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Thiel D, Yañez Guerra LA, Kieswetter A, Cole AG, Temmerman L, Technau U, Jékely G. Large-scale deorphanization of Nematostella vectensis neuropeptide G protein-coupled receptors supports the independent expansion of bilaterian and cnidarian peptidergic systems. eLife 2024; 12:RP90674. [PMID: 38727714 PMCID: PMC11087051 DOI: 10.7554/elife.90674] [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] [Indexed: 05/12/2024] Open
Abstract
Neuropeptides are ancient signaling molecules in animals but only few peptide receptors are known outside bilaterians. Cnidarians possess a large number of G protein-coupled receptors (GPCRs) - the most common receptors of bilaterian neuropeptides - but most of these remain orphan with no known ligands. We searched for neuropeptides in the sea anemone Nematostella vectensis and created a library of 64 peptides derived from 33 precursors. In a large-scale pharmacological screen with these peptides and 161 N. vectensis GPCRs, we identified 31 receptors specifically activated by 1 to 3 of 14 peptides. Mapping GPCR and neuropeptide expression to single-cell sequencing data revealed how cnidarian tissues are extensively connected by multilayer peptidergic networks. Phylogenetic analysis identified no direct orthology to bilaterian peptidergic systems and supports the independent expansion of neuropeptide signaling in cnidarians from a few ancestral peptide-receptor pairs.
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Affiliation(s)
- Daniel Thiel
- Living Systems Institute, University of ExeterExeterUnited Kingdom
| | | | - Amanda Kieswetter
- Animal Physiology & Neurobiology, Department of Biology, University of LeuvenLeuvenBelgium
| | - Alison G Cole
- Department of Neurosciences and Developmental Biology, Faculty of Life Sciences, University of ViennaViennaAustria
| | - Liesbet Temmerman
- Animal Physiology & Neurobiology, Department of Biology, University of LeuvenLeuvenBelgium
| | - Ulrich Technau
- Department of Neurosciences and Developmental Biology, Faculty of Life Sciences, University of ViennaViennaAustria
| | - Gáspár Jékely
- Living Systems Institute, University of ExeterExeterUnited Kingdom
- Centre for Organismal Studies (COS), Heidelberg UniversityHeidelbergGermany
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2
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Romanova DY, Varoqueaux F, Eitel M, Yoshida MA, Nikitin MA, Moroz LL. Long-Term Culturing of Placozoans (Trichoplax and Hoilungia). Methods Mol Biol 2024; 2757:509-529. [PMID: 38668981 DOI: 10.1007/978-1-0716-3642-8_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2024]
Abstract
The phylum Placozoa remains one of the least explored among early-branching metazoan lineages. For over 130 years, this phylum had been represented by the single species Trichoplax adhaerens-an animal with the simplest known body plan (three cell layers without any organs) but complex behaviors. Recently, extensive sampling of placozoans across the globe and their subsequent genetic analysis have revealed incredible biodiversity with numerous cryptic species worldwide. However, only a few culture protocols are available to date, and all are for one species only. Here, we describe the breeding of four different species representing two placozoan genera: Trichoplax adhaerens, Trichoplax sp. H2, Hoilungia sp. H4, and Hoilungia hongkongensis originating from diverse biotopes. Our protocols allow to culture all species under comparable conditions. Next, we outlined various food sources and optimized strain-specific parameters enabling long-term culturing. These protocols can facilitate comparative analyses of placozoan biology and behaviors, which together will contribute to deciphering general principles of animal organization.
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Affiliation(s)
- Daria Y Romanova
- Institute of Higher Nervous Activity and Neurophysiology of RAS, Moscow, Russia.
| | - Frédérique Varoqueaux
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland.
| | - Michael Eitel
- Department of Earth and Environmental Sciences Palaeontology & Geobiology, LMU München, Munich, Germany
| | - Masa-Aki Yoshida
- Marine Biological Science Section, Education and Research Center for Biological Resources, Faculty of Life and Environmental Science, Shimane University, Okinoshima, Oki, Shimane, Japan
| | - Mikhail A Nikitin
- Institute of Higher Nervous Activity and Neurophysiology of RAS, Moscow, Russia
- Belozersky Institute for Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
- Kharkevich Institute for Information Transmission Problems, RAS, Moscow, Russia
| | - Leonid L Moroz
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, USA.
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, USA.
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3
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Hsiao J, Deng LC, Moroz LL, Chalasani SH, Edsinger E. Ocean to Tree: Leveraging Single-Molecule RNA-Seq to Repair Genome Gene Models and Improve Phylogenomic Analysis of Gene and Species Evolution. Methods Mol Biol 2024; 2757:461-490. [PMID: 38668979 PMCID: PMC11112408 DOI: 10.1007/978-1-0716-3642-8_19] [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] [Indexed: 05/16/2024]
Abstract
Understanding gene evolution across genomes and organisms, including ctenophores, can provide unexpected biological insights. It enables powerful integrative approaches that leverage sequence diversity to advance biomedicine. Sequencing and bioinformatic tools can be inexpensive and user-friendly, but numerous options and coding can intimidate new users. Distinct challenges exist in working with data from diverse species but may go unrecognized by researchers accustomed to gold-standard genomes. Here, we provide a high-level workflow and detailed pipeline to enable animal collection, single-molecule sequencing, and phylogenomic analysis of gene and species evolution. As a demonstration, we focus on (1) PacBio RNA-seq of the genome-sequenced ctenophore Mnemiopsis leidyi, (2) diversity and evolution of the mechanosensitive ion channel Piezo in genetic models and basal-branching animals, and (3) associated challenges and solutions to working with diverse species and genomes, including gene model updating and repair using single-molecule RNA-seq. We provide a Python Jupyter Notebook version of our pipeline (GitHub Repository: Ctenophore-Ocean-To-Tree-2023 https://github.com/000generic/Ctenophore-Ocean-To-Tree-2023 ) that can be run for free in the Google Colab cloud to replicate our findings or modified for specific or greater use. Our protocol enables users to design new sequencing projects in ctenophores, marine invertebrates, or other novel organisms. It provides a simple, comprehensive platform that can ease new user entry into running their evolutionary sequence analyses.
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Affiliation(s)
- Jan Hsiao
- Molecular Neurobiology Laboratory, Salk Institute for Biological Study, La Jolla, CA 92037
| | - Lola Chenxi Deng
- Molecular Neurobiology Laboratory, Salk Institute for Biological Study, La Jolla, CA 92037
| | - Leonid L. Moroz
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, 32080
- Department of Neuroscience and McKnight Brain Institute, University of Florida, Gainesville, FL32611
| | - Sreekanth H. Chalasani
- Molecular Neurobiology Laboratory, Salk Institute for Biological Study, La Jolla, CA 92037
| | - Eric Edsinger
- Molecular Neurobiology Laboratory, Salk Institute for Biological Study, La Jolla, CA 92037
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4
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Moroz LL, Romanova DY. Homologous vs. homocratic neurons: revisiting complex evolutionary trajectories. Front Cell Dev Biol 2023; 11:1336093. [PMID: 38178869 PMCID: PMC10764524 DOI: 10.3389/fcell.2023.1336093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 12/08/2023] [Indexed: 01/06/2024] Open
Affiliation(s)
- Leonid L. Moroz
- Department of Neuroscience and McKnight Brain Institute, University of Florida, Gainesville, FL, United States
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, United States
| | - Daria Y. Romanova
- Institute of Higher Nervous Activity and Neurophysiology of RAS, Moscow, Russia
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Tolstenkov O, Chatzigeorgiou M, Gorbushin A. Neuronal gene expression in two generations of the marine parasitic worm, Cryptocotyle lingua. Commun Biol 2023; 6:1279. [PMID: 38110640 PMCID: PMC10728431 DOI: 10.1038/s42003-023-05675-4] [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: 07/08/2023] [Accepted: 12/04/2023] [Indexed: 12/20/2023] Open
Abstract
Trematodes, or flukes, undergo intricate anatomical and behavioral transformations during their life cycle, yet the functional changes in their nervous system remain poorly understood. We investigated the molecular basis of nervous system function in Cryptocotyle lingua, a species of relevance for fisheries. Transcriptomic analysis revealed a streamlined molecular toolkit with the absence of key signaling pathways and ion channels. Notably, we observed the loss of nitric oxide synthase across the Platyhelminthes. Furthermore, we identified upregulated neuronal genes in dispersal larvae, including those involved in aminergic pathways, synaptic vesicle trafficking, TRPA channels, and surprisingly nitric oxide receptors. Using neuronal markers and in situ hybridization, we hypothesized their functional relevance to larval adaptations and host-finding strategies. Additionally, employing a behavior quantification toolkit, we assessed cercaria motility, facilitating further investigations into the behavior and physiology of parasitic flatworms. This study enhances our understanding of trematode neurobiology and provides insights for targeted antiparasitic strategies.
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Affiliation(s)
| | | | - Alexander Gorbushin
- Sechenov Institute of Evolutionary Physiology and Biochemistry, St Petersburg, Russia
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Gianni G, Pasqualetti M. Wiring and Volume Transmission: An Overview of the Dual Modality for Serotonin Neurotransmission. ACS Chem Neurosci 2023; 14:4093-4104. [PMID: 37966717 DOI: 10.1021/acschemneuro.3c00648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2023] Open
Abstract
Serotonin is a neurotransmitter involved in the modulation of a multitude of physiological and behavioral processes. In spite of the relatively reduced number of serotonin-producing neurons present in the mammalian CNS, a complex long-range projection system provides profuse innervation to the whole brain. Heterogeneity of serotonin receptors, grouped in seven families, and their spatiotemporal expression pattern account for its widespread impact. Although neuronal communication occurs primarily at tiny gaps called synapses, wiring transmission, another mechanism based on extrasynaptic diffusion of neuroactive molecules and referred to as volume transmission, has been described. While wiring transmission is a rapid and specific one-to-one modality of communication, volume transmission is a broader and slower mode in which a single element can simultaneously act on several different targets in a one-to-many mode. Some experimental evidence regarding ultrastructural features, extrasynaptic localization of receptors and transporters, and serotonin-glia interactions collected over the past four decades supports the existence of a serotonergic system of a dual modality of neurotransmission, in which wiring and volume transmission coexist. To date, in spite of the radical difference in the two modalities, limited information is available on the way they are coordinated to mediate the specific activities in which serotonin participates. Understanding how wiring and volume transmission modalities contribute to serotonergic neurotransmission is of utmost relevance for the comprehension of serotonin functions in both physiological and pathological conditions.
