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Wingrove J, de Hoog E, Spencer GE. Disruptions in network plasticity precede deficits in memory following inhibition of retinoid signaling. J Neurophysiol 2023; 129:41-55. [PMID: 36448682 DOI: 10.1152/jn.00270.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Retinoic acid, the active metabolite of vitamin A, is important for vertebrate cognition and hippocampal plasticity, but few studies have examined its role in invertebrate learning and memory, and its actions in the invertebrate central nervous system are currently unknown. Using the mollusc Lymnaea stagnalis, we examined operant conditioning of the respiratory behavior, controlled by a well-defined central pattern generator (CPG), and used citral to inhibit retinoic acid signaling. Both citral- and vehicle-treated animals showed normal learning, but citral-treated animals failed to exhibit long-term memory at 24 h. Cohorts of citral- or vehicle-treated animals were dissected into semi-intact preparations, either 1 h after training, or after the memory test 24 h later. Simultaneous electrophysiological recordings from the CPG pacemaker cell (right pedal dorsal 1; RPeD1) and an identified motorneuron (VI) were made while monitoring respiratory activity (pneumostome opening). Activity of the CPG pneumostome opener interneuron (input 3 interneuron; IP3) was also monitored indirectly. Vehicle-treated conditioned preparations showed significant changes in network parameters immediately after learning, such as reduced motorneuron bursting activity (from IP3 input), delayed pneumostome opening, and decoupling of coincident IP3 input within the network. However, citral-treated preparations failed to exhibit these network changes and more closely resembled naïve preparations. Importantly, these citral-induced differences were manifested immediately after training and before any overt changes in the behavioral response (memory impairment). These studies shed light on where and when retinoid signaling might affect a central pattern-generating network to promote memory formation during conditioning of a homeostatic behavior.NEW & NOTEWORTHY We provide novel evidence for how conditioning-induced changes in a CPG network are disrupted when retinoid signaling is inhibited. Inhibition of retinoic acid signaling prevents long-term memory formation following operant conditioning, but has no effect on learning. Simultaneous electrophysiological and behavioral analyses indicate network changes immediately following learning, but these changes are prevented with inhibition of retinoid signaling, before any overt changes in behavior. These data suggest sites for retinoid actions during memory formation.
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Affiliation(s)
- Joel Wingrove
- Department Biological Sciences, Brock University, St Catharines, Ontario, Canada
| | - Eric de Hoog
- Department Biological Sciences, Brock University, St Catharines, Ontario, Canada
| | - Gaynor E Spencer
- Department Biological Sciences, Brock University, St Catharines, Ontario, Canada
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Dong N, Bandura J, Zhang Z, Wang Y, Labadie K, Noel B, Davison A, Koene JM, Sun HS, Coutellec MA, Feng ZP. Ion channel profiling of the Lymnaea stagnalis ganglia via transcriptome analysis. BMC Genomics 2021; 22:18. [PMID: 33407100 PMCID: PMC7789530 DOI: 10.1186/s12864-020-07287-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 11/28/2020] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND The pond snail Lymnaea stagnalis (L. stagnalis) has been widely used as a model organism in neurobiology, ecotoxicology, and parasitology due to the relative simplicity of its central nervous system (CNS). However, its usefulness is restricted by a limited availability of transcriptome data. While sequence information for the L. stagnalis CNS transcripts has been obtained from EST libraries and a de novo RNA-seq assembly, the quality of these assemblies is limited by a combination of low coverage of EST libraries, the fragmented nature of de novo assemblies, and lack of reference genome. RESULTS In this study, taking advantage of the recent availability of a preliminary L. stagnalis genome, we generated an RNA-seq library from the adult L. stagnalis CNS, using a combination of genome-guided and de novo assembly programs to identify 17,832 protein-coding L. stagnalis transcripts. We combined our library with existing resources to produce a transcript set with greater sequence length, completeness, and diversity than previously available ones. Using our assembly and functional domain analysis, we profiled L. stagnalis CNS transcripts encoding ion channels and ionotropic receptors, which are key proteins for CNS function, and compared their sequences to other vertebrate and invertebrate model organisms. Interestingly, L. stagnalis transcripts encoding numerous putative Ca2+ channels showed the most sequence similarity to those of Mus musculus, Danio rerio, Xenopus tropicalis, Drosophila melanogaster, and Caenorhabditis elegans, suggesting that many calcium channel-related signaling pathways may be evolutionarily conserved. CONCLUSIONS Our study provides the most thorough characterization to date of the L. stagnalis transcriptome and provides insights into differences between vertebrates and invertebrates in CNS transcript diversity, according to function and protein class. Furthermore, this study provides a complete characterization of the ion channels of Lymnaea stagnalis, opening new avenues for future research on fundamental neurobiological processes in this model system.
