1
|
Miranda-Riestra A, Cercós MG, Trueta C, Oikawa-Sala J, Argueta J, Constantino-Jonapa LA, Cruz-Garduño R, Benítez-King G, Estrada-Reyes R. Participation of Ca 2+-Calmodulin-Dependent Protein Kinase II in the Antidepressant-Like Effects of Melatonin. Mol Pharmacol 2024; 106:107-116. [PMID: 39079719 DOI: 10.1124/molpharm.124.000890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Accepted: 06/26/2024] [Indexed: 08/18/2024] Open
Abstract
Melatonin (N-acetyl-5-methoxytryptamine) is an indoleamine secreted by the pineal gland during the dark phase of the photoperiod. Its main function is the synchronization of different body rhythms with the dark-light cycle. Research on melatonin has significantly advanced since its discovery and we now know that it has considerable significance in various physiological processes, including immunity, aging, and reproduction. Moreover, in recent years evidence of the pharmacological possibilities of melatonin has increased. Indoleamine, on the other hand, has antidepressant-like effects in rodents, which may be mediated by the activation of calcium-calmodulin-dependent kinase II (CaMKII) and are also related to the regulation of neuroplasticity processes, including neurogenesis, synaptic maintenance, and long-term potentiation. Remarkably, patients with major depression show decreased levels of circulating melatonin in plasma. This review presents evidence of the antidepressant-like effects of melatonin in preclinical models and the participation of CaMKII in these actions. CaMKII's role in cognition and memory processes, which are altered in depressive states, are part of the review, and the effects of melatonin in these processes are also reviewed. Furthermore, participation of CaMKII on structural and synaptic plasticity and the effects of melatonin are also described. Finally, the advantages of using melatonin in combination with other antidepressants such as ketamine for neuroplasticity are described. Evidence supports that CaMKII is activated by melatonin and downstream melatonin receptors and may be the common effector in the synergistic effects of melatonin with other antidepressants. SIGNIFICANCE STATEMENT: This review compiled evidence supporting that melatonin causes antidepressant-like effects in mice through calmodulin kinase II stimulation of downstream melatonin receptors as well as the participation of this enzyme in neuroplasticity, memory, and cognition. Finally, we describe evidence about the effectiveness of antidepressant-like effects of melatonin in combination with ketamine.
Collapse
Affiliation(s)
- Armida Miranda-Riestra
- Laboratorio de Neurofarmacología (A.M.-R., J.O.-S., J.A., L.A.C.-J., G.B.-K.), Departamento de Neurofisiología, Dirección de Investigaciones en Neurociencias (M.G.C., C.T., R.C.-G.), and Laboratorio de Fitofarmacología, Dirección de Investigaciones en Neurociencias (R.E.-R.), Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Mexico City, Mexico
| | - Montserrat G Cercós
- Laboratorio de Neurofarmacología (A.M.-R., J.O.-S., J.A., L.A.C.-J., G.B.-K.), Departamento de Neurofisiología, Dirección de Investigaciones en Neurociencias (M.G.C., C.T., R.C.-G.), and Laboratorio de Fitofarmacología, Dirección de Investigaciones en Neurociencias (R.E.-R.), Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Mexico City, Mexico
| | - Citlali Trueta
- Laboratorio de Neurofarmacología (A.M.-R., J.O.-S., J.A., L.A.C.-J., G.B.-K.), Departamento de Neurofisiología, Dirección de Investigaciones en Neurociencias (M.G.C., C.T., R.C.-G.), and Laboratorio de Fitofarmacología, Dirección de Investigaciones en Neurociencias (R.E.-R.), Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Mexico City, Mexico
| | - Julián Oikawa-Sala
- Laboratorio de Neurofarmacología (A.M.-R., J.O.-S., J.A., L.A.C.-J., G.B.-K.), Departamento de Neurofisiología, Dirección de Investigaciones en Neurociencias (M.G.C., C.T., R.C.-G.), and Laboratorio de Fitofarmacología, Dirección de Investigaciones en Neurociencias (R.E.-R.), Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Mexico City, Mexico
| | - Jesús Argueta
- Laboratorio de Neurofarmacología (A.M.-R., J.O.-S., J.A., L.A.C.-J., G.B.-K.), Departamento de Neurofisiología, Dirección de Investigaciones en Neurociencias (M.G.C., C.T., R.C.-G.), and Laboratorio de Fitofarmacología, Dirección de Investigaciones en Neurociencias (R.E.-R.), Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Mexico City, Mexico
| | - Luis A Constantino-Jonapa
- Laboratorio de Neurofarmacología (A.M.-R., J.O.-S., J.A., L.A.C.-J., G.B.-K.), Departamento de Neurofisiología, Dirección de Investigaciones en Neurociencias (M.G.C., C.T., R.C.-G.), and Laboratorio de Fitofarmacología, Dirección de Investigaciones en Neurociencias (R.E.-R.), Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Mexico City, Mexico
| | - Ricardo Cruz-Garduño
- Laboratorio de Neurofarmacología (A.M.-R., J.O.-S., J.A., L.A.C.-J., G.B.-K.), Departamento de Neurofisiología, Dirección de Investigaciones en Neurociencias (M.G.C., C.T., R.C.-G.), and Laboratorio de Fitofarmacología, Dirección de Investigaciones en Neurociencias (R.E.-R.), Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Mexico City, Mexico
| | - Gloria Benítez-King
- Laboratorio de Neurofarmacología (A.M.-R., J.O.-S., J.A., L.A.C.-J., G.B.-K.), Departamento de Neurofisiología, Dirección de Investigaciones en Neurociencias (M.G.C., C.T., R.C.-G.), and Laboratorio de Fitofarmacología, Dirección de Investigaciones en Neurociencias (R.E.-R.), Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Mexico City, Mexico
| | - Rosa Estrada-Reyes
- Laboratorio de Neurofarmacología (A.M.-R., J.O.-S., J.A., L.A.C.-J., G.B.-K.), Departamento de Neurofisiología, Dirección de Investigaciones en Neurociencias (M.G.C., C.T., R.C.-G.), and Laboratorio de Fitofarmacología, Dirección de Investigaciones en Neurociencias (R.E.-R.), Instituto Nacional de Psiquiatría Ramón de la Fuente Muñiz, Mexico City, Mexico
| |
Collapse
|
2
|
Longhena F, Faustini G, Brembati V, Pizzi M, Benfenati F, Bellucci A. An updated reappraisal of synapsins: structure, function and role in neurological and psychiatric disorders. Neurosci Biobehav Rev 2021; 130:33-60. [PMID: 34407457 DOI: 10.1016/j.neubiorev.2021.08.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 07/29/2021] [Accepted: 08/09/2021] [Indexed: 01/02/2023]
Abstract
Synapsins (Syns) are phosphoproteins strongly involved in neuronal development and neurotransmitter release. Three distinct genes SYN1, SYN2 and SYN3, with elevated evolutionary conservation, have been described to encode for Synapsin I, Synapsin II and Synapsin III, respectively. Syns display a series of common features, but also exhibit distinctive localization, expression pattern, post-translational modifications (PTM). These characteristics enable their interaction with other synaptic proteins, membranes and cytoskeletal components, which is essential for the proper execution of their multiple functions in neuronal cells. These include the control of synapse formation and growth, neuron maturation and renewal, as well as synaptic vesicle mobilization, docking, fusion, recycling. Perturbations in the balanced expression of Syns, alterations of their PTM, mutations and polymorphisms of their encoding genes induce severe dysregulations in brain networks functions leading to the onset of psychiatric or neurological disorders. This review presents what we have learned since the discovery of Syn I in 1977, providing the state of the art on Syns structure, function, physiology and involvement in central nervous system disorders.