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Affiliation(s)
- Giulia Gianni
- Unit of Cell and Developmental Biology, Department of Biology, University of Pisa, 56127 Pisa, Italy
| | - Massimo Pasqualetti
- Unit of Cell and Developmental Biology, Department of Biology, University of Pisa, 56127 Pisa, Italy
- Center for Neuroscience and Cognitive Systems @UniTn, Istituto Italiano di Tecnologia, 38068 Rovereto, Italy
- Centro per l'Integrazione della Strumentazione Scientifica dell'Università di Pisa (CISUP), 56126 Pisa, Italy
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7
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Moroz LL. Syncytial nets vs. chemical signaling: emerging properties of alternative integrative systems. Front Cell Dev Biol 2023; 11:1320209. [PMID: 38125877 PMCID: PMC10730927 DOI: 10.3389/fcell.2023.1320209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 11/22/2023] [Indexed: 12/23/2023] Open
Affiliation(s)
- Leonid L. Moroz
- Department of Neuroscience, University of Florida, Gainesville, FL, United States
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, United States
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Walters ET. Exaptation and Evolutionary Adaptation in Nociceptor Mechanisms Driving Persistent Pain. BRAIN, BEHAVIOR AND EVOLUTION 2023; 98:314-330. [PMID: 38035556 PMCID: PMC10922759 DOI: 10.1159/000535552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 11/23/2023] [Indexed: 12/02/2023]
Abstract
BACKGROUND Several evolutionary explanations have been proposed for why chronic pain is a major clinical problem. One is that some mechanisms important for driving chronic pain, while maladaptive for modern humans, were adaptive because they enhanced survival. Evidence is reviewed for persistent nociceptor hyperactivity (PNH), known to promote chronic pain in rodents and humans, being an evolutionarily adaptive response to significant bodily injury, and primitive molecular mechanisms related to cellular injury and stress being exapted (co-opted or repurposed) to drive PNH and consequent pain. SUMMARY PNH in a snail (Aplysia californica), squid (Doryteuthis pealeii), fruit fly (Drosophila melanogaster), mice, rats, and humans has been documented as long-lasting enhancement of action potential discharge evoked by peripheral stimuli, and in some of these species as persistent extrinsically driven ongoing activity and/or intrinsic spontaneous activity (OA and SA, respectively). In mammals, OA and SA are often initiated within the protected nociceptor soma long after an inducing injury. Generation of OA or SA in nociceptor somata may be very rare in invertebrates, but prolonged afterdischarge in nociceptor somata readily occurs in sensitized Aplysia. Evidence for the adaptiveness of injury-induced PNH has come from observations of decreased survival of injured squid exposed to predators when PNH is blocked, from plausible survival benefits of chronic sensitization after severe injuries such as amputation, and from the functional coherence and intricacy of mammalian PNH mechanisms. Major contributions of cAMP-PKA signaling (with associated calcium signaling) to the maintenance of PNH both in mammals and molluscs suggest that this ancient stress signaling system was exapted early during the evolution of nociceptors to drive hyperactivity following bodily injury. Vertebrates have retained core cAMP-PKA signaling modules for PNH while adding new extracellular modulators (e.g., opioids) and cAMP-regulated ion channels (e.g., TRPV1 and Nav1.8 channels). KEY MESSAGES Evidence from multiple phyla indicates that PNH is a physiological adaptation that decreases the risk of attacks on injured animals. Core cAMP-PKA signaling modules make major contributions to the maintenance of PNH in molluscs and mammals. This conserved signaling has been linked to ancient cellular responses to stress, which may have been exapted in early nociceptors to drive protective hyperactivity that can persist while bodily functions recover after significant injury.
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Affiliation(s)
- Edgar T Walters
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
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9
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Lianguzova A, Arbuzova N, Laskova E, Gafarova E, Repkin E, Matach D, Enshina I, Miroliubov A. Tricks of the puppet masters: morphological adaptations to the interaction with nervous system underlying host manipulation by rhizocephalan barnacle Polyascus polygeneus. PeerJ 2023; 11:e16348. [PMID: 38025701 PMCID: PMC10655712 DOI: 10.7717/peerj.16348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 10/03/2023] [Indexed: 12/01/2023] Open
Abstract
Background Rhizocephalan interaction with their decapod hosts is a superb example of host manipulation. These parasites are able to alter the host's physiology and behavior. Host-parasite interaction is performed, presumably, via special modified rootlets invading the ventral ganglions. Methods In this study, we focus on the morphology and ultrastructure of these special rootlets in Polyascus polygeneus (Lützen & Takahashi, 1997), family Polyascidae, invading the neuropil of the host's nervous tissue. The ventral ganglionic mass of the infected crabs were fixed, and the observed sites of the host-parasite interplay were studied using transmission electron microscopy, immunolabeling and confocal microscopy. Results The goblet-shaped organs present in the basal families of parasitic barnacles were presumably lost in a common ancestor of Polyascidae and crown "Akentrogonida", but the observed invasive rootlets appear to perform similar functions, including the synthesis of various substances which are transferred to the host's nervous tissue. Invasive rootlets significantly differ from trophic ones in cell layer composition and cuticle thickness. Numerous multilamellar bodies are present in the rootlets indicating the intrinsic cell rearrangement. The invasive rootlets of P. polygeneus are enlaced by the thin projections of glial cells. Thus, glial cells can be both the first hosts' respondents to the nervous tissue damage and the mediator of the rhizocephalan interaction with the nervous cells. One of the potential molecules engaged in the relationships of P. polygeneus and its host is serotonin, a neurotransmitter which is found exclusively in the invasive rootlets but not in trophic ones. Serotonin participates in different biological pathways in metazoans including the regulation of aggression in crustaceans, which is reduced in infected crabs. We conclude that rootlets associated with the host's nervous tissue are crucial for the regulation of host-parasite interplay and for evolution of the Rhizocephala.
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Affiliation(s)
- Anastasia Lianguzova
- Department of Invertebrate Zoology, St. Petersburg State University, St Petersburg, Russian Federation
- Laboratory of Parasitic Worms and Protists, Zoological Institute of the Russian Academy of Science, St Petersburg, Russian Federation
| | - Natalia Arbuzova
- Department of Invertebrate Zoology, St. Petersburg State University, St Petersburg, Russian Federation
- Laboratory of Parasitic Worms and Protists, Zoological Institute of the Russian Academy of Science, St Petersburg, Russian Federation
| | - Ekaterina Laskova
- Department of Invertebrate Zoology, St. Petersburg State University, St Petersburg, Russian Federation
| | - Elizaveta Gafarova
- Department of Invertebrate Zoology, St. Petersburg State University, St Petersburg, Russian Federation
| | - Egor Repkin
- Department of Invertebrate Zoology, St. Petersburg State University, St Petersburg, Russian Federation
- Research Park, Center for Molecular and Cell Technologies, St. Petersburg State University, St Petersburg, Russian Federation
| | - Dzmitry Matach
- Department of Invertebrate Zoology, St. Petersburg State University, St Petersburg, Russian Federation
| | - Irina Enshina
- Department of Invertebrate Zoology, St. Petersburg State University, St Petersburg, Russian Federation
| | - Aleksei Miroliubov
- Laboratory of Parasitic Worms and Protists, Zoological Institute of the Russian Academy of Science, St Petersburg, Russian Federation
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Dyakonova VE. DNA Instability in Neurons: Lifespan Clock and Driver of Evolution. BIOCHEMISTRY. BIOKHIMIIA 2023; 88:1719-1731. [PMID: 38105193 DOI: 10.1134/s0006297923110044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 07/19/2023] [Accepted: 09/20/2023] [Indexed: 12/19/2023]
Abstract
In the last ten years, the discovery of neuronal DNA postmitotic instability has changed the theoretical landscape in neuroscience and, more broadly, biology. In 2003, A. M. Olovnikov suggested that neuronal DNA is the "initial substrate of aging". Recent experimental data have significantly increased the likelihood of this hypothesis. How does neuronal DNA accumulate damage and in what genome regions? What factors contribute to this process and how are they associated with aging and lifespan? These questions will be discussed in the review. In the course of Metazoan evolution, the instability of neuronal DNA has been accompanied by searching for the pathways to reduce the biological cost of brain activity. Various processes and activities, such as sleep, evolutionary increase in the number of neurons in the vertebrate brain, adult neurogenesis, distribution of neuronal activity, somatic polyploidy, and RNA editing in cephalopods, can be reconsidered in the light of the trade-off between neuronal plasticity and DNA instability in neurons. This topic is of considerable importance for both fundamental neuroscience and translational medicine.
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Affiliation(s)
- Varvara E Dyakonova
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, 119334, Russia.
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11
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Ros-Rocher N, Brunet T. What is it like to be a choanoflagellate? Sensation, processing and behavior in the closest unicellular relatives of animals. Anim Cogn 2023; 26:1767-1782. [PMID: 37067637 PMCID: PMC10770216 DOI: 10.1007/s10071-023-01776-z] [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: 01/12/2023] [Revised: 04/05/2023] [Accepted: 04/07/2023] [Indexed: 04/18/2023]
Abstract
All animals evolved from a single lineage of unicellular precursors more than 600 million years ago. Thus, the biological and genetic foundations for animal sensation, cognition and behavior must necessarily have arisen by modifications of pre-existing features in their unicellular ancestors. Given that the single-celled ancestors of the animal kingdom are extinct, the only way to reconstruct how these features evolved is by comparing the biology and genomic content of extant animals to their closest living relatives. Here, we reconstruct the Umwelt (the subjective, perceptive world) inhabited by choanoflagellates, a group of unicellular (or facultatively multicellular) aquatic microeukaryotes that are the closest living relatives of animals. Although behavioral research on choanoflagellates remains patchy, existing evidence shows that they are capable of chemosensation, photosensation and mechanosensation. These processes often involve specialized sensorimotor cellular appendages (cilia, microvilli, and/or filopodia) that resemble those that underlie perception in most animal sensory cells. Furthermore, comparative genomics predicts an extensive "sensory molecular toolkit" in choanoflagellates, which both provides a potential basis for known behaviors and suggests the existence of a largely undescribed behavioral complexity that presents exciting avenues for future research. Finally, we discuss how facultative multicellularity in choanoflagellates might help us understand how evolution displaced the locus of decision-making from a single cell to a collective, and how a new space of behavioral complexity might have become accessible in the process.
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Affiliation(s)
- Núria Ros-Rocher
- Evolutionary Cell Biology and Evolution of Morphogenesis Unit, Institut Pasteur, Université Paris-Cité, CNRS UMR3691, 25-28 Rue du Docteur Roux, 75015, Paris, France
| | - Thibaut Brunet
- Evolutionary Cell Biology and Evolution of Morphogenesis Unit, Institut Pasteur, Université Paris-Cité, CNRS UMR3691, 25-28 Rue du Docteur Roux, 75015, Paris, France.
