1
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Inwood SN, Harrop TWR, Shields MW, Goldson SL, Dearden PK. Immune system modulation & virus transmission during parasitism identified by multi-species transcriptomics of a declining insect biocontrol system. BMC Genomics 2024; 25:311. [PMID: 38532315 DOI: 10.1186/s12864-024-10215-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2023] [Accepted: 03/12/2024] [Indexed: 03/28/2024] Open
Abstract
BACKGROUND The Argentine stem weevil (ASW, Listronotus bonariensis) is a significant pasture pest in Aotearoa New Zealand, primarily controlled by the parasitoid biocontrol agent Microctonus hyperodae. Despite providing effective control of ASW soon after release, M. hyperodae parasitism rates have since declined significantly, with ASW hypothesised to have evolved resistance to its biocontrol agent. While the parasitism arsenal of M. hyperodae has previously been investigated, revealing many venom components and an exogenous novel DNA virus Microctonus hyperodae filamentous virus (MhFV), the effects of said arsenal on gene expression in ASW during parasitism have not been examined. In this study, we performed a multi-species transcriptomic analysis to investigate the biology of ASW parasitism by M. hyperodae, as well as the decline in efficacy of this biocontrol system. RESULTS The transcriptomic response of ASW to parasitism by M. hyperodae involves modulation of the weevil's innate immune system, flight muscle components, and lipid and glucose metabolism. The multispecies approach also revealed continued expression of venom components in parasitised ASW, as well as the transmission of MhFV to weevils during parasitism and some interrupted parasitism attempts. Transcriptomics did not detect a clear indication of parasitoid avoidance or other mechanisms to explain biocontrol decline. CONCLUSIONS This study has expanded our understanding of interactions between M. hyperodae and ASW in a biocontrol system of critical importance to Aotearoa-New Zealand's agricultural economy. Transmission of MhFV to ASW during successful and interrupted parasitism attempts may link to a premature mortality phenomenon in ASW, hypothesised to be a result of a toxin-antitoxin system. Further research into MhFV and its potential role in ASW premature mortality is required to explore whether manipulation of this viral infection has the potential to increase biocontrol efficacy in future.
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Affiliation(s)
- Sarah N Inwood
- Bioprotection Aotearoa, Genomics Aotearoa, and the Biochemistry Department, University of Otago, Dunedin, New Zealand
| | - Thomas W R Harrop
- Bioprotection Aotearoa, Genomics Aotearoa, and the Biochemistry Department, University of Otago, Dunedin, New Zealand
- Melbourne Bioinformatics, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Morgan W Shields
- BioProtection Research Centre, Lincoln University, Lincoln, New Zealand
| | - Stephen L Goldson
- Biocontrol and Biosecurity Group, AgResearch Limited, Lincoln, Aotearoa, New Zealand
| | - Peter K Dearden
- Bioprotection Aotearoa, Genomics Aotearoa, and the Biochemistry Department, University of Otago, Dunedin, New Zealand.
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2
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Rabah Y, Francés R, Minatchy J, Guédon L, Desnous C, Plaçais PY, Preat T. Glycolysis-derived alanine from glia fuels neuronal mitochondria for memory in Drosophila. Nat Metab 2023; 5:2002-2019. [PMID: 37932430 PMCID: PMC10663161 DOI: 10.1038/s42255-023-00910-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 09/20/2023] [Indexed: 11/08/2023]
Abstract
Glucose is the primary source of energy for the brain; however, it remains controversial whether, upon neuronal activation, glucose is primarily used by neurons for ATP production or if it is partially oxidized in astrocytes, as proposed by the astrocyte-neuron lactate shuttle model for glutamatergic neurons. Thus, an in vivo picture of glucose metabolism during cognitive processes is missing. Here, we uncover in Drosophila melanogaster a glia-to-neuron alanine transfer involving alanine aminotransferase that sustains memory formation. Following associative conditioning, glycolysis in glial cells produces alanine, which is back-converted into pyruvate in cholinergic neurons of the olfactory memory center to uphold their increased mitochondrial needs. Alanine, as a mediator of glia-neuron coupling, could be an alternative to lactate in cholinergic systems. In parallel, a dedicated glial glucose transporter imports glucose specifically for long-term memory, by directly transferring it to neurons for use by the pentose phosphate pathway. Our results demonstrate in vivo the compartmentalization of glucose metabolism between neurons and glial cells during memory formation.