Collapse
Affiliation(s)
- Francesca Longhena
- Division of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy.
| | - Gaia Faustini
- Division of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy.
| | - Viviana Brembati
- Division of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy.
| | - Marina Pizzi
- Division of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy.
| | - Fabio Benfenati
- Italian Institute of Technology, Via Morego 30, Genova, Italy; IRCSS Policlinico San Martino Hospital, Largo Rosanna Benzi 10, 16132, Genova, Italy.
| | - Arianna Bellucci
- Division of Pharmacology, Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy; Laboratory for Preventive and Personalized Medicine, Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, 25123, Brescia, Italy.
| |
Collapse
|
3
|
Zhang M, Augustine GJ. Synapsins and the Synaptic Vesicle Reserve Pool: Floats or Anchors? Cells 2021; 10:cells10030658. [PMID: 33809712 PMCID: PMC8002314 DOI: 10.3390/cells10030658] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 03/08/2021] [Accepted: 03/11/2021] [Indexed: 11/24/2022] Open
Abstract
In presynaptic terminals, synaptic vesicles (SVs) are found in a discrete cluster that includes a reserve pool that is mobilized during synaptic activity. Synapsins serve as a key protein for maintaining SVs within this reserve pool, but the mechanism that allows synapsins to do this is unclear. This mechanism is likely to involve synapsins either cross-linking SVs, thereby anchoring SVs to each other, or creating a liquid phase that allows SVs to float within a synapsin droplet. Here, we summarize what is known about the role of synapsins in clustering of SVs and evaluate experimental evidence supporting these two models.
Collapse
|
4
|
Bonnycastle K, Davenport EC, Cousin MA. Presynaptic dysfunction in neurodevelopmental disorders: Insights from the synaptic vesicle life cycle. J Neurochem 2020; 157:179-207. [PMID: 32378740 DOI: 10.1111/jnc.15035] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/14/2020] [Accepted: 04/22/2020] [Indexed: 12/11/2022]
Abstract
The activity-dependent fusion, retrieval and recycling of synaptic vesicles is essential for the maintenance of neurotransmission. Until relatively recently it was believed that most mutations in genes that were essential for this process would be incompatible with life, because of this fundamental role. However, an ever-expanding number of mutations in this very cohort of genes are being identified in individuals with neurodevelopmental disorders, including autism, intellectual disability and epilepsy. This article will summarize the current state of knowledge linking mutations in presynaptic genes to neurodevelopmental disorders by sequentially covering the various stages of the synaptic vesicle life cycle. It will also discuss how perturbations of specific stages within this recycling process could translate into human disease. Finally, it will also provide perspectives on the potential for future therapy that are targeted to presynaptic function.
Collapse
Affiliation(s)
- Katherine Bonnycastle
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
| | - Elizabeth C Davenport
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
| | - Michael A Cousin
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,Muir Maxwell Epilepsy Centre, University of Edinburgh, Edinburgh, UK.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, UK
| |
Collapse
|
5
|
Shiotani H, Maruo T, Sakakibara S, Miyata M, Mandai K, Mochizuki H, Takai Y. Aging-dependent expression of synapse-related proteins in the mouse brain. Genes Cells 2017; 22:472-484. [DOI: 10.1111/gtc.12489] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 03/08/2017] [Indexed: 01/13/2023]
Affiliation(s)
- Hajime Shiotani
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology; Kobe University Graduate School of Medicine; Kobe 650-0047 Japan
- Department of Neurology; Osaka University Graduate School of Medicine; Suita 565-0871 Japan
| | - Tomohiko Maruo
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology; Kobe University Graduate School of Medicine; Kobe 650-0047 Japan
| | - Shotaro Sakakibara
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology; Kobe University Graduate School of Medicine; Kobe 650-0047 Japan
| | - Muneaki Miyata
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology; Kobe University Graduate School of Medicine; Kobe 650-0047 Japan
| | - Kenji Mandai
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology; Kobe University Graduate School of Medicine; Kobe 650-0047 Japan
| | - Hideki Mochizuki
- Department of Neurology; Osaka University Graduate School of Medicine; Suita 565-0871 Japan
| | - Yoshimi Takai
- Division of Pathogenetic Signaling, Department of Biochemistry and Molecular Biology; Kobe University Graduate School of Medicine; Kobe 650-0047 Japan
| |
Collapse
|
6
|
Steuer Costa W, Yu SC, Liewald JF, Gottschalk A. Fast cAMP Modulation of Neurotransmission via Neuropeptide Signals and Vesicle Loading. Curr Biol 2017; 27:495-507. [PMID: 28162892 DOI: 10.1016/j.cub.2016.12.055] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Revised: 12/06/2016] [Accepted: 12/27/2016] [Indexed: 02/02/2023]
Abstract
Cyclic AMP (cAMP) signaling augments synaptic transmission, but because many targets of cAMP and protein kinase A (PKA) may be involved, mechanisms underlying this pathway remain unclear. To probe this mechanism, we used optogenetic stimulation of cAMP signaling by Beggiatoa-photoactivated adenylyl cyclase (bPAC) in Caenorhabditis elegans motor neurons. Behavioral, electron microscopy (EM), and electrophysiology analyses revealed cAMP effects on both the rate and on quantal size of transmitter release and led to the identification of a neuropeptidergic pathway affecting quantal size. cAMP enhanced synaptic vesicle (SV) fusion by increasing mobilization and docking/priming. cAMP further evoked dense core vesicle (DCV) release of neuropeptides, in contrast to channelrhodopsin (ChR2) stimulation. cAMP-evoked DCV release required UNC-31/Ca2+-dependent activator protein for secretion (CAPS). Thus, DCVs accumulated in unc-31 mutant synapses. bPAC-induced neuropeptide signaling acts presynaptically to enhance vAChT-dependent SV loading with acetylcholine, thus causing increased miniature postsynaptic current amplitudes (mPSCs) and significantly enlarged SVs.
Collapse
Affiliation(s)
- Wagner Steuer Costa
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max-von-Laue-Strasse 15, 60438 Frankfurt, Germany; Department of Biochemistry, Chemistry and Pharmacy, Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438 Frankfurt, Germany
| | - Szi-Chieh Yu
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max-von-Laue-Strasse 15, 60438 Frankfurt, Germany; Department of Biochemistry, Chemistry and Pharmacy, Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438 Frankfurt, Germany
| | - Jana F Liewald
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max-von-Laue-Strasse 15, 60438 Frankfurt, Germany; Department of Biochemistry, Chemistry and Pharmacy, Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438 Frankfurt, Germany
| | - Alexander Gottschalk
- Buchmann Institute for Molecular Life Sciences, Goethe University, Max-von-Laue-Strasse 15, 60438 Frankfurt, Germany; Department of Biochemistry, Chemistry and Pharmacy, Institute for Biophysical Chemistry, Goethe University, Max-von-Laue-Strasse 9, 60438 Frankfurt, Germany.
| |
Collapse
|
7
|
Bonifacino T, Musazzi L, Milanese M, Seguini M, Marte A, Gallia E, Cattaneo L, Onofri F, Popoli M, Bonanno G. Altered mechanisms underlying the abnormal glutamate release in amyotrophic lateral sclerosis at a pre-symptomatic stage of the disease. Neurobiol Dis 2016; 95:122-33. [PMID: 27425885 DOI: 10.1016/j.nbd.2016.07.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 07/08/2016] [Accepted: 07/13/2016] [Indexed: 01/29/2023] Open
Abstract
Abnormal Glu release occurs in the spinal cord of SOD1(G93A) mice, a transgenic animal model for human ALS. Here we studied the mechanisms underlying Glu release in spinal cord nerve terminals of SOD1(G93A) mice at a pre-symptomatic disease stage (30days) and found that the basal release of Glu was more elevated in SOD1(G93A) with respect to SOD1 mice, and that the surplus of release relies on synaptic vesicle exocytosis. Exposure to high KCl or ionomycin provoked Ca(2+)-dependent Glu release that was likewise augmented in SOD1(G93A) mice. Equally, the Ca(2+)-independent hypertonic sucrose-induced Glu release was abnormally elevated in SOD1(G93A) mice. Also in this case, the surplus of Glu release was exocytotic in nature. We could determine elevated cytosolic Ca(2+) levels, increased phosphorylation of Synapsin-I, which was causally related to the abnormal Glu release measured in spinal cord synaptosomes of pre-symptomatic SOD1(G93A) mice, and increased phosphorylation of glycogen synthase kinase-3 at the inhibitory sites, an event that favours SNARE protein assembly. Western blot experiments revealed an increased number of SNARE protein complexes at the nerve terminal membrane, with no changes of the three SNARE proteins and increased expression of synaptotagmin-1 and β-Actin, but not of an array of other release-related presynaptic proteins. These results indicate that the abnormal exocytotic Glu release in spinal cord of pre-symptomatic SOD1(G93A) mice is mainly based on the increased size of the readily releasable pool of vesicles and release facilitation, supported by plastic changes of specific presynaptic mechanisms.