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12
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Roberta C, Vera S, Hans A H, Michael H H. Activation patterns of dopaminergic cell populations reflect different learning scenarios in a cichlid fish, Pseudotropheus zebra. J Chem Neuroanat 2023; 133:102342. [PMID: 37722435 DOI: 10.1016/j.jchemneu.2023.102342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 09/13/2023] [Accepted: 09/14/2023] [Indexed: 09/20/2023]
Abstract
Dopamine is present in all vertebrates and the functional roles of the subsystems are assumed to be similar. Whereas the effect of dopaminergic modulation is well investigated in different target systems, less is known about the factors that are causing the modulation of dopaminergic cells. Using the zebra mbuna, Pseudotropheus zebra, a cichlid fish from Lake Malawi as a model system, we investigated the activation of specific dopaminergic cell populations detected by double-labeling with TH and pS6 antibodies while the animals were solving different learning tasks. Specifically, we compared an intense avoidance learning situation, an instrumental learning task, and a non-learning isolated group and found strong activation of different dopaminergic cell populations. Preoptic-hypothalamic cell populations respond to the stress component in the avoidance task, and the forced movement/locomotion may be responsible for activation in the posterior tubercle. The instrumental learning task had little stress component, but the activation of the raphe superior in this group may be correlated with attention or arousal during the training sessions. At the same time, the weaker activation of the nucleus of the posterior commissure may be related to positive reward acting onto tectal circuits. Finally, we examined the co-activation patterns across all dopaminergic cell populations and recovered robust differences across experimental groups, largely driven by hypothalamic, posterior tubercle, and brain stem regions possibly encoding the valence and salience associated with stressful stimuli. Taken together, our results offer some insights into the different functions of the dopaminergic cell populations in the brain of a non-mammalian vertebrate in correlation with different behavioral conditions, extending our knowledge for a more comprehensive view of the mechanisms of dopaminergic modulation in vertebrates.
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Affiliation(s)
- Calvo Roberta
- Institute of Zoology, Rheinische Friedrich-Wilhelms-Universität Bonn, Poppelsdorfer Schloss, Meckenheimer Allee 169, 53115 Bonn, Germany.
| | - Schluessel Vera
- Institute of Zoology, Rheinische Friedrich-Wilhelms-Universität Bonn, Poppelsdorfer Schloss, Meckenheimer Allee 169, 53115 Bonn, Germany
| | - Hofmann Hans A
- Department of Integrative Biology, Institute for Neuroscience, University of Texas at Austin, 2415 Speedway, Austin, TX 78712, USA
| | - Hofmann Michael H
- Institute of Zoology, Rheinische Friedrich-Wilhelms-Universität Bonn, Poppelsdorfer Schloss, Meckenheimer Allee 169, 53115 Bonn, Germany
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Moroz LL, Romanova DY. Chemical cognition: chemoconnectomics and convergent evolution of integrative systems in animals. Anim Cogn 2023; 26:1851-1864. [PMID: 38015282 PMCID: PMC11106658 DOI: 10.1007/s10071-023-01833-7] [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] [Accepted: 11/16/2023] [Indexed: 11/29/2023]
Abstract
Neurons underpin cognition in animals. However, the roots of animal cognition are elusive from both mechanistic and evolutionary standpoints. Two conceptual frameworks both highlight and promise to address these challenges. First, we discuss evidence that animal neural and other integrative systems evolved more than once (convergent evolution) within basal metazoan lineages, giving us unique experiments by Nature for future studies. The most remarkable examples are neural systems in ctenophores and neuroid-like systems in placozoans and sponges. Second, in addition to classical synaptic wiring, a chemical connectome mediated by hundreds of signal molecules operates in tandem with neurons and is the most information-rich source of emerging properties and adaptability. The major gap-dynamic, multifunctional chemical micro-environments in nervous systems-is not understood well. Thus, novel tools and information are needed to establish mechanistic links between orchestrated, yet cell-specific, volume transmission and behaviors. Uniting what we call chemoconnectomics and analyses of the cellular bases of behavior in basal metazoan lineages arguably would form the foundation for deciphering the origins and early evolution of elementary cognition and intelligence.
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Affiliation(s)
- Leonid L Moroz
- Department of Neuroscience, University of Florida, Gainesville, USA.
- Whitney Laboratory for Marine Bioscience, University of Florida, Saint Augustine, USA.
| | - Daria Y Romanova
- Institute of Higher Nervous Activity and Neurophysiology of RAS, Moscow, Russia
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14
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Xiang X, Vilar Gomez AA, Blomberg SP, Yuan H, Degnan BM, Degnan SM. Potential for host-symbiont communication via neurotransmitters and neuromodulators in an aneural animal, the marine sponge Amphimedon queenslandica. Front Neural Circuits 2023; 17:1250694. [PMID: 37841893 PMCID: PMC10570526 DOI: 10.3389/fncir.2023.1250694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 09/12/2023] [Indexed: 10/17/2023] Open
Abstract
Interkingdom signalling within a holobiont allows host and symbionts to communicate and to regulate each other's physiological and developmental states. Here we show that a suite of signalling molecules that function as neurotransmitters and neuromodulators in most animals with nervous systems, specifically dopamine and trace amines, are produced exclusively by the bacterial symbionts of the demosponge Amphimedon queenslandica. Although sponges do not possess a nervous system, A. queenslandica expresses rhodopsin class G-protein-coupled receptors that are structurally similar to dopamine and trace amine receptors. When sponge larvae, which express these receptors, are exposed to agonists and antagonists of bilaterian dopamine and trace amine receptors, we observe marked changes in larval phototactic swimming behaviour, consistent with the sponge being competent to recognise and respond to symbiont-derived trace amine signals. These results indicate that monoamines synthesised by bacterial symbionts may be able to influence the physiology of the host sponge.
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Affiliation(s)
| | | | | | | | | | - Sandie M. Degnan
- Centre for Marine Science, School of the Environment, The University of Queensland, Brisbane, QLD, Australia
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15
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Sizemore TR, Jonaitis J, Dacks AM. Heterogeneous receptor expression underlies non-uniform peptidergic modulation of olfaction in Drosophila. Nat Commun 2023; 14:5280. [PMID: 37644052 PMCID: PMC10465596 DOI: 10.1038/s41467-023-41012-3] [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: 02/02/2023] [Accepted: 08/21/2023] [Indexed: 08/31/2023] Open
Abstract
Sensory systems are dynamically adjusted according to the animal's ongoing needs by neuromodulators, such as neuropeptides. Neuropeptides are often widely-distributed throughout sensory networks, but it is unclear whether such neuropeptides uniformly modulate network activity. Here, we leverage the Drosophila antennal lobe (AL) to resolve whether myoinhibitory peptide (MIP) uniformly modulates AL processing. Despite being uniformly distributed across the AL, MIP decreases olfactory input to some glomeruli, while increasing olfactory input to other glomeruli. We reveal that a heterogeneous ensemble of local interneurons (LNs) are the sole source of AL MIP, and show that differential expression of the inhibitory MIP receptor across glomeruli allows MIP to act on distinct intraglomerular substrates. Our findings demonstrate how even a seemingly simple case of modulation can have complex consequences on network processing by acting non-uniformly within different components of the overall network.
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Affiliation(s)
- Tyler R Sizemore
- Department of Biology, Life Sciences Building, West Virginia University, Morgantown, WV, 26506, USA.
- Department of Molecular, Cellular, and Developmental Biology, Yale Science Building, Yale University, New Haven, CT, 06520-8103, USA.
| | - Julius Jonaitis
- Department of Biology, Life Sciences Building, West Virginia University, Morgantown, WV, 26506, USA
| | - Andrew M Dacks
- Department of Biology, Life Sciences Building, West Virginia University, Morgantown, WV, 26506, USA.
- Department of Neuroscience, West Virginia University, Morgantown, WV, 26506, USA.
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16
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Goulty M, Botton-Amiot G, Rosato E, Sprecher SG, Feuda R. The monoaminergic system is a bilaterian innovation. Nat Commun 2023; 14:3284. [PMID: 37280201 DOI: 10.1038/s41467-023-39030-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 05/25/2023] [Indexed: 06/08/2023] Open
Abstract
Monoamines like serotonin, dopamine, and adrenaline/noradrenaline (epinephrine/norepinephrine) act as neuromodulators in the nervous system. They play a role in complex behaviours, cognitive functions such as learning and memory formation, as well as fundamental homeostatic processes such as sleep and feeding. However, the evolutionary origin of the genes required for monoaminergic modulation is uncertain. Using a phylogenomic approach, in this study, we show that most of the genes involved in monoamine production, modulation, and reception originated in the bilaterian stem group. This suggests that the monoaminergic system is a bilaterian novelty and that its evolution may have contributed to the Cambrian diversification.
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Affiliation(s)
- Matthew Goulty
- Department of Genetics and Genome Biology, University of Leicester, Leicestershire, UK
| | - Gaelle Botton-Amiot
- Department of Biology, Institute of Zoology, University of Fribourg, CH-1700, Fribourg, Switzerland
| | - Ezio Rosato
- Department of Genetics and Genome Biology, University of Leicester, Leicestershire, UK
| | - Simon G Sprecher
- Department of Biology, Institute of Zoology, University of Fribourg, CH-1700, Fribourg, Switzerland
| | - Roberto Feuda
- Department of Genetics and Genome Biology, University of Leicester, Leicestershire, UK.
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17
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Norekian TP, Moroz LL. Recording cilia activity in ctenophores: effects of nitric oxide and low molecular weight transmitters. Front Neurosci 2023; 17:1125476. [PMID: 37332869 PMCID: PMC10272528 DOI: 10.3389/fnins.2023.1125476] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 05/03/2023] [Indexed: 06/20/2023] Open
Abstract
Cilia are the major effectors in Ctenophores, but very little is known about their transmitter control and integration. Here, we present a simple protocol to monitor and quantify cilia activity and provide evidence for polysynaptic control of cilia coordination in ctenophores. We also screened the effects of several classical bilaterian neurotransmitters (acetylcholine, dopamine, L-DOPA, serotonin, octopamine, histamine, gamma-aminobutyric acid (GABA), L-aspartate, L-glutamate, glycine), neuropeptide (FMRFamide), and nitric oxide (NO) on cilia beating in Pleurobrachia bachei and Bolinopsis infundibulum. NO and FMRFamide produced noticeable inhibitory effects on cilia activity, whereas other tested transmitters were ineffective. These findings further suggest that ctenophore-specific neuropeptides could be major candidates for signal molecules controlling cilia activity in representatives of this early-branching metazoan lineage.
