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Szymański S, Baracchi D, Dingle L, Bowman AS, Manfredini F. Learning performance and GABAergic pathway link to deformed wing virus in the mushroom bodies of naturally infected honey bees. J Exp Biol 2024; 227:jeb246766. [PMID: 38894668 DOI: 10.1242/jeb.246766] [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: 10/08/2023] [Accepted: 06/07/2024] [Indexed: 06/21/2024]
Abstract
Viral infections can be detrimental to the foraging ability of the western honey bee, Apis mellifera. The deformed wing virus (DWV) is the most common honey bee virus and has been proposed as a possible cause of learning and memory impairment. However, evidence for this phenomenon so far has come from artificially infected bees, while less is known about the implications of natural infections with the virus. Using the proboscis extension reflex (PER), we uncovered no significant association between a simple associative learning task and natural DWV load. However, when assessed through a reversal associative learning assay, bees with higher DWV load performed better in the reversal learning phase. DWV is able to replicate in the honey bee mushroom bodies, where the GABAergic signalling pathway has an antagonistic effect on associative learning but is crucial for reversal learning. Hence, we assessed the pattern of expression of several GABA-related genes in bees with different learning responses. Intriguingly, mushroom body expression of selected genes was positively correlated with DWV load, but only for bees with good reversal learning performance. We hypothesise that DWV might improve olfactory learning performance by enhancing the GABAergic inhibition of responses to unrewarded stimuli, which is consistent with the behavioural patterns that we observed. However, at higher disease burdens, which might be induced by an artificial infection or by a severe, natural Varroa infestation, this DWV-associated increase in GABA signalling could impair associative learning as previously reported by other studies.
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Affiliation(s)
- Szymon Szymański
- School of Biological Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen, AB24 2TZ, UK
| | - David Baracchi
- Department of Biology, University of Florence, Via Madonna del Piano 6, 50019 Sesto Fiorentino, Italy
| | - Lauren Dingle
- School of Biological Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen, AB24 2TZ, UK
| | - Alan S Bowman
- School of Biological Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen, AB24 2TZ, UK
| | - Fabio Manfredini
- School of Biological Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen, AB24 2TZ, UK
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2
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Bhandari A, Seguin A, Rothenfluh A. Synaptic Mechanisms of Ethanol Tolerance and Neuroplasticity: Insights from Invertebrate Models. Int J Mol Sci 2024; 25:6838. [PMID: 38999947 PMCID: PMC11241699 DOI: 10.3390/ijms25136838] [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: 05/06/2024] [Revised: 06/09/2024] [Accepted: 06/10/2024] [Indexed: 07/14/2024] Open
Abstract
Alcohol tolerance is a neuroadaptive response that leads to a reduction in the effects of alcohol caused by previous exposure. Tolerance plays a critical role in the development of alcohol use disorder (AUD) because it leads to the escalation of drinking and dependence. Understanding the molecular mechanisms underlying alcohol tolerance is therefore important for the development of effective therapeutics and for understanding addiction in general. This review explores the molecular basis of alcohol tolerance in invertebrate models, Drosophila and C. elegans, focusing on synaptic transmission. Both organisms exhibit biphasic responses to ethanol and develop tolerance similar to that of mammals. Furthermore, the availability of several genetic tools makes them a great candidate to study the molecular basis of ethanol response. Studies in invertebrate models show that tolerance involves conserved changes in the neurotransmitter systems, ion channels, and synaptic proteins. These neuroadaptive changes lead to a change in neuronal excitability, most likely to compensate for the enhanced inhibition by ethanol.
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Affiliation(s)
- Aakriti Bhandari
- Department of Psychiatry, University of Utah, Salt Lake City, UT 84112, USA
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA
- Neuroscience Graduate Program, University of Utah, Salt Lake City, UT 84112, USA
| | - Alexandra Seguin
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA
| | - Adrian Rothenfluh
- Department of Psychiatry, University of Utah, Salt Lake City, UT 84112, USA
- Molecular Medicine Program, University of Utah, Salt Lake City, UT 84112, USA
- Neuroscience Graduate Program, University of Utah, Salt Lake City, UT 84112, USA
- Department of Neurobiology, University of Utah, Salt Lake City, UT 84112, USA
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA
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3
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Vaikakkara Chithran A, Allan DW, O'Connor TP. Adult expression of the cell adhesion protein Fasciclin 3 is required for the maintenance of adult olfactory interneurons. J Cell Sci 2024; 137:jcs261759. [PMID: 38934299 DOI: 10.1242/jcs.261759] [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: 10/30/2023] [Accepted: 05/20/2024] [Indexed: 06/28/2024] Open
Abstract
The proper functioning of the nervous system is dependent on the establishment and maintenance of intricate networks of neurons that form functional neural circuits. Once neural circuits are assembled during development, a distinct set of molecular programs is likely required to maintain their connectivity throughout the lifetime of the organism. Here, we demonstrate that Fasciclin 3 (Fas3), an axon guidance cell adhesion protein, is necessary for the maintenance of the olfactory circuit in adult Drosophila. We utilized the TARGET system to spatiotemporally knockdown Fas3 in selected populations of adult neurons. Our findings show that Fas3 knockdown results in the death of olfactory circuit neurons and reduced survival of adults. We also demonstrated that Fas3 knockdown activates caspase-3-mediated cell death in olfactory local interneurons, which can be rescued by overexpressing baculovirus p35, an anti-apoptotic protein. This work adds to the growing set of evidence indicating a crucial role for axon guidance proteins in the maintenance of neuronal circuits in adults.
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Affiliation(s)
- Aarya Vaikakkara Chithran
- Graduate Program in Neuroscience, 3402-2215 Wesbrook Mall, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
- Department of Cellular and Physiological Sciences, 2350 Health Sciences Mall, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Douglas W Allan
- Department of Cellular and Physiological Sciences, 2350 Health Sciences Mall, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
- Djavad Mowafaghian Centre for Brain Health, 2215 Wesbrook Mall, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Timothy P O'Connor
- Department of Cellular and Physiological Sciences, 2350 Health Sciences Mall, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
- Djavad Mowafaghian Centre for Brain Health, 2215 Wesbrook Mall, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
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4
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Kraft N, Muenz TS, Reinhard S, Werner C, Sauer M, Groh C, Rössler W. Expansion microscopy in honeybee brains for high-resolution neuroanatomical analyses in social insects. Cell Tissue Res 2023; 393:489-506. [PMID: 37421435 PMCID: PMC10484815 DOI: 10.1007/s00441-023-03803-4] [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: 01/27/2023] [Accepted: 06/28/2023] [Indexed: 07/10/2023]
Abstract
The diffraction limit of light microscopy poses a problem that is frequently faced in structural analyses of social insect brains. With the introduction of expansion microscopy (ExM), a tool became available to overcome this limitation by isotropic physical expansion of preserved specimens. Our analyses focus on synaptic microcircuits (microglomeruli, MG) in the mushroom body (MB) of social insects, high-order brain centers for sensory integration, learning, and memory. MG undergo significant structural reorganizations with age, sensory experience, and during long-term memory formation. However, the changes in subcellular architecture involved in this plasticity have only partially been accessed yet. Using the western honeybee Apis mellifera as an experimental model, we established ExM for the first time in a social insect species and applied it to investigate plasticity in synaptic microcircuits within MG of the MB calyces. Using combinations of antibody staining and neuronal tracing, we demonstrate that this technique enables quantitative and qualitative analyses of structural neuronal plasticity at high resolution in a social insect brain.