Collapse
Affiliation(s)
- Tiziana Bonifacino
- Department of Pharmacy, Unit of Pharmacology and Toxicology, and Center of Excellence for Biomedical Research, University of Genoa, 16148 Genoa, Italy.
| | - Laura Musazzi
- Department of Pharmacological and Biomolecular Sciences and Center of Excellence on Neurodegenerative Diseases, University of Milan, 20133 Milan, Italy.
| | - Marco Milanese
- Department of Pharmacy, Unit of Pharmacology and Toxicology, and Center of Excellence for Biomedical Research, University of Genoa, 16148 Genoa, Italy.
| | - Mara Seguini
- Department of Pharmacological and Biomolecular Sciences and Center of Excellence on Neurodegenerative Diseases, University of Milan, 20133 Milan, Italy.
| | - Antonella Marte
- Department of Experimental Medicine, Unit of Human Physiology, University of Genoa, Viale Benedetto XV, 16132 Genoa, Italy.
| | - Elena Gallia
- Department of Pharmacy, Unit of Pharmacology and Toxicology, and Center of Excellence for Biomedical Research, University of Genoa, 16148 Genoa, Italy.
| | - Luca Cattaneo
- Department of Pharmacy, Unit of Pharmacology and Toxicology, and Center of Excellence for Biomedical Research, University of Genoa, 16148 Genoa, Italy.
| | - Franco Onofri
- Department of Experimental Medicine, Unit of Human Physiology, University of Genoa, Viale Benedetto XV, 16132 Genoa, Italy.
| | - Maurizio Popoli
- Department of Pharmacological and Biomolecular Sciences and Center of Excellence on Neurodegenerative Diseases, University of Milan, 20133 Milan, Italy.
| | - Giambattista Bonanno
- Department of Pharmacy, Unit of Pharmacology and Toxicology, and Center of Excellence for Biomedical Research, University of Genoa, 16148 Genoa, Italy.
| |
Collapse
|
8
|
Exploiting aberrant mRNA expression in autism for gene discovery and diagnosis. Hum Genet 2016; 135:797-811. [DOI: 10.1007/s00439-016-1673-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 04/17/2016] [Indexed: 01/09/2023]
|
9
|
SUMOylation of synapsin Ia maintains synaptic vesicle availability and is reduced in an autism mutation. Nat Commun 2015; 6:7728. [PMID: 26173895 PMCID: PMC4504226 DOI: 10.1038/ncomms8728] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 06/04/2015] [Indexed: 11/08/2022] Open
Abstract
Synapsins are key components of the presynaptic neurotransmitter release machinery. Their main role is to cluster synaptic vesicles (SVs) to each other and anchor them to the actin cytoskeleton to establish the reserve vesicle pool, and then release them in response to appropriate membrane depolarization. Here we demonstrate that SUMOylation of synapsin Ia (SynIa) at K687 is necessary for SynIa function. Replacement of endogenous SynIa with a non-SUMOylatable mutant decreases the size of the releasable vesicle pool and impairs stimulated SV exocytosis. SUMOylation enhances SynIa association with SVs to promote the efficient reclustering of SynIa following neuronal stimulation and maintain its presynaptic localization. The A548T mutation in SynIa is strongly associated with autism and epilepsy and we show that it leads to defective SynIa SUMOylation. These results identify SUMOylation as a fundamental regulator of SynIa function and reveal a novel link between reduced SUMOylation of SynIa and neurological disorders.
Collapse
|
10
|
Perlini LE, Szczurkowska J, Ballif BA, Piccini A, Sacchetti S, Giovedì S, Benfenati F, Cancedda L. Synapsin III acts downstream of semaphorin 3A/CDK5 signaling to regulate radial migration and orientation of pyramidal neurons in vivo. Cell Rep 2015; 11:234-48. [PMID: 25843720 PMCID: PMC4405008 DOI: 10.1016/j.celrep.2015.03.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 02/13/2015] [Accepted: 03/06/2015] [Indexed: 11/04/2022] Open
Abstract
Synapsin III (SynIII) is a phosphoprotein that is highly expressed at early stages of neuronal development. Whereas in vitro evidence suggests a role for SynIII in neuronal differentiation, in vivo evidence is lacking. Here, we demonstrate that in vivo downregulation of SynIII expression affects neuronal migration and orientation. By contrast, SynIII overexpression affects neuronal migration, but not orientation. We identify a cyclin-dependent kinase-5 (CDK5) phosphorylation site on SynIII and use phosphomutant rescue experiments to demonstrate its role in SynIII function. Finally, we show that SynIII phosphorylation at the CDK5 site is induced by activation of the semaphorin-3A (Sema3A) pathway, which is implicated in migration and orientation of cortical pyramidal neurons (PNs) and is known to activate CDK5. Thus, fine-tuning of SynIII expression and phosphorylation by CDK5 activation through Sema3A activity is essential for proper neuronal migration and orientation. Precise regulation of SynIII expression is essential during brain development SynIII regulates neuronal migration, orientation, and morphological maturation SynIII acts downstream of the Sema3A pathway, which involves NP1 and kinase CDK5 Phosphorylation of SynIII by CDK5 on Ser404 is essential for SynIII function
Collapse
Affiliation(s)
- Laura E Perlini
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genoa 16163, Italy; Department of Experimental Medicine, University of Genoa, Genoa 16132, Italy
| | - Joanna Szczurkowska
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genoa 16163, Italy
| | - Bryan A Ballif
- Department of Biology, University of Vermont, Burlington, VT 05405-0086, USA
| | - Alessandra Piccini
- Department of Experimental Medicine, University of Genoa, Genoa 16132, Italy
| | - Silvio Sacchetti
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genoa 16163, Italy
| | - Silvia Giovedì
- Department of Experimental Medicine, University of Genoa, Genoa 16132, Italy
| | - Fabio Benfenati
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genoa 16163, Italy; Department of Experimental Medicine, University of Genoa, Genoa 16132, Italy
| | - Laura Cancedda
- Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genoa 16163, Italy.
| |
Collapse
|
11
|
Chen M, Križaj D, Thoreson WB. Intracellular calcium stores drive slow non-ribbon vesicle release from rod photoreceptors. Front Cell Neurosci 2014; 8:20. [PMID: 24550779 PMCID: PMC3910126 DOI: 10.3389/fncel.2014.00020] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 01/13/2014] [Indexed: 01/26/2023] Open
Abstract
Rods are capable of greater slow release than cones contributing to overall slower release kinetics. Slow release in rods involves Ca2+-induced Ca2+ release (CICR). By impairing release from ribbons, we found that unlike cones where release occurs entirely at ribbon-style active zones, slow release from rods occurs mostly at ectopic, non-ribbon sites. To investigate the role of CICR in ribbon and non-ribbon release from rods, we used total internal reflection fluorescence microscopy as a tool for visualizing terminals of isolated rods loaded with fluorescent Ca2+ indicator dyes and synaptic vesicles loaded with dextran-conjugated pH-sensitive rhodamine. We found that rather than simply facilitating release, activation of CICR by ryanodine triggered release directly in rods, independent of plasma membrane Ca2+ channel activation. Ryanodine-evoked release occurred mostly at non-ribbon sites and release evoked by sustained depolarization at non-ribbon sites was mostly due to CICR. Unlike release at ribbon-style active zones, non-ribbon release did not occur at fixed locations. Fluorescence recovery after photobleaching of endoplasmic reticulum (ER)-tracker dye in rod terminals showed that ER extends continuously from synapse to soma. Release of Ca2+ from terminal ER by lengthy depolarization did not significantly deplete Ca2+ from ER in the perikaryon. Collectively, these results indicate that CICR-triggered release at non-ribbon sites is a major mechanism for maintaining vesicle release from rods and that CICR in terminals may be sustained by diffusion of Ca2+ through ER from other parts of the cell.