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Affiliation(s)
- Tigran P. Norekian
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, United States
- Friday Harbor Laboratories, University of Washington, Friday Harbor, WA, United States
| | - Leonid L. Moroz
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, United States
- Departments of Neuroscience and McKnight, Brain Institute, University of Florida, Gainesville, FL, United States
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18
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Norekian TP, Moroz LL. Nitric oxide suppresses cilia activity in ctenophores. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.27.538508. [PMID: 37163038 PMCID: PMC10168380 DOI: 10.1101/2023.04.27.538508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Cilia are the major effectors in Ctenophores, but very little is known about their transmitter control and integration. Here, we present a simple protocol to monitor and quantify cilia activity in semi-intact preparations and provide evidence for polysynaptic control of cilia coordination in ctenophores. Next, we screen the effects of several classical bilaterian neurotransmitters (acetylcholine, dopamine, L-DOPA, serotonin, octopamine, histamine, gamma-aminobutyric acid (GABA), L-aspartate, L-glutamate, glycine), neuropeptides (FMRFamide), and nitric oxide (NO) on cilia beating in Pleurobrachia bachei and Bolinopsis infundibulum . Only NO inhibited cilia beating, whereas other tested transmitters were ineffective. These findings further suggest that ctenophore-specific neuropeptides could be major candidate signaling molecules controlling cilia activity in representatives of this early-branching metazoan lineage.
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19
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Monteagudo-Cascales E, Ortega Á, Velando F, Morel B, Matilla MA, Krell T. Study of NIT domain-containing chemoreceptors from two global phytopathogens and identification of NIT domains in eukaryotes. Mol Microbiol 2023. [PMID: 37186477 DOI: 10.1111/mmi.15069] [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: 03/24/2023] [Revised: 04/13/2023] [Accepted: 04/14/2023] [Indexed: 05/17/2023]
Abstract
Bacterial signal transduction systems are typically activated by the binding of signal molecules to receptor ligand binding domains (LBDs), such as the NIT LBD. We report here the identification of the NIT domain in more than 15,000 receptors that were present in 30 bacterial phyla, but also in 19 eukaryotic phyla, expanding its known phylogenetic distribution. The NIT domain formed part of seven receptor families that either control transcription, mediate chemotaxis or regulate second messenger levels. We have produced the NIT domains from chemoreceptors of the bacterial phytopathogens Pectobacterium atrosepticum (PacN) and Pseudomonas savastanoi (PscN) as individual purified proteins. High-throughput ligand screening using compound libraries revealed a specificity for nitrate and nitrite binding. Isothermal titration calorimetry experiments showed that PacN-LBD bound preferentially nitrate ( K D = 1.9 μM), whereas the affinity of PscN-LBD for nitrite ( K D = 2.1 μM) was 22 times higher than that for nitrate. Analytical ultracentrifugation experiments indicated that PscN-LBD is monomeric in the presence and absence of ligands. The R182A mutant of PscN did not bind nitrate or nitrite. This residue is not conserved in the NIT domain of the Pseudomonas aeruginosa chemoreceptor PA4520, which may be related to its failure to bind nitrate/nitrite. The magnitude of P. atrosepticum chemotaxis towards nitrate was significantly greater than that of nitrite and pacN deletion almost abolished responses to both compounds. This study highlights the important role of nitrate and nitrite as signal molecules in life and advances our knowledge on the NIT domain as universal nitrate/nitrite sensor module.
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Affiliation(s)
- Elizabet Monteagudo-Cascales
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Álvaro Ortega
- Department of Biochemistry and Molecular Biology 'B' and Immunology, Faculty of Chemistry, University of Murcia, Regional Campus of International Excellence 'Campus Mare Nostrum, Murcia, Spain
| | - Félix Velando
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Bertrand Morel
- Department of Physical Chemistry, Faculty of Sciences, University of Granada, Granada, Spain
| | - Miguel A Matilla
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Tino Krell
- Department of Biotechnology and Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
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20
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Rusin LY. Evolution of homology: From archetype towards a holistic concept of cell type. J Morphol 2023; 284:e21569. [PMID: 36789784 DOI: 10.1002/jmor.21569] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 01/10/2023] [Accepted: 02/13/2023] [Indexed: 02/16/2023]
Abstract
The concept of homology lies in the heart of comparative biological science. The distinction between homology as structure and analogy as function has shaped the evolutionary paradigm for a century and formed the axis of comparative anatomy and embryology, which accept the identity of structure as a ground measure of relatedness. The advent of single-cell genomics overturned the classical view of cell homology by establishing a backbone regulatory identity of cell types, the basic biological units bridging the molecular and phenotypic dimensions, to reveal that the cell is the most flexible unit of living matter and that many approaches of classical biology need to be revised to understand evolution and diversity at the cellular level. The emerging theory of cell types explicitly decouples cell identity from phenotype, essentially allowing for the divergence of evolutionarily related morphotypes beyond recognition, as well as it decouples ontogenetic cell lineage from cell-type phylogeny, whereby explicating that cell types can share common descent regardless of their structure, function or developmental origin. The article succinctly summarizes current progress and opinion in this field and formulates a more generalistic view of biological cell types as avatars, transient or terminal cell states deployed in a continuum of states by the developmental programme of one and the same omnipotent cell, capable of changing or combining identities with distinct evolutionary histories or inventing ad hoc identities that never existed in evolution or development. It highlights how the new logic grounded in the regulatory nature of cell identity transforms the concepts of cell homology and phenotypic stability, suggesting that cellular evolution is inherently and massively network-like, with one-to-one homologies being rather uncommon and restricted to shallower levels of the animal tree of life.
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Affiliation(s)
- Leonid Y Rusin
- Laboratory for Mathematic Methods and Models in Bioinformatics, Institute for Information Transmission Problems (Kharkevich Institute), Russian Academy of Sciences, Moscow, Russia
- EvoGenome Analytics LLC, Odintsovo, Moscow Region, Russia
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21
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Walters ET, Crook RJ, Neely GG, Price TJ, Smith ESJ. Persistent nociceptor hyperactivity as a painful evolutionary adaptation. Trends Neurosci 2023; 46:211-227. [PMID: 36610893 PMCID: PMC9974896 DOI: 10.1016/j.tins.2022.12.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 12/05/2022] [Accepted: 12/16/2022] [Indexed: 01/07/2023]
Abstract
Chronic pain caused by injury or disease of the nervous system (neuropathic pain) has been linked to persistent electrical hyperactivity of the sensory neurons (nociceptors) specialized to detect damaging stimuli and/or inflammation. This pain and hyperactivity are considered maladaptive because both can persist long after injured tissues have healed and inflammation has resolved. While the assumption of maladaptiveness is appropriate in many diseases, accumulating evidence from diverse species, including humans, challenges the assumption that neuropathic pain and persistent nociceptor hyperactivity are always maladaptive. We review studies indicating that persistent nociceptor hyperactivity has undergone evolutionary selection in widespread, albeit selected, animal groups as a physiological response that can increase survival long after bodily injury, using both highly conserved and divergent underlying mechanisms.
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Affiliation(s)
- Edgar T Walters
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
| | - Robyn J Crook
- Department of Biology, San Francisco State University, San Francisco, CA 94132, USA
| | - G Gregory Neely
- Charles Perkins Centre and School of Life and Environmental Sciences, The University of Sydney, NSW 2006, Australia
| | - Theodore J Price
- Department of Neuroscience and Center for Advanced Pain Studies, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Ewan St John Smith
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK
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22
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Ma F, Zheng C. Transcriptome age of individual cell types in Caenorhabditis elegans. Proc Natl Acad Sci U S A 2023; 120:e2216351120. [PMID: 36812209 PMCID: PMC9992843 DOI: 10.1073/pnas.2216351120] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 01/27/2023] [Indexed: 02/24/2023] Open
Abstract
The phylotranscriptomic analysis of development in several species revealed the expression of older and more conserved genes in midembryonic stages and younger and more divergent genes in early and late embryonic stages, which supported the hourglass mode of development. However, previous work only studied the transcriptome age of whole embryos or embryonic sublineages, leaving the cellular basis of the hourglass pattern and the variation of transcriptome ages among cell types unexplored. By analyzing both bulk and single-cell transcriptomic data, we studied the transcriptome age of the nematode Caenorhabditis elegans throughout development. Using the bulk RNA-seq data, we identified the morphogenesis phase in midembryonic development as the phylotypic stage with the oldest transcriptome and confirmed the results using whole-embryo transcriptome assembled from single-cell RNA-seq data. The variation in transcriptome ages among individual cell types remained small in early and midembryonic development and grew bigger in late embryonic and larval stages as cells and tissues differentiate. Lineages that give rise to certain tissues (e.g., hypodermis and some neurons) but not all recapitulated the hourglass pattern across development at the single-cell transcriptome level. Further analysis of the variation in transcriptome ages among the 128 neuron types in C. elegans nervous system found that a group of chemosensory neurons and their downstream interneurons expressed very young transcriptomes and may contribute to adaptation in recent evolution. Finally, the variation in transcriptome age among the neuron types, as well as the age of their cell fate regulators, led us to hypothesize the evolutionary history of some neuron types.
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Affiliation(s)
- Fuqiang Ma
- School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China
| | - Chaogu Zheng
- School of Biological Sciences, The University of Hong Kong, Hong Kong SAR, China
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23
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Moroz LL, Mukherjee K, Romanova DY. Nitric oxide signaling in ctenophores. Front Neurosci 2023; 17:1125433. [PMID: 37034176 PMCID: PMC10073611 DOI: 10.3389/fnins.2023.1125433] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 02/27/2023] [Indexed: 04/11/2023] Open
Abstract
Nitric oxide (NO) is one of the most ancient and versatile signal molecules across all domains of life. NO signaling might also play an essential role in the origin of animal organization. Yet, practically nothing is known about the distribution and functions of NO-dependent signaling pathways in representatives of early branching metazoans such as Ctenophora. Here, we explore the presence and organization of NO signaling components using Mnemiopsis and kin as essential reference species. We show that NO synthase (NOS) is present in at least eight ctenophore species, including Euplokamis and Coeloplana, representing the most basal ctenophore lineages. However, NOS could be secondarily lost in many other ctenophores, including Pleurobrachia and Beroe. In Mnemiopsis leidyi, NOS is present both in adult tissues and differentially expressed in later embryonic stages suggesting the involvement of NO in developmental mechanisms. Ctenophores also possess soluble guanylyl cyclases as potential NO receptors with weak but differential expression across tissues. Combined, these data indicate that the canonical NO-cGMP signaling pathways existed in the common ancestor of animals and could be involved in the control of morphogenesis, cilia activities, feeding and different behaviors.