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Affiliation(s)
- Nadine Kraft
- Department of Behavioral Physiology and Sociobiology (Zoology II), Theodor-Boveri-Institute, Biocenter, Julius Maximilian University, Würzburg, 97074, Germany.
| | - Thomas S Muenz
- Department of Behavioral Physiology and Sociobiology (Zoology II), Theodor-Boveri-Institute, Biocenter, Julius Maximilian University, Würzburg, 97074, Germany
| | - Sebastian Reinhard
- Department of Biotechnology and Biophysics, Theodor-Boveri-Institute, Biocenter, Julius Maximilian University, Würzburg, 97074, Germany
| | - Christian Werner
- Department of Biotechnology and Biophysics, Theodor-Boveri-Institute, Biocenter, Julius Maximilian University, Würzburg, 97074, Germany
| | - Markus Sauer
- Department of Biotechnology and Biophysics, Theodor-Boveri-Institute, Biocenter, Julius Maximilian University, Würzburg, 97074, Germany
| | - Claudia Groh
- Department of Behavioral Physiology and Sociobiology (Zoology II), Theodor-Boveri-Institute, Biocenter, Julius Maximilian University, Würzburg, 97074, Germany
| | - Wolfgang Rössler
- Department of Behavioral Physiology and Sociobiology (Zoology II), Theodor-Boveri-Institute, Biocenter, Julius Maximilian University, Würzburg, 97074, Germany
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5
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Blok LER, Boon M, van Reijmersdal B, Höffler KD, Fenckova M, Schenck A. Genetics, molecular control and clinical relevance of habituation learning. Neurosci Biobehav Rev 2022; 143:104883. [PMID: 36152842 DOI: 10.1016/j.neubiorev.2022.104883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 08/08/2022] [Accepted: 08/30/2022] [Indexed: 11/29/2022]
Abstract
Habituation is the most fundamental form of learning. As a firewall that protects our brain from sensory overload, it is indispensable for cognitive processes. Studies in humans and animal models provide increasing evidence that habituation is affected in autism and related monogenic neurodevelopmental disorders (NDDs). An integrated application of habituation assessment in NDDs and their animal models has unexploited potential for neuroscience and medical care. With the aim to gain mechanistic insights, we systematically retrieved genes that have been demonstrated in the literature to underlie habituation. We identified 258 evolutionarily conserved genes across species, describe the biological processes they converge on, and highlight regulatory pathways and drugs that may alleviate habituation deficits. We also summarize current habituation paradigms and extract the most decisive arguments that support the crucial role of habituation for cognition in health and disease. We conclude that habituation is a conserved, quantitative, cognition- and disease-relevant process that can connect preclinical and clinical work, and hence is a powerful tool to advance research, diagnostics, and treatment of NDDs.
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Affiliation(s)
- Laura Elisabeth Rosalie Blok
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525GA, Nijmegen, the Netherlands.
| | - Marina Boon
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525GA, Nijmegen, the Netherlands.
| | - Boyd van Reijmersdal
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525GA, Nijmegen, the Netherlands.
| | - Kira Daniela Höffler
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525GA, Nijmegen, the Netherlands.
| | - Michaela Fenckova
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525GA, Nijmegen, the Netherlands; Department of Molecular Biology and Genetics, Faculty of Science, University of South Bohemia in Ceske Budejovice, Branisovska 31, 37005, Ceske Budejovice, Czech Republic.
| | - Annette Schenck
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Geert Grooteplein Zuid 10, 6525GA, Nijmegen, the Netherlands.
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6
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Ryan TJ, Frankland PW. Forgetting as a form of adaptive engram cell plasticity. Nat Rev Neurosci 2022; 23:173-186. [PMID: 35027710 DOI: 10.1038/s41583-021-00548-3] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/25/2021] [Indexed: 12/30/2022]
Abstract
One leading hypothesis suggests that memories are stored in ensembles of neurons (or 'engram cells') and that successful recall involves reactivation of these ensembles. A logical extension of this idea is that forgetting occurs when engram cells cannot be reactivated. Forms of 'natural forgetting' vary considerably in terms of their underlying mechanisms, time course and reversibility. However, we suggest that all forms of forgetting involve circuit remodelling that switches engram cells from an accessible state (where they can be reactivated by natural recall cues) to an inaccessible state (where they cannot). In many cases, forgetting rates are modulated by environmental conditions and we therefore propose that forgetting is a form of neuroplasticity that alters engram cell accessibility in a manner that is sensitive to mismatches between expectations and the environment. Moreover, we hypothesize that disease states associated with forgetting may hijack natural forgetting mechanisms, resulting in reduced engram cell accessibility and memory loss.
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Affiliation(s)
- Tomás J Ryan
- School of Biochemistry and Immunology, Trinity College Dublin, Dublin, Ireland. .,Trinity College Institute for Neuroscience, Trinity College Dublin, Dublin, Ireland. .,Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Melbourne, Victoria, Australia. .,Child & Brain Development Program, Canadian Institute for Advanced Research (CIFAR), Toronto, Ontario, Canada.
| | - Paul W Frankland
- Child & Brain Development Program, Canadian Institute for Advanced Research (CIFAR), Toronto, Ontario, Canada. .,Program in Neurosciences & Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada. .,Department of Psychology, University of Toronto, Toronto, Ontario, Canada. .,Department of Physiology, University of Toronto, Toronto, Ontario, Canada. .,Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada.
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7
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Rozenfeld E, Tauber M, Ben-Chaim Y, Parnas M. GPCR voltage dependence controls neuronal plasticity and behavior. Nat Commun 2021; 12:7252. [PMID: 34903750 PMCID: PMC8668892 DOI: 10.1038/s41467-021-27593-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Accepted: 11/29/2021] [Indexed: 12/25/2022] Open
Abstract
G-protein coupled receptors (GPCRs) play a paramount role in diverse brain functions. Almost 20 years ago, GPCR activity was shown to be regulated by membrane potential in vitro, but whether the voltage dependence of GPCRs contributes to neuronal coding and behavioral output under physiological conditions in vivo has never been demonstrated. Here we show that muscarinic GPCR mediated neuronal potentiation in vivo is voltage dependent. This voltage dependent potentiation is abolished in mutant animals expressing a voltage independent receptor. Depolarization alone, without a muscarinic agonist, results in a nicotinic ionotropic receptor potentiation that is mediated by muscarinic receptor voltage dependency. Finally, muscarinic receptor voltage independence causes a strong behavioral effect of increased odor habituation. Together, this study identifies a physiological role for the voltage dependency of GPCRs by demonstrating crucial involvement of GPCR voltage dependence in neuronal plasticity and behavior. Thus, this study suggests that GPCR voltage dependency plays a role in many diverse neuronal functions including learning and memory.
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Affiliation(s)
- Eyal Rozenfeld
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Merav Tauber
- Department of Natural and Life Sciences, The Open University of Israel, Ra'anana, 43107, Israel
| | - Yair Ben-Chaim
- Department of Natural and Life Sciences, The Open University of Israel, Ra'anana, 43107, Israel
| | - Moshe Parnas
- Department of Physiology and Pharmacology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel.
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, 69978, Israel.
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8
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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.
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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.
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9
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Abstract
The olfactory system translates chemical signals into neuronal signals that inform behavioral decisions of the animal. Odors are cues for source identity, but if monitored long enough, they can also be used to localize the source. Odor representations should therefore be robust to changing conditions and flexible in order to drive an appropriate behavior. In this review, we aim at discussing the main computations that allow robust and flexible encoding of odor information in the olfactory neural pathway.