Collapse
Affiliation(s)
- Minghui Chen
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center Omaha, NE, USA ; Department of Ophthalmology and Visual Sciences, University of Nebraska Medical Center Omaha, NE, USA
| | - David Križaj
- Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah School of Medicine Salt Lake City, UT, USA
| | - Wallace B Thoreson
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center Omaha, NE, USA ; Department of Ophthalmology and Visual Sciences, University of Nebraska Medical Center Omaha, NE, USA
| |
Collapse
|
12
|
Giannandrea M, Guarnieri FC, Gehring NH, Monzani E, Benfenati F, Kulozik AE, Valtorta F. Nonsense-mediated mRNA decay and loss-of-function of the protein underlie the X-linked epilepsy associated with the W356× mutation in synapsin I. PLoS One 2013; 8:e67724. [PMID: 23818987 PMCID: PMC3688603 DOI: 10.1371/journal.pone.0067724] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 05/21/2013] [Indexed: 11/22/2022] Open
Abstract
Synapsins are a family of neuronal phosphoproteins associated with the cytosolic surface of synaptic vesicles. Experimental evidence suggests a role for synapsins in synaptic vesicle clustering and recycling at the presynaptic terminal, as well as in neuronal development and synaptogenesis. Synapsin knock-out (Syn1(-/-) ) mice display an epileptic phenotype and mutations in the SYN1 gene have been identified in individuals affected by epilepsy and/or autism spectrum disorder. We investigated the impact of the c.1067G>A nonsense transition, the first mutation described in a family affected by X-linked syndromic epilepsy, on the expression and functional properties of the synapsin I protein. We found that the presence of a premature termination codon in the human SYN1 transcript renders it susceptible to nonsense-mediated mRNA decay (NMD). Given that the NMD efficiency is highly variable among individuals and cell types, we investigated also the effects of expression of the mutant protein and found that it is expressed at lower levels compared to wild-type synapsin I, forms perinuclear aggregates and is unable to reach presynaptic terminals in mature hippocampal neurons grown in culture. Taken together, these data indicate that in patients carrying the W356× mutation the function of synapsin I is markedly impaired, due to both the strongly decreased translation and the altered function of the NMD-escaped protein, and support the value of Syn1(-/-) mice as an experimental model mimicking the human pathology.
Collapse
MESH Headings
- Animals
- Blotting, Northern
- Cells, Cultured
- Codon, Nonsense
- Epilepsy/genetics
- Epilepsy/metabolism
- Female
- Gene Expression
- Genetic Diseases, X-Linked/genetics
- Genetic Diseases, X-Linked/metabolism
- HeLa Cells
- Hippocampus/cytology
- Hippocampus/metabolism
- Humans
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Microscopy, Fluorescence
- Microtubule-Associated Proteins/metabolism
- Neurons/metabolism
- Nonsense Mediated mRNA Decay
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rats
- Rats, Sprague-Dawley
- Synapsins/genetics
- Synapsins/metabolism
Collapse
Affiliation(s)
- Maila Giannandrea
- Division of Neuroscience, San Raffaele Scientific Institute and Vita-Salute University, Milan, Italy
| | - Fabrizia C. Guarnieri
- Division of Neuroscience, San Raffaele Scientific Institute and Vita-Salute University, Milan, Italy
| | | | - Elena Monzani
- Division of Neuroscience, San Raffaele Scientific Institute and Vita-Salute University, Milan, Italy
| | - Fabio Benfenati
- Department of Neuroscience and Brain Technologies, The Italian Institute of Technology, Genoa, Italy
- Department of Experimental Medicine, University of Genoa, Genoa, Italy
| | - Andreas E. Kulozik
- Department of Pediatric Oncology, Hematology and Immunology, University of Heidelberg Medical Center and Molecular Medicine Partnership Unit, EMBL and University of Heidelberg, Heidelberg, Germany
| | - Flavia Valtorta
- Division of Neuroscience, San Raffaele Scientific Institute and Vita-Salute University, Milan, Italy
| |
Collapse
|
13
|
Skaper SD. Alzheimer's disease and amyloid: culprit or coincidence? INTERNATIONAL REVIEW OF NEUROBIOLOGY 2012; 102:277-316. [PMID: 22748834 DOI: 10.1016/b978-0-12-386986-9.00011-9] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Alzheimer's disease (AD) is the largest unmet medical need in neurology today. This most common form of irreversible dementia is placing a considerable and increasing burden on patients, caregivers, and society, as more people live long enough to become affected. Current drugs improve symptoms but do not have profound neuroprotective and/or disease-modifying effects. AD is characterized by loss of neurons, dystrophic neurites, senile/amyloid/neuritic plaques, neurofibrillary tangles, and synaptic loss. Beta-amyloid (Aβ) peptide deposition is the major pathological feature of AD. Increasing evidence suggests that overexpression of the amyloid precursor protein and subsequent generation of the 39-43 amino acid residue, Aβ, are central to neuronal degeneration observed in AD patients possessing familial AD mutations, while transgenic mice overexpressing amyloid precursor protein develop AD-like pathology. Despite the genetic and cell biological evidence that supports the amyloid hypothesis, it is becoming increasing clear that AD etiology is complex and that Aβ alone is unable to account for all aspects of AD. The fact that vast overproduction of Aβ peptides in the brain of transgenic mouse models fails to cause overt neurodegeneration raises the question as to whether accumulation of Aβ peptides is indeed the culprit for neurodegeneration in AD. There is increasing evidence to suggest that Aβ/amyloid-independent factors, including the actions of AD-related genes (microtubule-associated protein tau, polymorphisms of apolipoprotein E4), inflammation, and oxidative stress, also contribute to AD pathogenesis. This chapter reviews the current state of knowledge on these factors and their possible interactions, as well as their potential for neuroprotection targets.
Collapse
Affiliation(s)
- Stephen D Skaper
- Department of Pharmacology and Anesthesiology, University of Padova, Largo E. Meneghetti, Padova, Italy
| |
Collapse
|
14
|
Jensen MB, Bhatia VK, Jao CC, Rasmussen JE, Pedersen SL, Jensen KJ, Langen R, Stamou D. Membrane curvature sensing by amphipathic helices: a single liposome study using α-synuclein and annexin B12. J Biol Chem 2011; 286:42603-42614. [PMID: 21953452 DOI: 10.1074/jbc.m111.271130] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Preferential binding of proteins on curved membranes (membrane curvature sensing) is increasingly emerging as a general mechanism whereby cells may effect protein localization and trafficking. Here we use a novel single liposome fluorescence microscopy assay to examine a common sensing motif, the amphipathic helix (AH), and provide quantitative measures describing and distinguishing membrane binding and sensing behavior. By studying two AH-containing proteins, α-synuclein and annexin B12, as well as a range of AH peptide mutants, we reveal that both the hydrophobic and hydrophilic faces of the helix greatly influence binding and sensing. Although increased hydrophobic and electrostatic interactions with the membrane both lead to greater densities of bound protein, the former yields membrane curvature-sensitive binding, whereas the latter is not curvature-dependent. However, the relative contributions of both components determine the sensing of AHs. In contrast, charge density in the lipid membrane seems important primarily in attracting AHs to the membrane but does not significantly influence sensing. These observations were made possible by the ability of our assay to distinguish within our samples liposomes with and without bound protein as well as the density of bound protein. Our findings suggest that the description of membrane curvature-sensing requires consideration of several factors such as short and long range electrostatic interactions, hydrogen bonding, and the volume and structure of inserted hydrophobic residues.
