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Yang L, Zhang J, Liu S, Zhang Y, Wang L, Wang X, Wang S, Li K, Wei M, Zhang C. Establishment of transgenic fluorescent mice for labeling synapses and screening synaptogenic adhesion molecules. eLife 2024; 13:e81884. [PMID: 38450720 PMCID: PMC10948142 DOI: 10.7554/elife.81884] [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: 07/14/2022] [Accepted: 03/05/2024] [Indexed: 03/08/2024] Open
Abstract
Synapse is the fundamental structure for neurons to transmit information between cells. The proper synapse formation is crucial for developing neural circuits and cognitive functions of the brain. The aberrant synapse formation has been proved to cause many neurological disorders, including autism spectrum disorders and intellectual disability. Synaptic cell adhesion molecules (CAMs) are thought to play a major role in achieving mechanistic cell-cell recognition and initiating synapse formation via trans-synaptic interactions. Due to the diversity of synapses in different brain areas, circuits and neurons, although many synaptic CAMs, such as Neurexins (NRXNs), Neuroligins (NLGNs), Synaptic cell adhesion molecules (SynCAMs), Leucine-rich-repeat transmembrane neuronal proteins (LRRTMs), and SLIT and NTRK-like protein (SLITRKs) have been identified as synaptogenic molecules, how these molecules determine specific synapse formation and whether other molecules driving synapse formation remain undiscovered are unclear. Here, to provide a tool for synapse labeling and synaptic CAMs screening by artificial synapse formation (ASF) assay, we generated synaptotagmin-1-tdTomato (Syt1-tdTomato) transgenic mice by inserting the tdTomato-fused synaptotagmin-1 coding sequence into the genome of C57BL/6J mice. In the brain of Syt1-tdTomato transgenic mice, the tdTomato-fused synaptotagmin-1 (SYT1-tdTomato) signals were widely observed in different areas and overlapped with synapsin-1, a widely-used synaptic marker. In the olfactory bulb, the SYT1-tdTomato signals are highly enriched in the glomerulus. In the cultured hippocampal neurons, the SYT1-tdTomato signals showed colocalization with several synaptic markers. Compared to the wild-type (WT) mouse neurons, cultured hippocampal neurons from Syt1-tdTomato transgenic mice presented normal synaptic neurotransmission. In ASF assays, neurons from Syt1-tdTomato transgenic mice could form synaptic connections with HEK293T cells expressing NLGN2, LRRTM2, and SLITRK2 without immunostaining. Therefore, our work suggested that the Syt1-tdTomato transgenic mice with the ability to label synapses by tdTomato, and it will be a convenient tool for screening synaptogenic molecules.
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Affiliation(s)
- Lei Yang
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical UniversityBeijingChina
| | - Jingtao Zhang
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical UniversityBeijingChina
| | - Sen Liu
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical UniversityBeijingChina
| | - Yanning Zhang
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical UniversityBeijingChina
| | - Li Wang
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical UniversityBeijingChina
| | - Xiaotong Wang
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical UniversityBeijingChina
| | - Shanshan Wang
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking UniversityBeijingChina
| | - Ke Li
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical UniversityBeijingChina
| | - Mengping Wei
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical UniversityBeijingChina
| | - Chen Zhang
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical UniversityBeijingChina
- Chinese Institute for Brain ResearchBeijingChina
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Autocrine signaling by an Aplysia neurotrophin forms a presynaptic positive feedback loop. Proc Natl Acad Sci U S A 2018; 115:E11168-E11177. [PMID: 30397154 DOI: 10.1073/pnas.1810649115] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Whereas short-term plasticity is often initiated on one side of the synapse, long-term plasticity involves coordinated changes on both sides, implying extracellular signaling. We have investigated the possible signaling role of an Aplysia neurotrophin (ApNT) in facilitation induced by serotonin (5HT) at sensory-to-motor neuron synapses in culture. ApNT is an ortholog of mammalian BDNF, which has been reported to act as either an anterograde, retrograde, or autocrine signal, so that its pre- and postsynaptic sources and targets remain unclear. We now report that ApNT acts as a presynaptic autocrine signal that forms part of a positive feedback loop with ApTrk and PKA. That loop stimulates spontaneous transmitter release, which recruits postsynaptic mechanisms, and presynaptic protein synthesis during the transition from short- to intermediate-term facilitation and may also initiate gene regulation to trigger the transition to long-term facilitation. These results suggest that a presynaptic ApNT feedback loop plays several key roles during consolidation of learning-related synaptic plasticity.
