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Xu C, Wu X, Qiu J, Ye J, Lin Q, Deng J, Zeng Y, Wang W, Zhang H, Zheng H. Genome-wide identification of gap junction gene family and their expression profiles under low temperature stress in noble scallop Chlamys nobilis. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART D, GENOMICS & PROTEOMICS 2024; 52:101310. [PMID: 39137603 DOI: 10.1016/j.cbd.2024.101310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Revised: 07/13/2024] [Accepted: 08/08/2024] [Indexed: 08/15/2024]
Abstract
Gap junctions, formed by gap junction proteins (GJ), play crucial roles in cell signaling and immune responses. The structure and function of the GJ from vertebrates (called connexins) have been extensively studied. However, little is known about the proteins forming gap junctions in invertebrates (called innexins). In this study, 14 GJ genes of Chlamys nobilis were identified. GJ proteins are mainly distributed on the plasma membrane, and all proteins are hydrophilic Phylogenetic tree analysis showed that the GJ proteins in C. nobilis were distantly related to those in vertebrates but closely related to those in invertebrates. Conserved motifs analysis of these GJ proteins in C. nobilis identified to have 10 conserved motifs, similar to gap junction proteins in other bivalves. Moreover, expression profiles of CnGJ genes under chronic and acute low temperature stress were also investigated. Results showed that chronic low temperature stress had a significant effect on the expression levels of CnGJ genes, and the expression profiles of CnGJ genes showed significantly variation under acute low temperature stress. All these results indicated that CnGJ genes play important roles in environmental adaptation in scallops. The present study initially elucidated the function of gap junction genes in noble scallop C. nobilis, which provides new insights into the GJ genes in mollusks and will help us better understand their roles in environmental stress in scallops.
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Affiliation(s)
- Changping Xu
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou 515063, China; Research Center of Engineering Technology for Subtropical Mariculture of Guangdong Province, Shantou 515063, China; STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou 515063, China
| | - Xuanbing Wu
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou 515063, China; Research Center of Engineering Technology for Subtropical Mariculture of Guangdong Province, Shantou 515063, China; STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou 515063, China
| | - Jiale Qiu
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou 515063, China; Research Center of Engineering Technology for Subtropical Mariculture of Guangdong Province, Shantou 515063, China; STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou 515063, China
| | - Jianming Ye
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou 515063, China; Research Center of Engineering Technology for Subtropical Mariculture of Guangdong Province, Shantou 515063, China; STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou 515063, China
| | - Qing Lin
- Shantou Fruit Tree and Aquatic Technology Promotion Station, Shantou 515063, China
| | - Jingwen Deng
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou 515063, China; Research Center of Engineering Technology for Subtropical Mariculture of Guangdong Province, Shantou 515063, China; STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou 515063, China
| | - Yetao Zeng
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou 515063, China; Research Center of Engineering Technology for Subtropical Mariculture of Guangdong Province, Shantou 515063, China; STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou 515063, China
| | - Weili Wang
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou 515063, China; Research Center of Engineering Technology for Subtropical Mariculture of Guangdong Province, Shantou 515063, China; STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou 515063, China
| | - Hongkuan Zhang
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou 515063, China; Research Center of Engineering Technology for Subtropical Mariculture of Guangdong Province, Shantou 515063, China; STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou 515063, China.
| | - Huaiping Zheng
- Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou 515063, China; Research Center of Engineering Technology for Subtropical Mariculture of Guangdong Province, Shantou 515063, China; STU-UMT Joint Shellfish Research Laboratory, Shantou University, Shantou 515063, China.