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Affiliation(s)
- Yasmine Rabah
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
| | - Raquel Francés
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
| | - Julia Minatchy
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
| | - Laura Guédon
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
| | - Coraline Desnous
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
| | - Pierre-Yves Plaçais
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France.
| | - Thomas Preat
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France.
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3
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Turrel O, Ramesh N, Escher MJF, Pooryasin A, Sigrist SJ. Transient active zone remodeling in the Drosophila mushroom body supports memory. Curr Biol 2022; 32:4900-4913.e4. [PMID: 36327980 DOI: 10.1016/j.cub.2022.10.017] [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: 12/16/2021] [Revised: 08/15/2022] [Accepted: 10/06/2022] [Indexed: 11/22/2022]
Abstract
Elucidating how the distinct components of synaptic plasticity dynamically orchestrate the distinct stages of memory acquisition and maintenance within neuronal networks remains a major challenge. Specifically, plasticity processes tuning the functional and also structural state of presynaptic active zone (AZ) release sites are widely observed in vertebrates and invertebrates, but their behavioral relevance remains mostly unclear. We here provide evidence that a transient upregulation of presynaptic AZ release site proteins supports aversive olfactory mid-term memory in the Drosophila mushroom body (MB). Upon paired aversive olfactory conditioning, AZ protein levels (ELKS-family BRP/(m)unc13-family release factor Unc13A) increased for a few hours with MB-lobe-specific dynamics. Kenyon cell (KC, intrinsic MB neurons)-specific knockdown (KD) of BRP did not affect aversive olfactory short-term memory (STM) but strongly suppressed aversive mid-term memory (MTM). Different proteins crucial for the transport of AZ biosynthetic precursors (transport adaptor Aplip1/Jip-1; kinesin motor IMAC/Unc104; small GTPase Arl8) were also specifically required for the formation of aversive olfactory MTM. Consistent with the merely transitory increase of AZ proteins, BRP KD did not interfere with the formation of aversive olfactory long-term memory (LTM; i.e., 1 day). Our data suggest that the remodeling of presynaptic AZ refines the MB circuitry after paired aversive conditioning, over a time window of a few hours, to display aversive olfactory memories.
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Affiliation(s)
- Oriane Turrel
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Niraja Ramesh
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Marc J F Escher
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Atefeh Pooryasin
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany
| | - Stephan J Sigrist
- Institute for Biology/Genetics, Freie Universität Berlin, Takustrasse 6, 14195 Berlin, Germany; NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Charitéplatz 1, 10117 Berlin, Germany.
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4
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Vasilev DS, Dubrovskaya NМ, Tumanova NL, Nalivaeva NN. Analysis of Expression of the Amyloid-Degrading Enzyme Neprilysin in Brain Structures of 5xFAD Transgenic Mice. J EVOL BIOCHEM PHYS+ 2022. [DOI: 10.1134/s0022093022010173] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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5
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Silva B, Mantha OL, Schor J, Pascual A, Plaçais PY, Pavlowsky A, Preat T. Glia fuel neurons with locally synthesized ketone bodies to sustain memory under starvation. Nat Metab 2022; 4:213-224. [PMID: 35177854 PMCID: PMC8885408 DOI: 10.1038/s42255-022-00528-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 01/07/2022] [Indexed: 11/15/2022]
Abstract
During starvation, mammalian brains can adapt their metabolism, switching from glucose to alternative peripheral fuel sources. In the Drosophila starved brain, memory formation is subject to adaptative plasticity, but whether this adaptive plasticity relies on metabolic adaptation remains unclear. Here we show that during starvation, neurons of the fly olfactory memory centre import and use ketone bodies (KBs) as an energy substrate to sustain aversive memory formation. We identify local providers within the brain, the cortex glia, that use their own lipid store to synthesize KBs before exporting them to neurons via monocarboxylate transporters. Finally, we show that the master energy sensor AMP-activated protein kinase regulates both lipid mobilization and KB export in cortex glia. Our data provide a general schema of the metabolic interactions within the brain to support memory when glucose is scarce.