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Bogodvid TK, Andrianov VV, Deryabina IB, Muranova LN, Silantyeva DI, Vinarskaya A, Balaban PM, Gainutdinov KL. Responses of Withdrawal Interneurons to Serotonin Applications in Naïve and Learned Snails Are Different. Front Cell Neurosci 2017; 11:403. [PMID: 29311833 PMCID: PMC5735116 DOI: 10.3389/fncel.2017.00403] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 12/04/2017] [Indexed: 02/04/2023] Open
Abstract
Long-term changes in membrane potential after associative training were described previously in identified premotor interneurons for withdrawal of the terrestrial snail Helix. Serotonin was shown to be a major transmitter involved in triggering the long-term changes in mollusks. In the present study we compared the changes in electrophysiological characteristics of identifiable premotor interneurons for withdrawal in response to bath applications of serotonin (5-HT) or serotonin precursor 5-hydroxytryptophan (5-HTP) in preparations from naïve, neurotoxin-injected or associatively trained snails. It was found that 5-HT or 5-HTP applications caused a significant decrease of membrane potential in premotor interneurons of naïve snails, associatively trained snails and snails with impaired serotonergic system by injection of a selective neurotoxin 5,7-dihydroxytryptamine (5,7-DHT) 1 week before the experiments. Applications of 5-HT or 5-HTP did not cause significant changes in the action potential (AP) threshold potential of these neurons in naïve snails. Conversely, applications of 5-HT or 5-HTP to the premotor interneurons of previously trained or 5,7-DHT-injected snails caused a significant increase in the firing threshold potential in spite of a depolarizing shift of the resting membrane potential. Results demonstrate that responsiveness of premotor interneurons to extracellularly applied 5-HT or 5-HTP changes for days after the associative training or serotonin depletion. Similarity of the effects in trained and 5,7-DHT-injected animals may be due to massive release of serotonin elicited by 5,7-DHT injection. Our results suggest that serotonin release due to aversive conditionining or elicited by the neurotoxin administration triggers similar changes in resting membrane potential and AP threshold in response to bath applications of 5-HT or its precursor 5-HTP.
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Affiliation(s)
- Tatiana K. Bogodvid
- Laboratory of Neuroreabilitation of Motor Disorders, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
- Department of Biomedical Sciences, Volga Region State Academy of Physical Culture, Sport and Tourism, Kazan, Russia
| | - Vyatcheslav V. Andrianov
- Laboratory of Neuroreabilitation of Motor Disorders, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | - Irina B. Deryabina
- Laboratory of Neuroreabilitation of Motor Disorders, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | - Lyudmila N. Muranova
- Laboratory of Neuroreabilitation of Motor Disorders, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | - Dinara I. Silantyeva
- Laboratory of Neuroreabilitation of Motor Disorders, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
| | - Aliya Vinarskaya
- Laboratory of Cellular Neurobiology of Learning, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Pavel M. Balaban
- Laboratory of Cellular Neurobiology of Learning, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russia
| | - Khalil L. Gainutdinov
- Laboratory of Neuroreabilitation of Motor Disorders, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russia
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Zhou L, McInnes J, Wierda K, Holt M, Herrmann AG, Jackson RJ, Wang YC, Swerts J, Beyens J, Miskiewicz K, Vilain S, Dewachter I, Moechars D, De Strooper B, Spires-Jones TL, De Wit J, Verstreken P. Tau association with synaptic vesicles causes presynaptic dysfunction. Nat Commun 2017; 8:15295. [PMID: 28492240 PMCID: PMC5437271 DOI: 10.1038/ncomms15295] [Citation(s) in RCA: 240] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 03/17/2017] [Indexed: 12/18/2022] Open
Abstract
Tau is implicated in more than 20 neurodegenerative diseases, including Alzheimer's disease. Under pathological conditions, Tau dissociates from axonal microtubules and missorts to pre- and postsynaptic terminals. Patients suffer from early synaptic dysfunction prior to Tau aggregate formation, but the underlying mechanism is unclear. Here we show that pathogenic Tau binds to synaptic vesicles via its N-terminal domain and interferes with presynaptic functions, including synaptic vesicle mobility and release rate, lowering neurotransmission in fly and rat neurons. Pathological Tau mutants lacking the vesicle binding domain still localize to the presynaptic compartment but do not impair synaptic function in fly neurons. Moreover, an exogenously applied membrane-permeable peptide that competes for Tau-vesicle binding suppresses Tau-induced synaptic toxicity in rat neurons. Our work uncovers a presynaptic role of Tau that may be part of the early pathology in various Tauopathies and could be exploited therapeutically.