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Goel T, Adams EM, Bialas AL, Tran CM, Rowe T, Martin S, Chandler M, Schubert J, Diamond PH, Collins EMS. Nonlinear elasticity and short-range mechanical coupling govern the rate and symmetry of mouth opening in Hydra. Proc Biol Sci 2024; 291:20232123. [PMID: 38378148 PMCID: PMC10878823 DOI: 10.1098/rspb.2023.2123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 01/18/2024] [Indexed: 02/22/2024] Open
Abstract
Hydra has a tubular bilayered epithelial body column with a dome-shaped head on one end and a foot on the other. Hydra lacks a permanent mouth: its head epithelium is sealed. Upon neuronal activation, a mouth opens at the apex of the head which can exceed the body column diameter in seconds, allowing Hydra to ingest prey larger than itself. While the kinematics of mouth opening are well characterized, the underlying mechanism is unknown. We show that Hydra mouth opening is generated by independent local contractions that require tissue-level coordination. We model the head epithelium as an active viscoelastic nonlinear spring network. The model reproduces the size, timescale and symmetry of mouth opening. It shows that radial contractions, travelling inwards from the outer boundary of the head, pull the mouth open. Nonlinear elasticity makes mouth opening larger and faster, contrary to expectations. The model correctly predicts changes in mouth shape in response to external forces. By generating innervated : nerve-free chimera in experiments and simulations, we show that nearest-neighbour mechanical signalling suffices to coordinate mouth opening. Hydra mouth opening shows that in the absence of long-range chemical or neuronal signals, short-range mechanical coupling is sufficient to produce long-range order in tissue deformations.
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Affiliation(s)
- Tapan Goel
- Department of Physics, University of California San Diego, La Jolla, CA 92093, USA
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
- Department of Biology, University of Maryland, College Park, MD 20742, USA
| | - Ellen M. Adams
- Department of Biology, Swarthmore College, Swarthmore, PA 19081, USA
| | - April L. Bialas
- Department of Biology, Swarthmore College, Swarthmore, PA 19081, USA
| | - Cassidy M. Tran
- Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Trevor Rowe
- Department of Physics, University of California San Diego, La Jolla, CA 92093, USA
| | - Sara Martin
- Department of Biology, Swarthmore College, Swarthmore, PA 19081, USA
| | - Maia Chandler
- Department of Biology, Swarthmore College, Swarthmore, PA 19081, USA
| | - Johanna Schubert
- Department of Biology, Swarthmore College, Swarthmore, PA 19081, USA
| | - Patrick H. Diamond
- Department of Physics, University of California San Diego, La Jolla, CA 92093, USA
| | - Eva-Maria S. Collins
- Department of Physics, University of California San Diego, La Jolla, CA 92093, USA
- Department of Biology, Swarthmore College, Swarthmore, PA 19081, USA
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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3
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Keramidioti A, Schneid S, Busse C, Cramer von Laue C, Bertulat B, Salvenmoser W, Hess M, Alexandrova O, Glauber KM, Steele RE, Hobmayer B, Holstein TW, David CN. A new look at the architecture and dynamics of the Hydra nerve net. eLife 2024; 12:RP87330. [PMID: 38407174 PMCID: PMC10942621 DOI: 10.7554/elife.87330] [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: 02/27/2024] Open
Abstract
The Hydra nervous system is the paradigm of a 'simple nerve net'. Nerve cells in Hydra, as in many cnidarian polyps, are organized in a nerve net extending throughout the body column. This nerve net is required for control of spontaneous behavior: elimination of nerve cells leads to polyps that do not move and are incapable of capturing and ingesting prey (Campbell, 1976). We have re-examined the structure of the Hydra nerve net by immunostaining fixed polyps with a novel antibody that stains all nerve cells in Hydra. Confocal imaging shows that there are two distinct nerve nets, one in the ectoderm and one in the endoderm, with the unexpected absence of nerve cells in the endoderm of the tentacles. The nerve nets in the ectoderm and endoderm do not contact each other. High-resolution TEM (transmission electron microscopy) and serial block face SEM (scanning electron microscopy) show that the nerve nets consist of bundles of parallel overlapping neurites. Results from transgenic lines show that neurite bundles include different neural circuits and hence that neurites in bundles require circuit-specific recognition. Nerve cell-specific innexins indicate that gap junctions can provide this specificity. The occurrence of bundles of neurites supports a model for continuous growth and differentiation of the nerve net by lateral addition of new nerve cells to the existing net. This model was confirmed by tracking newly differentiated nerve cells.