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10
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Kepler LD, McDiarmid TA, Rankin CH. Habituation in high-throughput genetic model organisms as a tool to investigate the mechanisms of neurodevelopmental disorders. Neurobiol Learn Mem 2020; 171:107208. [DOI: 10.1016/j.nlm.2020.107208] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 02/14/2020] [Accepted: 03/02/2020] [Indexed: 10/24/2022]
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11
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Blanco-Redondo B, Nuwal N, Kneitz S, Nuwal T, Halder P, Liu Y, Ehmann N, Scholz N, Mayer A, Kleber J, Kähne T, Schmitt D, Sadanandappa MK, Funk N, Albertova V, Helfrich-Förster C, Ramaswami M, Hasan G, Kittel RJ, Langenhan T, Gerber B, Buchner E. Implications of the Sap47 null mutation for synapsin phosphorylation, longevity, climbing proficiency and behavioural plasticity in adult Drosophila. ACTA ACUST UNITED AC 2019; 222:jeb.203505. [PMID: 31488622 DOI: 10.1242/jeb.203505] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 08/29/2019] [Indexed: 12/18/2022]
Abstract
The Sap47 gene of Drosophila melanogaster encodes a highly abundant 47 kDa synaptic vesicle-associated protein. Sap47 null mutants show defects in synaptic plasticity and larval olfactory associative learning but the molecular function of Sap47 at the synapse is unknown. We demonstrate that Sap47 modulates the phosphorylation of another highly abundant conserved presynaptic protein, synapsin. Site-specific phosphorylation of Drosophila synapsin has repeatedly been shown to be important for behavioural plasticity but it was not known where these phospho-synapsin isoforms are localized in the brain. Here, we report the distribution of serine-6-phosphorylated synapsin in the adult brain and show that it is highly enriched in rings of synapses in the ellipsoid body and in large synapses near the lateral triangle. The effects of knockout of Sap47 or synapsin on olfactory associative learning/memory support the hypothesis that both proteins operate in the same molecular pathway. We therefore asked if this might also be true for other aspects of their function. We show that knockout of Sap47 but not synapsin reduces lifespan, whereas knockout of Sap47 and synapsin, either individually or together, affects climbing proficiency, as well as plasticity in circadian rhythms and sleep. Furthermore, electrophysiological assessment of synaptic properties at the larval neuromuscular junction (NMJ) reveals increased spontaneous synaptic vesicle fusion and reduced paired pulse facilitation in Sap47 and synapsin single and double mutants. Our results imply that Sap47 and synapsin cooperate non-uniformly in the control of synaptic properties in different behaviourally relevant neuronal networks of the fruitfly.
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Affiliation(s)
- Beatriz Blanco-Redondo
- Institute of Clinical Neurobiology, University of Würzburg, 97078 Würzburg, Germany .,Department of Neurobiology and Genetics, Biocenter of the University of Würzburg, 97074 Würzburg, Germany.,Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Leipzig University, 04103 Leipzig, Germany
| | - Nidhi Nuwal
- Department of Neurobiology and Genetics, Biocenter of the University of Würzburg, 97074 Würzburg, Germany
| | - Susanne Kneitz
- Department of Physiological Chemistry, Biocenter of the University of Würzburg, 97074 Würzburg, Germany
| | - Tulip Nuwal
- Department of Neurobiology and Genetics, Biocenter of the University of Würzburg, 97074 Würzburg, Germany
| | - Partho Halder
- Department of Neurobiology and Genetics, Biocenter of the University of Würzburg, 97074 Würzburg, Germany
| | - Yiting Liu
- Department of Neurobiology and Genetics, Biocenter of the University of Würzburg, 97074 Würzburg, Germany
| | - Nadine Ehmann
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, 97070 Würzburg, Germany.,Department of Animal Physiology, Institute of Biology, Leipzig University, 04103 Leipzig, Germany.,Carl-Ludwig-Institute for Physiology, Leipzig University, 04103 Leipzig, Germany
| | - Nicole Scholz
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Leipzig University, 04103 Leipzig, Germany.,Department of Neurophysiology, Institute of Physiology, University of Würzburg, 97070 Würzburg, Germany
| | - Annika Mayer
- Institute of Clinical Neurobiology, University of Würzburg, 97078 Würzburg, Germany
| | - Jörg Kleber
- Leibniz Institute of Neurobiology, 39118 Magdeburg, Germany
| | - Thilo Kähne
- Institute of Experimental Internal Medicine, Otto von Guericke University, 39120 Magdeburg, Germany
| | - Dominique Schmitt
- Institute of Clinical Neurobiology, University of Würzburg, 97078 Würzburg, Germany
| | - Madhumala K Sadanandappa
- Institute of Clinical Neurobiology, University of Würzburg, 97078 Würzburg, Germany.,National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka 560065, India
| | - Natalja Funk
- Department of Neurobiology and Genetics, Biocenter of the University of Würzburg, 97074 Würzburg, Germany
| | - Viera Albertova
- Institute of Clinical Neurobiology, University of Würzburg, 97078 Würzburg, Germany.,Department of Neurobiology and Genetics, Biocenter of the University of Würzburg, 97074 Würzburg, Germany
| | - Charlotte Helfrich-Förster
- Department of Neurobiology and Genetics, Biocenter of the University of Würzburg, 97074 Würzburg, Germany
| | - Mani Ramaswami
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka 560065, India
| | - Gaiti Hasan
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka 560065, India
| | - Robert J Kittel
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, 97070 Würzburg, Germany.,Department of Animal Physiology, Institute of Biology, Leipzig University, 04103 Leipzig, Germany.,Carl-Ludwig-Institute for Physiology, Leipzig University, 04103 Leipzig, Germany
| | - Tobias Langenhan
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Leipzig University, 04103 Leipzig, Germany.,Department of Neurophysiology, Institute of Physiology, University of Würzburg, 97070 Würzburg, Germany
| | - Bertram Gerber
- Leibniz Institute of Neurobiology, 39118 Magdeburg, Germany.,Institute of Biology, University of Magdeburg, 39120 Magdeburg, Germany.,Center for Behavioral Brain Sciences, 39106 Magdeburg, Germany
| | - Erich Buchner
- Institute of Clinical Neurobiology, University of Würzburg, 97078 Würzburg, Germany .,Department of Neurobiology and Genetics, Biocenter of the University of Würzburg, 97074 Würzburg, Germany
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12
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Fenckova M, Blok LER, Asztalos L, Goodman DP, Cizek P, Singgih EL, Glennon JC, IntHout J, Zweier C, Eichler EE, von Reyn CR, Bernier RA, Asztalos Z, Schenck A. Habituation Learning Is a Widely Affected Mechanism in Drosophila Models of Intellectual Disability and Autism Spectrum Disorders. Biol Psychiatry 2019; 86:294-305. [PMID: 31272685 PMCID: PMC7053436 DOI: 10.1016/j.biopsych.2019.04.029] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Revised: 04/02/2019] [Accepted: 04/08/2019] [Indexed: 01/07/2023]
Abstract
BACKGROUND Although habituation is one of the most ancient and fundamental forms of learning, its regulators and its relevance for human disease are poorly understood. METHODS We manipulated the orthologs of 286 genes implicated in intellectual disability (ID) with or without comorbid autism spectrum disorder (ASD) specifically in Drosophila neurons, and we tested these models in light-off jump habituation. We dissected neuronal substrates underlying the identified habituation deficits and integrated genotype-phenotype annotations, gene ontologies, and interaction networks to determine the clinical features and molecular processes that are associated with habituation deficits. RESULTS We identified >100 genes required for habituation learning. For 93 of these genes, a role in habituation learning was previously unknown. These genes characterize ID disorders with macrocephaly and/or overgrowth and comorbid ASD. Moreover, individuals with ASD from the Simons Simplex Collection carrying damaging de novo mutations in these genes exhibit increased aberrant behaviors associated with inappropriate, stereotypic speech. At the molecular level, ID genes required for normal habituation are enriched in synaptic function and converge on Ras/mitogen-activated protein kinase (Ras/MAPK) signaling. Both increased Ras/MAPK signaling in gamma-aminobutyric acidergic (GABAergic) neurons and decreased Ras/MAPK signaling in cholinergic neurons specifically inhibit the adaptive habituation response. CONCLUSIONS Our work supports the relevance of habituation learning to ASD, identifies an unprecedented number of novel habituation players, supports an emerging role for inhibitory neurons in habituation, and reveals an opposing, circuit-level-based mechanism for Ras/MAPK signaling. These findings establish habituation as a possible, widely applicable functional readout and target for pharmacologic intervention in ID/ASD.