Collapse
Affiliation(s)
- Martin Borch Jensen
- Bionanotechnology and Nanomedicine Laboratory, Department of Neuroscience and Pharmacology, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark; Nano-Science Center, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Vikram Kjøller Bhatia
- Bionanotechnology and Nanomedicine Laboratory, Department of Neuroscience and Pharmacology, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark; Nano-Science Center, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark; Lundbeck Foundation Center Biomembranes in Nanomedicine, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
| | - Christine C Jao
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California 90033
| | - Jakob Ewald Rasmussen
- IGM-Bioorganic Chemistry, Faculty of Life Sciences, University of Copenhagen, 1871 Frederiksberg C, Denmark
| | - Søren L Pedersen
- IGM-Bioorganic Chemistry, Faculty of Life Sciences, University of Copenhagen, 1871 Frederiksberg C, Denmark
| | - Knud J Jensen
- IGM-Bioorganic Chemistry, Faculty of Life Sciences, University of Copenhagen, 1871 Frederiksberg C, Denmark
| | - Ralf Langen
- Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, California 90033
| | - Dimitrios Stamou
- Bionanotechnology and Nanomedicine Laboratory, Department of Neuroscience and Pharmacology, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark; Nano-Science Center, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark; Lundbeck Foundation Center Biomembranes in Nanomedicine, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark.
| |
Collapse
|
15
|
Gasperini L, Piubelli C, Carboni L. Proteomics of rat hypothalamus, hippocampus and pre-frontal/frontal cortex after central administration of the neuropeptide PACAP. Mol Biol Rep 2011; 39:2921-35. [PMID: 21687973 DOI: 10.1007/s11033-011-1054-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2010] [Accepted: 06/08/2011] [Indexed: 11/25/2022]
Abstract
Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide that exerts pleiotropic functions, acting as a hypophysiotropic factor, a neurotrophic and a neuroprotective agent. The molecular pathways activated by PACAP to exert its physiological roles in brain are incompletely understood. In this study, adrenocorticotropic hormone (ACTH), prolactin, luteinising hormone (LH), follicle-stimulating hormone (FSH), thyroid-stimulating hormone (TSH), brain-derived neurotrophic factor and corticosterone blood levels were determined before and 20, 40, 60, and 120 min after PACAP intracerebroventricular administration. PACAP treatment increased ACTH, corticosterone, LH and FSH blood concentrations, while it decreased TSH levels. A proteomics investigation was carried out in hypothalamus, hippocampus and pre-frontal/frontal cortex (P/FC) using 2-dimensional gel electrophoresis at 120 min, the end-point suggested by studies on PACAP hypophysiotropic activities. Spots showing statistically significant alterations after PACAP treatment were identified by Matrix-assisted laser desorption/ionization-Time of flight mass spectrometry. Identified proteins were consistent with PACAP involvement in different molecular processes in brain. Altered expression levels were observed for proteins involved in cytoskeleton modulation and synaptic plasticity: actin in the hypothalamus; stathmin, dynamin, profilin and cofilin in hippocampus; synapsin in P/FC. Proteins involved in cellular differentiation were also modulated: glutathione-S-transferase α and peroxiredoxin in hippocampus; nucleoside diphosphate kinase in P/FC. Alterations were detected in proteins involved in neuroprotection, neurodegeneration and apoptosis: ubiquitin carboxyl-terminal hydrolase isozyme L1 and heat shock protein 90-β in hypothalamus; α-synuclein in hippocampus; glyceraldehyde-3-phosphate dehydrogenase and prohibitin in P/FC. This proteomics study identified new proteins involved in molecular mechanisms mediating PACAP functions in the central nervous system.
Collapse
Affiliation(s)
- Lisa Gasperini
- Neurosciences CEDD, GlaxoSmithKline Medicines Research Centre, Via A Fleming 4, 37135 Verona, Italy
| | | | | |
Collapse
|
16
|
Shupliakov O, Haucke V, Pechstein A. How synapsin I may cluster synaptic vesicles. Semin Cell Dev Biol 2011; 22:393-9. [DOI: 10.1016/j.semcdb.2011.07.006] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Accepted: 07/13/2011] [Indexed: 12/14/2022]
|
17
|
Nuwal T, Heo S, Lubec G, Buchner E. Mass spectrometric analysis of synapsins in Drosophila melanogaster and identification of novel phosphorylation sites. J Proteome Res 2010; 10:541-50. [PMID: 21028912 DOI: 10.1021/pr100746s] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Synapsins are synaptic vesicle-associated phosphoproteins that play a major role in the fine regulation of neurotransmitter release. In Drosophila, synapsins are required for complex behavior including learning and memory. Synapsin isoforms were immunoprecipitated from homogenates of wild-type Drosophila heads using monoclonal antibody 3C11. Synapsin null mutants (Syn(97)) served as negative controls. The eluted proteins were separated by SDS-PAGE and visualized by silver staining. Gel pieces picked from five bands specific for wild type were analyzed by nano-LC-ESI-MS/MS following multienzyme digestion (trypsin, chymotrypsin, AspN, subtilisin, pepsin, and proteinase K). The protein was unambiguously identified with high sequence coverage (90.83%). A number of sequence conflicts were observed and the N-terminal amino acid was identified as methionine rather than leucine expected from the cDNA sequence. Several peptides from the larger isoform demonstrated that the in-frame UAG stop codon at position 582 which separates two large open reading frames is read through by tRNAs for lysine. Seven novel phosphorylation sites in Drosophila synapsin were identified at Thr-86, Ser-87, Ser-464, Thr-466, Ser-538, Ser-961, and Tyr-982 and verified by phosphatase treatment. No phosphorylation was observed at the conserved PKA/CaM kinase-I/IV site (RRFS, edited to RGFS) in domain A or a potential PKA site near domain E.
Collapse
Affiliation(s)
- Tulip Nuwal
- Department of Neurobiology and Genetics, Biozentrum, University of Wuerzburg, Wuerzburg, Germany
| | | | | | | |
Collapse
|
18
|
Abeta(1-42) reduces synapse number and inhibits neurite outgrowth in primary cortical and hippocampal neurons: a quantitative analysis. J Neurosci Methods 2008; 175:96-103. [PMID: 18761375 DOI: 10.1016/j.jneumeth.2008.08.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Revised: 07/11/2008] [Accepted: 08/05/2008] [Indexed: 11/22/2022]
Abstract
Synaptic loss represents one of the earliest signs of neuronal damage and is observed within both Alzheimer's disease patients and transgenic mouse models of the disease. We have developed a novel in vitro assay using high content screening technology to measure changes in a number of cell physiological parameters simultaneously within a neuronal population. Using Hoechst-33342 to label nuclei, betaIII-tubulin as a neuron-specific marker, and synapsin-I as an indicator of pre-synaptic sites, we have designed software to interrogate triple-labelled images, counting only those synaptic puncta associated with tubulin-positive structures. Here we demonstrate that addition of amyloid beta peptide (Abeta(1-42)), to either primary hippocampal or cortical neurons for 4 days in vitro has deleterious effects upon synapse formation, neurite outgrowth and arborisation in a concentration-dependent manner. Control reverse peptide showed no effect over the same concentration range. The effects of Abeta(1-42) were inhibited by D-KLVFFA, which contains residues 16-20 of Abeta that function as a self-recognition element during Abeta assembly and bind to the homologous region of Abeta and block its oligomerisation. These effects of Abeta(1-42) on synapse number and neurite outgrowth are similar to those described within AD patient pathology and transgenic mouse models.