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Affiliation(s)
- Athina Keramidioti
- Department of Biology, Ludwig-Maximilians-University MunichMartinsriedGermany
| | - Sandra Schneid
- Department of Biology, Ludwig-Maximilians-University MunichMartinsriedGermany
| | - Christina Busse
- Department of Biology, Ludwig-Maximilians-University MunichMartinsriedGermany
| | | | - Bianca Bertulat
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg UniversityHeidelbergGermany
| | - Willi Salvenmoser
- Department of Zoology and Center for Molecular Biosciences Innsbruck (CMBI), University of InnsbruckInnsbruckAustria
| | - Martin Hess
- Department of Biology, Ludwig-Maximilians-University MunichMartinsriedGermany
| | - Olga Alexandrova
- Department of Biology, Ludwig-Maximilians-University MunichMartinsriedGermany
| | - Kristine M Glauber
- Department of Biological Chemistry, University of CaliforniaIrvineUnited States
| | - Robert E Steele
- Department of Biological Chemistry, University of CaliforniaIrvineUnited States
| | - Bert Hobmayer
- Department of Zoology and Center for Molecular Biosciences Innsbruck (CMBI), University of InnsbruckInnsbruckAustria
| | - Thomas W Holstein
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg UniversityHeidelbergGermany
| | - Charles N David
- Department of Biology, Ludwig-Maximilians-University MunichMartinsriedGermany
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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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5
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Beckham JL, van Venrooy AR, Kim S, Li G, Li B, Duret G, Arnold D, Zhao X, Li JT, Santos AL, Chaudhry G, Liu D, Robinson JT, Tour JM. Molecular machines stimulate intercellular calcium waves and cause muscle contraction. NATURE NANOTECHNOLOGY 2023; 18:1051-1059. [PMID: 37430037 DOI: 10.1038/s41565-023-01436-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 05/03/2023] [Indexed: 07/12/2023]
Abstract
Intercellular calcium waves (ICW) are complex signalling phenomena that control many essential biological activities, including smooth muscle contraction, vesicle secretion, gene expression and changes in neuronal excitability. Accordingly, the remote stimulation of ICW could result in versatile biomodulation and therapeutic strategies. Here we demonstrate that light-activated molecular machines (MM)-molecules that perform mechanical work on the molecular scale-can remotely stimulate ICW. MM consist of a polycyclic rotor and stator that rotate around a central alkene when activated with visible light. Live-cell calcium-tracking and pharmacological experiments reveal that MM-induced ICW are driven by the activation of inositol-triphosphate-mediated signalling pathways by unidirectional, fast-rotating MM. Our data suggest that MM-induced ICW can control muscle contraction in vitro in cardiomyocytes and animal behaviour in vivo in Hydra vulgaris. This work demonstrates a strategy for directly controlling cell signalling and downstream biological function using molecular-scale devices.
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Affiliation(s)
| | | | - Soonyoung Kim
- Department of Electrical Engineering, Rice University, Houston, TX, USA
| | - Gang Li
- Department of Chemistry, Rice University, Houston, TX, USA
| | - Bowen Li
- Department of Chemistry, Rice University, Houston, TX, USA
| | - Guillaume Duret
- Department of Electrical Engineering, Rice University, Houston, TX, USA
| | - Dallin Arnold
- Department of Chemistry, Rice University, Houston, TX, USA
| | - Xuan Zhao
- Department of Electrical Engineering, Rice University, Houston, TX, USA
| | - John T Li
- Department of Chemistry, Rice University, Houston, TX, USA
| | - Ana L Santos
- Department of Chemistry, Rice University, Houston, TX, USA
- IdISBA-Fundación de Investigación Sanitaria de las Islas Baleares, Palma, Spain
| | | | - Dongdong Liu
- Department of Chemistry, Rice University, Houston, TX, USA
| | - Jacob T Robinson
- Department of Bioengineering, Department of Electrical Engineering, Rice University, Houston, TX, USA.
| | - James M Tour
- Department of Chemistry, Smalley-Curl Institute, NanoCarbon Center and Rice Advanced Materials Institute, Department of Materials Science and Nanoengineering, Department of Computer Science, Rice University, Houston, TX, USA.
