1
|
Kutsarova E, Schohl A, Munz M, Wang A, Zhang YY, Bilash OM, Ruthazer ES. BDNF signaling in correlation-dependent structural plasticity in the developing visual system. PLoS Biol 2023; 21:e3002070. [PMID: 37011100 PMCID: PMC10101647 DOI: 10.1371/journal.pbio.3002070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 04/13/2023] [Accepted: 03/08/2023] [Indexed: 04/05/2023] Open
Abstract
During development, patterned neural activity instructs topographic map refinement. Axons with similar patterns of neural activity converge onto target neurons and stabilize their synapses with these postsynaptic partners, restricting exploratory branch elaboration (Hebbian structural plasticity). On the other hand, non-correlated firing in inputs leads to synapse weakening and increased exploratory growth of axons (Stentian structural plasticity). We used visual stimulation to control the correlation structure of neural activity in a few ipsilaterally projecting (ipsi) retinal ganglion cell (RGC) axons with respect to the majority contralateral eye inputs in the optic tectum of albino Xenopus laevis tadpoles. Multiphoton live imaging of ipsi axons, combined with specific targeted disruptions of brain-derived neurotrophic factor (BDNF) signaling, revealed that both presynaptic p75NTR and TrkB are required for Stentian axonal branch addition, whereas presumptive postsynaptic BDNF signaling is necessary for Hebbian axon stabilization. Additionally, we found that BDNF signaling mediates local suppression of branch elimination in response to correlated firing of inputs. Daily in vivo imaging of contralateral RGC axons demonstrated that p75NTR knockdown reduces axon branch elongation and arbor spanning field volume.
Collapse
Affiliation(s)
- Elena Kutsarova
- Montreal Neurological Institute-Hospital, McGill University, Montreal, Canada
- Max Planck Institute for Brain Research, Frankfurt, Germany
| | - Anne Schohl
- Montreal Neurological Institute-Hospital, McGill University, Montreal, Canada
| | - Martin Munz
- Montreal Neurological Institute-Hospital, McGill University, Montreal, Canada
- Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland
- Department of Ophthalmology, University of Basel, Basel, Switzerland
| | - Alex Wang
- Montreal Neurological Institute-Hospital, McGill University, Montreal, Canada
- Interdepartmental Neuroscience, Yale University, New Haven, Connecticut, United States of America
| | - Yuan Yuan Zhang
- Montreal Neurological Institute-Hospital, McGill University, Montreal, Canada
- Faculty of Medicine, University of Ottawa, Ottawa, Canada
| | - Olesia M Bilash
- Montreal Neurological Institute-Hospital, McGill University, Montreal, Canada
- NYU Neuroscience Institute, New York University, New York, New York, United States of America
| | - Edward S Ruthazer
- Montreal Neurological Institute-Hospital, McGill University, Montreal, Canada
| |
Collapse
|
2
|
Cline HT, Lau M, Hiramoto M. Activity-dependent Organization of Topographic Neural Circuits. Neuroscience 2023; 508:3-18. [PMID: 36470479 PMCID: PMC9839526 DOI: 10.1016/j.neuroscience.2022.11.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 11/25/2022] [Accepted: 11/28/2022] [Indexed: 12/12/2022]
Abstract
Sensory information in the brain is organized into spatial representations, including retinotopic, somatotopic, and tonotopic maps, as well as ocular dominance columns. The spatial representation of sensory inputs is thought to be a fundamental organizational principle that is important for information processing. Topographic maps are plastic throughout an animal's life, reflecting changes in development and aging of brain circuitry, changes in the periphery and sensory input, and changes in circuitry, for instance in response to experience and learning. Here, we review mechanisms underlying the role of activity in the development, stability and plasticity of topographic maps, focusing on recent work suggesting that the spatial information in the visual field, and the resulting spatiotemporal patterns of activity, provide instructive cues that organize visual projections.
Collapse
Affiliation(s)
- Hollis T Cline
- Department of Neuroscience and the Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA, USA.
| | - Melissa Lau
- Department of Neuroscience and the Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA, USA
| | - Masaki Hiramoto
- Department of Neuroscience and the Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, CA, USA
| |
Collapse
|
3
|
Tone D, Ode KL, Zhang Q, Fujishima H, Yamada RG, Nagashima Y, Matsumoto K, Wen Z, Yoshida SY, Mitani TT, Arisato Y, Ohno RI, Ukai-Tadenuma M, Yoshida Garçon J, Kaneko M, Shi S, Ukai H, Miyamichi K, Okada T, Sumiyama K, Kiyonari H, Ueda HR. Distinct phosphorylation states of mammalian CaMKIIβ control the induction and maintenance of sleep. PLoS Biol 2022; 20:e3001813. [PMID: 36194579 PMCID: PMC9531794 DOI: 10.1371/journal.pbio.3001813] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Accepted: 09/01/2022] [Indexed: 11/17/2022] Open
Abstract
The reduced sleep duration previously observed in Camk2b knockout mice revealed a role for Ca2+/calmodulin-dependent protein kinase II (CaMKII)β as a sleep-promoting kinase. However, the underlying mechanism by which CaMKIIβ supports sleep regulation is largely unknown. Here, we demonstrate that activation or inhibition of CaMKIIβ can increase or decrease sleep duration in mice by almost 2-fold, supporting the role of CaMKIIβ as a core sleep regulator in mammals. Importantly, we show that this sleep regulation depends on the kinase activity of CaMKIIβ. A CaMKIIβ mutant mimicking the constitutive-active (auto)phosphorylation state promotes the transition from awake state to sleep state, while mutants mimicking subsequent multisite (auto)phosphorylation states suppress the transition from sleep state to awake state. These results suggest that the phosphorylation states of CaMKIIβ differently control sleep induction and maintenance processes, leading us to propose a "phosphorylation hypothesis of sleep" for the molecular control of sleep in mammals.
Collapse
Affiliation(s)
- Daisuke Tone
- Laboratory for Synthetic Biology, RIKEN Center for Biosystems Dynamics Research, Suita, Osaka, Japan
- Department of Systems Pharmacology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Koji L. Ode
- Laboratory for Synthetic Biology, RIKEN Center for Biosystems Dynamics Research, Suita, Osaka, Japan
- Department of Systems Pharmacology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Qianhui Zhang
- Department of Systems Pharmacology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Hiroshi Fujishima
- Laboratory for Synthetic Biology, RIKEN Center for Biosystems Dynamics Research, Suita, Osaka, Japan
| | - Rikuhiro G. Yamada
- Laboratory for Synthetic Biology, RIKEN Center for Biosystems Dynamics Research, Suita, Osaka, Japan
| | - Yoshiki Nagashima
- Department of Systems Pharmacology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- Thermo Fisher Scientific K.K., Yokohama, Kanagawa, Japan
| | - Katsuhiko Matsumoto
- Laboratory for Synthetic Biology, RIKEN Center for Biosystems Dynamics Research, Suita, Osaka, Japan
| | - Zhiqing Wen
- Department of Systems Pharmacology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Shota Y. Yoshida
- Laboratory for Synthetic Biology, RIKEN Center for Biosystems Dynamics Research, Suita, Osaka, Japan
- Graduate school of Medicine, Osaka University, Suita, Osaka, Japan
| | - Tomoki T. Mitani
- Laboratory for Synthetic Biology, RIKEN Center for Biosystems Dynamics Research, Suita, Osaka, Japan
- Graduate school of Medicine, Osaka University, Suita, Osaka, Japan
| | - Yuki Arisato
- Department of Systems Pharmacology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- Faculty of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Rei-ichiro Ohno
- Department of Systems Pharmacology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Maki Ukai-Tadenuma
- Laboratory for Synthetic Biology, RIKEN Center for Biosystems Dynamics Research, Suita, Osaka, Japan
| | - Junko Yoshida Garçon
- Laboratory for Synthetic Biology, RIKEN Center for Biosystems Dynamics Research, Suita, Osaka, Japan
| | - Mari Kaneko
- Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Biosystems Dynamics Research, Chuo-ku, Kobe, Hyogo, Japan
| | - Shoi Shi
- Laboratory for Synthetic Biology, RIKEN Center for Biosystems Dynamics Research, Suita, Osaka, Japan
- Department of Systems Pharmacology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Hideki Ukai
- Laboratory for Synthetic Biology, RIKEN Center for Biosystems Dynamics Research, Suita, Osaka, Japan
| | - Kazunari Miyamichi
- Laboratory for Comparative Connections, RIKEN Center for Biosystems Dynamics Research, Chuo-ku, Kobe, Hyogo, Japan
| | - Takashi Okada
- Division of Molecular and Medical Genetics, Center for Gene and Cell Therapy, The Institute of Medical Science, the University of Tokyo, Minato-city, Tokyo, Japan
| | - Kenta Sumiyama
- Laboratory for Mouse Genetic Engineering, RIKEN Center for Biosystems Dynamics Research, Suita, Osaka, Japan
| | - Hiroshi Kiyonari
- Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Biosystems Dynamics Research, Chuo-ku, Kobe, Hyogo, Japan
| | - Hiroki R. Ueda
- Laboratory for Synthetic Biology, RIKEN Center for Biosystems Dynamics Research, Suita, Osaka, Japan
- Department of Systems Pharmacology, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- * E-mail:
| |
Collapse
|
4
|
Cline HT. Imaging Structural and Functional Dynamics in Xenopus Neurons. Cold Spring Harb Protoc 2021; 2022:pdb.top106773. [PMID: 34531329 DOI: 10.1101/pdb.top106773] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In vivo time-lapse imaging has been a fruitful approach to identify structural and functional changes in the Xenopus nervous system in tadpoles and adult frogs. Structural imaging studies have identified fundamental aspects of brain connectivity, development, plasticity, and disease and have been instrumental in elucidating mechanisms regulating these events in vivo. Similarly, assessment of nervous system function using dynamic changes in calcium signals as a proxy for neuronal activity has demonstrated principles of neuron and circuit function and principles of information organization and transfer within the brain of living animals. Because of its many advantages as an experimental system, use of Xenopus has often been at the forefront of developing these imaging methods for in vivo applications. Protocols for in vivo structural and functional imaging-including cellular labeling strategies, image collection, and image analysis-will expand the use of Xenopus to understand brain development, function, and plasticity.