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Affiliation(s)
- Leonid L. Moroz
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, United States
- The Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, United States
- *Correspondence: Leonid L. Moroz, ; orcid.org/0000-0002-1333-3176
| | - Krishanu Mukherjee
- The Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, United States
| | - Daria Y. Romanova
- Institute of Higher Nervous Activity and Neurophysiology of RAS, Moscow, Russia
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24
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Nikitin MA, Romanova DY, Borman SI, Moroz LL. Amino acids integrate behaviors in nerveless placozoans. Front Neurosci 2023; 17:1125624. [PMID: 37123368 PMCID: PMC10133484 DOI: 10.3389/fnins.2023.1125624] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 03/10/2023] [Indexed: 05/02/2023] Open
Abstract
Placozoans are the simplest known free-living animals without recognized neurons and muscles but a complex behavioral repertoire. However, mechanisms and cellular bases of behavioral coordination are unknown. Here, using Trichoplax adhaerens as a model, we described 0.02-0.002 Hz oscillations in locomotory and feeding patterns as evidence of complex multicellular integration; and showed their dependence on the endogenous secretion of signal molecules. Evolutionary conserved low-molecular-weight transmitters (glutamate, aspartate, glycine, GABA, and ATP) acted as coordinators of distinct locomotory and feeding patterns. Specifically, L-glutamate induced and partially mimicked endogenous feeding cycles, whereas glycine and GABA suppressed feeding. ATP-modified feeding is complex, first causing feeding-like cycles and then suppressing feeding. Trichoplax locomotion was modulated by glycine, GABA, and, surprisingly, by animals' own mucus trails. Mucus triples locomotory speed compared to clean substrates. Glycine and GABA increased the frequency of turns. The effects of the amino acids are likely mediated by numerous receptors (R), including those from ionotropic GluRs, metabotropic GluRs, and GABA-BR families. Eighty-five of these receptors are encoded in the Trichoplax genome, more than in any other animal sequenced. Phylogenetic reconstructions illuminate massive lineage-specific expansions of amino acid receptors in Placozoa, Cnidaria, and Porifera and parallel evolution of nutritional sensing. Furthermore, we view the integration of feeding behaviors in nerveless animals by amino acids as ancestral exaptations that pave the way for co-options of glutamate, glycine, GABA, and ATP as classical neurotransmitters in eumetazoans.
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Affiliation(s)
- Mikhail A. Nikitin
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Daria Y. Romanova
- Institute of Higher Nervous Activity and Neurophysiology of RAS, Moscow, Russia
| | - Simkha I. Borman
- Koltzov Institute of Developmental Biology Russian Academy of Sciences, Moscow, Russia
| | - Leonid L. Moroz
- Departments of Neuroscience and McKnight Brain Institute, University of Florida, Gainesville, FL, United States
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, United States
- *Correspondence: Leonid L. Moroz,
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25
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Moroz LL, Romanova DY. Alternative neural systems: What is a neuron? (Ctenophores, sponges and placozoans). Front Cell Dev Biol 2022; 10:1071961. [PMID: 36619868 PMCID: PMC9816575 DOI: 10.3389/fcell.2022.1071961] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 12/13/2022] [Indexed: 12/24/2022] Open
Abstract
How to make a neuron, a synapse, and a neural circuit? Is there only one 'design' for a neural architecture with a universally shared genomic blueprint across species? The brief answer is "No." Four early divergent lineages from the nerveless common ancestor of all animals independently evolved distinct neuroid-type integrative systems. One of these is a subset of neural nets in comb jellies with unique synapses; the second lineage is the well-known Cnidaria + Bilateria; the two others are non-synaptic neuroid systems in sponges and placozoans. By integrating scRNA-seq and microscopy data, we revise the definition of neurons as synaptically-coupled polarized and highly heterogenous secretory cells at the top of behavioral hierarchies with learning capabilities. This physiological (not phylogenetic) definition separates 'true' neurons from non-synaptically and gap junction-coupled integrative systems executing more stereotyped behaviors. Growing evidence supports the hypothesis of multiple origins of neurons and synapses. Thus, many non-bilaterian and bilaterian neuronal classes, circuits or systems are considered functional rather than genetic categories, composed of non-homologous cell types. In summary, little-explored examples of convergent neuronal evolution in representatives of early branching metazoans provide conceptually novel microanatomical and physiological architectures of behavioral controls in animals with prospects of neuro-engineering and synthetic biology.
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Affiliation(s)
- Leonid L. Moroz
- Departments of Neuroscience and McKnight Brain Institute, University of Florida, Gainesville, FL, United States,Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, United States,*Correspondence: Leonid L. Moroz, ; Daria Y. Romanova,
| | - Daria Y. Romanova
- Institute of Higher Nervous Activity and Neurophysiology of RAS, 5A Butlerova, Moscow, Russia,*Correspondence: Leonid L. Moroz, ; Daria Y. Romanova,
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26
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Verkhratsky A, Arranz AM, Ciuba K, Pękowska A. Evolution of neuroglia. Ann N Y Acad Sci 2022; 1518:120-130. [PMID: 36285711 DOI: 10.1111/nyas.14917] [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: 02/05/2023]
Abstract
The evolution of the nervous system progressed through cellular diversification and specialization of functions. Conceptually, the nervous system is composed of electrically excitable neuronal networks connected by chemical synapses and nonexcitable glial cells that provide for homeostasis and defense. The evolution of neuroglia began with the emergence of the centralized nervous system and proceeded through a continuous increase in their complexity. In the primate brain, especially in the brain of humans, the astrocyte lineage is exceedingly complex, with the emergence of new types of astroglial cells possibly involved in interlayer communication and integration.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.,Achucarro Basque Center for Neuroscience, Leioa, Spain.,IKERBASQUE Basque Foundation for Science, Bilbao, Spain.,Department of Forensic Analytical Toxicology, School of Forensic Medicine, China Medical University, Shenyang, China.,Department of Stem Cell Biology, State Research Institute Centre for Innovative Medicine, Vilnius, Lithuania
| | - Amaia M Arranz
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,IKERBASQUE Basque Foundation for Science, Bilbao, Spain
| | - Katarzyna Ciuba
- Dioscuri Centre of Chromatin Biology and Epigenomics, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Aleksandra Pękowska
- Dioscuri Centre of Chromatin Biology and Epigenomics, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
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27
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Hingorani M, Viviani AML, Sanfilippo JE, Janušonis S. High-resolution spatiotemporal analysis of single serotonergic axons in an in vitro system. Front Neurosci 2022; 16:994735. [PMID: 36353595 PMCID: PMC9638127 DOI: 10.3389/fnins.2022.994735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 09/28/2022] [Indexed: 12/04/2022] Open
Abstract
Vertebrate brains have a dual structure, composed of (i) axons that can be well-captured with graph-theoretical methods and (ii) axons that form a dense matrix in which neurons with precise connections operate. A core part of this matrix is formed by axons (fibers) that store and release 5-hydroxytryptamine (5-HT, serotonin), an ancient neurotransmitter that supports neuroplasticity and has profound implications for mental health. The self-organization of the serotonergic matrix is not well understood, despite recent advances in experimental and theoretical approaches. In particular, individual serotonergic axons produce highly stochastic trajectories, fundamental to the construction of regional fiber densities, but further advances in predictive computer simulations require more accurate experimental information. This study examined single serotonergic axons in culture systems (co-cultures and monolayers), by using a set of complementary high-resolution methods: confocal microscopy, holotomography (refractive index-based live imaging), and super-resolution (STED) microscopy. It shows that serotonergic axon walks in neural tissue may strongly reflect the stochastic geometry of this tissue and it also provides new insights into the morphology and branching properties of serotonergic axons. The proposed experimental platform can support next-generation analyses of the serotonergic matrix, including seamless integration with supercomputing approaches.
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28
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Tuning the neurogenesis channel. Neuron 2022; 110:3056-3058. [PMID: 36202087 DOI: 10.1016/j.neuron.2022.08.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Earlier work has implicated the neurotransmitter GABA in controlling forebrain progenitor proliferation. In this issue of Neuron, Everlien et al. (2022) demonstrate that diazepam binding inhibitor acts to keep the neurogenesis-promoting effect of GABA at bay.
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29
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Bechtel W. Reductionistic Explanations of Cognitive Information Processing: Bottoming Out in Neurochemistry. Front Integr Neurosci 2022; 16:944303. [PMID: 35859708 PMCID: PMC9292585 DOI: 10.3389/fnint.2022.944303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 06/13/2022] [Indexed: 11/17/2022] Open
Abstract
A common motivation for engaging in reductionistic research is to ground explanations in the most basic processes operative in the mechanism responsible for the phenomenon to be explained. I argue for a different motivation—directing inquiry to the level of organization at which the components of a mechanism enable the work that results in the phenomenon. In the context of reductionistic accounts of cognitive information processing I argue that this requires going down to a level that is largely overlooked in these discussions, that of chemistry. In discussions of cognitive information processing, the brain is often viewed as essentially an electrical switching system and many theorists treat electrical switching as the level at which mechanistic explanations should bottom out. I argue, drawing on examples of peptidergic and monoaminergic neurons, that how information is processed is determined by the specific chemical reactions occurring in individual neurons. Accordingly, mechanistic explanations of cognitive information processing need to take into account the chemical reactions involved.
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30
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Dyakonova VE. Origin and Evolution of the Nervous System: New Data from Comparative Whole Genome Studies of Multicellular Animals. Russ J Dev Biol 2022. [DOI: 10.1134/s1062360422010088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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31
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Romanova DY, Nikitin MA, Shchenkov SV, Moroz LL. Expanding of Life Strategies in Placozoa: Insights From Long-Term Culturing of Trichoplax and Hoilungia. Front Cell Dev Biol 2022; 10:823283. [PMID: 35223848 PMCID: PMC8864292 DOI: 10.3389/fcell.2022.823283] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Accepted: 01/20/2022] [Indexed: 12/05/2022] Open
Abstract
Placozoans are essential reference species for understanding the origins and evolution of animal organization. However, little is known about their life strategies in natural habitats. Here, by maintaining long-term culturing for four species of Trichoplax and Hoilungia, we extend our knowledge about feeding and reproductive adaptations relevant to the diversity of life forms and immune mechanisms. Three modes of population dynamics depended upon feeding sources, including induction of social behaviors, morphogenesis, and reproductive strategies. In addition to fission, representatives of all species produced “swarmers” (a separate vegetative reproduction stage), which could also be formed from the lower epithelium with greater cell-type diversity. We monitored the formation of specialized spheroid structures from the upper cell layer in aging culture. These “spheres” could be transformed into juvenile animals under favorable conditions. We hypothesize that spheroid structures represent a component of the innate immune defense response with the involvement of fiber cells. Finally, we showed that regeneration could be a part of the adaptive reproductive strategies in placozoans and a unique experimental model for regenerative biology.