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6
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Santini S, Schenkelaars Q, Jourda C, Duchesne M, Belahbib H, Rocher C, Selva M, Riesgo A, Vervoort M, Leys SP, Kodjabachian L, Le Bivic A, Borchiellini C, Claverie JM, Renard E. The compact genome of the sponge Oopsacas minuta (Hexactinellida) is lacking key metazoan core genes. BMC Biol 2023; 21:139. [PMID: 37337252 DOI: 10.1186/s12915-023-01619-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 05/09/2023] [Indexed: 06/21/2023] Open
Abstract
BACKGROUND Explaining the emergence of the hallmarks of bilaterians is a central focus of evolutionary developmental biology-evodevo-and evolutionary genomics. For this purpose, we must both expand and also refine our knowledge of non-bilaterian genomes, especially by studying early branching animals, in particular those in the metazoan phylum Porifera. RESULTS We present a comprehensive analysis of the first whole genome of a glass sponge, Oopsacas minuta, a member of the Hexactinellida. Studying this class of sponge is evolutionary relevant because it differs from the three other Porifera classes in terms of development, tissue organization, ecology, and physiology. Although O. minuta does not exhibit drastic body simplifications, its genome is among the smallest of animal genomes sequenced so far, and surprisingly lacks several metazoan core genes (including Wnt and several key transcription factors). Our study also provides the complete genome of a symbiotic Archaea dominating the associated microbial community: a new Thaumarchaeota species. CONCLUSIONS The genome of the glass sponge O. minuta differs from all other available sponge genomes by its compactness and smaller number of encoded proteins. The unexpected loss of numerous genes previously considered ancestral and pivotal for metazoan morphogenetic processes most likely reflects the peculiar syncytial tissue organization in this group. Our work further documents the importance of convergence during animal evolution, with multiple convergent evolution of septate-like junctions, electrical-signaling and multiciliated cells in metazoans.
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Affiliation(s)
- Sébastien Santini
- Aix Marseille Univ, CNRS, IGS, UMR 7256, IMM, IM2B, IOM, Marseille, France
| | - Quentin Schenkelaars
- Aix Marseille Univ, Avignon Univ, CNRS, IRD, IMBE, Marseille, France
- Institut Jacques Monod, CNRS, UMR 7592, Univ Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Cyril Jourda
- Aix Marseille Univ, CNRS, IGS, UMR 7256, IMM, IM2B, IOM, Marseille, France
- CIRAD, UMR PVBMT, La Réunion, France
| | - Marc Duchesne
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada
| | - Hassiba Belahbib
- Aix Marseille Univ, CNRS, IGS, UMR 7256, IMM, IM2B, IOM, Marseille, France
| | - Caroline Rocher
- Aix Marseille Univ, Avignon Univ, CNRS, IRD, IMBE, Marseille, France
| | - Marjorie Selva
- Aix Marseille Univ, Avignon Univ, CNRS, IRD, IMBE, Marseille, France
| | - Ana Riesgo
- Department of Biodiversity and Evolutionary Biology, Madrid, Spain
- Department of Life Sciences, Natural History Museum of London, London, SW7 5BD, UK
| | - Michel Vervoort
- Institut Jacques Monod, CNRS, UMR 7592, Univ Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Sally P Leys
- Department of Biological Sciences, University of Alberta, Edmonton, AB, T6G 2E9, Canada
| | - Laurent Kodjabachian
- Aix Marseille Univ, CNRS, IBDM, UMR 7288, Turing Center for Living Systems, Marseille, France
| | - André Le Bivic
- Aix Marseille Univ, CNRS, IBDM, UMR 7288, Marseille, France
| | | | | | - Emmanuelle Renard
- Aix Marseille Univ, Avignon Univ, CNRS, IRD, IMBE, Marseille, France.
- Aix Marseille Univ, CNRS, IBDM, UMR 7288, Marseille, France.
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7
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Wang H, Swore J, Sharma S, Szymanski JR, Yuste R, Daniel TL, Regnier M, Bosma MM, Fairhall AL. A complete biomechanical model of Hydra contractile behaviors, from neural drive to muscle to movement. Proc Natl Acad Sci U S A 2023; 120:e2210439120. [PMID: 36897982 PMCID: PMC10089167 DOI: 10.1073/pnas.2210439120] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 01/03/2023] [Indexed: 03/12/2023] Open
Abstract
How does neural activity drive muscles to produce behavior? The recent development of genetic lines in Hydra that allow complete calcium imaging of both neuronal and muscle activity, as well as systematic machine learning quantification of behaviors, makes this small cnidarian an ideal model system to understand and model the complete transformation from neural firing to body movements. To achieve this, we have built a neuromechanical model of Hydra's fluid-filled hydrostatic skeleton, showing how drive by neuronal activity activates distinct patterns of muscle activity and body column biomechanics. Our model is based on experimental measurements of neuronal and muscle activity and assumes gap junctional coupling among muscle cells and calcium-dependent force generation by muscles. With these assumptions, we can robustly reproduce a basic set of Hydra's behaviors. We can further explain puzzling experimental observations, including the dual timescale kinetics observed in muscle activation and the engagement of ectodermal and endodermal muscles in different behaviors. This work delineates the spatiotemporal control space of Hydra movement and can serve as a template for future efforts to systematically decipher the transformations in the neural basis of behavior.