Collapse
Affiliation(s)
- Hollis T Cline
- Department of Neuroscience, Dorris Neuroscience Center, The Scripps Research Center, La Jolla, California 92039, USA
| |
Collapse
|
5
|
Kesner P, Schohl A, Warren EC, Ma F, Ruthazer ES. Postsynaptic and Presynaptic NMDARs Have Distinct Roles in Visual Circuit Development. Cell Rep 2021; 32:107955. [PMID: 32726620 DOI: 10.1016/j.celrep.2020.107955] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 05/26/2020] [Accepted: 07/01/2020] [Indexed: 12/11/2022] Open
Abstract
To study contributions of N-methyl-D-aspartate receptors (NMDARs) in presynaptic and postsynaptic neurons of the developing visual system, we microinject antisense Morpholino oligonucleotide (MO) against GluN1 into one cell of two-cell-stage Xenopus laevis embryos. The resulting bilateral segregation of MO induces postsynaptic NMDAR (postNMDAR) knockdown in tectal neurons on one side and presynaptic NMDAR (preNMDAR) knockdown in ganglion cells projecting to the other side. PostNMDAR knockdown reduces evoked NMDAR- and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR)-mediated retinotectal currents. Although the frequency of spontaneous synaptic events is increased, the probability of evoked release is reduced. PreNMDAR knockdown results in larger evoked and unitary synaptic responses. Structurally, postNMDAR and preNMDAR knockdown produce complementary effects. Axonal arbor complexity is reduced by preNMDAR-MO and increased by postNMDAR-MO, whereas tectal dendritic arbors exhibit the inverse. The current study illustrates distinct roles for pre- and postNMDARs in circuit development and reveals extensive transsynaptic regulation of form and function.
Collapse
Affiliation(s)
- Philip Kesner
- Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, Montreal QC H3A 2B4, Canada
| | - Anne Schohl
- Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, Montreal QC H3A 2B4, Canada
| | - Elodie C Warren
- Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, Montreal QC H3A 2B4, Canada
| | - Fan Ma
- Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, Montreal QC H3A 2B4, Canada
| | - Edward S Ruthazer
- Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, McGill University, Montreal QC H3A 2B4, Canada.
| |
Collapse
|
6
|
Activation State-Dependent Substrate Gating in Ca 2+/Calmodulin-Dependent Protein Kinase II. Neural Plast 2017; 2017:9601046. [PMID: 29391954 PMCID: PMC5748111 DOI: 10.1155/2017/9601046] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Accepted: 10/23/2017] [Indexed: 12/15/2022] Open
Abstract
Calcium/calmodulin-dependent protein kinase II (CaMKII) is highly concentrated in the brain where its activation by the Ca2+ sensor CaM, multivalent structure, and complex autoregulatory features make it an ideal translator of Ca2+ signals created by different patterns of neuronal activity. We provide direct evidence that graded levels of kinase activity and extent of T287 (T286 α isoform) autophosphorylation drive changes in catalytic output and substrate selectivity. The catalytic domains of CaMKII phosphorylate purified PSDs much more effectively when tethered together in the holoenzyme versus individual subunits. Using multisubstrate SPOT arrays, high-affinity substrates are preferentially phosphorylated with limited subunit activity per holoenzyme, whereas multiple subunits or maximal subunit activation is required for intermediate- and low-affinity, weak substrates, respectively. Using a monomeric form of CaMKII to control T287 autophosphorylation, we demonstrate that increased Ca2+/CaM-dependent activity for all substrates tested, with the extent of weak, low-affinity substrate phosphorylation governed by the extent of T287 autophosphorylation. Our data suggest T287 autophosphorylation regulates substrate gating, an intrinsic property of the catalytic domain, which is amplified within the multivalent architecture of the CaMKII holoenzyme.
Collapse
|
7
|
Kutsarova E, Munz M, Ruthazer ES. Rules for Shaping Neural Connections in the Developing Brain. Front Neural Circuits 2017; 10:111. [PMID: 28119574 PMCID: PMC5223306 DOI: 10.3389/fncir.2016.00111] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Accepted: 12/16/2016] [Indexed: 11/13/2022] Open
Abstract
It is well established that spontaneous activity in the developing mammalian brain plays a fundamental role in setting up the precise connectivity found in mature sensory circuits. Experiments that produce abnormal activity or that systematically alter neural firing patterns during periods of circuit development strongly suggest that the specific patterns and the degree of correlation in firing may contribute in an instructive manner to circuit refinement. In fish and amphibians, unlike amniotic vertebrates, sensory input directly drives patterned activity during the period of initial projection outgrowth and innervation. Experiments combining sensory stimulation with live imaging, which can be performed non-invasively in these simple vertebrate models, have provided important insights into the mechanisms by which neurons read out and respond to activity patterns. This article reviews the classic and recent literature on spontaneous and evoked activity-dependent circuit refinement in sensory systems and formalizes a set of mechanistic rules for the transformation of patterned activity into accurate neuronal connectivity in the developing brain.
Collapse
Affiliation(s)
- Elena Kutsarova
- Montreal Neurological Institute, McGill University Montreal, QC, Canada
| | - Martin Munz
- Friedrich Miescher Institute, Neurobiology Group Basel, Switzerland
| | - Edward S Ruthazer
- Montreal Neurological Institute, McGill University Montreal, QC, Canada
| |
Collapse
|
8
|
Optic flow instructs retinotopic map formation through a spatial to temporal to spatial transformation of visual information. Proc Natl Acad Sci U S A 2014; 111:E5105-13. [PMID: 25385606 DOI: 10.1073/pnas.1416953111] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Retinotopic maps are plastic in response to changes in sensory input; however, the experience-dependent instructive cues that organize retinotopy are unclear. In animals with forward-directed locomotion, the predominant anterior to posterior optic flow activates retinal ganglion cells in a stereotyped temporal to nasal sequence. Here we imaged retinotectal axon arbor location and structural plasticity to assess map refinement in vivo while exposing Xenopus tadpoles to visual stimuli. We show that the temporal sequence of retinal activity driven by natural optic flow organizes retinotopy by regulating axon arbor branch dynamics, whereas the opposite sequence of retinal activity prevents map refinement. Our study demonstrates that a spatial to temporal to spatial transformation of visual information controls experience-dependent topographic map plasticity. This organizational principle is likely to apply to other sensory modalities and projections in the brain.
Collapse
|
9
|
McFarlane S, Lom B. The Xenopus retinal ganglion cell as a model neuron to study the establishment of neuronal connectivity. Dev Neurobiol 2012; 72:520-36. [PMID: 21634016 DOI: 10.1002/dneu.20928] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Neurons receive inputs through their multiple branched dendrites and pass this information on to the next neuron via long axons, which branch within the target. The shape the neuron acquires is thus the key to its proper functioning in the neural circuit in which it participates. Both axons and dendrites grow in a directed fashion to their target partner neurons by responding to a large number of molecular cues in the milieu through which they extend. They then go through the process of synaptogenesis, first choosing a neuron on which to synapse, and then the appropriate subcellular location. How a neuron acquires its unique shape, establishes and modifies appropriate synaptic connectivity, and the molecular signals involved, are key questions in developmental neurobiology. Such questions of nervous system wiring are being pursued actively with a variety of different animal models and neuron types, each with its own unique advantages. Among these, the developing retinal ganglion cell (RGC) of the South African clawed frog, Xenopus laevis, has proven particularly fruitful for revealing the secrets of how axons and dendrites acquire their final morphology and connectivity. In this review, we describe how this system can be used to understand the multiple molecular events that instruct the incorporation of RGCs into the neural circuit that controls vision.
Collapse
Affiliation(s)
- Sarah McFarlane
- Department of Cell Biology and Anatomy, University of Calgary, Hotchkiss Brain Institute, Calgary, Alberta, Canada.
| | | |
Collapse
|
10
|
Constitutive activation of Ca2+/calmodulin-dependent protein kinase II during development impairs central cholinergic transmission in a circuit underlying escape behavior in Drosophila. J Neurosci 2012; 32:170-82. [PMID: 22219280 DOI: 10.1523/jneurosci.6583-10.2012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Development of neural circuitry relies on precise matching between correct synaptic partners and appropriate synaptic strength tuning. Adaptive developmental adjustments may emerge from activity and calcium-dependent mechanisms. Calcium/calmodulin-dependent protein kinase II (CaMKII) has been associated with developmental synaptic plasticity, but its varied roles in different synapses and developmental stages make mechanistic generalizations difficult. In contrast, we focused on synaptic development roles of CaMKII in a defined sensory-motor circuit. Thus, different forms of CaMKII were expressed with UAS-Gal4 in distinct components of the giant fiber system, the escape circuit of Drosophila, consisting of photoreceptors, interneurons, motoneurons, and muscles. The results demonstrate that the constitutively active CaMKII-T287D impairs development of cholinergic synapses in giant fiber dendrites and thoracic motoneurons, preventing light-induced escape behavior. The locus of the defects is postsynaptic as demonstrated by selective expression of transgenes in distinct components of the circuit. Furthermore, defects among these cholinergic synapses varied in severity, while the glutamatergic neuromuscular junctions appeared unaffected, demonstrating differential effects of CaMKII misregulation on distinct synapses of the same circuit. Limiting transgene expression to adult circuits had no effects, supporting the role of misregulated kinase activity in the development of the system rather than in acutely mediating escape responses. Overexpression of wild-type transgenes did not affect circuit development and function, suggesting but not proving that the CaMKII-T287D effects are not due to ectopic expression. Therefore, regulated CaMKII autophosphorylation appears essential in central synapse development, and particular cholinergic synapses are affected differentially, although they operate via the same nicotinic receptor.