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Affiliation(s)
- Michaela Fenckova
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Laura E R Blok
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Lenke Asztalos
- Aktogen Limited, Department of Genetics, University of Cambridge, Cambridge, United Kingdom; Aktogen Hungary Limited, Bay Zoltán Nonprofit Limited for Applied Research, Institute for Biotechnology, Szeged, Hungary
| | - David P Goodman
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania
| | - Pavel Cizek
- Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Euginia L Singgih
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands; Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jeffrey C Glennon
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joanna IntHout
- Department for Health Evidence, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Christiane Zweier
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Evan E Eichler
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, Washington; Howard Hughes Medical Institute, University of Washington, Seattle, Washington
| | - Catherine R von Reyn
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania; Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania
| | - Raphael A Bernier
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, Washington
| | - Zoltan Asztalos
- Aktogen Limited, Department of Genetics, University of Cambridge, Cambridge, United Kingdom; Aktogen Hungary Limited, Bay Zoltán Nonprofit Limited for Applied Research, Institute for Biotechnology, Szeged, Hungary; Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
| | - Annette Schenck
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands.
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13
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Semelidou O, Acevedo SF, Skoulakis EM. Temporally specific engagement of distinct neuronal circuits regulating olfactory habituation in Drosophila. eLife 2018; 7:39569. [PMID: 30576281 PMCID: PMC6303106 DOI: 10.7554/elife.39569] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 11/29/2018] [Indexed: 11/13/2022] Open
Abstract
Habituation is the process that enables salience filtering, precipitating perceptual changes that alter the value of environmental stimuli. To discern the neuronal circuits underlying habituation to brief inconsequential stimuli, we developed a novel olfactory habituation paradigm, identifying two distinct phases of the response that engage distinct neuronal circuits. Responsiveness to the continuous odor stimulus is maintained initially, a phase we term habituation latency and requires Rutabaga Adenylyl-Cyclase-depended neurotransmission from GABAergic Antennal Lobe Interneurons and activation of excitatory Projection Neurons (PNs) and the Mushroom Bodies. In contrast, habituation depends on the inhibitory PNs of the middle Antenno-Cerebral Track, requires inner Antenno-Cerebral Track PN activation and defines a temporally distinct phase. Collectively, our data support the involvement of Lateral Horn excitatory and inhibitory stimulation in habituation. These results provide essential cellular substrates for future analyses of the molecular mechanisms that govern the duration and transition between these distinct temporal habituation phases. Editorial note: This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter).
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Affiliation(s)
- Ourania Semelidou
- Division of Neuroscience, Biomedical Sciences Research Centre "Alexander Fleming", Vari, Greece.,School of Medicine, University of Crete, Heraklion, Greece
| | - Summer F Acevedo
- Division of Neuroscience, Biomedical Sciences Research Centre "Alexander Fleming", Vari, Greece
| | - Efthimios Mc Skoulakis
- Division of Neuroscience, Biomedical Sciences Research Centre "Alexander Fleming", Vari, Greece
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14
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Schleyer M, Fendt M, Schuller S, Gerber B. Associative Learning of Stimuli Paired and Unpaired With Reinforcement: Evaluating Evidence From Maggots, Flies, Bees, and Rats. Front Psychol 2018; 9:1494. [PMID: 30197613 PMCID: PMC6117914 DOI: 10.3389/fpsyg.2018.01494] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 07/30/2018] [Indexed: 12/02/2022] Open
Abstract
Finding rewards and avoiding punishments are powerful goals of behavior. To maximize reward and minimize punishment, it is beneficial to learn about the stimuli that predict their occurrence, and decades of research have provided insight into the brain processes underlying such associative reinforcement learning. In addition, it is well known in experimental psychology, yet often unacknowledged in neighboring scientific disciplines, that subjects also learn about the stimuli that predict the absence of reinforcement. Here we evaluate evidence for both these learning processes. We focus on two study cases that both provide a baseline level of behavior against which the effects of associative learning can be assessed. Firstly, we report pertinent evidence from Drosophila larvae. A re-analysis of the literature reveals that through paired presentations of an odor A and a sugar reward (A+) the animals learn that the reward can be found where the odor is, and therefore show an above-baseline preference for the odor. In contrast, through unpaired training (A/+) the animals learn that the reward can be found precisely where the odor is not, and accordingly these larvae show a below-baseline preference for it (the same is the case, with inverted signs, for learning through taste punishment). In addition, we present previously unpublished data demonstrating that also during a two-odor, differential conditioning protocol (A+/B) both these learning processes take place in larvae, i.e., learning about both the rewarded stimulus A and the non-rewarded stimulus B (again, this is likewise the case for differential conditioning with taste punishment). Secondly, after briefly discussing published evidence from adult Drosophila, honeybees, and rats, we report an unpublished data set showing that relative to baseline behavior after truly random presentations of a visual stimulus A and punishment, rats exhibit memories of opposite valence upon paired and unpaired training. Collectively, the evidence conforms to classical findings in experimental psychology and suggests that across species animals associatively learn both through paired and through unpaired presentations of stimuli with reinforcement – with opposite valence. While the brain mechanisms of unpaired learning for the most part still need to be uncovered, the immediate implication is that using unpaired procedures as a mnemonically neutral control for associative reinforcement learning may be leading analyses astray.
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Affiliation(s)
- Michael Schleyer
- Department Genetics of Learning and Memory, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Markus Fendt
- Institute for Pharmacology and Toxicology, Otto von Guericke University Magdeburg, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany
| | - Sarah Schuller
- Department Genetics of Learning and Memory, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Bertram Gerber
- Department Genetics of Learning and Memory, Leibniz Institute for Neurobiology, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany.,Behavior Genetics, Institute for Biology, Otto von Guericke University Magdeburg, Magdeburg, Germany
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15
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Bakthavachalu B, Huelsmeier J, Sudhakaran IP, Hillebrand J, Singh A, Petrauskas A, Thiagarajan D, Sankaranarayanan M, Mizoue L, Anderson EN, Pandey UB, Ross E, VijayRaghavan K, Parker R, Ramaswami M. RNP-Granule Assembly via Ataxin-2 Disordered Domains Is Required for Long-Term Memory and Neurodegeneration. Neuron 2018; 98:754-766.e4. [PMID: 29772202 DOI: 10.1016/j.neuron.2018.04.032] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 03/07/2018] [Accepted: 04/23/2018] [Indexed: 02/07/2023]
Abstract
Human Ataxin-2 is implicated in the cause and progression of amyotrophic lateral sclerosis (ALS) and type 2 spinocerebellar ataxia (SCA-2). In Drosophila, a conserved atx2 gene is essential for animal survival as well as for normal RNP-granule assembly, translational control, and long-term habituation. Like its human homolog, Drosophila Ataxin-2 (Atx2) contains polyQ repeats and additional intrinsically disordered regions (IDRs). We demonstrate that Atx2 IDRs, which are capable of mediating liquid-liquid phase transitions in vitro, are essential for efficient formation of neuronal mRNP assemblies in vivo. Remarkably, ΔIDR mutants that lack neuronal RNP granules show normal animal development, survival, and fertility. However, they show defects in long-term memory formation/consolidation as well as in C9ORF72 dipeptide repeat or FUS-induced neurodegeneration. Together, our findings demonstrate (1) that higher-order mRNP assemblies contribute to long-term neuronal plasticity and memory, and (2) that a targeted reduction in RNP-granule formation efficiency can alleviate specific forms of neurodegeneration.
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Affiliation(s)
| | - Joern Huelsmeier
- Trinity College Institute of Neuroscience, School of Genetics and Microbiology, Smurfit Institute of Genetics and School of Natural Sciences, Trinity College Dublin, Dublin-2, Ireland
| | | | - Jens Hillebrand
- Trinity College Institute of Neuroscience, School of Genetics and Microbiology, Smurfit Institute of Genetics and School of Natural Sciences, Trinity College Dublin, Dublin-2, Ireland
| | - Amanjot Singh
- National Centre for Biological Sciences, TIFR, Bangalore 560065, India
| | - Arnas Petrauskas
- Trinity College Institute of Neuroscience, School of Genetics and Microbiology, Smurfit Institute of Genetics and School of Natural Sciences, Trinity College Dublin, Dublin-2, Ireland
| | | | | | - Laura Mizoue
- Department of Chemistry, University of Colorado, Boulder, CO 80309, USA; HHMI, University of Colorado, Boulder, CO 80309, USA
| | - Eric N Anderson
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Udai Bhan Pandey
- Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Eric Ross
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - K VijayRaghavan
- National Centre for Biological Sciences, TIFR, Bangalore 560065, India
| | - Roy Parker
- Department of Chemistry, University of Colorado, Boulder, CO 80309, USA; HHMI, University of Colorado, Boulder, CO 80309, USA
| | - Mani Ramaswami
- National Centre for Biological Sciences, TIFR, Bangalore 560065, India; Trinity College Institute of Neuroscience, School of Genetics and Microbiology, Smurfit Institute of Genetics and School of Natural Sciences, Trinity College Dublin, Dublin-2, Ireland.