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Affiliation(s)
- Bryon Silva
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
| | - Olivier L Mantha
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
- INSERM UMR1069 'Nutrition, Croissance et Cancer', Tours, France
| | - Johann Schor
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
| | - Alberto Pascual
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain
| | - Pierre-Yves Plaçais
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
| | - Alice Pavlowsky
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France.
| | - Thomas Preat
- Energy & Memory, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France.
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6
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Meyer H, Buhr A, Callaerts P, Schiemann R, Wolfner MF, Marygold SJ. Identification and bioinformatic analysis of neprilysin and neprilysin-like metalloendopeptidases in Drosophila melanogaster. MICROPUBLICATION BIOLOGY 2021; 2021:10.17912/micropub.biology.000410. [PMID: 34189422 PMCID: PMC8223033 DOI: 10.17912/micropub.biology.000410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The neprilysin (M13) family of metalloendopeptidases comprises highly conserved ectoenzymes that cleave and thereby inactivate many physiologically relevant peptides in the extracellular space. Impaired neprilysin activity is associated with numerous human diseases. Here, we present a comprehensive list and classification of M13 family members in Drosophila melanogaster. Seven Neprilysin (Nep) genes encode active peptidases, while 21 Neprilysin-like (Nepl) genes encode proteins predicted to be catalytically inactive. RNAseq data demonstrate that all 28 genes are expressed during development, often in a tissue-specific pattern. Most Nep proteins possess a transmembrane domain, whereas almost all Nepl proteins are predicted to be secreted.
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Affiliation(s)
- Heiko Meyer
- Department of Zoology & Developmental Biology, Osnabrück University, 49076 Osnabrück, Germany,
Correspondence to: Heiko Meyer (); Steven J. Marygold ()
| | - Annika Buhr
- Department of Zoology & Developmental Biology, Osnabrück University, 49076 Osnabrück, Germany
| | - Patrick Callaerts
- Laboratory of Behavioral and Developmental Genetics, Department of Human Genetics, KULeuven, University of Leuven, B-3000 Leuven, Belgium
| | - Ronja Schiemann
- Department of Zoology & Developmental Biology, Osnabrück University, 49076 Osnabrück, Germany
| | - Mariana F. Wolfner
- Department of Molecular Biology & Genetics, Cornell University, Ithaca NY 14853 USA
| | - Steven J. Marygold
- FlyBase, Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3DY, U.K.,
Correspondence to: Heiko Meyer (); Steven J. Marygold ()
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7
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Vasilev DS, Dubrovskaya NM, Zhuravin IA, Nalivaeva NN. Developmental Profile of Brain Neprilysin Expression Correlates with Olfactory Behaviour of Rats. J Mol Neurosci 2021; 71:1772-1785. [PMID: 33433852 DOI: 10.1007/s12031-020-01786-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 12/25/2020] [Indexed: 12/26/2022]
Abstract
A neuropeptidase, neprilysin (NEP), is a major amyloid (Aβ)-degrading enzyme involved in the pathogenesis of Alzheimer's disease (AD). The olfactory system is affected early in AD with characteristic Aβ accumulation, but data on the dynamics of NEP expression in the olfactory system are absent. Our study demonstrates that NEP mRNA expression in rat olfactory bulbs (OB), entorhinal cortex (ECx), hippocampus (Hip), parietal cortex (PCx) and striatum (Str) increases during the first postnatal month being the highest in the OB and Str. By 3 months, NEP mRNA levels sharply decrease in the ECx, Hip and PCx and by 9 months in the OB, but not in the Str, which correlates with declining olfaction in aged rats tested in the food search paradigm. One-month-old rats subjected to prenatal hypoxia on E14 had lower NEP mRNA levels in the ECx, Hip and PCx (but not in the OB and Str) compared with the control offspring and demonstrated impaired olfaction in the odour preference and food search paradigms. Administration to these rats of a histone deacetylase inhibitor, sodium valproate, restored NEP expression in the ECx, Hip and PCx and improved olfaction. Our data support NEP involvement in olfactory function.
