1
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Sachkova MY. Evolutionary origin of the nervous system from Ctenophora prospective. Evol Dev 2024:e12472. [PMID: 38390763 DOI: 10.1111/ede.12472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 02/09/2024] [Accepted: 02/10/2024] [Indexed: 02/24/2024]
Abstract
Nervous system is one of the key adaptations underlying the evolutionary success of the majority of animal groups. Ctenophores (or comb jellies) are gelatinous marine invertebrates that were probably the first lineage to diverge from the rest of animals. Due to the key phylogenetic position and multiple unique adaptations, the noncentralized nervous system of comb jellies has been in the center of the debate around the origin of the nervous system in the animal kingdom and whether it happened only once or twice. Here, we discuss the latest findings in ctenophore neuroscience and multiple challenges on the way to build a clear evolutionary picture of the origin of the nervous system.
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Affiliation(s)
- Maria Y Sachkova
- School of Biological Sciences, University of Bristol, Bristol, UK
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2
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Soto-Angel JJ, Nordmann EL, Sturm D, Sachkova M, Pang K, Burkhardt P. Stable Laboratory Culture System for the Ctenophore Mnemiopsis leidyi. Methods Mol Biol 2024; 2757:123-145. [PMID: 38668964 DOI: 10.1007/978-1-0716-3642-8_4] [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
Ctenophores are marine organisms attracting significant attention from evolutionary biology, molecular biology, and ecological research. Here, we describe an easy and affordable setup to maintain a stable culture of the ctenophore Mnemiopsis leidyi. The challenging delicacy of the lobate ctenophores can be met by monitoring the water quality, providing the right nutrition, and adapting the handling and tank set-up to their fragile gelatinous body plan. Following this protocol allows stable laboratory lines, a continuous supply of embryos for molecular biological studies, and independence from population responses to environmental fluctuations.
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Affiliation(s)
| | | | | | - Maria Sachkova
- Michael Sars Centre, University of Bergen, Bergen, Norway
| | - Kevin Pang
- Michael Sars Centre, University of Bergen, Bergen, Norway
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3
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Hanson A. On being a Hydra with, and without, a nervous system: what do neurons add? Anim Cogn 2023; 26:1799-1816. [PMID: 37540280 PMCID: PMC10770230 DOI: 10.1007/s10071-023-01816-8] [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: 07/05/2023] [Revised: 07/05/2023] [Accepted: 07/27/2023] [Indexed: 08/05/2023]
Abstract
The small freshwater cnidarian Hydra has been the subject of scientific inquiry for over 300 years due to its remarkable regenerative capacities and apparent immortality. More recently, Hydra has been recognized as an excellent model system within neuroscience because of its small size, transparency, and simple nervous system, which allow high-resolution imaging of its entire nerve net while behaving. In less than a decade, studies of Hydra's nervous system have yielded insights into the activity of neural circuits in vivo unobtainable in most other animals. In addition to these unique attributes, there is yet another lesser-known feature of Hydra that makes it even more intriguing: it does not require its neural hardware to live. The extraordinary ability to survive the removal and replacement of its entire nervous system makes Hydra uniquely suited to address the question of what neurons add to an extant organism. Here, I will review what early work on nerve-free Hydra reveals about the potential role of the nervous system in these animals and point towards future directions for this work.
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Affiliation(s)
- Alison Hanson
- Department of Biological Sciences, Neurotechnology Center, Columbia University, New York, NY, USA.
- Department of Psychiatry, New York State Psychiatric Institute, Columbia University, New York, NY, USA.