Collapse
|
19
|
Levitan ES. Signaling for vesicle mobilization and synaptic plasticity. Mol Neurobiol 2008; 37:39-43. [PMID: 18446451 DOI: 10.1007/s12035-008-8014-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2008] [Accepted: 03/17/2008] [Indexed: 10/22/2022]
Abstract
The hypothesis that release of classical neurotransmitters and neuropeptides is facilitated by increasing the mobility of small synaptic vesicles (SSVs) and dense core vesicles (DCVs) could not be tested until the advent of methods for visualizing these secretory vesicles in living nerve terminals. In fact, fluorescence imaging studies have only since 2005 established that activity increases secretory vesicle mobility in motoneuron terminals and chromaffin cells. Mobilization of DCVs and SSVs appears to be due to liberation of hindered vesicles to promote quicker diffusion. However, F-actin and synapsin, which have been featured in mobilization models, are not required for activity-dependent increases in the mobility of DCVs or SSVs. Most recently, the signaling required for sustained mobilization has been identified for Drosophila motoneuron DCVs and shown to increase synaptic transmission. Specifically, presynaptic endoplasmic reticulum ryanodine receptor-mediated Ca2+ release activates Ca2+/calmodulin-dependent kinase II to mobilize DCVs and induce post-tetanic potentiation (PTP) of neuropeptide release in the Drosophila neuromuscular junction. The shared signaling for increasing vesicle mobility and PTP links vesicle mobilization and synaptic plasticity.
Collapse
Affiliation(s)
- Edwin S Levitan
- Department of Pharmacology, University of Pittsburgh, Pittsburgh, PA 15261, USA.
| |
Collapse
|
20
|
Abstract
Neuronal communication is tightly regulated in time and space. Following neuronal activation, an electrical signal triggers neurotransmitter (NT) release at the active zone. The process starts by the signal reaching the synapse followed by a fusion of the synaptic vesicle (SV) and diffusion of the released NT in the synaptic cleft. The NT then binds to the appropriate receptor and induces a membrane potential change at the target cell membrane. The entire process is controlled by a fairly small set of synaptic proteins, collectively called SYCONs. The biochemical features of SYCONs underlie the properties of NT release. SYCONs are characterized by their ability to detect and respond to changes in environmental signals. For example, consider synaptotagmin I (Syt1), a prototype of a protein family with over 20 gene and variants in mammals. Syt1 is a specific example of a multi-sensor device with a large repertoire of discrete states. Several of these states are stimulated by a local concentration of signaling molecules such as Ca2+. The ability of this protein to sense signaling molecules and to adopt multiple biochemical states is shared by other SYCONs such as the synapsins (Syns). Specific biochemical states of Syns determine the accessibility of SV for NT release. Each of these states is defined by a specific alternative spliced variant with a unique profile of phosphorylation modified sites. The plasticity of the synapse is a direct reflection of SYCON's multiple biochemical states. State transitions occurs in a wide range of time scales, and therefore these molecules need to cope with events that last milliseconds (i.e., exocytosis in fast responding synapses) and with events that can carry on for many minutes (i.e., organization of SV pools). We suggest that SYCONs are optimized throughout evolution as multi-sensor devices. A full repertoire of the switches leading to alternation of protein states and a detailed characterization of protein-protein network within the synapse is critical for the development of a dynamic model of synaptic transmission.
Collapse
Affiliation(s)
- Guy Brachya
- Dept of Biological Chemistry, The Hebrew University of Jerusalem, 91904, Israel
| | - Chava Yanay
- Dept of Biological Chemistry, The Hebrew University of Jerusalem, 91904, Israel
| | - Michal Linial
- Dept of Biological Chemistry, The Hebrew University of Jerusalem, 91904, Israel
| |
Collapse
|
21
|
Lonart G, Simsek-Duran F. Deletion of synapsins I and II genes alters the size of vesicular pools and rabphilin phosphorylation. Brain Res 2006; 1107:42-51. [PMID: 16844103 DOI: 10.1016/j.brainres.2006.05.092] [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] [Received: 09/21/2005] [Revised: 05/04/2006] [Accepted: 05/28/2006] [Indexed: 01/21/2023]
Abstract
Previous studies established that genetic deletion of synapsins, synaptic vesicle-associated phosphoproteins that regulate neurotransmitter release, decreases the number of synaptic vesicles in nerve terminals. To investigate whether these changes affect the release properties of the remaining synaptic vesicles, we used a radioactive labeling technique to measure release independently of the total number of synaptic vesicles. 3H-glutamate and 14C-gamma-amino-butyric-acid (GABA) release from isolated nerve terminals prepared from the neocortex of synapsins I and II double knock-out mice (DKO) was assayed and compared to wild-type preparations. Hyperosmotic shock-evoked 3H-glutamate was reduced by 20+/-3% from DKO nerve terminals and potassium depolarization-evoked glutamate release was also decreased by 28+/-2%. Surprisingly, sucrose or potassium depolarization-evoked release of 14C-GABA was increased by 32+/-4% and 29+/-5%, respectively. The basal efflux of both 3H-glutamate and 14C-GABA increased by 17+/-2% and 12+/-2% from DKO nerve terminals. As lack of synapsins I and II, major phosphoproteins of synaptic vesicles, may lead to deregulation of phosphorylation events, we compared phosphorylation state of another synaptic vesicle protein, rabphilin. In DKO nerve terminals, membrane-associated rabphilin level was reduced by approximately 0.28-fold, its phosphorylation at 234serine was increased by approximately 1.61-fold whereas cytosolic rabphilin levels showed both more dramatic reduction in abundance, approximately 16.5-fold, and increase in phosphorylation, approximately 4.8-fold. Collectively, these data suggest that deletion of major synapsin isoforms leads to (1) deregulation of basal neurotransmission causing "leaky" basal release, (2) changes in either the size or mobilization of releasable or reserve pools, and (3) a decrease in rabphilin abundance accompanied by an increase in basal phosphorylation of the remaining rabphilin.
Collapse
Affiliation(s)
- György Lonart
- Department of Pathology and Anatomy, Eastern Virginia Medical School, 700 W. Olney Rd. Norfolk, VA 23507, USA.
| | | |
Collapse
|
22
|
Muly EC, Smith Y, Allen P, Greengard P. Subcellular distribution of spinophilin immunolabeling in primate prefrontal cortex: localization to and within dendritic spines. J Comp Neurol 2004; 469:185-97. [PMID: 14694533 DOI: 10.1002/cne.11001] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Signal transduction in the nervous system depends on kinases and phosphatases, whose localization is regulated by a large group of scaffolding proteins. In particular, protein phosphatase-1 mediates dopamine's actions on a variety of substrates, including glutamate receptors, and this, in turn, depends on the binding of protein phosphatase-1 to its binding protein spinophilin. To better understand spinophilin's role in targeting protein phosphatase-1 within neurons, we used a combination of preembedding immunoperoxidase and postembedding immunogold labeling and electron microscopy to determine the localization of this scaffolding protein in macaque prefrontal cortex. Consistent with previous reports, spinophilin was found predominantly in dendritic spines, but a significant number of labeled dendritic shafts and, less frequently, glia and preterminal axons were also identified. By using the postembedding immunogold method, we further examined the distribution of spinophilin within dendritic spines. Spinophilin immunoreactivity was present throughout the spine, but the density of label was heterogeneous and defined two domains. The highest density of label was associated with the postsynaptic density and the 100 nm immediately subjacent to it. The deeper region of the spine, further than 100 nm from the postsynaptic density, had a lower density of spinophilin label. The distribution of spinophilin reported in this study supports its role in modulating glutamatergic neurotransmission but also suggests the possibility that spinophilin may target protein phosphatase-1 to other sites within the spine or to other neuronal or glial compartments.