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Affiliation(s)
- Dimitrii S Vasilev
- I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry, RAS, 44 Thorez Avenue, Saint Petersburg, 194223, Russia
| | - Nadezhda M Dubrovskaya
- I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry, RAS, 44 Thorez Avenue, Saint Petersburg, 194223, Russia
| | - Igor A Zhuravin
- I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry, RAS, 44 Thorez Avenue, Saint Petersburg, 194223, Russia
| | - Natalia N Nalivaeva
- I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry, RAS, 44 Thorez Avenue, Saint Petersburg, 194223, Russia. .,School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
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8
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Ahmed A, Ghallab EH, Shehata M, Zekri ARN, Ahmed OS. Impact of nano-conjugate on Drosophila for early diagnosis of Alzheimer's disease. NANOTECHNOLOGY 2020; 31:365102. [PMID: 32045897 DOI: 10.1088/1361-6528/ab7535] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Alzheimer's disease (AD) is an irreversible neurodegenerative disease. Recent identification of AD biomarkers has led to the diagnosis of AD before the onset of dementia. It has been shown that Drosophila melanogaster is a valuable model for studying human neurodegeneration, including AD. According to its properties, curcumin shows promising potential for the diagnosis of AD. In order to improve its use, new formulations, including nanotechnology-based delivery systems, have been applied. The current study aims to diagnose AD by detecting the accumulation of amyloid beta-peptide via carbon-dot-curcumin nanoparticle conjugation in Drosophila. The accumulation of amyloid beta-peptide has been detected via the conjugate using the fluorescence imaging technique. These results suggest that carbon-dot-curcumin nanoparticle conjugation could be used as a diagnostic tool for AD.
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Affiliation(s)
- Aya Ahmed
- Molecular Virology and Immunology Unit, Cancer Biology Department, National Cancer Institute, Cairo University, Kasr Al-Ainist., Fom El-Khaleeg, Cairo 11976, Egypt
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9
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Drosophila Middle-Term Memory: Amnesiac is Required for PKA Activation in the Mushroom Bodies, a Function Modulated by Neprilysin 1. J Neurosci 2020; 40:4219-4229. [PMID: 32303647 DOI: 10.1523/jneurosci.2311-19.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 03/30/2020] [Accepted: 04/05/2020] [Indexed: 11/21/2022] Open
Abstract
In Drosophila, the mushroom bodies (MB) constitute the central brain structure for olfactory associative memory. As in mammals, the cAMP/PKA pathway plays a key role in memory formation. In the MB, Rutabaga (Rut) adenylate cyclase acts as a coincidence detector during associative conditioning to integrate calcium influx resulting from acetylcholine stimulation and G-protein activation resulting from dopaminergic stimulation. Amnesiac encodes a secreted neuropeptide required in the MB for two phases of aversive olfactory memory. Previous sequence analysis has revealed strong homology with the mammalian pituitary adenylate cyclase-activating peptide (PACAP). Here, we examined whether amnesiac is involved in cAMP/PKA dynamics in response to dopamine and acetylcholine co-stimulation in living flies. Experiments were conducted with both sexes, or with either sex. Our data show that amnesiac is necessary for the PKA activation process that results from coincidence detection in the MB. Since PACAP peptide is cleaved by the human membrane neprilysin hNEP, we searched for an interaction between Amnesiac and Neprilysin 1 (Nep1), a fly neprilysin involved in memory. We show that when Nep1 expression is acutely knocked down in adult MB, memory deficits displayed by amn hypomorphic mutants are rescued. Consistently, Nep1 inhibition also restores normal PKA activation in amn mutant flies. Taken together, the results suggest that Nep1 targets Amnesiac degradation to terminate its signaling function. Our work thus highlights a key role for Amnesiac in establishing within the MB the PKA dynamics that sustain middle-term memory (MTM) formation, a function modulated by Nep1.SIGNIFICANCE STATEMENT The Drosophila amnesiac gene encodes a secreted neuropeptide whose expression is required for specific memory phases in the mushroom bodies (MB), the olfactory memory center. Here, we show that Amnesiac is required for PKA activation resulting from coincidence detection, a mechanism by which the MB integrate two spatially distinct stimuli to encode associative memory. Furthermore, our results uncover a functional relationship between Amnesiac and Neprilysin 1 (Nep1), a membrane peptidase involved in memory and expressed in the MB. These results suggest that Nep1 modulates Amnesiac levels. We propose that on conditioning, Amnesiac release from the MB allows, via an autocrine process, the sustaining of PKA activation-mediating memory, which subsequently is inactivated by Nep1 degradation.