Collapse
|
11
|
|
12
|
Zha XM, Dailey ME, Green SH. Role of Ca2+/calmodulin-dependent protein kinase II in dendritic spine remodeling during epileptiform activity in vitro. J Neurosci Res 2009; 87:1969-79. [PMID: 19235894 DOI: 10.1002/jnr.22033] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Epileptiform activity (EA) in vivo and in vitro induces a loss of dendritic spines and synapses. Because CaMKII has been implicated in synaptogenesis and synaptic plasticity, we investigated the role of CaMKII in the effects of EA on spines, using rat hippocampal slice cultures. To visualize dendrites and postsynaptic densities (PSDs) in pyramidal neurons in the slices, we used biolistic transfection to express either free GFP or a PSD95-YFP construct that specifically labels PSDs. This allowed us to distinguish two classes of dendritic protrusions: spines that contain PSDs, and filopodia that lack PSDs and that are, on average, longer than spines. By these criteria, 48 hr of EA caused a decrease specifically in the number of spines. Immunoblots showed that EA increased CaMKII activity in the slices. Inhibition of CaMKII by expression of AIP, a specific peptide inhibitor of CaMKII, reduced spine number under basal conditions and failed to prevent EA-induced spine loss. However, under EA conditions, AIP increased the number of filopodia and the number of PSDs on the dendritic shaft. These data show at least two roles for CaMKII activity in maintenance and remodeling of dendritic spines under basal or EA conditions. First, CaMKII activity promotes the maintenance of spines and spine PSDs. Second, CaMKII activity suppresses EA-induced formation of filopodia and suppresses an increase in shaft PSDs, apparently by promoting translocation of PSDs from dendritic shafts to spines and/or selectively stabilizing spine rather than shaft PSDs.
Collapse
Affiliation(s)
- Xiang-ming Zha
- Department of Biology, University of Iowa, Iowa City, IA 52242-1324, USA
| | | | | |
Collapse
|
13
|
Abstract
The thalamocortical (TC) projection in the mammalian brain involves fundamental aspects in branch formation during development. TC axons are known to form branches not only in a genetically defined but also in an activity-dependent fashion. Recent evidence indicates that TC axon branching is generated by positive and negative regulators that are expressed with laminar specificity in the developing cortex. Moreover, in vitro studies using organotypic cocultures demonstrate that neural activity, including firing and synaptic activity, controls lamina-specific TC axon branching by altering its remodeling process with addition and elimination. Taken together, activity-dependent mechanisms can contribute to branch formation, affecting expression of branch-promoting and inhibiting factors and/or their receptor molecules.
Collapse
Affiliation(s)
- Yasufumi Hayano
- Neuroscience Laboratories, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | | |
Collapse
|
14
|
CaMKII promotes TLR-triggered proinflammatory cytokine and type I interferon production by directly binding and activating TAK1 and IRF3 in macrophages. Blood 2008; 112:4961-70. [PMID: 18818394 DOI: 10.1182/blood-2008-03-144022] [Citation(s) in RCA: 153] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Calcium and its major downstream effector, calcium/calmodulin-dependent protein kinase II (CaMKII), are found to be important for the functions of immune cells. Lipopolysaccharide (LPS) has been shown to induce intracellular calcium release in macrophages; however, whether and how CaMKII is required for Toll-like receptor (TLR) signaling remain unknown. Here we demonstrate that TLR 4, 9, and 3 ligands markedly induce intracellular calcium fluxes and activate CaMKII-alpha in macrophages. Selective inhibition or RNA interference of CaMKII significantly suppresses TLR4, 9, 3-triggered production of interleukin-6 (IL-6), tumor necrosis factor-alpha, and interferon-alpha/beta (IFN-alpha/beta) in macrophages. Coincidently, overexpression of constitutively active CaMKII-alpha significantly enhances production of the above cytokines. In addition to the activation of mitogen-activated protein kinase and nuclear factor kappaB pathways, CaMKII-alpha can directly bind and phosphorylate transforming growth factor beta-activated kinase 1 (TAK1) and IFN regulatory factor 3 (IRF3; serine on 386) via the N-terminal part of its regulatory domain. Therefore, CaMKII can be activated by TLR ligands, and in turn promotes both myeloid differentiating factor 88 and Toll/IL-1 receptor domain-containing adaptor protein-inducing IFN-beta-dependent inflammatory responses by directly activating TAK1 and IRF3. The cross-talk with the calcium/CaMKII pathway is needed for full activation of TLR signaling in macrophages.
Collapse
|
15
|
Rothschild SC, Lister JA, Tombes RM. Differential expression of CaMK-II genes during early zebrafish embryogenesis. Dev Dyn 2007; 236:295-305. [PMID: 17103413 DOI: 10.1002/dvdy.21005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
CaMK-II is a highly conserved Ca(2+)/calmodulin-dependent protein kinase expressed throughout the lifespan of all vertebrates. During early development, CaMK-II regulates cell cycle progression and "non-canonical" Wnt-dependent convergent extension. In the zebrafish, Danio rerio, CaMK-II activity rises within 2 hr after fertilization. At the time of somite formation, zygotic expression from six genes (camk2a1, camk2b1, camk2g1, camk2g2, camk2d1, camk2d2) results in a second phase of increased activity. Zebrafish CaMK-II genes are 92-95% identical to their human counterparts in the non-variable regions. During the first three days of development, alternative splicing yields at least 20 splice variants, many of which are unique. Whole-mount in situ hybridization reveals that camk2g1 comprises the majority of maternal expression. All six genes are expressed strongly in ventral regions at the 18-somite stage. Later, camk2a1 is expressed in anterior somites, heart, and then forebrain. Camk2b1 is expressed in somites, mid- and forebrain, gut, retina, and pectoral fins. Camk2g1 appears strongly along the midline and then in brain, gut, and pectoral fins. Camk2g2 is expressed early in the midbrain and trunk and exhibits the earliest retinal expression. Camk2d1 is elevated early at somite boundaries, then epidermal tissue, while camk2d2 is expressed in discrete anterior locations, steadily increasing along either side of the dorsal midline and then throughout the brain, including the retina. These findings reveal a complex pattern of CaMK-II gene expression consistent with pleiotropic roles during development.
Collapse
Affiliation(s)
- Sarah C Rothschild
- Department of Biology, Virginia Commonwealth University, Richmond, Virginia, USA
| | | | | |
Collapse
|
16
|
Lohr C, Bergstein S, Hirnet D. Developmental distribution of CaM kinase II in the antennal lobe of the sphinx moth Manduca sexta. Cell Tissue Res 2006; 327:189-97. [PMID: 16896952 DOI: 10.1007/s00441-006-0249-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2006] [Accepted: 05/15/2006] [Indexed: 01/09/2023]
Abstract
The antennal lobe (primary olfactory center of insects) is completely reorganized during metamorphosis. This reorganization is accompanied by changing patterns of calcium signaling in neurons and glial cells. In the present study, we investigated the developmental distribution of a major calcium-dependent protein, viz., calcium/calmodulin-dependent protein kinase II (CaM kinase II), in the antennal lobe of the sphinx moth Manduca sexta by using a monoclonal antibody. During synaptogenesis (developmental stages 6-10), we found a redistribution of CaM kinase II immunoreactivity, from a homogeneous distribution in the immature neuropil to an accumulation in the neuropil of the glomeruli. CaM kinase II immunoreactivity was less intense in olfactory receptor axons of the antennal nerve and antennal lobe glial cells. Western blot analysis revealed a growing content of CaM kinase II in antennal lobe tissue throughout metamorphosis. Injection of the CaM kinase inhibitor KN-93 into pupae resulted in a reduced number of antennal lobe glial cells migrating into the neuropil to form borders around glomeruli. The results suggest that CaM kinase II is involved in glial cell migration.
Collapse
Affiliation(s)
- Christian Lohr
- Abteilung für Allgemeine Zoologie, Fachbereich Biologie, TU Kaiserslautern, Postfach 3049, 67653 Kaiserslautern, Germany.
| | | | | |
Collapse
|
17
|
Abstract
Axonal branching is an important process for establishing the final pattern of connections between a neuron and its target cells. Cortical connections between upper-layer cells in the neocortex have provided insights into the cellular mechanisms by which electrical activity regulates neural connectivity, including branch formation. Recent evidence further indicates that spontaneous firing and synaptic transmission contribute to axonal branching of cortical neurons through postsynaptic activation.
Collapse
Affiliation(s)
- Naofumi Uesaka
- Neuroscience Laboratories, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | | | | |
Collapse
|
18
|
Easley CA, Faison MO, Kirsch TL, Lee JA, Seward ME, Tombes RM. Laminin activates CaMK-II to stabilize nascent embryonic axons. Brain Res 2006; 1092:59-68. [PMID: 16690036 DOI: 10.1016/j.brainres.2006.03.099] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2005] [Revised: 03/21/2006] [Accepted: 03/23/2006] [Indexed: 11/25/2022]
Abstract
In neurons, the interaction of laminin with its receptor, beta1 integrin, is accompanied by an increase in cytosolic Ca2+. Neuronal behavior is influenced by CaMK-II, the type II Ca2+/calmodulin-dependent protein kinase, which is enriched in axons of mouse embryonic neurons. In this study, we sought to determine whether CaMK-II is activated by laminin, and if so, how CaMK-II influences axonal growth and stability. Axons grew up to 200 microm within 1 day of plating P19 embryoid bodies on laminin-1 (EHS laminin). Activated CaMK-II was found enriched along the axon and in the growth cone as detected using a phospho-Thr(287) specific CaMK-II antibody. beta1 integrin was found in a similar pattern along the axon and in the growth cone. Direct inhibition of CaMK-II in 1-day-old neurons immediately froze growth cone dynamics, disorganized F-actin and ultimately led to axon retraction. Collapsed axonal remnants exhibited diminished phospho-CaMK-II levels. Treatment of 1-day neurons with a beta1 integrin-blocking antibody (CD29) also reduced axon length and phospho-CaMK-II levels and, like CaMK-II inhibitors, decreased CaMK-II activation. Among several CaMK-II variants detected in these cultures, the 52-kDa delta variant preferentially associated with actin and beta 3 tubulin as determined by reciprocal immunoprecipitation. Our findings indicate that persistent activation of delta CaMK-II by laminin stabilizes nascent embryonic axons through its influence on the actin cytoskeleton.