Collapse
Affiliation(s)
- E Chris Muly
- Department of Psychiatry and Behavioral Sciences, Emory University, Atlanta, Georgia 30329, USA.
| | | | | | | |
Collapse
|
23
|
Bloom O, Evergren E, Tomilin N, Kjaerulff O, Löw P, Brodin L, Pieribone VA, Greengard P, Shupliakov O. Colocalization of synapsin and actin during synaptic vesicle recycling. J Cell Biol 2003; 161:737-47. [PMID: 12756235 PMCID: PMC2199372 DOI: 10.1083/jcb.200212140] [Citation(s) in RCA: 177] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2002] [Revised: 04/16/2003] [Accepted: 04/16/2003] [Indexed: 01/21/2023] Open
Abstract
It has been hypothesized that in the mature nerve terminal, interactions between synapsin and actin regulate the clustering of synaptic vesicles and the availability of vesicles for release during synaptic activity. Here, we have used immunogold electron microscopy to examine the subcellular localization of actin and synapsin in the giant synapse in lamprey at different states of synaptic activity. In agreement with earlier observations, in synapses at rest, synapsin immunoreactivity was preferentially localized to a portion of the vesicle cluster distal to the active zone. During synaptic activity, however, synapsin was detected in the pool of vesicles proximal to the active zone. In addition, actin and synapsin were found colocalized in a dynamic filamentous cytomatrix at the sites of synaptic vesicle recycling, endocytic zones. Synapsin immunolabeling was not associated with clathrin-coated intermediates but was found on vesicles that appeared to be recycling back to the cluster. Disruption of synapsin function by microinjection of antisynapsin antibodies resulted in a prominent reduction of the cytomatrix at endocytic zones of active synapses. Our data suggest that in addition to its known function in clustering of vesicles in the reserve pool, synapsin migrates from the synaptic vesicle cluster and participates in the organization of the actin-rich cytomatrix in the endocytic zone during synaptic activity.
Collapse
Affiliation(s)
- Ona Bloom
- The Rockefeller University, New York, NY 10021, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Chi P, Greengard P, Ryan TA. Synaptic vesicle mobilization is regulated by distinct synapsin I phosphorylation pathways at different frequencies. Neuron 2003; 38:69-78. [PMID: 12691665 DOI: 10.1016/s0896-6273(03)00151-x] [Citation(s) in RCA: 255] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
During action potential firing, the rate of synapsin dissociation from synaptic vesicles and dispersion into axons controls the rate of vesicle availability for exocytosis at the plasma membrane. Here we show that synapsin Ia's dispersion rate tracks the synaptic vesicle pool turnover rate linearly over the range 5-20 Hz and that the molecular basis for this lies in regulation at both the calcium-calmodulin-dependent kinase (CaM kinase) and the mitogen-activated protein (MAP) kinase/calcineurin sites. Our results show that CaM kinase sites control vesicle mobilization at low stimulus frequency, while MAP kinase/calcineurin sites are critical at both lower and higher stimulus frequencies. Thus, multiple signaling pathways serve to allow synapsin's control of vesicle mobilization over different stimulus frequencies.
Collapse
Affiliation(s)
- Ping Chi
- Department of Biochemistry, The Weill Medical College of Cornell University, 1300 York Avenue, New York, New York 10021, USA
| | | | | |
Collapse
|
25
|
Abstract
Synapsin III is the most recently identified member of the synapsin family, a group of synaptic vesicle proteins that play essential roles in neurotransmitter release and neurite outgrowth. Here, through the generation and analysis of synapsin III knock-out mice, we demonstrate that synapsin III regulates neurotransmitter release in a manner that is distinct from that of synapsin I or synapsin II. In mice lacking synapsin III, the size of the recycling pool of synaptic vesicles was increased, and synaptic depression was reduced. The number of vesicles that fuse per action potential was similar between synapsin III knock-out and wild-type mice, and there was no change in the quantal content of EPSCs; however, IPSCs were greatly reduced in synapsin III-deficient neurons. The density and distribution of synaptic vesicles in presynaptic terminals did not appear to be different in synapsin III knock-out mice in comparison to wild-type littermates. In addition to the changes in neurotransmitter release, we observed a specific delay in axon outgrowth in cultured hippocampal neurons from synapsin III knock-out mice. Our data indicate that synapsin III plays unique roles both in early axon outgrowth and in the regulation of synaptic vesicle trafficking.
Collapse
|
26
|
Chi P, Greengard P, Ryan TA. Synapsin dispersion and reclustering during synaptic activity. Nat Neurosci 2001; 4:1187-93. [PMID: 11685225 DOI: 10.1038/nn756] [Citation(s) in RCA: 282] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Presynaptic modulation of synaptic transmission provides an important basis for control of synaptic function. The synapsins, a family of highly conserved proteins associated with synaptic vesicles, have long been implicated in the regulation of neurotransmitter release. However, direct physiological measurements of the molecular mechanisms have been lacking. Here we show that in living hippocampal terminals, green fluorescent protein (GFP)-labeled synapsin Ia dissociates from synaptic vesicles, disperses into axons during action potential (AP) firing, and reclusters to synapses after the cessation of synaptic activity. Using various mutated forms of synapsin Ia that prevent phosphorylation at specific sites, we performed simultaneous FM 4-64 measurements of vesicle pool mobilization along with synapsin dispersion kinetics. These studies indicate that the rate of synapsin dispersion is controlled by phosphorylation, which in turn controls the kinetics of vesicle pool turnover. Thus synapsin acts as a phosphorylation-state-dependent regulator of synaptic vesicle mobilization, and hence, neurotransmitter release.
Collapse
Affiliation(s)
- P Chi
- Department of Biochemistry, Weill Medical College of Cornell University, 1300 York Avenue, New York, New York 10021, USA
| | | | | |
Collapse
|
27
|
Carlson K, Ehrich M. Organophosphorus compounds alter intracellular F-actin content in SH-SY5Y human neuroblastoma cells. Neurotoxicology 2001; 22:819-27. [PMID: 11829415 DOI: 10.1016/s0161-813x(01)00073-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Cytoskeletal components, especially f-actin (filamentous actin), are responsible for neurite extension and maintenance. Alterations in neurite length and quality precede in vitro cell death induced by organophosphorus (OP) compounds and implicate f-actin proteins in this process. We, therefore, investigated changes in f-actin in SH-SY5Y human neuroblastoma cells exposed to 0.1 and 1 mM paraoxon, parathion, phenyl saligenin phosphate (PSP), tri-ortho-tolyl phosphate (TOTP), triphenyl phosphite (TPPi), and di-isopropyl phosphorofluoridate (DFP) for 0-48 h. The f-actin was measured by flow cytometry in cells labeled with Alexa 488 phalloidin. The relative amount off-actin was compared to total protein levels as determined by spectrophotometry. The cellular content of f-actin significantly decreasedfollowing exposure to PSP (0.1 mM, >30 min; 1 mM, >15 min), TOTP (0.1 mM, 16 h; 1 mM, >15 min), TPPi (1 mM, >4 h), paraoxon (1 mM, >24 h), and parathion (1 mM, 48 h). Exposure to DFP (0.1 and 1 mM) did not significantly alter f-actin content at any time point. Exposure to parathion (0.1 mM, 48 h) significantly increased the amount of cellular f-actin. Total protein was significantly decreased after exposure to PSP (0.1 and 1 mM, >8 h) and TPPi (1 mM, 48 h). Significant increases in total protein were observed following exposure to parathion (0.1 mM, >3 h). Consistent alterations in the protein content of DFP-exposed samples were not observed. These results suggest that the loss off-actin is an early event following OP compound exposure and that this loss significantly precedes a loss of protein content for some OP compounds (PSP, TPPi). Results also imply that under other exposure conditions (TOTP, paraoxon, parathion) alterations in the f-actin content are independent of protein content.