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4
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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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5
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Silakov MI, Kuznetsov AV, Temnykh AV, Anninsky BE. Effect of monochromatic light on the behavior of the ctenophore Mnemiopsis leidyi (A. Agassiz, 1865). Biosystems 2023; 231:104987. [PMID: 37516316 DOI: 10.1016/j.biosystems.2023.104987] [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: 05/03/2023] [Revised: 07/25/2023] [Accepted: 07/26/2023] [Indexed: 07/31/2023]
Abstract
Ctenophores are invertebrate, gelatinous predators that perform complex movements due to their numerous ciliary comb plates. We investigated the behavioral responses of the ctenophore Mnemiopsis leidyi A. Agassiz, 1865 to red, green, and blue lights of different powers and fluxes emitted by LEDs or lasers. White LEDs were used to mimic natural sunlight. When laser light was directed to the aboral organ, the animals tended to leave the illumination zone. The blue-light reaction was six times faster than the red-light reaction. The behavioral strategy of the animals changed significantly when their freedom of maneuvering was restricted. Typical locomotions were ranked according to the laser beam avoidance time from the beginning of exposure to going into darkness. The minimum reaction time was required for turning and moving the ctenophore, while moving along the laser beam and turning around required more time. Typical patterns of behavior of M. leidyi in the light flux were established using cluster analysis. Three preferential behavioral strategies were identified for avoiding laser irradiation: 1) body rotation; 2) shifting sideways; and 3) movement with deviation from the beam. The elementary ability of ctenophores to make decisions in situative conditions has been demonstrated.
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Affiliation(s)
- M I Silakov
- A.O. Kovalevsky Institute of Biology of the Southern Seas, RAS, Leninsky Avenue 38, Moscow, 119991, Russia
| | - A V Kuznetsov
- A.O. Kovalevsky Institute of Biology of the Southern Seas, RAS, Leninsky Avenue 38, Moscow, 119991, Russia.
| | - A V Temnykh
- A.O. Kovalevsky Institute of Biology of the Southern Seas, RAS, Leninsky Avenue 38, Moscow, 119991, Russia
| | - B E Anninsky
- A.O. Kovalevsky Institute of Biology of the Southern Seas, RAS, Leninsky Avenue 38, Moscow, 119991, Russia
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6
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Hehmeyer J, Spitz F, Marlow H. Shifting landscapes: the role of 3D genomic organizations in gene regulatory strategies. Curr Opin Genet Dev 2023; 81:102064. [PMID: 37390583 PMCID: PMC10547022 DOI: 10.1016/j.gde.2023.102064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 05/23/2023] [Accepted: 05/24/2023] [Indexed: 07/02/2023]
Abstract
3D genome folding enables the physical storage of chromosomes into the compact volume of a cell's nucleus, allows for the accurate segregation of chromatin to daughter cells, and has been shown to be tightly coupled to the way in which genetic information is converted into transcriptional programs [1-3]. Importantly, this link between chromatin architecture and gene regulation is a selectable feature in which modifications to chromatin organization accompany, or perhaps even drive the establishment of new regulatory strategies with enduring impacts on animal body plan complexity. Here, we discuss the nature of different 3D genome folding systems found across the tree of life, with particular emphasis on metazoans, and the relative influence of these systems on gene regulation. We suggest how the properties of these folding systems have influenced regulatory strategies employed by different lineages and may have catalyzed the partitioning and specialization of genetic programs that enabled multicellularity and organ-grade body plan complexity.
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Affiliation(s)
- Jenks Hehmeyer
- Department of Organismal Biology and Anatomy, The University of Chicago, USA
| | - François Spitz
- Department of Human Genetics, The University of Chicago, USA
| | - Heather Marlow
- Department of Organismal Biology and Anatomy, The University of Chicago, USA.
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7
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Burkhardt P, Colgren J, Medhus A, Digel L, Naumann B, Soto-Angel JJ, Nordmann EL, Sachkova MY, Kittelmann M. Syncytial nerve net in a ctenophore adds insights on the evolution of nervous systems. Science 2023; 380:293-297. [PMID: 37079688 DOI: 10.1126/science.ade5645] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2023]
Abstract
A fundamental breakthrough in neurobiology has been the formulation of the neuron doctrine by Santiago Ramón y Cajal, which stated that the nervous system is composed of discrete cells. Electron microscopy later confirmed the doctrine and allowed the identification of synaptic connections. In this work, we used volume electron microscopy and three-dimensional reconstructions to characterize the nerve net of a ctenophore, a marine invertebrate that belongs to one of the earliest-branching animal lineages. We found that neurons in the subepithelial nerve net have a continuous plasma membrane that forms a syncytium. Our findings suggest fundamental differences of nerve net architectures between ctenophores and cnidarians or bilaterians and offer an alternative perspective on neural network organization and neurotransmission.