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10
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Silva B, Niehage C, Maglione M, Hoflack B, Sigrist SJ, Wassmer T, Pavlowsky A, Preat T. Interactions between amyloid precursor protein-like (APPL) and MAGUK scaffolding proteins contribute to appetitive long-term memory in Drosophila melanogaster. J Neurogenet 2020; 34:92-105. [PMID: 31965876 DOI: 10.1080/01677063.2020.1712597] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Amyloid precursor protein (APP), the precursor of amyloid beta peptide, plays a central role in Alzheimer's disease (AD), a pathology characterized by memory decline and synaptic loss upon aging. Understanding the physiological role of APP is fundamental in deciphering the progression of AD, and several studies suggest a synaptic function via protein-protein interactions. Nevertheless, it remains unclear whether and how these interactions contribute to memory. In Drosophila, we previously showed that APP-like (APPL), the fly APP homolog, is required for aversive associative memory in the olfactory memory center, the mushroom body (MB). In the present study, we show that APPL is required for appetitive long-term memory (LTM), another form of associative memory, in a specific neuronal subpopulation of the MB, the α'/β' Kenyon cells. Using a biochemical approach, we identify the synaptic MAGUK (membrane-associated guanylate kinase) proteins X11, CASK, Dlgh2 and Dlgh4 as interactants of the APP intracellular domain (AICD). Next, we show that the Drosophila homologs CASK and Dlg are also required for appetitive LTM in the α'/β' neurons. Finally, using a double RNAi approach, we demonstrate that genetic interactions between APPL and CASK, as well as between APPL and Dlg, are critical for appetitive LTM. In summary, our results suggest that APPL contributes to associative long-term memory through its interactions with the main synaptic scaffolding proteins CASK and Dlg. This function should be conserved across species.
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Affiliation(s)
- Bryon Silva
- Genes and Dynamics of Memory Systems, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
| | | | - Marta Maglione
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany.,NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Berlin, Germany
| | | | - Stephan J Sigrist
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany.,NeuroCure Cluster of Excellence, Charité Universitätsmedizin, Berlin, Germany
| | - Thomas Wassmer
- School of Life and Health Sciences, Aston University, Birmingham, UK
| | - Alice Pavlowsky
- Genes and Dynamics of Memory Systems, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
| | - Thomas Preat
- Genes and Dynamics of Memory Systems, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, Paris, France
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11
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Amnesiac Is Required in the Adult Mushroom Body for Memory Formation. J Neurosci 2018; 38:9202-9214. [PMID: 30201766 DOI: 10.1523/jneurosci.0876-18.2018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 08/08/2018] [Accepted: 08/30/2018] [Indexed: 11/21/2022] Open
Abstract
It was proposed that the Drosophila amnesiac gene (amn) is required for consolidation of aversive memory in the dorsal paired medial (DPM) neurons, a pair of large neurons that broadly innervate the mushroom bodies (MB), the fly center for olfactory learning and memory (Waddell et al., 2000). Yet, a conditional analysis showed that it was not possible to rescue the memory deficit of amnX8 null mutant flies when amn expression was restored only in the adult (DeZazzo et al., 1999), which led the authors to suggest that amn might be involved in the development of brain structures that normally promote adult olfactory memory. To further investigate temporal and spatial requirements of Amnesiac (AMN) peptide in memory, we used RNA interference in combination with conditional drivers. Experiments were conducted either in both sexes, or in either sexes. Our data show that acute modulation of amn expression in adult DPM neurons does not impact memory. We further show that amn expression is required for normal development of DPM neurons. Detailed