Collapse
Affiliation(s)
- Charles A Easley
- Department of Biology and Biochemistry, Virginia Commonwealth University, Richmond, VA 23284-2012, USA
| | | | | | | | | | | |
Collapse
|
19
|
Schmidt JT. Activity-driven sharpening of the retinotectal projection: the search for retrograde synaptic signaling pathways. ACTA ACUST UNITED AC 2004; 59:114-33. [PMID: 15007831 DOI: 10.1002/neu.10343] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Patterned visual activity, acting via NMDA receptors, refines developing retinotectal maps by shaping individual retinal arbors. Because NMDA receptors are postsynaptic but the retinal arbors are presynaptic, there must be retrograde signals generated downstream of Ca(++) entry through NMDA receptors that direct the presynaptic retinal terminals to stabilize and grow or to withdraw. This review defines criteria for retrograde synaptic messengers, and then applies them to the leading candidates: nitric oxide (NO), brain-derived neurotrophic factor (BDNF), and arachidonic acid (AA). NO is not likely to be a general mechanism, as it operates only in selected projections of warm blooded vertebrates to speed up synaptic refinement, but is not essential. BDNF is a neurotrophin with strong growth promoting properties and complex interactions with activity both in its release and receptor signaling, but may modulate rather than mediate the retrograde signaling. AA promotes growth and stabilization of synaptic terminals by tapping into a pre-existing axonal growth-promoting pathway that is utilized by L1, NCAM, N-cadherin, and FGF and acts via PKC, GAP43, and F-actin stabilization, and it shares some overlap with BDNF pathways. The actions of both are consistent with recent demonstrations that activity-driven stabilization includes directed growth of new synaptic contacts. Certain nondiffusible factors (synapse-specific CAMs, ephrins, neurexin/neuroligin, and matrix molecules) may also play a role in activity-driven synapse stabilization. Interactions between these pathways are discussed.
Collapse
Affiliation(s)
- John T Schmidt
- Department of Biological Sciences and Center for Neuroscience Research, University at Albany-SUNY, 1400 Washington Avenue, Albany, New York 12222, USA.
| |
Collapse
|
20
|
Schmidt JT, Fleming MR, Leu B. Presynaptic protein kinase C controls maturation and branch dynamics of developing retinotectal arbors: possible role in activity-driven sharpening. ACTA ACUST UNITED AC 2004; 58:328-40. [PMID: 14750146 DOI: 10.1002/neu.10286] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Visual activity refines developing retinotectal maps and shapes individual retinal arbors via an NMDA receptor-dependent mechanism. As retinal axons grow into tectum, they slow markedly and emit many transient side branches behind the tip, assuming a "bottlebrush" morphology. Some branches are stabilized and branch further, giving rise to a compact arbor. The dynamic rate of branch addition and deletion is increased twofold when MK801 is used to block NMDA receptors, as if this prevents release of a stabilizing signal such as arachidonic acid (AA) from the postsynaptic neuron. In optic tract, AA mediates NCAM and L1 stimulation of axon growth by activating presynaptic protein kinase C (PKC) to phosphorylate GAP-43 and stabilize F-actin, and, if present in tectum, this growth control pathway could be modulated by postsynaptic activation. To test for the effects on arbor morphology of blocking PKC or AA release, we examined DiO-labeled retinal axons of larval zebrafish with time-lapse videomicroscopy. Bath application of the selective PKC inhibitor bisindolylmaleimide from 2 or 3 days onward doubled the rate at which side branches were added and deleted, as seen with MK801, and also prevented maturation of the arbor so that it retained a "bottlebrush" morphology. In order to selectively block the PKC being transported to retinal terminals, we injected the irreversible inhibitor calphostin C into the eye from which the ganglion cells were labeled, and this produced both effects seen with bath application. In contrast, there were no effects of control injections, which included Ringers into the same eye and the same dose into the opposite eye (actually much closer to the tectum of interest), to rule out the possibility that the inhibitor leaked from the eye to act on tectal cells. For comparison, we examined arbors treated with the NMDA blocker MK801 at half-hour time-lapse intervals, and detected the twofold rise in rates of branch addition and deletion previously reported in Xenopus larvae, but not the structural effect seen with the PKC inhibitors. In addition, we could produce both effects seen with PKC inhibitors by using RHC80267 to block AA release from DAG lipase, indicating that AA is the main drive for PKC activation. Thus, the results show a distinct role of AA and presynaptic PKC in both maturation of arbor structure and in the dynamic control of branching. The effects on branch dynamics were present regardless of the level of maturity of arbor structure. The fact that they mimicked those of MK801 suggests that presynaptic PKC may be involved in the NMDA receptor-driven stabilization of developing retinal arbors.
Collapse
Affiliation(s)
- John T Schmidt
- Department of Biological Sciences and Center for Neuroscience Research, University at Albany-SUNY, 1400 Washington Avenue, Albany, New York 12222, USA.
| | | | | |
Collapse
|
21
|
Takeda K, Matsuzawa A, Nishitoh H, Tobiume K, Kishida S, Ninomiya-Tsuji J, Matsumoto K, Ichijo H. Involvement of ASK1 in Ca2+-induced p38 MAP kinase activation. EMBO Rep 2004; 5:161-6. [PMID: 14749717 PMCID: PMC1298983 DOI: 10.1038/sj.embor.7400072] [Citation(s) in RCA: 152] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2003] [Revised: 11/06/2003] [Accepted: 11/28/2003] [Indexed: 11/08/2022] Open
Abstract
The mammalian mitogen-activated protein (MAP) kinase kinase kinase apoptosis signal-regulating kinase 1 (ASK1) is a pivotal component in cytokine- and stress-induced apoptosis. It also regulates cell differentiation and survival through p38 MAP kinase activation. Here we show that Ca2+ signalling regulates the ASK1-p38 MAP kinase cascade. Ca2+ influx evoked by membrane depolarization in primary neurons and synaptosomes induced activation of p38, which was impaired in those derived from ASK1-deficient mice. Ca2+/calmodulin-dependent protein kinase type II (CaMKII) activated ASK1 by phosphorylation. Moreover, p38 activation induced by the expression of constitutively active CaMKII required endogenous ASK1. Thus, ASK1 is a critical intermediate of Ca2+ signalling between CaMKII and p38 MAP kinase.
Collapse
Affiliation(s)
- Kohsuke Takeda
- Laboratory of Cell Signaling, Graduate School of Pharmaceutical Sciences, The University of Tokyo, and CREST, Japan Science and Technology Corporation, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Atsushi Matsuzawa
- Laboratory of Cell Signaling, Graduate School of Pharmaceutical Sciences, The University of Tokyo, and CREST, Japan Science and Technology Corporation, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Hideki Nishitoh
- Laboratory of Cell Signaling, Graduate School of Pharmaceutical Sciences, The University of Tokyo, and CREST, Japan Science and Technology Corporation, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Laboratory of Cell Signaling, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
| | - Kei Tobiume
- Department of Molecular Oncology, Institute of Gerontology, Nippon Medical School, 1-396 Kosugi-cho, Nakahara-ku, Kawasaki 211-8533, Japan
| | - Satoshi Kishida
- Department of Molecular Biology, Graduate School of Science, Nagoya University, and CREST, Japan Society and Technology Corporation, Chikusa-ku, Nagoya 464-8602, Japan
| | - Jun Ninomiya-Tsuji
- Department of Molecular Biology, Graduate School of Science, Nagoya University, and CREST, Japan Society and Technology Corporation, Chikusa-ku, Nagoya 464-8602, Japan
| | - Kunihiro Matsumoto
- Department of Molecular Biology, Graduate School of Science, Nagoya University, and CREST, Japan Society and Technology Corporation, Chikusa-ku, Nagoya 464-8602, Japan
| | - Hidenori Ichijo
- Laboratory of Cell Signaling, Graduate School of Pharmaceutical Sciences, The University of Tokyo, and CREST, Japan Science and Technology Corporation, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
- Tel: +81 5841 4859; Fax: +81 5841 4778; E-mail:
| |
Collapse
|
22
|
Tombes RM, Faison MO, Turbeville JM. Organization and evolution of multifunctional Ca2+/CaM-dependent protein kinase genes. Gene 2003; 322:17-31. [PMID: 14644494 DOI: 10.1016/j.gene.2003.08.023] [Citation(s) in RCA: 154] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The "multi-functional" Ca(2+) and calmodulin-dependent protein kinase, type II (CaMK-II) is an evolutionarily conserved protein. It has been found as a single gene in the horseshoe crab, marine sponge, sea urchin, nematode, and fruit fly, whereas most vertebrates possess four genes (alpha, beta, gamma, and delta). Species from fruit flies to humans encode alternative splice variants which are differentially targeted to phosphorylate diverse downstream targets of Ca(2+) signaling. By comparing known CaMK-II protein and nucleotide sequences, we have now provided evidence for the evolutionary relatedness of CaMK-IIs. Parsimony analyses unambiguously indicate that the four vertebrate CaMK-II genes arose via repeated duplications. Nucleotide phylogenies show consistent but moderate support for the placement of the vertebrate delta CaMK-II as the earliest diverging vertebrate gene. delta CaMK-II is the only gene with both central and C-terminal variable domains and has three to four times more intronic sequence than the other three genes. beta and gamma CaMK-II genes show strong sequence similarity and have comparable exon and intron organization and utilization. alpha CaMK-II is absent from amphibians (Xenopus laevis) and has the most restricted tissue specificity in mammals, whereas beta, gamma, and delta CaMK-IIs are expressed in most tissues. All 38 known mammalian CaMK-II splice variants were compiled with their tissue specificity and exon usage. Some of these variants use alternative 5' and 3' donors within a single exon as well as alternative promoters. These findings serve as an important benchmark for future phylogenetic, developmental, or biochemical studies on this important, conserved, and highly regulated gene family.