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Affiliation(s)
- Lujia Zhou
- VIB-KU Leuven Center for Brain & Disease Research, Leuven 3000, Belgium
- KU Leuven, Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), Leuven 3000, Belgium
| | - Joseph McInnes
- VIB-KU Leuven Center for Brain & Disease Research, Leuven 3000, Belgium
- KU Leuven, Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), Leuven 3000, Belgium
| | - Keimpe Wierda
- VIB-KU Leuven Center for Brain & Disease Research, Leuven 3000, Belgium
- KU Leuven, Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), Leuven 3000, Belgium
| | - Matthew Holt
- VIB-KU Leuven Center for Brain & Disease Research, Leuven 3000, Belgium
- KU Leuven, Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), Leuven 3000, Belgium
| | - Abigail G. Herrmann
- University of Edinburgh, Centre for Cognitive and Neural Systems, Center for Dementia Prevention and Euan MacDonald Centre, Edinburgh EH8 9JZ, UK
| | - Rosemary J. Jackson
- University of Edinburgh, Centre for Cognitive and Neural Systems, Center for Dementia Prevention and Euan MacDonald Centre, Edinburgh EH8 9JZ, UK
| | - Yu-Chun Wang
- VIB-KU Leuven Center for Brain & Disease Research, Leuven 3000, Belgium
- KU Leuven, Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), Leuven 3000, Belgium
| | - Jef Swerts
- VIB-KU Leuven Center for Brain & Disease Research, Leuven 3000, Belgium
- KU Leuven, Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), Leuven 3000, Belgium
| | - Jelle Beyens
- VIB-KU Leuven Center for Brain & Disease Research, Leuven 3000, Belgium
- KU Leuven, Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), Leuven 3000, Belgium
| | - Katarzyna Miskiewicz
- VIB-KU Leuven Center for Brain & Disease Research, Leuven 3000, Belgium
- KU Leuven, Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), Leuven 3000, Belgium
| | - Sven Vilain
- VIB-KU Leuven Center for Brain & Disease Research, Leuven 3000, Belgium
- KU Leuven, Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), Leuven 3000, Belgium
| | - Ilse Dewachter
- Catholic University of Louvain, Alzheimer Dementia Group, Institute of Neuroscience, Brussels 1200, Belgium
- University of Hasselt, Biomedical Research Institute, Hasselt 3500, Belgium
| | - Diederik Moechars
- A Division of Janssen Pharmaceutica NV, Neuroscience Department, Janssen Research and Development, Beerse 2340, Belgium
| | - Bart De Strooper
- VIB-KU Leuven Center for Brain & Disease Research, Leuven 3000, Belgium
- KU Leuven, Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), Leuven 3000, Belgium
| | - Tara L. Spires-Jones
- University of Edinburgh, Centre for Cognitive and Neural Systems, Center for Dementia Prevention and Euan MacDonald Centre, Edinburgh EH8 9JZ, UK
| | - Joris De Wit
- VIB-KU Leuven Center for Brain & Disease Research, Leuven 3000, Belgium
- KU Leuven, Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), Leuven 3000, Belgium
| | - Patrik Verstreken
- VIB-KU Leuven Center for Brain & Disease Research, Leuven 3000, Belgium
- KU Leuven, Department of Neurosciences, Leuven Research Institute for Neuroscience and Disease (LIND), Leuven 3000, Belgium
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Neurotoxicity induced by zinc oxide nanoparticles: age-related differences and interaction. Sci Rep 2015; 5:16117. [PMID: 26527454 PMCID: PMC4630782 DOI: 10.1038/srep16117] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 10/08/2015] [Indexed: 12/11/2022] Open
Abstract
This study mainly investigated the neurotoxicity induced by zinc oxide nanoparticle (ZnO NP) in different-aged mice and the interaction between age and ZnO NP exposure. Sixty adult and old male C57BL/6J mice were assigned to four groups based on a two-factor (age and ZnO NP exposure) design. Results showed that ZnO NPs (5.6 mg/kg, intraperitoneal) induced increased production of pro-inflammatory cytokines in the serum and the brain of mice. A synergistic reaction between aging and ZnO NP exposure occurred regarding serum interleukin 1 (IL-1) and interleukin 6 (IL-6). In the brain, increased oxidative stress level, impaired learning and memory abilities, and hippocampal pathological changes were identified, especially in old mice, following ZnO NP exposure. Then, a potential mechanism of cognitive impairment was examined. The contents of hippocampal cAMP response element binding protein (CREB), phosphorylated CREB, synapsin I, and cAMP were decreased in an age-dependent manner, and the most substantial decrease occurred in old mice treated with ZnO NPs. These findings demonstrated for the first time that aging and ZnO NP exposure synergistically influenced systemic inflammation, and indicated old individuals were more susceptible to ZnO NP-induced neurotoxicity. One of the mechanisms might due to the supression of cAMP/CREB signaling.
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Andrianov VV, Bogodvid TK, Deryabina IB, Golovchenko AN, Muranova LN, Tagirova RR, Vinarskaya AK, Gainutdinov KL. Modulation of defensive reflex conditioning in snails by serotonin. Front Behav Neurosci 2015; 9:279. [PMID: 26557063 PMCID: PMC4615812 DOI: 10.3389/fnbeh.2015.00279] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 10/02/2015] [Indexed: 01/24/2023] Open
Abstract
Highlights Daily injection of serotonin before a training session accelerated defensive reflex conditioning in snails.Daily injection of 5-hydroxytryptophan before a training session in snails with a deficiency of serotonin induced by the "neurotoxic" analog of serotonin 5,7-dihydroxytryptamine, restored the ability of snails to learn.After injection of the "neurotoxic" analogs of serotonin 5,6- and 5,7-dihydroxytryptamine as well as serotonin, depolarization of the membrane and decrease of the threshold potential of premotor interneurons was observed. We studied the role of serotonin in the mechanisms of learning in terrestrial snails. To produce a serotonin deficit, the "neurotoxic" analogs of serotonin, 5,6- or 5,7-dihydroxytryptamine (5,6/5,7-DHT) were used. Injection of 5,6/5,7-DHT was found to disrupt defensive reflex conditioning. Within 2 weeks of neurotoxin application, the ability to learn had recovered. Daily injection of serotonin before a training session accelerated defensive reflex conditioning and daily injections of 5-HTP in snails with a deficiency of serotonin induced by 5,7-DHT restored the snail's ability to learn. We discovered that injections of the neurotoxins 5,6/5,7-DHT as well as serotonin, caused a decrease in the resting and threshold potentials of the premotor interneurons LPa3 and RPa3.