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Affiliation(s)
- Hengji Wang
- Department of Physics, University of Washington, Seattle, WA98195
- Computational Neuroscience Center, University of Washington, Seattle, WA98195
| | - Joshua Swore
- Department of Biology, University of Washington, Seattle, WA98195
| | - Shashank Sharma
- Department of Physiology and Biophysics, University of Washington, Seattle, WA98195
| | - John R. Szymanski
- NeuroTechnology Center, Department of Biological Sciences, Columbia University, New York, NY10027
- Marine Biological Laboratory, Woods Hole, MA02543
| | - Rafael Yuste
- NeuroTechnology Center, Department of Biological Sciences, Columbia University, New York, NY10027
- Marine Biological Laboratory, Woods Hole, MA02543
| | - Thomas L. Daniel
- Department of Biology, University of Washington, Seattle, WA98195
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, WA98195
| | - Martha M. Bosma
- Department of Biology, University of Washington, Seattle, WA98195
| | - Adrienne L. Fairhall
- Department of Physics, University of Washington, Seattle, WA98195
- Computational Neuroscience Center, University of Washington, Seattle, WA98195
- Department of Physiology and Biophysics, University of Washington, Seattle, WA98195
- Marine Biological Laboratory, Woods Hole, MA02543
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8
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Moros M, Fergola E, Marchesano V, Mutarelli M, Tommasini G, Miedziak B, Palumbo G, Ambrosone A, Tino A, Tortiglione C. The Aquatic Invertebrate Hydra vulgaris Releases Molecular Messages Through Extracellular Vesicles. Front Cell Dev Biol 2022; 9:788117. [PMID: 34988080 PMCID: PMC8721104 DOI: 10.3389/fcell.2021.788117] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Accepted: 11/15/2021] [Indexed: 12/11/2022] Open
Abstract
Recent body of evidence demonstrates that extracellular vesicles (EVs) represent the first language of cell-cell communication emerged during evolution. In aquatic environments, transferring signals between cells by EVs offers protection against degradation, allowing delivering of chemical information in high local concentrations to the target cells. The packaging of multiple signals, including those of hydrophobic nature, ensures target cells to receive the same EV-conveyed messages, and the coordination of a variety of physiological processes across cells of a single organisms, or at the population level, i.e., mediating the population’s response to changing environmental conditions. Here, we purified EVs from the medium of the freshwater invertebrate Hydra vulgaris, and the molecular profiling by proteomic and transcriptomic analyses revealed multiple markers of the exosome EV subtype, from structural proteins to stress induced messages promoting cell survival. Moreover, positive and negative regulators of the Wnt/β-catenin signaling pathway, the major developmental pathway acting in body axial patterning, were identified. Functional analysis on amputated polyps revealed EV ability to modulate both head and foot regeneration, suggesting bioactivity of the EV cargo and opening new perspectives on the mechanisms of developmental signalling. Our results open the path to unravel EV biogenesis and function in all cnidarian species, tracing back the origin of the cell-cell, cross-species or cross-kingdom communication in aquatic ecosystems.