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Affiliation(s)
- Nancy Dong
- Department of Physiology, University of Toronto, 3308 MSB, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Julia Bandura
- Department of Physiology, University of Toronto, 3308 MSB, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
| | - Zhaolei Zhang
- Donnelly Centre for Cellular and Biomolecular Research and Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Yan Wang
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, M5S 3B2, Canada
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, M1C 1A4, Canada
| | - Karine Labadie
- Genoscope, Institut de biologie François Jacob, Commissariat à l'Energie Atomique (CEA), Université Paris-Saclay, BP5706, 91057, Evry, France
| | - Benjamin Noel
- Génomique Métabolique, Genoscope, Institut François Jacob, CEA, CNRS, University of Evry, Université Paris-Saclay, 91057, Evry, France
| | - Angus Davison
- School of Life Sciences, University of Nottingham, University Park, Nottingham, UK, NG7 2RD, UK
| | - Joris M Koene
- Department of Ecological Science, Faculty of Science, Vrije Universiteit, Amsterdam, The Netherlands
| | - Hong-Shuo Sun
- Department of Physiology, University of Toronto, 3308 MSB, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada
- Department of Surgery, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
| | | | - Zhong-Ping Feng
- Department of Physiology, University of Toronto, 3308 MSB, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
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Young AP, Landry CF, Jackson DJ, Wyeth RC. Tissue-specific evaluation of suitable reference genes for RT-qPCR in the pond snail, Lymnaea stagnalis. PeerJ 2019; 7:e7888. [PMID: 31637135 PMCID: PMC6798871 DOI: 10.7717/peerj.7888] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 09/13/2019] [Indexed: 01/02/2023] Open
Abstract
Reverse transcription quantitative PCR (RT-qPCR) is a robust technique for the quantification and comparison of gene expression. To obtain reliable results with this method, one or more reference genes must be employed to normalize expression measurements among treatments or tissue samples. Candidate reference genes must be validated to ensure that they are stable prior to use in qPCR experiments. The pond snail (Lymnaea stagnalis) is a common research organism, particularly in the areas of learning and memory, and is an emerging model for the study of biological asymmetry, biomineralization, and evolution and development. However, no systematic assessment of qPCR reference genes has been performed in this animal. Therefore, the aim of our research was to identify stable reference genes to normalize gene expression data from several commonly studied tissues in L. stagnalis as well as across the entire body. We evaluated a panel of seven reference genes across six different tissues in L. stagnalis with RT-qPCR. The genes included: elongation factor 1-alpha, glyceraldehyde-3-phosphate dehydrogenase, beta-actin, beta-tubulin, ubiquitin, prenylated rab acceptor protein 1, and a voltage gated potassium channel. These genes exhibited a wide range of expression levels among tissues. The tissue-specific stability of each of the genes was consistent when measured by the standard stability assessment algorithms: geNorm, NormFinder, BestKeeper, and RefFinder. Our data indicate that the most stable reference genes vary among the tissues that we examined (central nervous system, tentacles, lips, penis, foot, mantle). Our results were generally congruent with those obtained from similar studies in other molluscs. Given that a minimum of two reference genes are recommended for data normalization, we provide suggestions for strong pairs of reference genes for single- and multi-tissue analyses of RT-qPCR data in L. stagnalis.
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Affiliation(s)
- Alexander P Young
- Department of Biology, St. Francis Xavier University, Antigonish, NS, Canada
| | - Carmen F Landry
- Department of Biology, St. Francis Xavier University, Antigonish, NS, Canada
| | - Daniel J Jackson
- Department of Geobiology, Georg-August Universität Göttingen, Göttingen, Germany
| | - Russell C Wyeth
- Department of Biology, St. Francis Xavier University, Antigonish, NS, Canada
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