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Affiliation(s)
- Vyatcheslav V. Andrianov
- Laboratory of Neurobiology, Institute of Fundamental Medicine and Biology, Kazan Federal UniversityKazan, Russia
- Group of Biophysics, Zavoisky Physical-Technical Institute, Russian Academy of SciencesKazan, Russia
| | - Tatiana K. Bogodvid
- Laboratory of Neurobiology, Institute of Fundamental Medicine and Biology, Kazan Federal UniversityKazan, Russia
- Department of Biomedical Sciences, Volga Region State Academy of Physical Culture, Sport and TourismKazan, Russia
| | - Irina B. Deryabina
- Laboratory of Neurobiology, Institute of Fundamental Medicine and Biology, Kazan Federal UniversityKazan, Russia
| | - Aleksandra N. Golovchenko
- Laboratory of Neurobiology, Institute of Fundamental Medicine and Biology, Kazan Federal UniversityKazan, Russia
| | - Lyudmila N. Muranova
- Laboratory of Neurobiology, Institute of Fundamental Medicine and Biology, Kazan Federal UniversityKazan, Russia
| | - Roza R. Tagirova
- Laboratory of Neurobiology, Institute of Fundamental Medicine and Biology, Kazan Federal UniversityKazan, Russia
| | - Aliya K. Vinarskaya
- Laboratory of Cellular Neurobiology of Learning, Institute of High Nerve Activity and Neurophysiology, Russian Academy of SciencesMoscow, Russia
| | - Khalil L. Gainutdinov
- Laboratory of Neurobiology, Institute of Fundamental Medicine and Biology, Kazan Federal UniversityKazan, Russia
- Group of Biophysics, Zavoisky Physical-Technical Institute, Russian Academy of SciencesKazan, Russia
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Erez H, Shemesh OA, Spira ME. Rescue of tau-induced synaptic transmission pathology by paclitaxel. Front Cell Neurosci 2014; 8:34. [PMID: 24574970 PMCID: PMC3918585 DOI: 10.3389/fncel.2014.00034] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 01/23/2014] [Indexed: 12/30/2022] Open
Abstract
Behavioral and electrophysiological studies of Alzheimer’s disease (AD) and other tauopathies have revealed that the onset of cognitive decline correlates better with synaptic dysfunctions than with hallmark pathologies such as extracellular amyloid-β plaques, intracellular hyperphosphorylated tau or neuronal loss. Recent experiments have also demonstrated that anti-cancer microtubule (MT)-stabilizing drugs can rescue tau-induced behavioral decline and hallmark neuron pathologies. Nevertheless, the mechanisms underlying tau-induced synaptic dysfunction as well as those involved in the rescue of cognitive decline by MTs-stabilizing drugs remain unclear. Here we began to study these mechanisms using the glutaminergic sensory-motoneuron synapse derived from Aplysia ganglia, electrophysiological methods, the expression of mutant-human tau (mt-htau) either pre or postsynaptically and the antimitotic drug paclitaxel. Expression of mt-htau in the presynaptic neurons led to reduced excitatory postsynaptic potential (EPSP) amplitude generated by rested synapses within 3 days of mt-htau expression, and to deeper levels of homosynaptic depression. mt-htau-induced synaptic weakening correlated with reduced releasable presynaptic vesicle pools as revealed by the induction of asynchronous neurotransmitter release by hypertonic sucrose solution. Paclitaxel totally rescued tau-induced synaptic weakening by maintaining the availability of the presynaptic vesicle stores. Postsynaptic expression of mt-htau did not impair the above described synaptic-transmission parameters for up to 5 days. Along with earlier confocal microscope observations from our laboratory, these findings suggest that tau-induced synaptic dysfunction is the outcome of impaired axoplasmic transport and the ensuing reduction in the releasable presynaptic vesicle stores rather than the direct effects of mt-htau or paclitaxel on the synaptic release mechanisms.