Collapse
Affiliation(s)
- Robert M Tombes
- Department of Biology, Virginia Commonwealth University, Richmond, VA 23284-2012, USA.
| | | | | |
Collapse
|
23
|
N- and C-terminal domains of beta-catenin, respectively, are required to initiate and shape axon arbors of retinal ganglion cells in vivo. J Neurosci 2003. [PMID: 12878698 DOI: 10.1523/jneurosci.23-16-06567.2003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We used deletion mutants to study beta-catenin function in axon arborization of retinal ganglion cells (RGCs) in live Xenopus laevis tadpoles. A deletion mutant betacatDeltaARM consists of the N- and C-terminal domains of wild-type beta-catenin that contain, respectively, alpha-catenin and postsynaptic density-95 (PSD-95)/discs large (Dlg)/zona occludens-1 (ZO-1) (PDZ) binding sites but lacks the central armadillo repeat region that binds cadherins and other proteins. Expression of DeltaARM in RGCs of live tadpoles perturbed axon arborization in two distinct ways: some RGC axons did not form arbors, whereas the remaining RGC axons formed arbors with abnormally long and tangled branches. Expression of the N- and C-terminal domains of beta-catenin separately in RGCs resulted in segregation of these two phenotypes. The axons of RGCs overexpressing the N-terminal domain of beta-catenin developed no or very few branches, whereas axons of RGCs overexpressing the C-terminal domain of beta-catenin formed arbors with long, tangled branches. Additional analysis revealed that the axons of RGCs that did not form arbors after overexpression of DeltaARM or the N-terminal domain of beta-catenin were frequently mistargeted within the tectum. These results suggest that interactions of the N-terminal domain of beta-catenin with alpha-catenin and of the C-terminal domain with PDZ domain-containing proteins are required, respectively, to initiate and shape axon arbors of RGCs in vivo.
Collapse
|
24
|
Pratt KG, Watt AJ, Griffith LC, Nelson SB, Turrigiano GG. Activity-dependent remodeling of presynaptic inputs by postsynaptic expression of activated CaMKII. Neuron 2003; 39:269-81. [PMID: 12873384 DOI: 10.1016/s0896-6273(03)00422-7] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Competitive synaptic remodeling is an important feature of developmental plasticity, but the molecular mechanisms remain largely unknown. Calcium/calmodulin-dependent protein kinase II (CaMKII) can induce postsynaptic changes in synaptic strength. We show that postsynaptic CaMKII also generates structural synaptic rearrangements between cultured cortical neurons. Postsynaptic expression of activated CaMKII (T286D) increased the strength of transmission between pairs of pyramidal neuron by a factor of 4, through a modest increase in quantal amplitude and a larger increase in the number of synaptic contacts. Concurrently, T286D reduced overall excitatory synaptic density and increased the proportion of unconnected pairs. This suggests that connectivity from some synaptic partners was increased while other partners were eliminated. The enhancement of connectivity required activity and NMDA receptor activation, while the elimination did not. These data suggest that postsynaptic activation of CaMKII induces a structural remodeling of presynaptic inputs that favors the retention of active presynaptic partners.
Collapse
Affiliation(s)
- Kara G Pratt
- Department of Biology, Volen National Center for Complex Systems, Brandeis University, Waltham, MA 02454, USA
| | | | | | | | | |
Collapse
|
25
|
Regulation by glycogen synthase kinase-3beta of the arborization field and maturation of retinotectal projection in zebrafish. J Neurosci 2002. [PMID: 12451132 DOI: 10.1523/jneurosci.22-23-10324.2002] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The retinotectal projection is one of the best systems to study the molecular basis of synapse formation in the CNS because of the well characterized topographic connections and activity-dependent refinement. Here, we developed a presynaptic neuron-specific gene manipulation system in the zebrafish retinotectal projection in vivo using the nicotinic acetylcholine receptor beta3 (nAChRbeta3) gene promoter. Enhanced green fluorescent protein (EGFP) expression signals in living transgenic zebrafish lines carrying the nAChRbeta3 gene promoter-directed EGFP expression vector visualized the development of entire retinal ganglion cell (RGC) axon projection to the tectum. Microinjection of the nAChRbeta3 gene promoter-driven double-cassette vectors directing the expression of both dominant-negative glycogen synthase kinase-3beta (dnGSK-3beta) and EGFP enabled us to follow the development of individual RGCs and to examine the effect of the molecule on the axonal arborization and maturation of the same neurons in living zebrafish. We found that the expression of the dominant-negative form of zebrafish GSK-3beta suppressed the arborization field of RGC axon terminals in the tectum as estimated by the reduction of arbor branch length and arbor areas. Furthermore, the suppression of GSK-3beta activity increased the size of vesicle-associated membrane protein 2-EGFP puncta in RGC axon terminals at the early stage of innervation to the tectum. These results suggest that GSK-3beta regulates the arborization field and maturation of RGC axon terminals in vivo.
Collapse
|
26
|
Kotak VC, Sanes DH. Postsynaptic kinase signaling underlies inhibitory synaptic plasticity in the lateral superior olive. JOURNAL OF NEUROBIOLOGY 2002; 53:36-43. [PMID: 12360581 DOI: 10.1002/neu.10107] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
UNLABELLED In the auditory system, inhibitory transmission from the medial nucleus of the trapezoid body (MNTB) to neurons of the lateral superior olivary nucleus (LSO) undergoes activity-dependent long-term depression, and may be associated with developmental elimination of these synapses [Sanes DH, Friauf E (2000). REVIEW development and influence of inhibition in the laterial superior olivary nucleus. Hear Res 147:46-58]. Although GABA(B) receptor activation and postsynaptic free calcium are implicated in this depression, little is known about intracellular signaling mechanisms in this or other forms of inhibitory plasticity. In this study, we asked whether the calcium dependency of inhibitory depression was associated with the activation of calcium/calmodulin-dependent protein kinase II (CaMKII), protein kinase C (PKC), and/or cAMP-dependent protein kinase A (PKA). Whole-cell voltage-clamp recordings were obtained from LSO neurons in a brain slice preparation, permitting for the selective pharmacologic manipulation of individual postsynaptic LSO neurons. Inclusion of a CaMKII antagonist (KN-62) in the internal pipet solution blocked inhibitory synaptic depression. A second CaMKII inhibitor (autocamtide peptide fragment) significantly decreased inhibitory depression. Inclusion of a specific antagonist of protein kinase C (PKC fragment 19-36) in the internal recording solution also blocked inhibitory depression. To test involvement of a cAMP-dependent intracellular cascade, two different manipulations were performed. Inclusion of PKA antagonists (Rp-cAMPS or a cAMP dependent protein kinase inhibitor peptide) prevented inhibitory depression. In contrast, when a nonhydrolyzable cAMP analog (Sp-cAMPS) was permitted to enter the postsynaptic cell, the MNTB-evoked IPSCs became depressed in the absence of low-frequency stimulation. Thus, three key postsynaptic kinases, CaMKII, PKC, and PKA, participate in the activity-dependent depression of inhibitory MNTB-LSO synapses during postnatal development.
Collapse
Affiliation(s)
- Vibhakar C Kotak
- Center for Neural Science, 4 Washington Place, New York University, New York, New York 10003, USA
| | | |
Collapse
|
27
|
Spatial and temporal regulation of Ca2+/calmodulin-dependent protein kinase II activity in developing neurons. J Neurosci 2002. [PMID: 12177199 DOI: 10.1523/jneurosci.22-16-07016.2002] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We have studied Ca2+/calmodulin-dependent protein kinase II (CaMKII) isoform distribution and activity in embryonic hippocampal neurons developing in culture. We have found a strong correlation between the expression of the alpha subunit of the enzyme and the ability to undergo depolarization-dependent phosphorylation, which in young neurons is limited to the somatodendritic pool of the kinase. The lack of responsiveness of the axons of young alphaCaMKII-positive neurons is not caused by a lower Ca2+ influx but rather by a differential balance between kinase and phosphatase activities in this compartment. After the establishment of synaptic contacts, the presynaptic pool of the kinase displays an increasing level of activity and acquires the parallel ability to phosphorylate synapsin I, which represents one of the major CaMKII presynaptic targets in mature nerve terminals. In contrast, the activity of the postsynaptic pool of the kinase remains constant throughout synaptogenesis. In the presence of a nearly homogeneous subcellular distribution, this highly regionalized regulation of activity may reflect the multifunctional roles of CaMKII in both developing and mature neurons.
Collapse
|
28
|
Libersat F, Duch C. Morphometric analysis of dendritic remodeling in an identified motoneuron during postembryonic development. J Comp Neurol 2002; 450:153-66. [PMID: 12124760 DOI: 10.1002/cne.10318] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A detailed quantitative description of modifications in neuronal architecture is an important prerequisite to investigate the signals underlying behaviorally relevant changes in neuronal shape. Extensive morphological remodeling of neurons occurs during the metamorphosis of holometabolous insects, such as Manduca sexta, in which new adult behaviors develop postembryonically. In this study, a morphometric analysis of the structural changes of an identified Manduca motoneuron, MN5, was conducted by sampling its metric parameters at different developmental stages. The remodeling of MN5 is divided into three main phases. The regression of most larval dendrites (1) is followed by the formation of dendritic growth-cones (2), and subsequently, adult dendrite formation (3). In contrast, the cell body and link segment surface increase during dendritic regression and regrowth, indicating that different cell compartments receive different signals, or respond differently to the same signal. During dendritic growth-cone formation, the growth of the cell body and the link segment are arrested. Sholl and branch frequency analysis suggest two different modes of dendritic growth. During a first growth-cone-dependent phase, new branch formation occurs at all dendrites. The maximum path length of the major dendritic tree changes little, whereas branch order increases from 20 to 45. Changes in total dendritic length are correlated with strong changes in the number of nodes but with minor changes in the average dendritic segment length, indicating a mode of growth similar to that induced by steroid hormone application to cultured motoneurons. The second phase is growth-cone-independent, and branching is limited to high order dendrites.
