li X, Zhang X, Li X, Wang X, Wang S, Ding J. Cyclosporine A protects podocytes via stabilization of cofilin-1 expression in the unphosphorylated state. Exp Biol Med (Maywood) 2014; 239:922-936. [PMID: 24737737 DOI: 10.1177/1535370214530365] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Podocyte foot process (FP) is dysregulated in nephrotic syndrome. The effacement of podocyte FPs typically arises following perturbations in the actin cytoskeleton. Recent data suggest that the effects of calcineurin (CaN) inhibitor cyclosporine A (CsA) are independent of its effects on T-cells, and CsA has been identified as stabilizing the actin cytoskeleton through stabilizing synaptopodin in podocytes, and thereby directly reducing proteinuria. Other studies showed that CsA could regulate cofilin-1 directly within tubular epithelial cells. However, whether synaptopodin is the only target of CsA or whether the antiproteinuric role of CsA is played by regulating cofilin-1 in podocytes has not been studied. In the present study, changes in the expression and distribution of nephrin, synaptopodin, cofilin-1 and phosphorylated cofilin-1 (pho-cofilin-1) were detected in both puromycin aminonucleoside (PAN) induced nephrotic rats treated with CsA and cultured podocytes exposed to PAN with/without CsA. Cofilin-1, synaptopodin mRNA was knocked down or combined by siRNA to investigate whether cofilin-1 was critical for the protective effect of CsA and whether the effect of CsA on cofilin-1 was independent of its effect on synaptopodin. We found that CsA reduced proteinuria and repaired FP effacement of PAN-induced nephropathy, restored expression of nephrin, synaptopodin, cofilin-1, pho-cofilin-1 both in vivo and in vitro. CsA also repaired actin cytoskeleton impaired by PAN in vitro. The protective effect of CsA was diminished when cofilin-1 was knocked down compared to negative control. Synaptopodin knocked down had no effect on cofilin-1. The protective effect of CsA decreased significantly when cofilin-1 and synaptopodin were simultaneously knocked down compared to only cofilin-1 knock down. In conclusion, the antiproteinuric effect of CsA is derived from the stabilization of the podocyte actin cytoskeleton by upregulating expression of cofilin-1, which was independent of its effect on synaptopodin.
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Affiliation(s)
- Xiaoyan Li
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Xiaoyan Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Xuejuan Li
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Xuejing Wang
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Suxia Wang
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
| | - Jie Ding
- Department of Pediatrics, Peking University First Hospital, Beijing 100034, China
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200
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Shen HW, Gipson CD, Huits M, Kalivas PW. Prelimbic cortex and ventral tegmental area modulate synaptic plasticity differentially in nucleus accumbens during cocaine-reinstated drug seeking. Neuropsychopharmacology 2014; 39:1169-77. [PMID: 24232172 PMCID: PMC3957111 DOI: 10.1038/npp.2013.318] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 10/10/2013] [Accepted: 10/16/2013] [Indexed: 12/14/2022]
Abstract
Addictive drug use causes long-lasting changes in synaptic strength and dendritic spine morphology in the nucleus accumbens that might underlie the vulnerability to relapse. Although activity in mesocorticolimbic circuitry is required for reinstating cocaine seeking, its role in reinstatement-associated synaptic plasticity is not well characterized. Using rats extinguished from cocaine self-administration, we found potentiated synaptic strength (assessed as the AMPA/NMDA current amplitude ratio) and increased spine head diameter in medium spiny neurons in the accumbens core (NAcore). The basal changes in synaptic strength and morphology in cocaine-extinguished animals were further augmented during cocaine-induced reinstatement. Two NAcore afferents contributing to cocaine reinstatement are glutamatergic inputs from the prelimbic prefrontal cortex (PL) and dopamine from the ventral tegmental area (VTA). Pharmacological inhibition of either PL or VTA prevented cocaine-primed reinstatement. However, inhibiting the PL further potentiated AMPA/NMDA and spine head diameter, while inactivating the VTA or the combined systemic administration of dopamine D1 and D2 antagonists prevented the increase in AMPA/NMDA and spine diameter induced by cocaine priming. These data indicate that neuronal activity in the VTA and associated dopamine receptor stimulation is necessary for the synaptic potentiation in the NAcore during cocaine-induced reinstatement. Although activity in the PL was necessary for reinstatement, it inhibited synaptic potentiation initiated by an acute cocaine injection. Thus, although the PL and VTA differentially regulate the direction of synaptic plasticity induced by a cocaine-priming injection, coordinated synaptic potentiation by both NAcore afferents is necessary for cocaine-induced relapse.
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Affiliation(s)
- Hao-wei Shen
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA,National Institute on Drug Dependence, Peking University, Beijing, People's Republic of China,National Institute on Drug Dependence, Peking University, 38 Xueyuan Road, Beijing 100191, People's Republic of China, Tel: +86 10 82802470 (ext. 520), Fax: +86 10 62032624, E-mail:
| | - Cassandra D Gipson
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
| | - Martijn Huits
- Department of Neuroscience, Vrije University of Amsterdam, Amsterdam, The Netherlands
| | - Peter W Kalivas
- Department of Neuroscience, Medical University of South Carolina, Charleston, SC, USA
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