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Affiliation(s)
- Hadas Erez
- Department of Neurobiology, The Life Sciences Institute, The Hebrew University of Jerusalem Jerusalem, Israel
| | - Or A Shemesh
- Department of Neurobiology, The Life Sciences Institute, The Hebrew University of Jerusalem Jerusalem, Israel
| | - Micha E Spira
- Department of Neurobiology, The Life Sciences Institute, The Hebrew University of Jerusalem Jerusalem, Israel
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Vasileva M, Renden R, Horstmann H, Gitler D, Kuner T. Overexpression of synapsin Ia in the rat calyx of Held accelerates short-term plasticity and decreases synaptic vesicle volume and active zone area. Front Cell Neurosci 2013; 7:270. [PMID: 24391547 PMCID: PMC3868894 DOI: 10.3389/fncel.2013.00270] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 12/04/2013] [Indexed: 01/10/2023] Open
Abstract
Synapsins are synaptic vesicle (SV) proteins organizing a component of the reserve pool of vesicles at most central nervous system synapses. Alternative splicing of the three mammalian genes results in multiple isoforms that may differentially contribute to the organization and maintenance of the SV pools. To address this, we first characterized the expression pattern of synapsin isoforms in the rat calyx of Held. At postnatal day 16, synapsins Ia, Ib, IIb and IIIa were present, while IIa-known to sustain repetitive transmission in glutamatergic terminals-was not detectable. To test if the synapsin I isoforms could mediate IIa-like effect, and if this depends on the presence of the E-domain, we overexpressed either synapsin Ia or synapsin Ib in the rat calyx of Held via recombinant adeno-associated virus-mediated gene transfer. Although the size and overall structure of the perturbed calyces remained unchanged, short-term depression and recovery from depression were accelerated upon overexpression of synapsin I isoforms. Using electron microscopic three-dimensional reconstructions we found a redistribution of SV clusters proximal to the active zones (AZ) alongside with a decrease of both AZ area and SV volume. The number of SVs at individual AZs was strongly reduced. Hence, our data indicate that the amount of synapsin Ia expressed in the calyx regulates the rate and extent of short-term synaptic plasticity by affecting vesicle recruitment to the AZ. Finally, our study reveals a novel contribution of synapsin Ia to define the surface area of AZs.
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Affiliation(s)
- Mariya Vasileva
- Institute of Anatomy and Cell Biology, Heidelberg University Heidelberg, Germany
| | - Robert Renden
- Institute of Anatomy and Cell Biology, Heidelberg University Heidelberg, Germany
| | - Heinz Horstmann
- Institute of Anatomy and Cell Biology, Heidelberg University Heidelberg, Germany
| | - Daniel Gitler
- Department of Physiology and Cell Biology, Faculty of Health Sciences and Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev Beer-Sheva, Israel
| | - Thomas Kuner
- Institute of Anatomy and Cell Biology, Heidelberg University Heidelberg, Germany
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Diegelmann S, Klagges B, Michels B, Schleyer M, Gerber B. Maggot learning and Synapsin function. ACTA ACUST UNITED AC 2013; 216:939-51. [PMID: 23447663 DOI: 10.1242/jeb.076208] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Drosophila larvae are focused on feeding and have few neurons. Within these bounds, however, there still are behavioural degrees of freedom. This review is devoted to what these elements of flexibility are, and how they come about. Regarding odour-food associative learning, the emerging working hypothesis is that when a mushroom body neuron is activated as a part of an odour-specific set of mushroom body neurons, and coincidently receives a reinforcement signal carried by aminergic neurons, the AC-cAMP-PKA cascade is triggered. One substrate of this cascade is Synapsin, and therefore this review features a general and comparative discussion of Synapsin function. Phosphorylation of Synapsin ensures an alteration of synaptic strength between this mushroom body neuron and its target neuron(s). If the trained odour is encountered again, the pattern of mushroom body neurons coding this odour is activated, such that their modified output now allows conditioned behaviour. However, such an activated memory trace does not automatically cause conditioned behaviour. Rather, in a process that remains off-line from behaviour, the larvae compare the value of the testing situation (based on gustatory input) with the value of the odour-activated memory trace (based on mushroom body output). The circuit towards appetitive conditioned behaviour is closed only if the memory trace suggests that tracking down the learned odour will lead to a place better than the current one. It is this expectation of a positive outcome that is the immediate cause of appetitive conditioned behaviour. Such conditioned search for reward corresponds to a view of aversive conditioned behaviour as conditioned escape from punishment, which is enabled only if there is something to escape from - much in the same way as we only search for things that are not there, and run for the emergency exit only when there is an emergency. One may now ask whether beyond 'value' additional information about reinforcement is contained in the memory trace, such as information about the kind and intensity of the reinforcer used. The Drosophila larva may allow us to develop satisfyingly detailed accounts of such mnemonic richness - if it exists.