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Affiliation(s)
- Daria Y. Romanova
- Institute of Higher Nervous Activity and Neurophysiology of RAS, Moscow, Russia
- *Correspondence: Daria Y. Romanova, ; Leonid L. Moroz,
| | - Mikhail A. Nikitin
- Belozersky Institute for Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
- Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
| | - Sergey V. Shchenkov
- Department of Invertebrate Zoology, Faculty of Biology, Saint Petersburg State University, Saint Petersburg, Russia
| | - Leonid L. Moroz
- Departments of Neuroscience and McKnight Brain Institute, University of Florida, Gainesville, FL, United States
- Whitney Laboratory for Marine Biosciences, University of Florida, St. Augustine, FL, United States
- *Correspondence: Daria Y. Romanova, ; Leonid L. Moroz,
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32
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Shmukler YB, Nikishin DA. Non-Neuronal Transmitter Systems in Bacteria, Non-Nervous Eukaryotes, and Invertebrate Embryos. Biomolecules 2022; 12:biom12020271. [PMID: 35204771 PMCID: PMC8961645 DOI: 10.3390/biom12020271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 02/04/2022] [Accepted: 02/05/2022] [Indexed: 11/16/2022] Open
Abstract
In 1921, Otto Loewi published his report that ushered in the era of chemical transmission of biological signals. January 2021 marked the 90th anniversary of the birth of Professor Gennady A. Buznikov, who was the first to study the functions of transmitters in embryogenesis. A year earlier it was 60 years since his first publication in this field. These data are a venerable occasion for a review of current knowledge on the mechanisms related to classical transmitters such as 5-hydroxytryptamine, acetylcholine, catecholamines, etc., in animals lacking neural elements and prenervous invertebrate embryos.
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33
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Abstract
We propose an expansion of neuroecological comparisons to include the capabilities of brainless and non-neural organisms. We begin this enterprise by conducting a systematic search for studies on learning in echinoderms. Echinodermata are marine invertebrates comprising starfish, brittle stars, sea cucumbers, sea urchins, and sea lilies. Animals in this phylum lack any centralized brain and instead possess diffuse neural networks known as nerve nets. The learning abilities of these animals are of particular interest as, within the bilaterian clade, they are close evolutionary neighbors to chordates, a phylum whose members exhibit complex feats in learning and contain highly specialized brains. The learning capacities and limitations of echinoderms can inform the evolution of nervous systems and learning in Bilateria. We find evidence of both non-associative and associative learning (in the form of classical conditioning) in echinoderms, which was primarily focused on starfish. Additional evidence of learning is documented in brittle stars, sand dollars, and sea urchins. We then discuss the evolutionary significance of learning capabilities without a brain, the presence of embodied cognition across multiple groups, and compare the learning present in echinoderms with the impressive cognitive abilities documented in the oldest linage group within vertebrates (the major group within the phylum of chordates), fish.
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34
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Williams EA, Jékely G. Nervous systems: Neuropeptides define enigmatic comb-jelly neurons. Curr Biol 2021; 31:R1515-R1517. [PMID: 34875238 DOI: 10.1016/j.cub.2021.10.054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The apparently simple nerve net of comb-jellies has long intrigued biologists. A new study identifies multiple unique neuropeptides in the comb-jelly nervous system and exploits these as indicators of neuronal identity and morphology.
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Affiliation(s)
- Elizabeth A Williams
- College of Live and Environmental Sciences, Biosciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK.
| | - Gáspár Jékely
- Living Systems Institute, University of Exeter, Stocker Road, Exeter EX4 4QD, UK.
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35
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Burkhardt P, Jékely G. Evolution of synapses and neurotransmitter systems: The divide-and-conquer model for early neural cell-type evolution. Curr Opin Neurobiol 2021; 71:127-138. [PMID: 34826676 DOI: 10.1016/j.conb.2021.11.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 09/09/2021] [Accepted: 11/02/2021] [Indexed: 01/08/2023]
Abstract
Nervous systems evolved around 560 million years ago to coordinate and empower animal bodies. Ctenophores - one of the earliest-branching lineages - are thought to share a few neuronal genes with bilaterians and may have evolved neurons convergently. Here we review our current understanding of the evolution of neuronal molecules in nonbilaterians. We also reanalyse single-cell sequencing data in light of new cell-cluster identities from a ctenophore and uncover evidence supporting the homology of one ctenophore neuron-type with neurons in Bilateria. The specific coexpression of the presynaptic proteins Unc13 and RIM with voltage-gated channels, neuropeptides and homeobox genes pinpoint a spiking sensory-peptidergic cell in the ctenophore mouth. Similar Unc13-RIM neurons may have been present in the first eumetazoans to rise to dominance only in stem Bilateria. We hypothesise that the Unc13-RIM lineage ancestrally innervated the mouth and conquered other parts of the body with the rise of macrophagy and predation during the Cambrian explosion.
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Affiliation(s)
- Pawel Burkhardt
- Sars International Centre for Marine Molecular Biology, University of Bergen, Norway.
| | - Gáspár Jékely
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, UK.
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36
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Smith SJ. Transcriptomic evidence for dense peptidergic networks within forebrains of four widely divergent tetrapods. Curr Opin Neurobiol 2021; 71:100-109. [PMID: 34775262 DOI: 10.1016/j.conb.2021.09.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 09/21/2021] [Accepted: 09/27/2021] [Indexed: 12/15/2022]
Abstract
The primary function common to every neuron is communication with other neurons. Such cell-cell signaling can take numerous forms, including fast synaptic transmission and slower neuromodulation via secreted messengers, such as neuropeptides, dopamine, and many other diffusible small molecules. Individual neurons are quite diverse, however, in all particulars of both synaptic and neuromodulatory communication. Neuron classification schemes have therefore proven very useful in exploring the emergence of network function, behavior, and cognition from the communication functions of individual neurons. Recently published single-cell mRNA sequencing data and corresponding transcriptomic neuron classifications from turtle, songbird, mouse, and human provide evidence for a long evolutionary history and adaptive significance of localized peptidergic signaling. Across all four species, sets of at least twenty orthologous cognate pairs of neuropeptide precursor protein and receptor genes are expressed in individually sparse but heavily overlapping patterns suggesting that all forebrain neuron types are densely interconnected by local peptidergic signals.
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37
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Timsit Y, Grégoire SP. Towards the Idea of Molecular Brains. Int J Mol Sci 2021; 22:ijms222111868. [PMID: 34769300 PMCID: PMC8584932 DOI: 10.3390/ijms222111868] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/24/2021] [Accepted: 10/28/2021] [Indexed: 02/06/2023] Open
Abstract
How can single cells without nervous systems perform complex behaviours such as habituation, associative learning and decision making, which are considered the hallmark of animals with a brain? Are there molecular systems that underlie cognitive properties equivalent to those of the brain? This review follows the development of the idea of molecular brains from Darwin’s “root brain hypothesis”, through bacterial chemotaxis, to the recent discovery of neuron-like r-protein networks in the ribosome. By combining a structural biology view with a Bayesian brain approach, this review explores the evolutionary labyrinth of information processing systems across scales. Ribosomal protein networks open a window into what were probably the earliest signalling systems to emerge before the radiation of the three kingdoms. While ribosomal networks are characterised by long-lasting interactions between their protein nodes, cell signalling networks are essentially based on transient interactions. As a corollary, while signals propagated in persistent networks may be ephemeral, networks whose interactions are transient constrain signals diffusing into the cytoplasm to be durable in time, such as post-translational modifications of proteins or second messenger synthesis. The duration and nature of the signals, in turn, implies different mechanisms for the integration of multiple signals and decision making. Evolution then reinvented networks with persistent interactions with the development of nervous systems in metazoans. Ribosomal protein networks and simple nervous systems display architectural and functional analogies whose comparison could suggest scale invariance in information processing. At the molecular level, the significant complexification of eukaryotic ribosomal protein networks is associated with a burst in the acquisition of new conserved aromatic amino acids. Knowing that aromatic residues play a critical role in allosteric receptors and channels, this observation suggests a general role of π systems and their interactions with charged amino acids in multiple signal integration and information processing. We think that these findings may provide the molecular basis for designing future computers with organic processors.
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Affiliation(s)
- Youri Timsit
- Aix Marseille Université, Université de Toulon, CNRS, IRD, MIO UM110, 13288 Marseille, France
- Research Federation for the Study of Global Ocean Systems Ecology and Evolution, FR2022/Tara GOSEE, 3 rue Michel-Ange, 75016 Paris, France
- Correspondence:
| | - Sergeant-Perthuis Grégoire
- Institut de Mathématiques de Jussieu—Paris Rive Gauche (IMJ-PRG), UMR 7586, CNRS-Université Paris Diderot, 75013 Paris, France;
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38
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Miguel-Tomé S, Llinás RR. Broadening the definition of a nervous system to better understand the evolution of plants and animals. PLANT SIGNALING & BEHAVIOR 2021; 16:1927562. [PMID: 34120565 PMCID: PMC8331040 DOI: 10.1080/15592324.2021.1927562] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 04/30/2021] [Accepted: 05/03/2021] [Indexed: 05/10/2023]
Abstract
Most textbook definitions recognize only animals as having nervous systems. However, for the past couple decades, botanists have been meticulously studying long-distance signaling systems in plants, and some researchers have stated that plants have a simple nervous system. Thus, an academic conflict has emerged between those who defend and those who deny the existence of a nervous system in plants. This article analyses that debate, and we propose an alternative to answering yes or no: broadening the definition of a nervous system to include plants. We claim that a definition broader than the current one, which is based only on a phylogenetic viewpoint, would be helpful in obtaining a deeper understanding of how evolution has driven the features of signal generation, transmission and processing in multicellular beings. Also, we propose two possible definitions and exemplify how broader a definition allows for new viewpoints on the evolution of plants, animals and the nervous system.