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16
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Ehmann N, Owald D, Kittel RJ. Drosophila active zones: From molecules to behaviour. Neurosci Res 2018; 127:14-24. [DOI: 10.1016/j.neures.2017.11.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Revised: 11/30/2017] [Accepted: 11/30/2017] [Indexed: 11/15/2022]
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17
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Oka M, Fujisaki N, Maruko-Otake A, Ohtake Y, Shimizu S, Saito T, Hisanaga SI, Iijima KM, Ando K. Ca2+/calmodulin-dependent protein kinase II promotes neurodegeneration caused by tau phosphorylated at Ser262/356 in a transgenic Drosophila model of tauopathy. J Biochem 2017; 162:335-342. [PMID: 28992057 DOI: 10.1093/jb/mvx038] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 05/19/2017] [Indexed: 01/07/2023] Open
Abstract
Abnormal deposition of the microtubule-associated protein tau is a common pathological feature of multiple neurodegenerative diseases, including Alzheimer's disease (AD), and plays critical roles in their pathogenesis. Disruption of calcium homeostasis and the downstream kinase Ca2+/calmodulin-dependent protein kinase II (CaMKII) coincides with pathological phosphorylation of tau in AD brains. However, it remains unclear whether and how dysregulation of CaMKII affects tau toxicity. Using a Drosophila model, we found that CaMKII promotes neurodegeneration caused by tau phosphorylated at the AD-associated sites Ser262/356. Overexpression of CaMKII promoted, while RNA-mediated knockdown of CaMKII and inhibition of CaMKII activity by expression of an inhibitory peptide suppressed, tau-mediated neurodegeneration. Blocking tau phosphorylation at Ser262/356 by alanine substitutions suppressed promotion of tau toxicity by CaMKII, suggesting that tau phosphorylation at these sites is required for this phenomenon. However, neither knockdown nor overexpression of CaMKII affected tau phosphorylation levels at Ser262/356, suggesting that CaMKII is not directly involved in tau phosphorylation at Ser262/356 in this model. These results suggest that a pathological cascade of events, including elevated levels of tau phosphorylated at Ser262/356 and aberrant activation of CaMKII, work in concert to promote tau-mediated neurodegeneration.
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Affiliation(s)
- Mikiko Oka
- Department of Biological Sciences, Graduate School of Science and Engineering, Tokyo Metropolitan University, Tokyo 192-0397, Japan
| | - Naoki Fujisaki
- Department of Alzheimer's Disease Research, National Center for Geriatrics and Gerontology, 7-430 Morioka-machi, Obu, Aichi 474-8511, Japan.,Department of Experimental Gerontology, Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan
| | - Akiko Maruko-Otake
- Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Yosuke Ohtake
- Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Sawako Shimizu
- Department of Biological Sciences, Graduate School of Science and Engineering, Tokyo Metropolitan University, Tokyo 192-0397, Japan
| | - Taro Saito
- Department of Biological Sciences, Graduate School of Science and Engineering, Tokyo Metropolitan University, Tokyo 192-0397, Japan
| | - Shin-Ichi Hisanaga
- Department of Biological Sciences, Graduate School of Science and Engineering, Tokyo Metropolitan University, Tokyo 192-0397, Japan
| | - Koichi M Iijima
- Department of Alzheimer's Disease Research, National Center for Geriatrics and Gerontology, 7-430 Morioka-machi, Obu, Aichi 474-8511, Japan.,Department of Experimental Gerontology, Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan
| | - Kanae Ando
- Department of Biological Sciences, Graduate School of Science and Engineering, Tokyo Metropolitan University, Tokyo 192-0397, Japan
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18
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Meese S, Cepeda AP, Gahlen F, Adams CM, Ficner R, Ricci AJ, Heller S, Reisinger E, Herget M. Activity-Dependent Phosphorylation by CaMKIIδ Alters the Ca 2+ Affinity of the Multi-C 2-Domain Protein Otoferlin. Front Synaptic Neurosci 2017; 9:13. [PMID: 29046633 PMCID: PMC5632675 DOI: 10.3389/fnsyn.2017.00013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 09/11/2017] [Indexed: 01/20/2023] Open
Abstract
Otoferlin is essential for fast Ca2+-triggered transmitter release from auditory inner hair cells (IHCs), playing key roles in synaptic vesicle release, replenishment and retrieval. Dysfunction of otoferlin results in profound prelingual deafness. Despite its crucial role in cochlear synaptic processes, mechanisms regulating otoferlin activity have not been studied to date. Here, we identified Ca2+/calmodulin-dependent serine/threonine kinase II delta (CaMKIIδ) as an otoferlin binding partner by pull-downs from chicken utricles and reassured interaction by a co-immunoprecipitation with heterologously expressed proteins in HEK cells. We confirmed the expression of CaMKIIδ in rodent IHCs by immunohistochemistry and real-time PCR. A proximity ligation assay indicates close proximity of the two proteins in rat IHCs, suggesting that otoferlin and CaMKIIδ also interact in mammalian IHCs. In vitro phosphorylation of otoferlin by CaMKIIδ revealed ten phosphorylation sites, five of which are located within C2-domains. Exchange of serines/threonines at phosphorylated sites into phosphomimetic aspartates reduces the Ca2+ affinity of the recombinant C2F domain 10-fold, and increases the Ca2+ affinity of the C2C domain. Concordantly, we show that phosphorylation of otoferlin and/or its interaction partners are enhanced upon hair cell depolarization and blocked by pharmacological CaMKII inhibition. We therefore propose that otoferlin activity is regulated by CaMKIIδ in IHCs.