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Affiliation(s)
- Sören Diegelmann
- Leibniz Institut für Neurobiologie (LIN), Abteilung Genetik von Lernen und Gedächtnis, Brenneckestrasse 6, 39118 Magdeburg, Germany
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Giachello CNG, Premoselli F, Montarolo PG, Ghirardi M. Pentylenetetrazol-induced epileptiform activity affects basal synaptic transmission and short-term plasticity in monosynaptic connections. PLoS One 2013; 8:e56968. [PMID: 23437283 PMCID: PMC3577694 DOI: 10.1371/journal.pone.0056968] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2012] [Accepted: 01/18/2013] [Indexed: 11/18/2022] Open
Abstract
Epileptic activity is generally induced in experimental models by local application of epileptogenic drugs, including pentylenetetrazol (PTZ), widely used on both vertebrate and invertebrate neurons. Despite the high prevalence of this neurological disorder and the extensive research on it, the cellular and molecular mechanisms underlying epileptogenesis still remain unclear. In this work, we examined PTZ-induced neuronal changes in Helix monosynaptic circuits formed in vitro, as a simpler experimental model to investigate the effects of epileptiform activity on both basal release and post-tetanic potentiation (PTP), a form of short-term plasticity. We observed a significant enhancement of basal synaptic strength, with kinetics resembling those of previously described use-dependent forms of plasticity, determined by changes in estimated quantal parameters, such as the readily releasable pool and the release probability. Moreover, these neurons exhibited a strong reduction in PTP expression and in its decay time constant, suggesting an impairment in the dynamic reorganization of synaptic vesicle pools following prolonged stimulation of synaptic transmission. In order to explain this imbalance, we determined whether epileptic activity is related to the phosphorylation level of synapsin, which is known to modulate synaptic plasticity. Using western blot and immunocytochemical staining we found a PTZ-dependent increase in synapsin phosphorylation at both PKA/CaMKI/IV and MAPK/Erk sites, both of which are important for modulating synaptic plasticity. Taken together, our findings suggest that prolonged epileptiform activity leads to an increase in the synapsin phosphorylation status, thereby contributing to an alteration of synaptic strength in both basal condition and tetanus-induced potentiation.
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Hart AK, Fioravante D, Liu RY, Phares GA, Cleary LJ, Byrne JH. Serotonin-mediated synapsin expression is necessary for long-term facilitation of the Aplysia sensorimotor synapse. J Neurosci 2011; 31:18401-11. [PMID: 22171042 PMCID: PMC3407595 DOI: 10.1523/jneurosci.2816-11.2011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Revised: 10/13/2011] [Accepted: 10/30/2011] [Indexed: 11/21/2022] Open
Abstract
Serotonin (5-HT)-induced long-term facilitation (LTF) of the Aplysia sensorimotor synapse depends on enhanced gene expression and protein synthesis, but identification of the genes whose expression and regulation are necessary for LTF remains incomplete. In this study, we found that one such gene is synapsin, which encodes a synaptic vesicle-associated protein known to regulate short-term synaptic plasticity. Both synapsin mRNA and protein levels were increased by 5-HT. Upregulation of synapsin protein occurred in presynaptic sensory neurons at neurotransmitter release sites. To investigate the molecular mechanisms underlying synapsin regulation, we cloned the promoter region of Aplysia synapsin, and found that the synapsin promoter contained a cAMP response element (CRE), raising the possibility that the transcriptional activator CRE-binding protein 1 (CREB1) mediates 5-HT-induced regulation of synapsin. Indeed, binding of CREB1 to the synapsin promoter was increased following treatment with 5-HT. Furthermore, increased acetylation of histones H3 and H4 and decreased association of histone deacetylase 5 near the CRE site are consistent with transcriptional activation by CREB1. RNA interference (RNAi) targeting synapsin mRNA blocked the 5-HT-induced increase in synapsin protein levels and LTF; in the absence of 5-HT treatment, basal synapsin levels were unaffected. These results indicate that the 5-HT-induced regulation of synapsin levels is necessary for LTF and that this regulation is part of the cascade of synaptic events involved in the consolidation of memory.