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Affiliation(s)
- Sergio Miguel-Tomé
- Grupo De Investigación En Minería De Datos (Mida), Universidad De Salamanca, Salamanca, Spain
| | - Rodolfo R. Llinás
- Department of Neuroscience and Physiology, New York University School of Medicine, New York, USA
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39
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Neuropeptide repertoire and 3D anatomy of the ctenophore nervous system. Curr Biol 2021; 31:5274-5285.e6. [PMID: 34587474 DOI: 10.1016/j.cub.2021.09.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 07/20/2021] [Accepted: 09/02/2021] [Indexed: 11/24/2022]
Abstract
Ctenophores are gelatinous marine animals famous for locomotion by ciliary combs. Due to the uncertainties of the phylogenetic placement of ctenophores and the absence of some key bilaterian neuronal genes, it has been hypothesized that their neurons evolved independently. Additionally, recent whole-body, single-cell RNA sequencing (scRNA-seq) analysis failed to identify ctenophore neurons using any of the known neuronal molecular markers. To reveal the molecular machinery of ctenophore neurons, we have characterized the neuropeptide repertoire of the ctenophore Mnemiopsis leidyi. Using the machine learning NeuroPID tool, we predicted 129 new putative neuropeptide precursors. Sixteen of them were localized to the subepithelial nerve net (SNN), sensory aboral organ (AO), and epithelial sensory cells (ESCs), providing evidence that they are neuropeptide precursors. Four of these putative neuropeptides had a behavioral effect and increased the animals' swimming speed. Intriguingly, these putative neuropeptides finally allowed us to identify neuronal cell types in single-cell transcriptomic data and reveal the molecular identity of ctenophore neurons. High-resolution electron microscopy and 3D reconstructions of the nerve net underlying the comb plates confirmed a more than 100-year-old hypothesis of anastomoses between neurites of the same cell in ctenophores and revealed that they occur through a continuous membrane. Our work demonstrates the unique ultrastructure of the peptidergic nerve net and a rich neuropeptide repertoire of ctenophores, supporting the hypothesis that the first nervous system(s) evolved as nets of peptidergic cells.
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40
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Voronezhskaya EE. Maternal Serotonin: Shaping Developmental Patterns and Behavioral Strategy on Progeny in Molluscs. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.739787] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Serotonin is a well-known neurotransmitter and neurohormone regulating mood, sleep, feeding, and learning in high organisms. Serotonin also affects the embryonic events related to neurogenesis and maturation of hormonal systems, the underlying organism adaptation to a changing environment. Such serotonin-based mother-to-embryo signaling is realized via direct interactions in case of internal fertilization and embryonic development inside the mother body. However, the possibility of such signaling is less obvious in organisms with the ancestral type of embryogenesis and embryo development within the egg, outside the mother body. Our data, based on the investigation of freshwater gastropod molluscs (Lymnaea and Helisoma), demonstrated a correlation between seasonal variations of serotonin content within the female reproductive system, and developmental patterns and the behavioral characteristics of progeny. The direct action of serotonin via posttranslational protein modification—serotonylation—during early development, as well as classical receptor-mediated effects, underlies such serotonin-modulated developmental changes. In the present paper, I will shortly overview our results on freshwater molluscs and parallel the experimental data with the living strategy of these species occupying almost all Holarctic regions.
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41
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Schierwater B, Osigus HJ, Bergmann T, Blackstone NW, Hadrys H, Hauslage J, Humbert PO, Kamm K, Kvansakul M, Wysocki K, DeSalle R. The enigmatic Placozoa part 1: Exploring evolutionary controversies and poor ecological knowledge. Bioessays 2021; 43:e2100080. [PMID: 34472126 DOI: 10.1002/bies.202100080] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 07/21/2021] [Accepted: 08/16/2021] [Indexed: 12/13/2022]
Abstract
The placozoan Trichoplax adhaerens is a tiny hairy plate and more simply organized than any other living metazoan. After its original description by F.E. Schulze in 1883, it attracted attention as a potential model for the ancestral state of metazoan organization, the "Urmetazoon". Trichoplax lacks any kind of symmetry, organs, nerve cells, muscle cells, basal lamina, and extracellular matrix. Furthermore, the placozoan genome is the smallest (not secondarily reduced) genome of all metazoan genomes. It harbors a remarkably rich diversity of genes and has been considered the best living surrogate for a metazoan ancestor genome. The phylum Placozoa presently harbors three formally described species, while several dozen "cryptic" species are yet awaiting their description. The phylogenetic position of placozoans has recently become a contested arena for modern phylogenetic analyses and view-driven claims. Trichoplax offers unique prospects for understanding the minimal requirements of metazoan animal organization and their corresponding malfunctions.
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Affiliation(s)
- Bernd Schierwater
- Institute of Animal Ecology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Hans-Jürgen Osigus
- Institute of Animal Ecology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Tjard Bergmann
- Institute of Animal Ecology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Neil W Blackstone
- Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois, USA
| | - Heike Hadrys
- Institute of Animal Ecology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Jens Hauslage
- Gravitational Biology, Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany
| | - Patrick O Humbert
- Department of Biochemistry & Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia.,Research Centre for Molecular Cancer Prevention, La Trobe University, Melbourne, Victoria, 3086, Australia
| | - Kai Kamm
- Institute of Animal Ecology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Marc Kvansakul
- Department of Biochemistry & Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia.,Research Centre for Molecular Cancer Prevention, La Trobe University, Melbourne, Victoria, 3086, Australia
| | - Kathrin Wysocki
- Institute of Animal Ecology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Rob DeSalle
- American Museum of Natural History, New York, New York, USA
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42
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Romanova DY, Varoqueaux F, Daraspe J, Nikitin MA, Eitel M, Fasshauer D, Moroz LL. Hidden cell diversity in Placozoa: ultrastructural insights from Hoilungia hongkongensis. Cell Tissue Res 2021; 385:623-637. [PMID: 33876313 PMCID: PMC8523601 DOI: 10.1007/s00441-021-03459-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 03/31/2021] [Indexed: 12/17/2022]
Abstract
From a morphological point of view, placozoans are among the most simple free-living animals. This enigmatic phylum is critical for our understanding of the evolution of animals and their cell types. Their millimeter-sized, disc-like bodies consist of only three cell layers that are shaped by roughly seven major cell types. Placozoans lack muscle cells and neurons but are able to move using their ciliated lower surface and take up food in a highly coordinated manner. Intriguingly, the genome of Trichoplax adhaerens, the founding member of the enigmatic phylum, has disclosed a surprising level of genetic complexity. Moreover, recent molecular and functional investigations have uncovered a much larger, so-far hidden cell-type diversity. Here, we have extended the microanatomical characterization of a recently described placozoan species-Hoilungia hongkongensis. In H. hongkongensis, we recognized the established canonical three-layered placozoan body plan but also came across several morphologically distinct and potentially novel cell types, among them novel gland cells and "shiny spheres"-bearing cells at the upper epithelium. Thus, the diversity of cell types in placozoans is indeed higher than anticipated.
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Affiliation(s)
- Daria Y Romanova
- Department of Fundamental Neurosciences, University of Lausanne, 1005, Lausanne, Switzerland.
- Cellular Neurobiology of Learning Lab, Institute of Higher Nervous Activity and Neurophysiology, Moscow, 117485, Russia.
| | - Frédérique Varoqueaux
- Department of Fundamental Neurosciences, University of Lausanne, 1005, Lausanne, Switzerland
- Department of Computational Biology, University of Lausanne, 1015, Lausanne, Switzerland
| | - Jean Daraspe
- Electron Microscopy Facility, University of Lausanne, Lausanne, Switzerland
| | - Mikhail A Nikitin
- Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, 119991, Russia
- Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, 127994, Russia
| | - Michael Eitel
- Department of Earth and Environmental Sciences, Paleontology and Geobiology, Ludwig-Maximilians Universität München, Munich, Germany
| | - Dirk Fasshauer
- Department of Fundamental Neurosciences, University of Lausanne, 1005, Lausanne, Switzerland.
- Department of Computational Biology, University of Lausanne, 1015, Lausanne, Switzerland.
| | - Leonid L Moroz
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, 32080, USA.
- Departments of Neuroscience and McKnight Brain Institute, University of Florida, Gainesville, FL, 32610, USA.
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43
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Moroz LL, Romanova DY. Selective Advantages of Synapses in Evolution. Front Cell Dev Biol 2021; 9:726563. [PMID: 34490275 PMCID: PMC8417881 DOI: 10.3389/fcell.2021.726563] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 07/29/2021] [Indexed: 12/23/2022] Open
Affiliation(s)
- Leonid L. Moroz
- Departments of Neuroscience and McKnight Brain Institute, University of Florida, Gainesville, FL, United States
- Whitney Laboratory for Marine Biosciences, University of Florida, St. Augustine, FL, United States
| | - Daria Y. Romanova
- Lab of Cellular Neurobiology of Learning, Institute of Higher Nervous Activity and Neurophysiology of Russian Academy of Sciences, Moscow, Russia
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44
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Moroz LL, Nikitin MA, Poličar PG, Kohn AB, Romanova DY. Evolution of glutamatergic signaling and synapses. Neuropharmacology 2021; 199:108740. [PMID: 34343611 DOI: 10.1016/j.neuropharm.2021.108740] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 07/28/2021] [Accepted: 07/29/2021] [Indexed: 12/13/2022]
Abstract
Glutamate (Glu) is the primary excitatory transmitter in the mammalian brain. But, we know little about the evolutionary history of this adaptation, including the selection of l-glutamate as a signaling molecule in the first place. Here, we used comparative metabolomics and genomic data to reconstruct the genealogy of glutamatergic signaling. The origin of Glu-mediated communications might be traced to primordial nitrogen and carbon metabolic pathways. The versatile chemistry of L-Glu placed this molecule at the crossroad of cellular biochemistry as one of the most abundant metabolites. From there, innovations multiplied. Many stress factors or injuries could increase extracellular glutamate concentration, which led to the development of modular molecular systems for its rapid sensing in bacteria and archaea. More than 20 evolutionarily distinct families of ionotropic glutamate receptors (iGluRs) have been identified in eukaryotes. The domain compositions of iGluRs correlate with the origins of multicellularity in eukaryotes. Although L-Glu was recruited as a neuro-muscular transmitter in the early-branching metazoans, it was predominantly a non-neuronal messenger, with a possibility that glutamatergic synapses evolved more than once. Furthermore, the molecular secretory complexity of glutamatergic synapses in invertebrates (e.g., Aplysia) can exceed their vertebrate counterparts. Comparative genomics also revealed 15+ subfamilies of iGluRs across Metazoa. However, most of this ancestral diversity had been lost in the vertebrate lineage, preserving AMPA, Kainate, Delta, and NMDA receptors. The widespread expansion of glutamate synapses in the cortical areas might be associated with the enhanced metabolic demands of the complex brain and compartmentalization of Glu signaling within modular neuronal ensembles.