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Affiliation(s)
- Sandra Meese
- Department of Molecular Structural Biology, Institute for Microbiology and Genetics, and Collaborative Research Center 889, University of Göttingen, Göttingen, Germany.,Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences, Göttingen, Germany
| | - Andreia P Cepeda
- Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences, Göttingen, Germany.,Molecular Biology of Cochlear Neurotransmission Group, Department of Otorhinolaryngology, University Medical Center Göttingen, and Collaborative Research Center 889, University of Göttingen, Göttingen, Germany
| | - Felix Gahlen
- Department of Otorhinolaryngology, Head and Neck Surgery, Ruhr-University Bochum, Bochum, Germany
| | - Christopher M Adams
- Stanford University Mass Spectrometry, Stanford University, Stanford, CA, United States
| | - Ralf Ficner
- Department of Molecular Structural Biology, Institute for Microbiology and Genetics, and Collaborative Research Center 889, University of Göttingen, Göttingen, Germany
| | - Anthony J Ricci
- Department of Otolaryngology, Head and Neck Surgery, Stanford School of Medicine, Stanford, CA, United States
| | - Stefan Heller
- Department of Otolaryngology, Head and Neck Surgery, Stanford School of Medicine, Stanford, CA, United States
| | - Ellen Reisinger
- Molecular Biology of Cochlear Neurotransmission Group, Department of Otorhinolaryngology, University Medical Center Göttingen, and Collaborative Research Center 889, University of Göttingen, Göttingen, Germany
| | - Meike Herget
- Department of Otolaryngology, Head and Neck Surgery, Stanford School of Medicine, Stanford, CA, United States
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19
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Ulian-Benitez S, Bishop S, Foldi I, Wentzell J, Okenwa C, Forero MG, Zhu B, Moreira M, Phizacklea M, McIlroy G, Li G, Gay NJ, Hidalgo A. Kek-6: A truncated-Trk-like receptor for Drosophila neurotrophin 2 regulates structural synaptic plasticity. PLoS Genet 2017; 13:e1006968. [PMID: 28846707 PMCID: PMC5591008 DOI: 10.1371/journal.pgen.1006968] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 09/08/2017] [Accepted: 08/08/2017] [Indexed: 01/19/2023] Open
Abstract
Neurotrophism, structural plasticity, learning and long-term memory in mammals critically depend on neurotrophins binding Trk receptors to activate tyrosine kinase (TyrK) signaling, but Drosophila lacks full-length Trks, raising the question of how these processes occur in the fly. Paradoxically, truncated Trk isoforms lacking the TyrK predominate in the adult human brain, but whether they have neuronal functions independently of full-length Trks is unknown. Drosophila has TyrK-less Trk-family receptors, encoded by the kekkon (kek) genes, suggesting that evolutionarily conserved functions for this receptor class may exist. Here, we asked whether Keks function together with Drosophila neurotrophins (DNTs) at the larval glutamatergic neuromuscular junction (NMJ). We tested the eleven LRR and Ig-containing (LIG) proteins encoded in the Drosophila genome for expression in the central nervous system (CNS) and potential interaction with DNTs. Kek-6 is expressed in the CNS, interacts genetically with DNTs and can bind DNT2 in signaling assays and co-immunoprecipitations. Ligand binding is promiscuous, as Kek-6 can also bind DNT1, and Kek-2 and Kek-5 can also bind DNT2. In vivo, Kek-6 is found presynaptically in motoneurons, and DNT2 is produced by the muscle to function as a retrograde factor at the NMJ. Kek-6 and DNT2 regulate NMJ growth and synaptic structure. Evidence indicates that Kek-6 does not antagonise the alternative DNT2 receptor Toll-6. Instead, Kek-6 and Toll-6 interact physically, and together regulate structural synaptic plasticity and homeostasis. Using pull-down assays, we identified and validated CaMKII and VAP33A as intracellular partners of Kek-6, and show that they regulate NMJ growth and active zone formation downstream of DNT2 and Kek-6. The synaptic functions of Kek-6 could be evolutionarily conserved. This raises the intriguing possibility that a novel mechanism of structural synaptic plasticity involving truncated Trk-family receptors independently of TyrK signaling may also operate in the human brain. A long-standing paradox had been to explain how brain structural plasticity, learning and long-term memory might occur in Drosophila in the absence of canonical Trk receptors for neurotrophin (NT) ligands. NTs link structure and function in the brain enabling adjustments in cell number, dendritic, axonal and synaptic patterns, in response to neuronal activity. These events are essential for brain development, learning and long-term memory, and are thought to depend on the tyrosine-kinase function of the NT Trk receptors. However, paradoxically, the most abundant Trk isoforms in the adult human brain lack the tyrosine kinase, and their neuronal function is unknown. Remarkably, Drosophila has kinase-less receptors of the Trk family encoded by the kekkon (kek) genes, suggesting that deep evolutionary functional conservation for this receptor class could be unveiled. Here, we show that Kek-6 is a receptor for Drosophila neurotrophin 2 (DNT2) that regulates structural synaptic plasticity via CaMKII and VAP33A. The latter are well-known factors regulating synaptic structure and plasticity and vesicle release. Furthemore, Kek-6 cooperates with the alternative DNT2 receptor Toll-6, and their concerted functions are required to regulate structural homeostasis at the NMJ. Our findings suggest that in mammals truncated Trk-family receptors could also have synaptic functions in neurons independently of Tyrosine kinase signaling. This might reveal a novel mechanism of brain plasticity, with important implications for understanding also the human brain, in health and disease.
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Affiliation(s)
- Suzana Ulian-Benitez
- NeuroDevelopment Group, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Simon Bishop
- NeuroDevelopment Group, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Istvan Foldi
- NeuroDevelopment Group, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Jill Wentzell
- NeuroDevelopment Group, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Chinenye Okenwa
- NeuroDevelopment Group, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | | | - Bangfu Zhu
- NeuroDevelopment Group, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Marta Moreira
- NeuroDevelopment Group, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Mark Phizacklea
- NeuroDevelopment Group, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Graham McIlroy
- NeuroDevelopment Group, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Guiyi Li
- NeuroDevelopment Group, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
| | - Nicholas J. Gay
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Alicia Hidalgo
- NeuroDevelopment Group, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
- * E-mail:
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20
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Sir2/Sirt1 Links Acute Inebriation to Presynaptic Changes and the Development of Alcohol Tolerance, Preference, and Reward. J Neurosci 2017; 36:5241-51. [PMID: 27170122 DOI: 10.1523/jneurosci.0499-16.2016] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 03/23/2016] [Indexed: 01/01/2023] Open
Abstract
UNLABELLED Acute ethanol inebriation causes neuroadaptive changes in behavior that favor increased intake. Ethanol-induced alterations in gene expression, through epigenetic and other means, are likely to change cellular and neural circuit function. Ethanol markedly changes histone acetylation, and the sirtuin Sir2/SIRT1 that deacetylates histones and transcription factors is essential for the rewarding effects of long-term drug use. The molecular transformations leading from short-term to long-term ethanol responses mostly remain to be discovered. We find that Sir2 in the mushroom bodies of the fruit fly Drosophila promotes short-term ethanol-induced behavioral plasticity by allowing changes in the expression of presynaptic molecules. Acute inebriation strongly reduces Sir2 levels and increases histone H3 acetylation in the brain. Flies lacking Sir2 globally, in the adult nervous system, or specifically in the mushroom body α/β-lobes show reduced ethanol sensitivity and tolerance. Sir2-dependent ethanol reward is also localized to the mushroom bodies, and Sir2 mutants prefer ethanol even without a priming ethanol pre-exposure. Transcriptomic analysis reveals that specific presynaptic molecules, including the synaptic vesicle pool regulator Synapsin, depend on Sir2 to be regulated by ethanol. Synapsin is required for ethanol sensitivity and tolerance. We propose that the regulation of Sir2/SIRT1 by acute inebriation forms part of a transcriptional program in mushroom body neurons to alter presynaptic properties and neural responses to favor the development of ethanol tolerance, preference, and reward. SIGNIFICANCE STATEMENT We identify a mechanism by which acute ethanol inebriation leads to changes in nervous system function that may be an important basis for increasing ethanol intake and addiction liability. The findings are significant because they identify ethanol-driven transcriptional events that target presynaptic properties and direct behavioral plasticity. They also demonstrate that multiple forms of ethanol behavioral plasticity that are relevant to alcoholism are initiated by a shared mechanism. Finally, they link these events to the Drosophila brain region that associates context with innate approach and avoidance responses to code for reward and other higher-order behavior, similar in aspects to the role of the vertebrate mesolimbic system.
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21
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Zhao F, Wang X, Zariwala HA, Uslaner JM, Houghton AK, Evelhoch JL, Hostetler E, Winkelmann CT, Hines CD. fMRI study of the role of glutamate NMDA receptor in the olfactory adaptation in rats: Insights into cellular and molecular mechanisms of olfactory adaptation. Neuroimage 2017; 149:348-360. [DOI: 10.1016/j.neuroimage.2017.01.068] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 12/23/2016] [Accepted: 01/28/2017] [Indexed: 11/16/2022] Open
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Kleber J, Chen YC, Michels B, Saumweber T, Schleyer M, Kähne T, Buchner E, Gerber B. Synapsin is required to "boost" memory strength for highly salient events. ACTA ACUST UNITED AC 2015; 23:9-20. [PMID: 26670182 PMCID: PMC4749839 DOI: 10.1101/lm.039685.115] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 10/28/2015] [Indexed: 12/11/2022]
Abstract
Synapsin is an evolutionarily conserved presynaptic phosphoprotein. It is encoded by only one gene in the Drosophila genome and is expressed throughout the nervous system. It regulates the balance between reserve and releasable vesicles, is required to maintain transmission upon heavy demand, and is essential for proper memory function at the behavioral level. Task-relevant sensorimotor functions, however, remain intact in the absence of Synapsin. Using an odor–sugar reward associative learning paradigm in larval Drosophila, we show that memory scores in mutants lacking Synapsin (syn97) are lower than in wild-type animals only when more salient, higher concentrations of odor or of the sugar reward are used. Furthermore, we show that Synapsin is selectively required for larval short-term memory. Thus, without Synapsin Drosophila larvae can learn and remember, but Synapsin is required to form memories that match in strength to event salience—in particular to a high saliency of odors, of rewards, or the salient recency of an event. We further show that the residual memory scores upon a lack of Synapsin are not further decreased by an additional lack of the Sap47 protein. In combination with mass spectrometry data showing an up-regulated phosphorylation of Synapsin in the larval nervous system upon a lack of Sap47, this is suggestive of a functional interdependence of Synapsin and Sap47.