Collapse
Affiliation(s)
- Frederic Libersat
- Zlotowski Center for Neuroscience and Department of Life Sciences, Ben Gurion University of the Negev, Beer Sheva 84105, Israel.
| | | |
Collapse
|
29
|
Borodinsky LN, Coso OA, Fiszman ML. Contribution of Ca2+ calmodulin-dependent protein kinase II and mitogen-activated protein kinase kinase to neural activity-induced neurite outgrowth and survival of cerebellar granule cells. J Neurochem 2002; 80:1062-70. [PMID: 11953456 DOI: 10.1046/j.1471-4159.2002.00795.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In this report we describe our studies on intracellular signals that mediate neurite outgrowth and long-term survival of cerebellar granule cells. The effect of voltage-gated calcium channel activation on neurite complexity was evaluated in cultured cerebellar granule cells grown for 48 h at low density; the parameter measured was the fractal dimension of the cell. We explored the contribution of two intracellular pathways, Ca2+ calmodulin-dependent protein kinase II and mitogen-activated protein kinase kinase (MEK1), to the effects of high [K+ ]e under serum-free conditions. We found that 25 mm KCl (25K) induced an increase in calcium influx through L subtype channels. In neurones grown for 24-48 h under low-density conditions, the activation of these channels induced neurite outgrowth through the activation of Ca2+ calmodulin-dependent protein kinase II. This also produced an increase in long-term neuronal survival with a partial contribution from the MEK1 pathway. We also found that the addition of 25K increased the levels of the phosphorylated forms of Ca2+ calmodulin-dependent protein kinase II and of the extracellular signal-regulated kinases 1 and 2. Neuronal survival under resting conditions is supported by the MEK1 pathway. We conclude that intracellular calcium oscillations can triggered different biological effects depending on the stage of maturation of the neuronal phenotype. Ca2+ calmodulin-dependent protein kinase II activation determines the growth of neurites and the development of neuronal complexity.
Collapse
Affiliation(s)
- Laura N Borodinsky
- Instituto de Investigaciones Farmacológicas, CONICET, FCEyN, UBA, Buenos Aires, Argentina
| | | | | |
Collapse
|
30
|
Lisman J, Schulman H, Cline H. The molecular basis of CaMKII function in synaptic and behavioural memory. Nat Rev Neurosci 2002; 3:175-90. [PMID: 11994750 DOI: 10.1038/nrn753] [Citation(s) in RCA: 1389] [Impact Index Per Article: 63.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Long-term potentiation (LTP) in the CA1 region of the hippocampus has been the primary model by which to study the cellular and molecular basis of memory. Calcium/calmodulin-dependent protein kinase II (CaMKII) is necessary for LTP induction, is persistently activated by stimuli that elicit LTP, and can, by itself, enhance the efficacy of synaptic transmission. The analysis of CaMKII autophosphorylation and dephosphorylation indicates that this kinase could serve as a molecular switch that is capable of long-term memory storage. Consistent with such a role, mutations that prevent persistent activation of CaMKII block LTP, experience-dependent plasticity and behavioural memory. These results make CaMKII a leading candidate in the search for the molecular basis of memory.
Collapse
Affiliation(s)
- J Lisman
- Department of Biology, Brandeis University, Waltham, Massachusetts 02454, USA
| | | | | |
Collapse
|
31
|
Zou DJ, Greer CA, Firestein S. Expression pattern of alpha CaMKII in the mouse main olfactory bulb. J Comp Neurol 2002; 443:226-36. [PMID: 11807833 DOI: 10.1002/cne.10125] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Multifunctional Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) is highly enriched at synapses and has been implicated in regulating the formation and function of several sensory systems, including the visual and the somatosensory systems. Although there is evidence for CaMKII expression in the olfactory system, the cellular localization of CaMKII has not been well studied and its function remains unknown. In this study, we examined the normal expression patterns of the predominant alpha CaMKII in the mouse main olfactory bulb. We showed that alpha CaMKII expression levels were high in the olfactory bulb and were developmentally regulated. Immunoreactivity to alpha CaMKII was heavy in the external plexiform layer and the granule cell layer but minimal in the olfactory nerve layer and the glomerular layer. At the cellular level, alpha CaMKII was selectively expressed in the gamma-aminobutyric acid (GABA)ergic granule cells but not in the GABAergic periglomerular cells. Unexpectedly, alpha CaMKII was not detected in the glutamatergic mitral/tufted cells. At the ultrastructural level, alpha CaMKII immunoreactivity was positive in granule cell spines and dendrites, but negative in mitral/tufted cell dendrites. In contrast, in the piriform cortex, as in the majority of cortical regions, alpha CaMKII was expressed in the glutamatergic neurons but not in the GABAergic neurons. Our results set the stage for ongoing investigations of the roles of CaMKII in the formation and function of the olfactory system.
Collapse
Affiliation(s)
- Dong-Jing Zou
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA.
| | | | | |
Collapse
|
32
|
Abstract
It is now 15 years since the discovery that N-methyl-d-aspartate receptor activity is required to maintain the refined topographic organization of retinotectal projections. Recent studies have identified additional components of the signaling pathways required for activity-dependent map formation and maintenance. Nitric oxide and brain-derived neurotrophic factor, candidate retrograde messengers, and serotonin and acetylcholine, modulators of neuronal excitability, all affect mapping. These studies indicate that the mapping process intersects with other processes fundamental to visual system development and function, such as process outgrowth, synaptic turnover and neuromodulation.
Collapse
Affiliation(s)
- Elizabeth A Debski
- Department of Biological Sciences, University of Kentucky, 101 Morgan Biological Science Building, Lexington, Kentucky 40506, USA
| | | |
Collapse
|
33
|
Glazewski S, Bejar R, Mayford M, Fox K. The effect of autonomous alpha-CaMKII expression on sensory responses and experience-dependent plasticity in mouse barrel cortex. Neuropharmacology 2001; 41:771-8. [PMID: 11640932 DOI: 10.1016/s0028-3908(01)00097-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The calcium/calmodulin kinase II (CaMKII) autophosphorylation site is thought to be important for plasticity, learning and memory. If autophosphorylation is prevented by a point mutation (T286A) LTP is blocked in the hippocampus and cortex. Conversely, if the point mutation mimics autophosphorylation (T286D) a range of frequencies that normally produce LTP in wild types cause LTD instead. In order to test whether the alphaCaMKII-T286D mutation increases levels of depression in vivo, we examined the effect of the alphaCaMKII-T286D transgene on plasticity induced in the barrel cortex by whisker deprivation. Surprisingly, the mutation did not affect depression or potentiation. However, in animals reared with the transgene turned on from birth, the surround receptive field responses were greater than normal. This effect may be due to the potentiating action of autophosphorylated CaMKII during early development.
Collapse
Affiliation(s)
- S Glazewski
- Cardiff School of Biosciences, Cardiff University, Museum Avenue, CF10 3US, Cardiff, UK
| | | | | | | |
Collapse
|
34
|
Nedivi E, Javaherian A, Cantallops I, Cline HT. Developmental regulation of CPG15 expression in Xenopus. J Comp Neurol 2001; 435:464-73. [PMID: 11406826 PMCID: PMC3070489 DOI: 10.1002/cne.1044] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Mechanisms controlling dendritic arbor formation affect the establishment of neuronal circuits. Candidate plasticity gene 15 (CPG15) is a glycosylphosphatidyl inositol (GPI)-linked activity-induced protein that has been shown to function as an intercellular signaling molecule that can promote the morphological and physiological development of the Xenopus retinotectal system. A thorough understanding of CPG15 function requires knowledge of the spatiotemporal expression of the endogenous protein. We therefore cloned Xenopus cpg15 and used RNA in situ hybridization and immunohistochemistry to determine the pattern of CPG15 expression. cpg15 mRNA and CPG15 protein are first detectable in the developing spinal cord and become widespread as development proceeds. CPG15 is expressed in sensory regions of the brain, including the visual, auditory, and olfactory systems. Within the retina, CPG15 is only expressed in retinal ganglion cells. CPG15 protein is concentrated in axon tracts, including retinal axons. These data support a model in which CPG15 expressed in retinal ganglion cells is trafficked to retinal axons, where it modulates postsynaptic dendritic arbor elaboration, and synaptic maturation.
Collapse
Affiliation(s)
- Elly Nedivi
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724
| | - Ashkan Javaherian
- Graduate Program in Genetics, State University of New York at Stony Brook, Stony Brook, New York 11790
| | | | - Hollis T. Cline
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724
| |
Collapse
|
35
|
Abstract
We report an electroporation technique for targeting gene transfer to individual cells in intact tissue. Electrical stimulation through a micropipette filled with DNA or other macromolecules electroporates a single cell at the tip of the micropipette. Electroporation of a plasmid encoding enhanced green fluorescent protein (GFP) into the brain of intact Xenopus tadpoles or rat hippocampal slices resulted in GFP expression in single neurons and glia. In vivo imaging showed morphologies, dendritic arbor dynamics, and growth rates characteristic of healthy cells. Coelectroporation of two plasmids resulted in expression of both proteins, while electroporation of fluorescent dextrans allowed direct visualization of transfer of molecules into cells. This technique will allow unprecedented spatial and temporal control over gene delivery and protein expression.