enhancer trap analyses suggest that amn transcription unit contains two distinct enhancers, one specific of DPM neurons, and the other specific of α/β MB neurons. This prompted us to investigate extensively the role of AMN in the adult MB. Together, our results demonstrate that amn is acutely required in adult α/β MB neurons for middle-term and long-term memory. The data thus establish that amn plays two distinct roles. Its expression is required in DPM neurons for their development, and in adult MB for olfactory memory.SIGNIFICANCE STATEMENT The Drosophila amnesiac gene encodes a neuropeptide whose expression was proposed to be required for consolidation of aversive memory in the dorsal paired medial (DPM) neurons, a pair of large neurons that broadly innervate the mushroom bodies (MB), the olfactory memory center. Here, we investigated amnesiac temporal and spatial requirement using conditional tools that allowed us to manipulate its expression in selected neurons. This work leads to a complete reassessment of the role of amnesiac in brain development and memory. We show that amnesiac is required for two distinct processes: for normal development of DPM neurons, and in adult MB for memory.
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12
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Pavlowsky A, Schor J, Plaçais PY, Preat T. A GABAergic Feedback Shapes Dopaminergic Input on the Drosophila Mushroom Body to Promote Appetitive Long-Term Memory. Curr Biol 2018; 28:1783-1793.e4. [PMID: 29779874 PMCID: PMC5988562 DOI: 10.1016/j.cub.2018.04.040] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 03/02/2018] [Accepted: 04/13/2018] [Indexed: 01/11/2023]
Abstract
Memory consolidation is a crucial step for long-term memory (LTM) storage. However, we still lack a clear picture of how memory consolidation is regulated at the neuronal circuit level. Here, we took advantage of the well-described anatomy of the Drosophila olfactory memory center, the mushroom body (MB), to address this question in the context of appetitive LTM. The MB lobes, which are made by the fascicled axons of the MB intrinsic neurons, are organized into discrete anatomical modules, each covered by the terminals of a defined type of dopaminergic neuron (DAN) and the dendrites of a corresponding type of MB output neuron (MBON). We previously revealed the essential role of one DAN, the MP1 neuron, in the formation of appetitive LTM. The MP1 neuron is anatomically matched to the GABAergic MBON MVP2, which has been attributed feedforward inhibitory functions recently. Here, we used behavior experiments and in vivo imaging to challenge the existence of MP1-MVP2 synapses and investigate their role in appetitive LTM consolidation. We show that MP1 and MVP2 neurons form an anatomically and functionally recurrent circuit, which features a feedback inhibition that regulates consolidation of appetitive memory. This circuit involves two opposite type 1 and type 2 dopamine receptors in MVP2 neurons and the metabotropic GABAB-R1 receptor in MP1 neurons. We propose that this dual-receptor feedback supports a bidirectional self-regulation of MP1 input to the MB. This mechanism displays striking similarities with the mammalian reward system, in which modulation of the dopaminergic signal is primarily assigned to inhibitory neurons. A feedback circuit between dopaminergic and GABAergic neurons consolidates memory Two antagonist dopamine receptors regulate the GABAergic neuron activity The GABAergic neuron regulates the calcium oscillations of the dopaminergic neuron
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Affiliation(s)
- Alice Pavlowsky
- Genes and Dynamics of Memory Systems, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, 10 rue Vauquelin, 75005 Paris, France
| | - Johann Schor
- Genes and Dynamics of Memory Systems, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, 10 rue Vauquelin, 75005 Paris, France
| | - Pierre-Yves Plaçais
- Genes and Dynamics of Memory Systems, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, 10 rue Vauquelin, 75005 Paris, France
| | - Thomas Preat
- Genes and Dynamics of Memory Systems, Brain Plasticity Unit, CNRS, ESPCI Paris, PSL Research University, 10 rue Vauquelin, 75005 Paris, France.