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Affiliation(s)
- Jörg Kleber
- Leibniz Institut für Neurobiologie (LIN), Abteilung Genetik von Lernen und Gedächtnis, 39118 Magdeburg, Germany
| | - Yi-Chun Chen
- Leibniz Institut für Neurobiologie (LIN), Abteilung Genetik von Lernen und Gedächtnis, 39118 Magdeburg, Germany
| | - Birgit Michels
- Leibniz Institut für Neurobiologie (LIN), Abteilung Genetik von Lernen und Gedächtnis, 39118 Magdeburg, Germany
| | - Timo Saumweber
- Leibniz Institut für Neurobiologie (LIN), Abteilung Genetik von Lernen und Gedächtnis, 39118 Magdeburg, Germany
| | - Michael Schleyer
- Leibniz Institut für Neurobiologie (LIN), Abteilung Genetik von Lernen und Gedächtnis, 39118 Magdeburg, Germany
| | - Thilo Kähne
- Otto von Guericke Universität Magdeburg, Institut für Experimentelle Innere Medizin, 39120 Magdeburg, Germany
| | - Erich Buchner
- Institut für Klinische Neurobiologie, 97078 Würzburg, Germany
| | - Bertram Gerber
- Leibniz Institut für Neurobiologie (LIN), Abteilung Genetik von Lernen und Gedächtnis, 39118 Magdeburg, Germany Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany Otto von Guericke Universität Magdeburg, Institut für Biologie, 39106 Magdeburg, Germany
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23
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Tachibana SI, Touhara K, Ejima A. Modification of Male Courtship Motivation by Olfactory Habituation via the GABAA Receptor in Drosophila melanogaster. PLoS One 2015; 10:e0135186. [PMID: 26252206 PMCID: PMC4529276 DOI: 10.1371/journal.pone.0135186] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2015] [Accepted: 07/18/2015] [Indexed: 11/29/2022] Open
Abstract
A male-specific component, 11-cis-vaccenyl acetate (cVA) works as an anti-aphrodisiac pheromone in Drosophila melanogaster. The presence of cVA on a male suppresses the courtship motivation of other males and contributes to suppression of male-male homosexual courtship, while the absence of cVA on a female stimulates the sexual motivation of nearby males and enhances the male-female interaction. However, little is known how a male distinguishes the presence or absence of cVA on a target fly from either self-produced cVA or secondhand cVA from other males in the vicinity. In this study, we demonstrate that male flies have keen sensitivity to cVA; therefore, the presence of another male in the area reduces courtship toward a female. This reduced level of sexual motivation, however, could be overcome by pretest odor exposure via olfactory habituation to cVA. Real-time imaging of cVA-responsive sensory neurons using the neural activity sensor revealed that prolonged exposure to cVA decreased the levels of cVA responses in the primary olfactory center. Pharmacological and genetic screening revealed that signal transduction via GABAA receptors contributed to this olfactory habituation. We also found that the habituation experience increased the copulation success of wild-type males in a group. In contrast, transgenic males, in which GABA input in a small subset of local neurons was blocked by RNAi, failed to acquire the sexual advantage conferred by habituation. Thus, we illustrate a novel phenomenon in which olfactory habituation positively affects sexual capability in a competitive environment.
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Affiliation(s)
- Shin-Ichiro Tachibana
- Career-Path Promotion Unit for Young Life Scientists, Kyoto University, Kyoto, 606–8501, Japan
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Osaka, 558–8585, Japan
| | - Kazushige Touhara
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, 113–8657, Japan
- ERATO Touhara Chemosensory Signal Project, JST, The University of Tokyo, Tokyo, 113–8657, Japan
| | - Aki Ejima
- Career-Path Promotion Unit for Young Life Scientists, Kyoto University, Kyoto, 606–8501, Japan
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, 113–8657, Japan
- ERATO Touhara Chemosensory Signal Project, JST, The University of Tokyo, Tokyo, 113–8657, Japan
- * E-mail:
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24
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Abstract
Adverse life events can induce two kinds of memory with opposite valence, dependent on timing: "negative" memories for stimuli preceding them and "positive" memories for stimuli experienced at the moment of "relief." Such punishment memory and relief memory are found in insects, rats, and man. For example, fruit flies (Drosophila melanogaster) avoid an odor after odor-shock training ("forward conditioning" of the odor), whereas after shock-odor training ("backward conditioning" of the odor) they approach it. Do these timing-dependent associative processes share molecular determinants? We focus on the role of Synapsin, a conserved presynaptic phosphoprotein regulating the balance between the reserve pool and the readily releasable pool of synaptic vesicles. We find that a lack of Synapsin leaves task-relevant sensory and motor faculties unaffected. In contrast, both punishment memory and relief memory scores are reduced. These defects reflect a true lessening of associative memory strength, as distortions in nonassociative processing (e.g., susceptibility to handling, adaptation, habituation, sensitization), discrimination ability, and changes in the time course of coincidence detection can be ruled out as alternative explanations. Reductions in punishment- and relief-memory strength are also observed upon an RNAi-mediated knock-down of Synapsin, and are rescued both by acutely restoring Synapsin and by locally restoring it in the mushroom bodies of mutant flies. Thus, both punishment memory and relief memory require the Synapsin protein and in this sense share genetic and molecular determinants. We note that corresponding molecular commonalities between punishment memory and relief memory in humans would constrain pharmacological attempts to selectively interfere with excessive associative punishment memories, e.g., after traumatic experiences.
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Gene dosage in the dysbindin schizophrenia susceptibility network differentially affect synaptic function and plasticity. J Neurosci 2015; 35:325-38. [PMID: 25568125 DOI: 10.1523/jneurosci.3542-14.2015] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Neurodevelopmental disorders arise from single or multiple gene defects. However, the way multiple loci interact to modify phenotypic outcomes remains poorly understood. Here, we studied phenotypes associated with mutations in the schizophrenia susceptibility gene dysbindin (dysb), in isolation or in combination with null alleles in the dysb network component Blos1. In humans, the Blos1 ortholog Bloc1s1 encodes a polypeptide that assembles, with dysbindin, into the octameric BLOC-1 complex. We biochemically confirmed BLOC-1 presence in Drosophila neurons, and measured synaptic output and complex adaptive behavior in response to BLOC-1 perturbation. Homozygous loss-of-function alleles of dysb, Blos1, or compound heterozygotes of these alleles impaired neurotransmitter release, synapse morphology, and homeostatic plasticity at the larval neuromuscular junction, and impaired olfactory habituation. This multiparameter assessment indicated that phenotypes were differentially sensitive to genetic dosages of loss-of-function BLOC-1 alleles. Our findings suggest that modification of a second genetic locus in a defined neurodevelopmental regulatory network does not follow a strict additive genetic inheritance, but rather, precise stoichiometry within the network determines phenotypic outcomes.