Collapse
Affiliation(s)
- K Haas
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | | | | | | | | |
Collapse
|
36
|
Cantallops I, Haas K, Cline HT. Postsynaptic CPG15 promotes synaptic maturation and presynaptic axon arbor elaboration in vivo. Nat Neurosci 2000; 3:1004-11. [PMID: 11017173 DOI: 10.1038/79823] [Citation(s) in RCA: 123] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The formation of CNS circuits is characterized by the coordinated development of neuronal structure and synaptic function. The activity-regulated candidate plasticity gene 15 (cpg15) encodes a glycosylphosphatidylinositol (GPI)-linked protein whose in vivo expression increases the dendritic arbor growth rate of Xenopus optic tectal cells. We now demonstrate that tectal cell expression of CPG15 significantly increases the elaboration of presynaptic retinal axons by decreasing rates of branch retractions. Whole-cell recordings from optic tectal neurons indicate that CPG15 expression promotes retinotectal synapse maturation by recruiting functional AMPA receptors to synapses. Expression of truncated CPG15, lacking its GPI anchor, does not promote axon arbor growth and blocks synaptic maturation. These results suggest that CPG15 coordinately increases the growth of pre- and postsynaptic structures and the number and strength of their synaptic contacts.
Collapse
Affiliation(s)
- I Cantallops
- Cold Spring Harbor Laboratory, 1 Bungtown Rd., Cold Spring Harbor, New York 11724, USA
| | | | | |
Collapse
|
37
|
Lesions of an avian forebrain nucleus that disrupt song development alter synaptic connectivity and transmission in the vocal premotor pathway. J Neurosci 1999. [PMID: 10531443 DOI: 10.1523/jneurosci.19-21-09385.1999] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The avian forebrain nucleus, the lateral magnocellular nucleus of the anterior neostriatum (LMAN), is necessary for normal song development because LMAN lesions made in juvenile birds disrupt song production but do not disrupt song when made in adults. Although these age-limited behavioral effects implicate LMAN in song learning, a potential confound is that LMAN lesions could disrupt normal vocal motor function independent of any learning role by altering LMAN's premotor target, the song nucleus, the robust nucleus of the archistriatum (RA). To date, however, no studies have examined directly the effects of LMAN lesions on the circuitry of the RA. We report here that juvenile LMAN lesions rapidly and profoundly affect RA, altering synaptic connectivity within this nucleus, including descending inputs from the song nucleus HVc. Specifically, morphological assays of the dendritic spines of RA projection neurons and axon terminal boutons arising from HVc show a numerical decline in the density of connections in RA in LMAN-lesioned juveniles compared with controls. Concurrently, LMAN lesions alter excitatory transmission within the juvenile RA: after LMAN lesions, the stimulus-response relationship between HVc fibers and RA neurons steepens, and the amplitude of spontaneous monophasic EPSCs increases. Rather than arresting RA in a juvenile state, LMAN lesions transform the structure and function of RA and its connections, such that it is distinct from that of the normal juvenile. In many ways, RA circuitry in LMAN-lesioned juveniles resembles that of normal adults, suggesting that LMAN lesions induce a premature maturation of the vocal motor pathway, which may lead to a loss of behavioral plasticity and abnormal song development.
Collapse
|
38
|
Postsynaptic calcium/calmodulin-dependent protein kinase II is required to limit elaboration of presynaptic and postsynaptic neuronal arbors. J Neurosci 1999. [PMID: 10516310 DOI: 10.1523/jneurosci.19-20-08909.1999] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Neuronal dendritic and axonal arbors grow to a characteristic size and then stabilize their structures. Activity-dependent stop-growing signals may limit neuronal process elaboration. We tested whether endogenous calcium/calmodulin-dependent protein kinase II (CaMKII) activity in postsynaptic optic tectal cells is required to restrict the elaboration of neuronal processes in the Xenopus tadpole retinotectal projection. Optic tectal cells were infected with vaccinia viruses that express CaMKII-specific inhibitory peptides. In vivo time-lapse imaging revealed that expression of CaMKII inhibitors blocked the growth restriction that normally occurs during maturation of tectal cell dendritic arbors. Postsynaptic CaMKII inhibition also increased the growth of presynaptic retinotectal axon arbors. The results indicate that endogenous postsynaptic CaMKII activity is required to limit the growth of presynaptic and postsynaptic arbor structures in vivo.
Collapse
|
39
|
Fan GH, Wang LZ, Qiu HC, Ma L, Pei G. Inhibition of calcium/calmodulin-dependent protein kinase II in rat hippocampus attenuates morphine tolerance and dependence. Mol Pharmacol 1999; 56:39-45. [PMID: 10385682 DOI: 10.1124/mol.56.1.39] [Citation(s) in RCA: 120] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Learning and memory have been suggested to be important in the development of opiate addiction. Based on the recent findings that calcium/calmodulin-dependent protein kinase II (CaMKII) is essential in learning and memory processes, and morphine treatment increases CaMKII activity in hippocampus, the present study was undertaken to examine whether inhibition of hippocampal CaMKII prevents morphine tolerance and dependence. Here, we report that inhibition of CaMKII by intrahippocampal dentate gyrus administration of the specific inhibitors KN-62 and KN-93 to rats significantly attenuated the tolerance to the analgesic effect of morphine and the abstinence syndrome precipitated by opiate antagonist naloxone. In contrast, both KN-04 and KN-92, the inactive structural analogs of KN-62 and KN-93, failed to attenuate morphine tolerance and dependence, indicating that the observed effects of KN-62 and KN-93 are mediated through inhibition of CaMKII. Furthermore, administration of CaMKII antisense oligonucleotide into rat hippocampal dentate gyrus, which decreased the expression of CaMKII specifically, also attenuated morphine tolerance and dependence, while the corresponding sense oligonucleotide of CaMKII did not exhibit such inhibitory effect. Moreover, the KN-62 treatment abolished the rewarding properties of morphine as measured by the conditioned place preference. These results suggest that hippocampal CaMKII is critically involved in the development of morphine tolerance and dependence, and inhibition of this kinase may have some therapeutic benefit in the treatment of opiate tolerance and dependence.
Collapse
Affiliation(s)
- G H Fan
- Shanghai Institute of Cell Biology, Chinese Academy of Sciences, Shanghai, People's Republic of China
| | | | | | | | | |
Collapse
|
40
|
Turrigiano GG. Homeostatic plasticity in neuronal networks: the more things change, the more they stay the same. Trends Neurosci 1999; 22:221-7. [PMID: 10322495 DOI: 10.1016/s0166-2236(98)01341-1] [Citation(s) in RCA: 530] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
During learning and development, neural circuitry is refined, in part, through changes in the number and strength of synapses. Most studies of long-term changes in synaptic strength have concentrated on Hebbian mechanisms, where these changes occur in a synapse-specific manner. While Hebbian mechanisms are important for modifying neuronal circuitry selectively, they might not be sufficient because they tend to destabilize the activity of neuronal networks. Recently, several forms of homeostatic plasticity that stabilize the properties of neural circuits have been identified. These include mechanisms that regulate neuronal excitability, stabilize total synaptic strength, and influence the rate and extent of synapse formation. These forms of homeostatic plasticity are likely to go 'hand-in-glove' with Hebbian mechanisms to allow experience to modify the properties of neuronal networks selectively.
Collapse
Affiliation(s)
- G G Turrigiano
- Dept of Biology and Center for Complex Systems, Brandeis University, Waltham, MA 02454, USA
| |
Collapse
|
41
|
Abstract
Many pathways in the developing visual system are restructured and become highly organized even before vision occurs. Yet the developmental processes underlying the remodeling of visual connectivity are crucially dependent on retinal activity. Surprisingly, the immature and light-insensitive retina spontaneously generates a pattern of rhythmic bursting activity during the period when the connectivity patterns of retinal ganglion cells are shaped. Spatially, the activity is seen to spread across the retina in the form of waves that bring into synchrony the bursts of neighboring cells. Waves are present in the developing retina of higher and lower vertebrates, which suggests that this form of activity may be a common and fundamental mechanism employed in the activity-dependent refinement of early patterns of visual connections. Unraveling the cues encoded by the waves promises to provide important insights into how interactions driven by specific patterns of activity could lead to the modification of connectivity during development.
Collapse
Affiliation(s)
- R O Wong
- Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
| |
Collapse
|
42
|
Rajan I, Witte S, Cline HT. NMDA receptor activity stabilizes presynaptic retinotectal axons and postsynaptic optic tectal cell dendrites in vivo. JOURNAL OF NEUROBIOLOGY 1999; 38:357-68. [PMID: 10022578 DOI: 10.1002/(sici)1097-4695(19990215)38:3<357::aid-neu5>3.0.co;2-#] [Citation(s) in RCA: 159] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
To investigate the role of N-methyl-D-aspartate (NMDA) receptor activity in the stability of the presynaptic axon arbor and postsynaptic dendritic arbors in vivo, we took time-lapse confocal images of single DiI-labeled Xenopus retinotectal axons and optic tectal neurons in the presence and absence of the NMDA receptor antagonist, APV. Retinotectal axons or tectal neurons were imaged at 30-min intervals over 2 h, or twice over a 24-h period. Retinal axons in animals exposed to DL-APV (100 microM) showed an increase in rates of branch additions and a decrease in branch lifetimes over 2 h compared to untreated axons. Under the same experimental conditions, tectal neurons showed a decreased rate of branch tip additions and retractions. APV treatment over 24 h had no apparent effect on axon arbor morphology, but did decrease tectal cell dendritic arbor elaboration. These observations demonstrate that NMDA receptor activity in postsynaptic neurons stabilizes pre- and postsynaptic neuronal morphology in vivo.. However, when NMDA receptor activity is blocked, presynaptic retinal axons respond with increased arbor dynamics while postsynaptic tectal cell dendrites decrease arbor dynamics. Such differential responses of pre- and postsynaptic partners might increase the probability of coactive afferents converging onto a common target under conditions of lower NMDA receptor activity.