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Affiliation(s)
- Anne K. Hart
- Department of Neurobiology and Anatomy, W.M. Keck Center for the Neurobiology of Learning and Memory, The University of Texas Medical School at Houston, Houston, Texas 77030
| | - Diasinou Fioravante
- Department of Neurobiology and Anatomy, W.M. Keck Center for the Neurobiology of Learning and Memory, The University of Texas Medical School at Houston, Houston, Texas 77030
| | - Rong-Yu Liu
- Department of Neurobiology and Anatomy, W.M. Keck Center for the Neurobiology of Learning and Memory, The University of Texas Medical School at Houston, Houston, Texas 77030
| | - Gregg A. Phares
- Department of Neurobiology and Anatomy, W.M. Keck Center for the Neurobiology of Learning and Memory, The University of Texas Medical School at Houston, Houston, Texas 77030
| | - Leonard J. Cleary
- Department of Neurobiology and Anatomy, W.M. Keck Center for the Neurobiology of Learning and Memory, The University of Texas Medical School at Houston, Houston, Texas 77030
| | - John H. Byrne
- Department of Neurobiology and Anatomy, W.M. Keck Center for the Neurobiology of Learning and Memory, The University of Texas Medical School at Houston, Houston, Texas 77030
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Humeau Y, Candiani S, Ghirardi M, Poulain B, Montarolo P. Functional roles of synapsin: Lessons from invertebrates. Semin Cell Dev Biol 2011; 22:425-33. [DOI: 10.1016/j.semcdb.2011.07.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Accepted: 07/13/2011] [Indexed: 12/18/2022]
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13
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A novel form of presynaptic plasticity based on the fast reactivation of release sites switched off during low-frequency depression. J Neurosci 2011; 30:16679-91. [PMID: 21148007 DOI: 10.1523/jneurosci.3644-09.2010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Repetitive firing of neurons at a low frequency often leads to a decrease in synaptic strength. The mechanism of this low-frequency depression (LFD) is poorly understood. Here, LFD was studied at Aplysia cholinergic synapses. The absence of a significant change in the paired-pulse ratio during LFD, together with the facts that neither the time course nor the extent of LFD were affected by the initial release probability, suggests that LFD is not related to a depletion of the ready-to-fuse synaptic vesicles (SVs) or to a decrease in the release probability, but results from the silencing of a subpopulation of release sites. A subset of SVs or release sites, which acquired a high release probability status during LFD, permits synapses to rapidly and temporarily recover the initial synaptic strength when the stimulation is stopped. However, the recovery of the full capacity of the synapse to sustain repetitive stimulations is slow and involves spontaneous reactivation of the silent release sites. Application of tetanic stimulations accelerates this recovery by immediately switching on the silent sites. This high-frequency-dependent phenomenon underlies a new form of synaptic plasticity that allows resetting of presynaptic efficiency independently of the recent history of the synapse. Microinjection of a mutated Aplysia synapsin that cannot be phosphorylated by cAMP-dependent protein kinase (PKA), or a PKA inhibitor both prevented high-frequency-dependent awakening of release sites. Changes in the firing pattern of neurons appear to be able to regulate the on-off status of release sites via a molecular cascade involving PKA-dependent phosphorylation of synapsin.
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Clustering of excess growth resources within leading growth cones underlies the recurrent "deposition" of varicosities along developing neurites. Exp Neurol 2010; 225:140-53. [PMID: 20558161 DOI: 10.1016/j.expneurol.2010.06.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2010] [Revised: 05/30/2010] [Accepted: 06/07/2010] [Indexed: 11/21/2022]
Abstract
Varicosities (VRs) are ubiquitous neuronal structures that are considered to serve as presynaptic structures. The mechanisms of their assembly are unknown. Using cultured Aplysia neurons, we found that in the absence of postsynaptic targets, VRs form at the leading edge of extending neurites when anterogradely transported organelles accumulate within the palm of the growth cone (GC) at a rate that exceeds their utilization by the GC machinery. The aggregation of excess organelles at the palm of the GC leads to slowdown of the GC's advance. As the size of the organelle clusters increases, the rate of organelle sequestration diminishes and the supply of building blocks to the GC resumes. The GCs' advance is re-initiated, "leaving behind" an organelle-loaded nascent VR. These mechanisms account for the recurrent "deposition" of almost equally spaced VRs by advancing GCs. Consistent with the view that VRs serve as "ready-to-go" presynaptic terminals, we found that a short train of action potentials leads to exocytosis of labeled vesicles within the varicosities. We propose that the formation and spacing of VRs by advancing GCs is the default outcome of the balance between the rate of supply of growth-supporting resources and the usage of these resources by the GC's machinery at the leading edges of specific neurites.
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Wu L, Peng J, Wei C, Liu G, Wang G, Li K, Yin F. Characterization, using comparative proteomics, of differentially expressed proteins in the hippocampus of the mesial temporal lobe of epileptic rats following treatment with valproate. Amino Acids 2010; 40:221-38. [PMID: 20524136 DOI: 10.1007/s00726-010-0638-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2009] [Accepted: 05/19/2010] [Indexed: 12/13/2022]
Abstract
The objective of the study was to explore the pathogenesis of mesial temporal lobe epilepsy (MTLE) and the mechanism of valproate administration in the early stage of MTLE development. We performed a global comparative analysis and function classification of differentially expressed proteins using proteomics. MTLE models of developmental rats were induced by lithium-pilocarpine. Proteins in the hippocampus were separated by 2-DE technology. PDQuest software was used to analyze 2-DE images, and MALDI-TOF-MS was used to identify the differentially expressed proteins. Western blot was used to determine the differential expression levels of synapse-related proteins synapsin-1, dynamin-1 and neurogranin in both MTLE rat and human hippocampus. A total of 48 differentially expressed proteins were identified between spontaneous and non-spontaneous MTLE rats, while 41 proteins between MTLE rats and post valproate-treatment rats were identified. All of the proteins can be categorized into several groups by biological functions: synaptic and neurotransmitter release, cytoskeletal structure and dynamics, cell junctions, energy metabolism and mitochondrial function, molecular chaperones, signal regulation and others. Western blot results were similar to the changes noted in 2-DE. The differentially expressed proteins, especially the proteins related to synaptic and neurotransmitter release function, such as synapsin-1, dynamin-1 and neurogranin, are probably involved in the mechanism of MTLE and the pharmacological effect of valproate. These findings may provide important clues to elucidate the mechanism of chronic MTLE and to identify an optimum medication intervention time and new biomarkers for the development of pharmacological therapies targeted at epilepsy.