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Affiliation(s)
- Pawel Burkhardt
- Michael Sars Centre, University of Bergen, 5008 Bergen, Norway
| | - Jeffrey Colgren
- Michael Sars Centre, University of Bergen, 5008 Bergen, Norway
| | - Astrid Medhus
- Michael Sars Centre, University of Bergen, 5008 Bergen, Norway
| | - Leonid Digel
- Michael Sars Centre, University of Bergen, 5008 Bergen, Norway
| | - Benjamin Naumann
- Institut für Biowissenschaften, Allgemeine und Spezielle Zoologie, Universität Rostock, 18055 Rostock, Germany
| | | | | | | | - Maike Kittelmann
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
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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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9
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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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10
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The premetazoan ancestry of the synaptic toolkit and appearance of first neurons. Essays Biochem 2022; 66:781-795. [PMID: 36205407 DOI: 10.1042/ebc20220042] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/31/2022] [Accepted: 09/13/2022] [Indexed: 12/13/2022]
Abstract
Neurons, especially when coupled with muscles, allow animals to interact with and navigate through their environment in ways unique to life on earth. Found in all major animal lineages except sponges and placozoans, nervous systems range widely in organization and complexity, with neurons possibly representing the most diverse cell-type. This diversity has led to much debate over the evolutionary origin of neurons as well as synapses, which allow for the directed transmission of information. The broad phylogenetic distribution of neurons and presence of many of the defining components outside of animals suggests an early origin of this cell type, potentially in the time between the first animal and the last common ancestor of extant animals. Here, we highlight the occurrence and function of key aspects of neurons outside of animals as well as recent findings from non-bilaterian animals in order to make predictions about when and how the first neuron(s) arose during animal evolution and their relationship to those found in extant lineages. With advancing technologies in single cell transcriptomics and proteomics as well as expanding functional techniques in non-bilaterian animals and the close relatives of animals, it is an exciting time to begin unraveling the complex evolutionary history of this fascinating animal cell type.
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11
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Hayakawa E, Guzman C, Horiguchi O, Kawano C, Shiraishi A, Mohri K, Lin MF, Nakamura R, Nakamura R, Kawai E, Komoto S, Jokura K, Shiba K, Shigenobu S, Satake H, Inaba K, Watanabe H. Mass spectrometry of short peptides reveals common features of metazoan peptidergic neurons. Nat Ecol Evol 2022; 6:1438-1448. [PMID: 35941202 PMCID: PMC9525235 DOI: 10.1038/s41559-022-01835-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 06/21/2022] [Indexed: 12/21/2022]
Abstract
The evolutionary origins of neurons remain unknown. Although recent genome data of extant early-branching animals have shown that neural genes existed in the common ancestor of animals, the physiological and genetic properties of neurons in the early evolutionary phase are still unclear. Here, we performed a mass spectrometry-based comprehensive survey of short peptides from early-branching lineages Cnidaria, Porifera and Ctenophora. We identified a number of mature ctenophore neuropeptides that are expressed in neurons associated with sensory, muscular and digestive systems. The ctenophore peptides are stored in vesicles in cell bodies and neurites, suggesting volume transmission similar to that of cnidarian and bilaterian peptidergic systems. A comparison of genetic characteristics revealed that the peptide-expressing cells of Cnidaria and Ctenophora express the vast majority of genes that have pivotal roles in maturation, secretion and degradation of neuropeptides in Bilateria. Functional analysis of neuropeptides and prediction of receptors with machine learning demonstrated peptide regulation of a wide range of target effector cells, including cells of muscular systems. The striking parallels between the peptidergic neuronal properties of Cnidaria and Bilateria and those of Ctenophora, the most basal neuron-bearing animals, suggest a common evolutionary origin of metazoan peptidergic nervous systems.