Collapse
Affiliation(s)
- I Rajan
- Cold Spring Harbor Laboratory, New York 11724, USA
| | | | | |
Collapse
|
43
|
NMDA receptor-mediated refinement of a transient retinotectal projection during development requires nitric oxide. J Neurosci 1999. [PMID: 9870953 DOI: 10.1523/jneurosci.19-01-00229.1999] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
A transient ipsilateral retinotectal projection is normally eliminated during embryonic development of the chick visual system. Administration of the NMDA receptor antagonist 5-methyl-10, 11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine (MK-801) during the developmental period in which this projection normally disappears prevented its complete elimination. Previous studies showed that tectal cells express nitric oxide synthase during development, and blocking synthesis of nitric oxide also prevented elimination of the ipsilateral retinotectal projection. The effect of NMDA receptor blockade on nitric oxide synthase activity in tectal cells was assessed biochemically in chick embryos. Increasing concentrations of MK-801 resulted in a dose-dependent decrease in nitric oxide synthase activity. This result suggests that NMDA receptor activation can regulate nitric oxide synthase activity in the tectum. The degree of rescue of the ipsilateral retinotectal projection was compared in embryos treated either with MK-801 or with an inhibitor of nitric oxide synthesis, Nomega-nitro-L-arginine (L-NoArg). At comparable levels of inhibition of nitric oxide synthesis, no significant difference was observed in the degree of rescue mediated by NMDA receptor blockade or nitric oxide synthesis blockade. These results suggest that NMDA receptor-mediated elimination of the ipsilateral retinotectal projection is completely mediated via nitric oxide.
Collapse
|
44
|
Ernst AF, Jurney WM, McLoon SC. Mechanisms involved in development of retinotectal connections: roles of Eph receptor tyrosine kinases, NMDA receptors and nitric oxide. PROGRESS IN BRAIN RESEARCH 1999; 118:115-31. [PMID: 9932438 DOI: 10.1016/s0079-6123(08)63204-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Axons of retinal ganglion cells exhibit a specific pattern of connections with the brain. Within each visual nucleus in the brain, retinal connections are topographic such that axons from neighboring ganglion cells have neighboring synapses. Research is beginning to shed light on the mechanisms responsible for development of topographic connections in the visual system. Much of this research is focused on the axonal connections of the retina with the tectum. In vivo and in vitro experiments indicate that the pattern of retinotectal connections develops in part due to positional labels carried by the growing retinal axons and by the tectal cells. Evidence suggests that gradients of Eph receptor tyrosine kinases serve as positional labels on the growing retinal axons, and gradients of ligands for these receptors serve as positional labels in the tectum. Blocking expression of EphA3, a receptor tyrosine kinase, in the developing retina resulted in disruption of the topography of the retinotectal connections, further supporting the role of these, molecules. Although positional labels appear to be important, other mechanisms must also be involved. The initial pattern of retinotectal connections lacks the precision seen in the adult. The adult pattern of connections arises during development by activity dependent refinement of a roughly ordered prepattern. The refinement process results in elimination of projections to the wrong side of the brain, to non-visual nuclei and to inappropriate regions within a nucleus. Blocking NMDA receptors during the period of refinement preserved anomalous retinotectal projections, which suggests that elimination of these projections is mediated by NMDA receptors. Furthermore, tectal cells normally express high levels of nitric oxide synthase (NOS) during the period of refinement, and blocking nitric oxide (NO) synthesis also preserved inappropriate projections. Thus, both NMDA receptors and NO appear to be involved in refinement. Blocking NMDA receptor activation reduced NOS activity in tectal cells, which suggests the possibility that NO is the downstream mediator of NMDA function related to refinement. A quantitative comparison of blocking NMDA receptors, NO synthesis or both showed that all three treatments have comparable effects on refinement. This indicates that the role of NMDA receptor activation relative to refinement may be completely mediated through nitric oxide. Quantitative analysis also suggests that other mechanisms not involving NMDA receptors or NO must be involved in refinement. Other mechanisms appear to include cell death.
Collapse
Affiliation(s)
- A F Ernst
- Department of Cell Biology and Neuroanatomy, University of Minnesota, Minneapolis 55455, USA
| | | | | |
Collapse
|
45
|
Edwards JA, Cline HT. Light-induced calcium influx into retinal axons is regulated by presynaptic nicotinic acetylcholine receptor activity in vivo. J Neurophysiol 1999; 81:895-907. [PMID: 10036287 DOI: 10.1152/jn.1999.81.2.895] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Visual activity is thought to be a critical factor in controlling the development of central retinal projections. Neuronal activity increases cytosolic calcium, which was hypothesized to regulate process outgrowth in neurons. We performed an in vivo imaging study in the retinotectal system of albino Xenopus laevis tadpoles with the fluorescent calcium indicator calcium green 1 dextran (CaGD) to test the role of calcium in regulating axon arbor development. We find that visual stimulus to the retina increased CaGD fluorescence intensity in retinal ganglion cell (RGC) axon arbors within the optic tectum and that branch additions to retinotectal axon arbors correlated with a local rise in calcium in the parent branch. We find three types of responses to visual stimulus, which roughly correlate with the ON, OFF, and SUSTAINED response types of RGC reported by physiological criteria. Imaging in bandscan mode indicated that patterns of calcium transients were nonuniform throughout the axons. We tested whether the increase in calcium in the retinotectal axons required synaptic activity in the retina; intraocular application of tetrodotoxin (10 microM) or nifedipine (1 and 10 microM) blocked the stimulus-induced increase in RGC axonal fluorescence. A second series of pharmacological investigations was designed to determine the mechanism of the calcium elevation in the axon terminals within the optic tectum. Injection of bis-(o-aminophenoxy)-N,N,N',N'-tetraacetic acid-AM (BAPTA-AM) (20 mM) into the tectal ventricle reduced axonal calcium levels, supporting the idea that visual stimulation increases axonal calcium. Injection of BAPTA (20 mM) into the tectal ventricle to chelate extracellular calcium also attenuated the calcium response to visual stimulation, indicating that calcium enters the axon from the extracellular medium. Caffeine (10 mM) caused a large increase in axonal calcium, indicating that intracellular stores contribute to the calcium signal. Presynaptic nicotinic acetylcholine receptors (nAChRs) may play a role in axon arbor development and the formation of the topographic retinotectal projection. Injection of nicotine (10 microM) into the tectal ventricle significantly elevated RGC axonal calcium levels, whereas application of the nAChR antagonist alphaBTX (100 nM) reduced the stimulus-evoked rise in RGC calcium fluorescence. These data suggest that light stimulus to the retina increases calcium in the axon terminal arbors through a mechanism that includes influx through nAChRs and amplification by calcium-induced calcium release from intracellular calcium stores. Such a mechanism may contribute to developmental plasticity of the retinotectal system by influencing both axon arbor elaboration and the strength of synaptic transmission.
Collapse
Affiliation(s)
- J A Edwards
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | | |
Collapse
|
46
|
Matheson SF, Levine RB. Steroid hormone enhancement of neurite outgrowth in identified insect motor neurons involves specific effects on growth cone form and function. ACTA ACUST UNITED AC 1999. [DOI: 10.1002/(sici)1097-4695(199901)38:1<27::aid-neu3>3.0.co;2-u] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
|
47
|
Presynaptic calcium/calmodulin-dependent protein kinase II regulates habituation of a simple reflex in adult Drosophila. J Neurosci 1998. [PMID: 9787001 DOI: 10.1523/jneurosci.18-21-08955.1998] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
On repetitive stimulation, the strength of a reflex controlling leg position in Drosophila decreased, and this response decrement conformed to the parametric features of habituation. To study the presynaptic function of CaMKII in this nonassociative form of learning, we used a P[Gal4] insertion line to target the expression of mutant forms of CaMKII to the sensory neurons controlling the reflex. Targeted expression of a calcium-independent CaMKII construct (T287D) in the sensory neurons eliminated habituation. Targeted expression of a mutant CaMKII incapable of achieving calcium independence (T287A) reduced the initial reflex response, but a strong facilitation then occurred, and this eliminated most of the habituation. Finally, when a CaMKII inhibitory peptide (ala) was expressed in sensory neurons, the initial response was reduced, followed by facilitation. These results suggest that basal CaMKII levels in the presynaptic neurons set the response level and dynamics of the entire neural circuit.
Collapse
|
48
|
Abstract
Throughout the developing nervous system, competition between axons causes the permanent removal of some synaptic connections. In mouse neuromuscular junctions at birth, terminal branches of different axons are intermingled. However, during the several weeks after birth, these branches progressively segregated into nonoverlapping compartments before the complete withdrawal of all but one axon. Segregation was caused by selective branch atrophy, detachment, and withdrawal; the axon branches that were nearest to the competitor's branches were removed before the more distant branches were removed. This progression suggests that the signals that mediate the competitive removal of synapses must decrease in potency over short distances.
Collapse
Affiliation(s)
- W B Gan
- Department of Anatomy and Neurobiology, Washington University School of Medicine, 660 South Euclid Avenue, Box 8108, St. Louis, MO 63110, USA
| | | |
Collapse
|
49
|
Abstract
Recent studies have provided convincing evidence that cellular forms of synaptic plasticity that are thought to represent the building blocks of learning and memory are also used during development to establish organized sensory projections within the brain.
Collapse
Affiliation(s)
- H T Cline
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, 11724, USA
| |
Collapse
|
50
|
Abstract
Activity-independent and activity-dependent mechanisms work in concert to regulate neuronal growth, ensuring the formation of accurate synaptic connections. CPG15, a protein regulated by synaptic activity, functions as a cell-surface growth-promoting molecule in vivo. In Xenopus laevis, CPG15 enhanced dendritic arbor growth in projection neurons, with no effect on interneurons. CPG15 controlled growth of neighboring neurons through an intercellular signaling mechanism that requires its glycosylphosphatidylinositol link. CPG15 may represent a new class of activity-regulated, membrane-bound, growth-promoting proteins that permit exquisite spatial and temporal control of neuronal structure.
Collapse
Affiliation(s)
- E Nedivi
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA.
| | | | | |
Collapse
|