Collapse
Affiliation(s)
- K Carlson
- Laboratory of Neurotoxicity Studies, Virginia-Maryland Regional College of Veterinary Medicine, Blacksburg, VA 24061, USA
| | | |
Collapse
|
28
|
Opposing changes in phosphorylation of specific sites in synapsin I during Ca2+-dependent glutamate release in isolated nerve terminals. J Neurosci 2001. [PMID: 11588168 DOI: 10.1523/jneurosci.21-20-07944.2001] [Citation(s) in RCA: 132] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Synapsins are major neuronal phosphoproteins involved in regulation of neurotransmitter release. Synapsins are well established targets for multiple protein kinases within the nerve terminal, yet little is known about dephosphorylation processes involved in regulation of synapsin function. Here, we observed a reciprocal relationship in the phosphorylation-dephosphorylation of the established phosphorylation sites on synapsin I. We demonstrate that, in vitro, phosphorylation sites 1, 2, and 3 of synapsin I (P-site 1 phosphorylated by cAMP-dependent protein kinase; P-sites 2 and 3 phosphorylated by Ca(2+)-calmodulin-dependent protein kinase II) were excellent substrates for protein phosphatase 2A, whereas P-sites 4, 5, and 6 (phosphorylated by mitogen-activated protein kinase) were efficiently dephosphorylated only by Ca(2+)-calmodulin-dependent protein phosphatase 2B-calcineurin. In isolated nerve terminals, rapid changes in synapsin I phosphorylation were observed after Ca(2+) entry, namely, a Ca(2+)-dependent phosphorylation of P-sites 1, 2, and 3 and a Ca(2+)-dependent dephosphorylation of P-sites 4, 5, and 6. Inhibition of calcineurin activity by cyclosporin A resulted in a complete block of Ca(2+)-dependent dephosphorylation of P-sites 4, 5, and 6 and correlated with a prominent increase in ionomycin-evoked glutamate release. These two opposing, rapid, Ca(2+)-dependent processes may play a crucial role in the modulation of synaptic vesicle trafficking within the presynaptic terminal.
Collapse
|
29
|
Warburton AL, Santer RM. Decrease in synapsin I staining in the hypogastric ganglion of aged rats. Neurosci Lett 1995; 194:157-60. [PMID: 7478227 DOI: 10.1016/0304-3940(95)11769-s] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The rat hypogastric ganglion (HG) contains populations of both sympathetic and parasympathetic postganglionic neurons which supply the lower pelvic viscera. These neuron populations can be identified by tyrosine hydroxylase (TH) and NADPH-diaphorase (NADPH-d) staining, respectively. The effects of age on the distribution of synapsin I, a nerve terminal marker, in relation to these neuron populations has been investigated in young adult and aged rats. Most synapsin staining was axosomatic and was markedly reduced in the aged animals particularly in relation to sympathetic (NADPH-d-negative/TH-positive) neurons. Image analysis of synapsin I staining in relation to individual sympathetic neurons confirmed that there was a reduction with age of about 50% but no change in synapsin I staining in relation to parasympathetic neurons. These results suggest that synaptic transmission and peripheral integration may be affected in old age and that the autonomic control of the pelvic viscera may be compromised as a result, particularly with regard to the sympathetic innervation. Other autonomic ganglia were also studied for comparison but no such age-related differences were observed.
Collapse
Affiliation(s)
- A L Warburton
- School of Molecular and Medical Biosciences (Anatomy Unit), University of Wales College of Cardiff, UK
| | | |
Collapse
|
30
|
Surkova I. Can exocytosis induced by alpha-latrotoxin be explained solely by its channel-forming activity? Ann N Y Acad Sci 1994; 710:48-64. [PMID: 7512316 DOI: 10.1111/j.1749-6632.1994.tb26613.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- I Surkova
- Department of Physiology, University College London, United Kingdom
| |
Collapse
|
31
|
Jacobs KM, Neve RL, Donoghue JP. Neocortex and hippocampus contain distinct distributions of calcium-calmodulin protein kinase II and GAP43 mRNA. J Comp Neurol 1993; 336:151-60. [PMID: 8254111 DOI: 10.1002/cne.903360112] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Calcium-calmodulin protein kinase II and GAP43 are two molecules which have been linked to synaptic plasticity. Localization of mRNA for these molecules identifies the neuronal populations which have the potential to utilize these mechanisms. General descriptions for calcium-calmodulin protein kinase II or GAP43 mRNA have been previously reported. In light of recent evidence that suggests that at some sites these two molecules may interact, we sought to determine the cortical distribution in detail, and to examine the extent of overlap between neuronal populations containing each mRNA. To this end we have used in situ hybridization techniques to study the distribution of calcium-calmodulin protein kinase II and GAP43 mRNA in adjacent sections of adult rat forebrain. Overall, the distribution patterns were distinct but partially overlapping. For both calcium-calmodulin protein kinase II and GAP43, mRNA levels were highest in hippocampus, allo- and neocortex, compared to moderate to low levels in striatum and thalamic nuclei. Within the heavily labeled regions certain populations expressed both calcium-calmodulin protein kinase II and GAP43 mRNA at high levels, while other populations were selective for calcium-calmodulin protein kinase II. In the hippocampus, the stratum pyramidale of CA1-3 expressed high levels of both calcium-calmodulin protein kinase II and GAP43 mRNA. Granule cells of the fascia dentata and the stratum radiatum of CA3 both contained moderate to high levels of calcium-calmodulin protein kinase II mRNA, but near background levels of GAP43 mRNA label. Within the neocortex, deep layers were distinguished from superficial layers by their lack of calcium-calmodulin protein kinase II mRNA expression within the neuropil, and the presence of GAP43 mRNA in neurons located in layer V and the deepest part of layer VI. Thus, layer V and deep layer VI neurons showed high levels of label for both GAP43 and calcium-calmodulin protein kinase II mRNA, while neurons of superficial layers contained only calcium-calmodulin protein kinase II mRNA. These markers differentiate neuronal populations which can also be distinguished on the basis of their ability to undergo specific forms of synaptic plasticity. These different forms of plasticity may be due in part to the laminar-specific patterns of GAP43 and calcium-calmodulin protein kinase II mRNA that we have described.
Collapse
Affiliation(s)
- K M Jacobs
- Department of Neuroscience, Brown University, Providence, Rhode Island 02912
| | | | | |
Collapse
|
32
|
Omlin FX, Riederer BM. Cells with neuronal characteristics differentiate and persist for one year in rat optic nerve explants cultures. Brain Res Bull 1992; 28:9-16. [PMID: 1540850 DOI: 10.1016/0361-9230(92)90225-m] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Evidence concerning the presence or absence of common neuronglia lineages in the postnatal mammalian central nervous system is still a matter of speculation. We address this problem using optic nerve explants, which show an extremely long survival in culture. Morphological, immunocytochemical and immunochemical methods were applied. The results obtained from in vitro tissue were compared with optic nerves (ONs) and whole-brain samples from animals of different ages. Newborn rat ONs represented the starting material of our tissue culture; they are composed of unmyelinated axons, astrocytes and progenitor cells but devoid of neuronal cell bodies. At this age, Western blots of ONs were positively stained by neurofilament and synapsin I specific antibodies. These bands increased in intensity during postnatal in situ development. In explant cultures, the glia cells reach a stage of functional differentiation and they maintain, together with undifferentiated cells, a complex histotypic organization. After 6 days in vitro, neurofilaments and synapsin I could not be detected on immunoblots, indicating that 1) axonal degeneration was completed, and 2) neuronal somata were absent at the time. Surprisingly, after about 4-5 weeks in culture, a new cell type appeared, which showed characteristics typical of neurons. After 406 days in vitro, neurofilaments and synapsin I were unequivocally detectable on Western blots. Furthermore, both immunocytochemical staining and light and electron microscopic examinations corroborated the presence of this earlier-observed cell type. These in vitro results clearly show the high developmental plasticity of ON progenitor cells, even late in development. The existence of a common neuron-glia precursor, which never gives rise to neurons in situ, is suggested.
Collapse
Affiliation(s)
- F X Omlin
- Institute of Histology, University of Lausanne, Switzerland
| | | |
Collapse
|
33
|
Time-resolved fluorescence study of the neuron-specific phosphoprotein synapsin I. Evidence for phosphorylation-dependent conformational changes. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)38384-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
|