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Affiliation(s)
- Leonid L Moroz
- Whitney Laboratory for Marine Biosciences, University of Florida, St. Augustine, FL, 32080, USA; Departments of Neuroscience and McKnight Brain Institute, University of Florida, Gainesville, FL, 32610, USA.
| | - Mikhail A Nikitin
- Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, 119991, Russia; Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, 127994, Russia
| | - Pavlin G Poličar
- Whitney Laboratory for Marine Biosciences, University of Florida, St. Augustine, FL, 32080, USA; Faculty of Computer and Information Science, University of Ljubljana, SI-1000, Ljubljana, Slovenia
| | - Andrea B Kohn
- Whitney Laboratory for Marine Biosciences, University of Florida, St. Augustine, FL, 32080, USA
| | - Daria Y Romanova
- Cellular Neurobiology of Learning Lab, Institute of Higher Nervous Activity and Neurophysiology, Moscow, 117485, Russia.
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45
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Norekian TP, Moroz LL. Development of the nervous system in the early hatching larvae of the ctenophore Mnemiopsis leidyi. J Morphol 2021; 282:1466-1477. [PMID: 34272895 DOI: 10.1002/jmor.21398] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 07/11/2021] [Accepted: 07/13/2021] [Indexed: 12/24/2022]
Abstract
Ctenophores are descendants of an early branching basal metazoan lineage, which may have evolved neurons and muscles independently from other animals. Mnemiopsis is one of the important reference ctenophore species. However, little is known about its neuromuscular organization. Here, we mapped and tracked the development of the neural and muscular elements in the early hatching cydippid larvae, as well as adult Mnemiopsis leidyi. The overall development of the neuromuscular system in Mnemiopsis was very similar to Pleurobrachia bachei, although in Mnemiopsis the entire process occurred significantly faster. The subepithelial neural cells were observed immediately after hatching. This population consisted of a dozen of separated individual neurons with short neurites. In about 2 days, when their neurites grew significantly longer and connected to their neighbors, they began to form a canonical polygonal subepithelial network. Mesogleal neural elements prominent in all studied adult ctenophores were not detectable in Mnemiopsis larvae but were clearly labeled in closely related Lobata species Bolinopsis infundibulum. Hatched larvae also had putative mechanoreceptors with long stereocilia and approximately two dozen muscle cells. In adult Mnemiopsis, the feeding lobes and auricles contained two distinct populations of neurons and neural ensembles that were not observed in other ctenophore lineages and likely represented elaborate neuronal innovations characteristic for the clade Lobata and their lifestyles.
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Affiliation(s)
- Tigran P Norekian
- Whitney Laboratory, University of Florida, St. Augustine, Florida, USA.,Friday Harbor Laboratories, University of Washington, Friday Harbor, Washington, USA.,Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russian Federation
| | - Leonid L Moroz
- Whitney Laboratory, University of Florida, St. Augustine, Florida, USA.,Departments of Neuroscience and McKnight Brain Institute, University of Florida, Gainesville, Florida, USA
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46
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Moroz LL. Multiple Origins of Neurons From Secretory Cells. Front Cell Dev Biol 2021; 9:669087. [PMID: 34307354 PMCID: PMC8293673 DOI: 10.3389/fcell.2021.669087] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 05/26/2021] [Indexed: 12/12/2022] Open
Affiliation(s)
- Leonid L. Moroz
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL, United States
- Whitney Laboratory for Marine Biosciences, University of Florida, St. Augustine, FL, United States
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Lyon P, Keijzer F, Arendt D, Levin M. Reframing cognition: getting down to biological basics. Philos Trans R Soc Lond B Biol Sci 2021; 376:20190750. [PMID: 33487107 PMCID: PMC7935032 DOI: 10.1098/rstb.2019.0750] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/07/2020] [Indexed: 12/12/2022] Open
Abstract
The premise of this two-part theme issue is simple: the cognitive sciences should join the rest of the life sciences in how they approach the quarry within their research domain. Specifically, understanding how organisms on the lower branches of the phylogenetic tree become familiar with, value and exploit elements of an ecological niche while avoiding harm can be expected to aid understanding of how organisms that evolved later (including Homo sapiens) do the same or similar things. We call this approach basal cognition. In this introductory essay, we explain what the approach involves. Because no definition of cognition exists that reflects its biological basis, we advance a working definition that can be operationalized; introduce a behaviour-generating toolkit of capacities that comprise the function (e.g. sensing/perception, memory, valence, learning, decision making, communication), each element of which can be studied relatively independently; and identify a (necessarily incomplete) suite of common biophysical mechanisms found throughout the domains of life involved in implementing the toolkit. The articles in this collection illuminate different aspects of basal cognition across different forms of biological organization, from prokaryotes and single-celled eukaryotes-the focus of Part 1-to plants and finally to animals, without and with nervous systems, the focus of Part 2. By showcasing work in diverse, currently disconnected fields, we hope to sketch the outline of a new multidisciplinary approach for comprehending cognition, arguably the most fascinating and hard-to-fathom evolved function on this planet. Doing so has the potential to shed light on problems in a wide variety of research domains, including microbiology, immunology, zoology, biophysics, botany, developmental biology, neurobiology/science, regenerative medicine, computational biology, artificial life and synthetic bioengineering. This article is part of the theme issue 'Basal cognition: conceptual tools and the view from the single cell'.
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Affiliation(s)
- Pamela Lyon
- Southgate Institute for Health, Society and Equity, College of Medicine and Public Health, Flinders University, Adelaide, SA 5042, Australia
| | - Fred Keijzer
- Department of Theoretical Philosophy, Universityof Groningen, Oude Boteringestraat 52, Groningen 9712GL, The Netherlands
| | - Detlev Arendt
- Developmental Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69012 Heidelberg, Germany
- Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Michael Levin
- Allen Discovery Center at Tufts University, Medford, MA 02155, USA
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Györi J, Kohn AB, Romanova DY, Moroz LL. ATP signaling in the integrative neural center of Aplysia californica. Sci Rep 2021; 11:5478. [PMID: 33750901 PMCID: PMC7943599 DOI: 10.1038/s41598-021-84981-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 02/23/2021] [Indexed: 11/22/2022] Open
Abstract
ATP and its ionotropic P2X receptors are components of the most ancient signaling system. However, little is known about the distribution and function of purinergic transmission in invertebrates. Here, we cloned, expressed, and pharmacologically characterized the P2X receptors in the sea slug Aplysia californica—a prominent neuroscience model. AcP2X receptors were successfully expressed in Xenopus oocytes and displayed activation by ATP with two-phased kinetics and Na+-dependence. Pharmacologically, they were different from other P2X receptors. The ATP analog, Bz-ATP, was a less effective agonist than ATP, and PPADS was a more potent inhibitor of the AcP2X receptors than the suramin. AcP2X were uniquely expressed within the cerebral F-cluster, the multifunctional integrative neurosecretory center. AcP2X receptors were also detected in the chemosensory structures and the early cleavage stages. Therefore, in molluscs, rapid ATP-dependent signaling can be implicated both in development and diverse homeostatic functions. Furthermore, this study illuminates novel cellular and systemic features of P2X-type ligand-gated ion channels for deciphering the evolution of neurotransmitters.
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Affiliation(s)
- János Györi
- Department of Experimental Zoology, Centre for Ecological Research, Balaton Limnological Institute, 8237, Tihany, Hungary.,Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, 32080, USA
| | - Andrea B Kohn
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, 32080, USA
| | - Daria Y Romanova
- Institute of Higher Nervous Activity and Neurophysiology of RAS, Moscow, 117485, Russia
| | - Leonid L Moroz
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL, 32080, USA. .,Departments of Neuroscience and McKnight Brain Institute, University of Florida, Gainesville, FL, 32610, USA.
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Levin M, Keijzer F, Lyon P, Arendt D. Uncovering cognitive similarities and differences, conservation and innovation. Philos Trans R Soc Lond B Biol Sci 2021; 376:20200458. [PMID: 33550950 DOI: 10.1098/rstb.2020.0458] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
This article is part of the theme issue 'Basal cognition: multicellularity, neurons and the cognitive lens'.
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Affiliation(s)
- Michael Levin
- Allen Discovery Center at Tufts University, Medford, MA 02155, USA
| | - Fred Keijzer
- Department of Theoretical Philosophy, University of Groningen, Oude Boteringestraat 52, Groningen 9712GL, The Netherlands
| | - Pamela Lyon
- Southgate Institute for Health, Society and Equity, College of Medicine and Public Health, Flinders University, Adelaide SA 5042, Australia
| | - Detlev Arendt
- Developmental Biology Unit, European Molecular Biology Laboratory, Meyerhofstraße 1, 69012 Heidelberg, Germany.,Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
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Ginsburg S, Jablonka E. Evolutionary transitions in learning and cognition. Philos Trans R Soc Lond B Biol Sci 2021; 376:20190766. [PMID: 33550955 DOI: 10.1098/rstb.2019.0766] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
We define a cognitive system as a system that can learn, and adopt an evolutionary-transition-oriented framework for analysing different types of neural cognition. This enables us to classify types of cognition and point to the continuities and discontinuities among them. The framework we use for studying evolutionary transitions in learning capacities focuses on qualitative changes in the integration, storage and use of neurally processed information. Although there are always grey areas around evolutionary transitions, we recognize five major neural transitions, the first two of which involve animals at the base of the phylogenetic tree: (i) the evolutionary transition from learning in non-neural animals to learning in the first neural animals; (ii) the transition to animals showing limited, elemental associative learning, entailing neural centralization and primary brain differentiation; (iii) the transition to animals capable of unlimited associative learning, which, on our account, constitutes sentience and entails hierarchical brain organization and dedicated memory and value networks; (iv) the transition to imaginative animals that can plan and learn through selection among virtual events; and (v) the transition to human symbol-based cognition and cultural learning. The focus on learning provides a unifying framework for experimental and theoretical studies of cognition in the living world. This article is part of the theme issue 'Basal cognition: multicellularity, neurons and the cognitive lens'.
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Affiliation(s)
- Simona Ginsburg
- Natural Science Department, The Open University of Israel, 1 University Road, POB 808, Raanana 4353701, Israel
| | - Eva Jablonka
- The Cohn Institute for the History and Philosophy of Science and Ideas, Tel Aviv University, 6934525 Ramat Aviv, Israel.,CPNSS, London School of Economics, Houghton Street, London WC2A 2AE, UK
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