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Affiliation(s)
- Eisuke Hayakawa
- Evolutionary Neurobiology Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan.
| | - Christine Guzman
- Evolutionary Neurobiology Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Osamu Horiguchi
- Evolutionary Neurobiology Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Chihiro Kawano
- Evolutionary Neurobiology Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Akira Shiraishi
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto, Japan
| | - Kurato Mohri
- Evolutionary Neurobiology Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Mei-Fang Lin
- Evolutionary Neurobiology Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
- College of Marine Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan
| | - Ryotaro Nakamura
- Evolutionary Neurobiology Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Ryo Nakamura
- Evolutionary Neurobiology Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Erina Kawai
- Evolutionary Neurobiology Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
- Marine Climate Change Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Shinya Komoto
- Evolutionary Neurobiology Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
- Imaging Section, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan
| | - Kei Jokura
- Shimoda Marine Research Center, University of Tsukuba, Shizuoka, Japan
- Living Systems Institute, University of Exeter, Exeter, UK
| | - Kogiku Shiba
- Shimoda Marine Research Center, University of Tsukuba, Shizuoka, Japan
| | - Shuji Shigenobu
- Center for the Development of New Model Organisms, National Institute for Basic Biology, Okazaki, Japan
| | - Honoo Satake
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Kyoto, Japan
| | - Kazuo Inaba
- Shimoda Marine Research Center, University of Tsukuba, Shizuoka, Japan
| | - Hiroshi Watanabe
- Evolutionary Neurobiology Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan.
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12
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Sachkova MY. Neuropeptides at the origin of neurons. Nat Ecol Evol 2022; 6:1410-1411. [PMID: 35941203 DOI: 10.1038/s41559-022-01828-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Maria Y Sachkova
- Sars International Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway.
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13
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Single-cell transcriptomics identifies conserved regulators of neuroglandular lineages. Cell Rep 2022; 40:111370. [PMID: 36130520 DOI: 10.1016/j.celrep.2022.111370] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 07/01/2022] [Accepted: 08/25/2022] [Indexed: 11/23/2022] Open
Abstract
Communication in bilaterian nervous systems is mediated by electrical and secreted signals; however, the evolutionary origin and relation of neurons to other secretory cell types has not been elucidated. Here, we use developmental single-cell RNA sequencing in the cnidarian Nematostella vectensis, representing an early evolutionary lineage with a simple nervous system. Validated by transgenics, we demonstrate that neurons, stinging cells, and gland cells arise from a common multipotent progenitor population. We identify the conserved transcription factor gene SoxC as a key upstream regulator of all neuroglandular lineages and demonstrate that SoxC knockdown eliminates both neuronal and secretory cell types. While in vertebrates and many other bilaterians neurogenesis is largely restricted to early developmental stages, we show that in the sea anemone, differentiation of neuroglandular cells is maintained throughout all life stages, and follows the same molecular trajectories from embryo to adulthood, ensuring lifelong homeostasis of neuroglandular cell lineages.
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14
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Abstract
Neuropeptides are a diverse class of signaling molecules in metazoans. They occur in all animals with a nervous system and also in neuron-less placozoans. However, their origin has remained unclear because no neuropeptide shows deep homology across lineages, and none have been found in sponges. Here, we identify two neuropeptide precursors, phoenixin (PNX) and nesfatin, with broad evolutionary conservation. By database searches, sequence alignments, and gene-structure comparisons, we show that both precursors are present in bilaterians, cnidarians, ctenophores, and sponges. We also found PNX and a secreted nesfatin precursor homolog in the choanoflagellate Salpingoeca rosetta. PNX, in particular, is highly conserved, including its cleavage sites, suggesting that prohormone processing occurs also in choanoflagellates. In addition, based on phyletic patterns and negative pharmacological assays, we question the originally proposed GPR-173 (SREB3) as a PNX receptor. Our findings revealed that secreted neuropeptide homologs derived from longer precursors have premetazoan origins and thus evolved before neurons.
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Affiliation(s)
| | - Daniel Thiel
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, UK
| | - Gáspár Jékely
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, UK
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