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13
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Drosophila Neprilysin 1 Rescues Memory Deficits Caused by Amyloid-β Peptide. J Neurosci 2017; 37:10334-10345. [PMID: 28931572 DOI: 10.1523/jneurosci.1634-17.2017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 09/07/2017] [Accepted: 09/15/2017] [Indexed: 02/02/2023] Open
Abstract
Neprilysins are Type II metalloproteinases known to degrade and inactivate a number of small peptides, in particular the mammalian amyloid-β peptide (Aβ). In Drosophila, several neprilysins expressed in the brain are required for middle-term (MTM) and long-term memory (LTM) in the dorsal paired medial (DPM) neurons, a pair of large neurons that broadly innervate the mushroom bodies (MB), the center of olfactory memory. These data indicate that one or several peptides need to be degraded for MTM and LTM. We have previously shown that the fly amyloid precursor protein (APPL) is required for memory in the MB. We show here that APPL is also required in adult DPM neurons for MTM and LTM formation. This finding prompted us to search for an interaction between neprilysins and Drosophila Aβ (dAβ), a cleavage product of APPL. To find out whether dAβ was a neprilysin's target, we used inducible drivers to modulate neprilysin 1 (Nep1) and dAβ expression in adult DPM neurons. Experiments were conducted either in both sexes or in females. We show that Nep1 inhibition makes dAβ expression detrimental to both MTM and LTM. Conversely, memory deficits displayed by dAβ-expressing flies are rescued by Nep1 overexpression. Consistent with behavioral data, biochemical analyses confirmed that Nep1 degrades dAβ. Together, our findings establish that Nep1 and dAβ expressed in DPM neurons are functionally linked for memory processes, suggesting that dAβ is a physiological target for Nep1.SIGNIFICANCE STATEMENT Neprilysins are endopeptidases known to degrade a number of small peptides and in particular the amyloid peptide. We previously showed that all four neprilysins expressed in the Drosophila brain are involved in specific phases of olfactory memory. Here we show that an increase in the level of the neprilysin 1 peptidase overcomes memory deficits induced by amyloid peptide in young flies. Together, the data reveal a functional interaction between neprilysin 1 and amyloid peptide, suggesting that neprilysin 1 degrades amyloid peptide. These findings raise the possibility that, under nonpathological conditions, mammalian neprilysins degrade amyloid peptide to ensure memory formation.
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Preat T, Goguel V. Role of Drosophila Amyloid Precursor Protein in Memory Formation. Front Mol Neurosci 2016; 9:142. [PMID: 28008309 PMCID: PMC5143682 DOI: 10.3389/fnmol.2016.00142] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 11/28/2016] [Indexed: 12/22/2022] Open
Abstract
The amyloid precursor protein (APP) is a membrane protein engaged in complex proteolytic pathways. APP and its derivatives have been shown to play a central role in Alzheimer’s disease (AD), a progressive neurodegenerative disease characterized by memory decline. Despite a huge effort from the research community, the primary cause of AD remains unclear, making it crucial to better understand the physiological role of the APP pathway in brain plasticity and memory. Drosophila melanogaster is a model system well-suited to address this issue. Although relatively simple, the fly brain is highly organized, sustains several forms of learning and memory, and drives numerous complex behaviors. Importantly, molecules and mechanisms underlying memory processes are conserved from flies to mammals. The fly encodes a single non-essential APP homolog named APP-Like (APPL). Using in vivo inducible RNA interference strategies, it was shown that APPL knockdown in the mushroom bodies (MB)—the central integrative brain structure for olfactory memory—results in loss of memory. Several APPL derivatives, such as secreted and full-length membrane APPL, may play different roles in distinct types of memory phases. Furthermore, overexpression of Drosophila amyloid peptide exacerbates the memory deficit caused by APPL knockdown, thus potentiating memory decline. Data obtained in the fly support the hypothesis that APP acts as a transmembrane receptor, and that disruption of its normal function may contribute to cognitive impairment during early AD.