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Affiliation(s)
- Liwen Wu
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha 410008, Hunan, People's Republic of China
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16
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Rapanelli M, Frick LR, Zanutto BS. Differential gene expression in the rat hippocampus during learning of an operant conditioning task. Neuroscience 2009; 163:1031-8. [PMID: 19632308 DOI: 10.1016/j.neuroscience.2009.07.037] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2009] [Revised: 07/07/2009] [Accepted: 07/18/2009] [Indexed: 12/31/2022]
Abstract
Changes in transcription levels of brain-derived neurotrophic factor (BDNF), cyclic adenosine monophosphate (cAMP) response element binding (CREB), Synapsin I, Ca(2+)/calmodulin-dependent protein kinase II (CamKII), activity-regulated cytoskeleton-associated protein (Arc), c-jun and c-fos have been associated to several learning paradigms in different brain areas. In this study, we measured mRNA expression in the hippocampus by real time (RT)-PCR mRNA levels of BDNF, CREB, Synapsin I, CamKII, Arc, c-jun and c-fos, during learning and operant conditioning task. Experimental groups were as follows: control (C, the animals never left the bioterium), when the animals reached 50-65% of the expected response (Incompletely Trained, IT), when animals reached 100% of the expected response with a latency time lower than 5 s (Trained, Tr), Box Control of Incompletely Trained (BCIT), animals spent the same time as the IT in the operant conditioning box and Box Control of Trained (BCTr) animals spent the same time as the Tr in the operant conditioning box. All rats were killed at the same time by cervical dislocation 15 min after training and hippocampi were removed and processed. We found increments of mRNA levels of most genes (BDNF, CREB, Synapsin I, Arc, c-jun and c-fos) in IT and Tr groups compared to their box controls, but increments in Tr were smaller compared with IT. These results describe a differential gene expression in the rat hippocampus when the animals are learning and when animals have already learned. Taking together the results presented herein with the known functions of these genes, we propose a link between changes in gene expression in the hippocampus and different degrees of cellular activation and plasticity during learning of an operant conditioning task.
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Affiliation(s)
- M Rapanelli
- IBYME-CONICET, Laboratorio de Biologia del Comportamiento, Vuelta de Obligado 2490, Ciudad de Buenos Aires, Buenos Aires, Argentina.
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Khoutorsky A, Spira ME. Activity-dependent calpain activation plays a critical role in synaptic facilitation and post-tetanic potentiation. Learn Mem 2009; 16:129-41. [DOI: 10.1101/lm.1275709] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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18
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Fioravante D, Liu RY, Byrne JH. The ubiquitin-proteasome system is necessary for long-term synaptic depression in Aplysia. J Neurosci 2008; 28:10245-56. [PMID: 18842884 PMCID: PMC2571080 DOI: 10.1523/jneurosci.2139-08.2008] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2008] [Revised: 07/20/2008] [Accepted: 08/05/2008] [Indexed: 01/24/2023] Open
Abstract
The neuropeptide Phe-Met-Arg-Phe-NH(2) (FMRFa) can induce transcription-dependent long-term synaptic depression (LTD) in Aplysia sensorimotor synapses. We investigated the role of the ubiquitin-proteasome system and the regulation of one of its components, ubiquitin C-terminal hydrolase (ap-uch), in LTD. LTD was sensitive to presynaptic inhibition of the proteasome and was associated with upregulation of ap-uch mRNA and protein. This upregulation appeared to be mediated by CREB2, which is generally regarded as a transcription repressor. Binding of CREB2 to the promoter region of ap-uch was accompanied by histone hyperacetylation, suggesting that CREB2 cannot only inhibit but also promote gene expression. CREB2 was phosphorylated after FMRFa, and blocking phospho-CREB2 blocked LTD. In addition to changes in the expression of ap-uch, the synaptic vesicle-associated protein synapsin was downregulated in LTD in a proteasome-dependent manner. These results suggest that proteasome-mediated protein degradation is engaged in LTD and that CREB2 may act as a transcription activator under certain conditions.
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Affiliation(s)
- Diasinou Fioravante
- Department of Neurobiology and Anatomy, W. M. Keck Center for the Neurobiology of Learning and Memory, The University of Texas Medical School at Houston, Houston, Texas 77030
| | - Rong-Yu Liu
- Department of Neurobiology and Anatomy, W. M. Keck Center for the Neurobiology of Learning and Memory, The University of Texas Medical School at Houston, Houston, Texas 77030
| | - John H. Byrne
- Department of Neurobiology and Anatomy, W. M. Keck Center for the Neurobiology of Learning and Memory, The University of Texas Medical School at Houston, Houston, Texas 77030
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