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Solomonia RO, McCabe BJ. Molecular mechanisms of memory in imprinting. Neurosci Biobehav Rev 2015; 50:56-69. [PMID: 25280906 PMCID: PMC4726915 DOI: 10.1016/j.neubiorev.2014.09.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 09/20/2014] [Accepted: 09/22/2014] [Indexed: 11/03/2022]
Abstract
Converging evidence implicates the intermediate and medial mesopallium (IMM) of the domestic chick forebrain in memory for a visual imprinting stimulus. During and after imprinting training, neuronal responsiveness in the IMM to the familiar stimulus exhibits a distinct temporal profile, suggesting several memory phases. We discuss the temporal progression of learning-related biochemical changes in the IMM, relative to the start of this electrophysiological profile. c-fos gene expression increases <15 min after training onset, followed by a learning-related increase in Fos expression, in neurons immunopositive for GABA, taurine and parvalbumin (not calbindin). Approximately simultaneously or shortly after, there are increases in phosphorylation level of glutamate (AMPA) receptor subunits and in releasable neurotransmitter pools of GABA and taurine. Later, the mean area of spine synapse post-synaptic densities, N-methyl-D-aspartate receptor number and phosphorylation level of further synaptic proteins are elevated. After ∼ 15 h, learning-related changes in amounts of several synaptic proteins are observed. The results indicate progression from transient/labile to trophic synaptic modification, culminating in stable recognition memory.
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Affiliation(s)
- Revaz O Solomonia
- Institute of Chemical Biology, Ilia State University, 3/5 K Cholokashvili Av, Tbilisi 0162, Georgia; I. Beritashvili Centre of Experimental Biomedicine, Tbilisi, Georgia.
| | - Brian J McCabe
- University of Cambridge, Department of Zoology, Sub-Department of Animal Behaviour, Madingley, Cambridge CB23 8AA, United Kingdom.
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27
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Abstract
The ability of organisms to seamlessly ignore familiar, inconsequential stimuli improves their selective attention and response to salient features of the environment. Here, I propose that this fundamental but unexplained phenomenon substantially derives from the ability of any pattern of neural excitation to create an enhanced inhibitory (or "negative") image of itself through target-specific scaling of inhibitory inputs onto active excitatory neurons. Familiar stimuli encounter strong negative images and are therefore less likely to be transmitted to higher brain centers. Integrating historical and recent observations, the negative-image model described here provides a mechanistic framework for understanding habituation, which is connected to ideas on dynamic predictive coding. In addition, it suggests insights for understanding autism spectrum disorders.
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de Carvalho Myskiw J, Furini CRG, Benetti F, Izquierdo I. Hippocampal molecular mechanisms involved in the enhancement of fear extinction caused by exposure to novelty. Proc Natl Acad Sci U S A 2014; 111:4572-7. [PMID: 24591622 PMCID: PMC3970530 DOI: 10.1073/pnas.1400423111] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Exposure to a novel environment enhances the extinction of contextual fear. This has been explained by tagging of the hippocampal synapses used in extinction, followed by capture of proteins from the synapses that process novelty. The effect is blocked by the inhibition of hippocampal protein synthesis following the novelty or the extinction. Here, we show that it can also be blocked by the postextinction or postnovelty intrahippocampal infusion of the NMDA receptor antagonist 2-amino-5-phosphono pentanoic acid; the inhibitor of calcium/calmodulin-dependent protein kinase II (CaMKII), autocamtide-2-related inhibitory peptide; or the blocker of L-voltage-dependent calcium channels (L-VDCCs), nifedipine. Inhibition of proteasomal protein degradation by β-lactacystin has no effect of its own on extinction or on the influence of novelty thereon but blocks the inhibitory effects of all the other substances except that of rapamycin on extinction, suggesting that their action depends on concomitant synaptic protein turnover. Thus, the tagging-and-capture mechanism through which novelty enhances fear extinction involves more molecular processes than hitherto thought: NMDA receptors, L-VDCCs, CaMKII, and synaptic protein turnover.
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Affiliation(s)
- Jociane de Carvalho Myskiw
- National Institute of Translational Neuroscience, National Research Council of Brazil, and Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, RS, 90610-000, Brazil
| | - Cristiane Regina Guerino Furini
- National Institute of Translational Neuroscience, National Research Council of Brazil, and Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, RS, 90610-000, Brazil
| | - Fernando Benetti
- National Institute of Translational Neuroscience, National Research Council of Brazil, and Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, RS, 90610-000, Brazil
| | - Ivan Izquierdo
- National Institute of Translational Neuroscience, National Research Council of Brazil, and Memory Center, Brain Institute, Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, RS, 90610-000, Brazil
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29
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Gerber B, Yarali A, Diegelmann S, Wotjak CT, Pauli P, Fendt M. Pain-relief learning in flies, rats, and man: basic research and applied perspectives. Learn Mem 2014; 21:232-52. [PMID: 24643725 PMCID: PMC3966540 DOI: 10.1101/lm.032995.113] [Citation(s) in RCA: 97] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Memories relating to a painful, negative event are adaptive and can be stored for a lifetime to support preemptive avoidance, escape, or attack behavior. However, under unfavorable circumstances such memories can become overwhelmingly powerful. They may trigger excessively negative psychological states and uncontrollable avoidance of locations, objects, or social interactions. It is therefore obvious that any process to counteract such effects will be of value. In this context, we stress from a basic-research perspective that painful, negative events are "Janus-faced" in the sense that there are actually two aspects about them that are worth remembering: What made them happen and what made them cease. We review published findings from fruit flies, rats, and man showing that both aspects, respectively related to the onset and the offset of the negative event, induce distinct and oppositely valenced memories: Stimuli experienced before an electric shock acquire negative valence as they signal upcoming punishment, whereas stimuli experienced after an electric shock acquire positive valence because of their association with the relieving cessation of pain. We discuss how memories for such punishment- and relief-learning are organized, how this organization fits into the threat-imminence model of defensive behavior, and what perspectives these considerations offer for applied psychology in the context of trauma, panic, and nonsuicidal self-injury.
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Affiliation(s)
- Bertram Gerber
- Leibniz Institut für Neurobiologie (LIN), Abteilung Genetik von Lernen und Gedächtnis, 39118 Magdeburg, Germany
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30
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Twick I, Lee JA, Ramaswami M. Olfactory habituation in Drosophila-odor encoding and its plasticity in the antennal lobe. PROGRESS IN BRAIN RESEARCH 2014; 208:3-38. [PMID: 24767477 DOI: 10.1016/b978-0-444-63350-7.00001-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
A ubiquitous feature of an animal's response to an odorant is that it declines when the odorant is frequently or continuously encountered. This decline in olfactory response, termed olfactory habituation, can have temporally or mechanistically different forms. The neural circuitry of the fruit fly Drosophila melanogaster's olfactory system is well defined in terms of component cells, which are readily accessible to functional studies and genetic manipulation. This makes it a particularly useful preparation for the investigation of olfactory habituation. In addition, the insect olfactory system shares many architectural and functional similarities with mammalian olfactory systems, suggesting that olfactory mechanisms in insects may be broadly relevant. In this chapter, we discuss the likely mechanisms of olfactory habituation in context of the participating cell types, their connectivity, and their roles in sensory processing. We overview the structure and function of key cell types, the mechanisms that stimulate them, and how they transduce and process odor signals. We then consider how each stage of olfactory processing could potentially contribute to behavioral habituation. After this, we overview a variety of recent mechanistic studies that point to an important role for potentiation of inhibitory synapses in the primary olfactory processing center, the antennal lobe, in driving the reduced response to familiar odorants. Following the discussion of mechanisms for short- and long-term olfactory habituation, we end by considering how these mechanisms may be regulated by neuromodulators, which likely play key roles in the induction, gating, or suppression of habituated behavior, and speculate on the relevance of these processes for other forms of learning and memory.
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Affiliation(s)
- Isabell Twick
- School of Genetics and Microbiology and School of Natural Sciences, Smurfit Institute of Genetics, Trinity College Institute of Neuroscience, Trinity College Dublin, Ireland.
| | - John Anthony Lee
- School of Genetics and Microbiology and School of Natural Sciences, Smurfit Institute of Genetics, Trinity College Institute of Neuroscience, Trinity College Dublin, Ireland.
| | - Mani Ramaswami
- School of Genetics and Microbiology and School of Natural Sciences, Smurfit Institute of Genetics, Trinity College Institute of Neuroscience, Trinity College Dublin, Ireland; National Centre for Biological Science, Bangalore, India
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