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Affiliation(s)
- Thomas Preat
- Genes and Dynamics of Memory Systems, Brain Plasticity Unit, Centre National de la Recherche Scientifique (CNRS), ESPCI Paris, PSL Research University Paris, France
| | - Valérie Goguel
- Genes and Dynamics of Memory Systems, Brain Plasticity Unit, Centre National de la Recherche Scientifique (CNRS), ESPCI Paris, PSL Research University Paris, France
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Hallier B, Schiemann R, Cordes E, Vitos-Faleato J, Walter S, Heinisch JJ, Malmendal A, Paululat A, Meyer H. Drosophila neprilysins control insulin signaling and food intake via cleavage of regulatory peptides. eLife 2016; 5. [PMID: 27919317 PMCID: PMC5140268 DOI: 10.7554/elife.19430] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 11/14/2016] [Indexed: 12/11/2022] Open
Abstract
Insulin and IGF signaling are critical to numerous developmental and physiological processes, with perturbations being pathognomonic of various diseases, including diabetes. Although the functional roles of the respective signaling pathways have been extensively studied, the control of insulin production and release is only partially understood. Herein, we show that in Drosophila expression of insulin-like peptides is regulated by neprilysin activity. Concomitant phenotypes of altered neprilysin expression included impaired food intake, reduced body size, and characteristic changes in the metabolite composition. Ectopic expression of a catalytically inactive mutant did not elicit any of the phenotypes, which confirms abnormal peptide hydrolysis as a causative factor. A screen for corresponding substrates of the neprilysin identified distinct peptides that regulate insulin-like peptide expression, feeding behavior, or both. The high functional conservation of neprilysins and their substrates renders the characterized principles applicable to numerous species, including higher eukaryotes and humans. DOI:http://dx.doi.org/10.7554/eLife.19430.001 The hormone insulin and similar molecules called insulin-like peptides act as signals to control many processes in the body, including growth, stress responses and aging. Disrupting these signaling pathways can cause many diseases, with diabetes being the most common of these. Although the roles of the signaling pathways have been well studied, it is less clear how the body controls the production of insulin and insulin-like peptides. Neprilysins are enzymes that can cut other proteins and peptides by a process known as hydrolysis. Their targets (known as “substrates”) include peptides that regulate a range of cell processes, and neprilysins have therefore been linked with many diseases. Fruit flies have at least five different neprilysin enzymes, but their substrates have not yet been identified. One of these, known as Nep4A, is produced in muscle tissue and appears to be important for muscles to work properly. Hallier, Schiemann et al. reveal that Nep4A regulates the production of insulin-like peptides. The experiments used fruit fly larvae that had been genetically engineered so that the level of Nep4A could be altered in muscle tissue. Larvae with very high or very low levels of Nep4A eat less food, have smaller bodies and produce different amounts of insulin-like peptides compared to normal larvae. Further experiments show that Nep4A can hydrolyze a number of peptides that regulate the production and the release of insulin-like peptides. This suggests that the enzymatic activity of neprilysins plays a direct role in controlling the production of insulin. The next challenge is to find out whether these findings apply to humans and other animals that also have neprilysins. DOI:http://dx.doi.org/10.7554/eLife.19430.002
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Affiliation(s)
- Benjamin Hallier
- Department of Developmental Biology, University of Osnabrück, Osnabrück, Germany
| | - Ronja Schiemann
- Department of Developmental Biology, University of Osnabrück, Osnabrück, Germany
| | - Eva Cordes
- Department of Developmental Biology, University of Osnabrück, Osnabrück, Germany
| | - Jessica Vitos-Faleato
- Department of Biomedical Research, Institute for Research in Biomedicine, Barcelona, Spain
| | - Stefan Walter
- Department of Microbiology, University of Osnabrück, Osnabrück, Germany
| | | | - Anders Malmendal
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Achim Paululat
- Department of Developmental Biology, University of Osnabrück, Osnabrück, Germany
| | - Heiko Meyer
- Department of Developmental Biology, University of Osnabrück, Osnabrück, Germany
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