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Affiliation(s)
- Maria Moros
- Instituto de Nanociencia y Materiales de Aragón(INMA), CSIC-Universidad de Zaragoza, Zaragoza, Spain.,Istituto di Scienze Applicate e Sistemi Intelligenti "E. Caianiello", Consiglio Nazionale Delle Ricerche, Pozzuoli, Italy
| | - Eugenio Fergola
- Istituto di Scienze Applicate e Sistemi Intelligenti "E. Caianiello", Consiglio Nazionale Delle Ricerche, Pozzuoli, Italy
| | - Valentina Marchesano
- Istituto di Scienze Applicate e Sistemi Intelligenti "E. Caianiello", Consiglio Nazionale Delle Ricerche, Pozzuoli, Italy
| | - Margherita Mutarelli
- Istituto di Scienze Applicate e Sistemi Intelligenti "E. Caianiello", Consiglio Nazionale Delle Ricerche, Pozzuoli, Italy
| | - Giuseppina Tommasini
- Istituto di Scienze Applicate e Sistemi Intelligenti "E. Caianiello", Consiglio Nazionale Delle Ricerche, Pozzuoli, Italy
| | - Beata Miedziak
- Istituto di Scienze Applicate e Sistemi Intelligenti "E. Caianiello", Consiglio Nazionale Delle Ricerche, Pozzuoli, Italy
| | - Giuliana Palumbo
- Istituto di Scienze Applicate e Sistemi Intelligenti "E. Caianiello", Consiglio Nazionale Delle Ricerche, Pozzuoli, Italy
| | - Alfredo Ambrosone
- Istituto di Scienze Applicate e Sistemi Intelligenti "E. Caianiello", Consiglio Nazionale Delle Ricerche, Pozzuoli, Italy
| | - Angela Tino
- Istituto di Scienze Applicate e Sistemi Intelligenti "E. Caianiello", Consiglio Nazionale Delle Ricerche, Pozzuoli, Italy
| | - Claudia Tortiglione
- Istituto di Scienze Applicate e Sistemi Intelligenti "E. Caianiello", Consiglio Nazionale Delle Ricerche, Pozzuoli, Italy
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9
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Unni M, Reddy PC, Pal M, Sagi I, Galande S. Identification of Components of the Hippo Pathway in Hydra and Potential Role of YAP in Cell Division and Differentiation. Front Genet 2021; 12:676182. [PMID: 34691138 PMCID: PMC8526868 DOI: 10.3389/fgene.2021.676182] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 09/15/2021] [Indexed: 11/22/2022] Open
Abstract
The Hippo signaling pathway has been shown to be involved in regulating cellular identity, cell/tissue size maintenance and mechanotransduction. The Hippo pathway consists of a kinase cascade which determines the nucleo-cytoplasmic localization of YAP in the cell. YAP is the effector protein in the Hippo pathway, which acts as a transcriptional cofactor for TEAD. Phosphorylation of YAP upon activation of the Hippo pathway prevents it from entering the nucleus and abrogates its function in the transcription of the target genes. In Cnidaria, the information on the regulatory roles of the Hippo pathway is virtually lacking. Here, we report the existence of a complete set of Hippo pathway core components in Hydra for the first time. By studying their phylogeny and domain organization, we report evolutionary conservation of the components of the Hippo pathway. Protein modelling suggested the conservation of YAP-TEAD interaction in Hydra. Further, we characterized the expression pattern of the homologs of yap, hippo, mob and sav in Hydra using whole-mount RNA in situ hybridization and report their possible role in stem cell maintenance. Immunofluorescence assay revealed that Hvul_YAP expressing cells occur in clusters in the body column and are excluded in the terminally differentiated regions. Actively proliferating cells marked by Ki67 exhibit YAP colocalization in their nuclei. Strikingly, a subset of these colocalized cells is actively recruited to the newly developing bud. Disruption of the YAP-TEAD interaction increased the budding rate indicating a critical role of YAP in regulating cell proliferation in Hydra. Collectively, we posit that the Hippo pathway is an essential signaling system in Hydra; its components are ubiquitously expressed in the Hydra body column and play a crucial role in Hydra tissue homeostasis.
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Affiliation(s)
- Manu Unni
- Centre of Excellence in Epigenetics, Department of Biology, Indian Institute of Science Education and Research, Pune, India
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel
| | - Puli Chandramouli Reddy
- Centre of Excellence in Epigenetics, Department of Biology, Indian Institute of Science Education and Research, Pune, India
| | - Mrinmoy Pal
- Centre of Excellence in Epigenetics, Department of Biology, Indian Institute of Science Education and Research, Pune, India
| | - Irit Sagi
- Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel
| | - Sanjeev Galande
- Centre of Excellence in Epigenetics, Department of Biology, Indian Institute of Science Education and Research, Pune, India
- Department of Life Sciences, Shiv Nadar University, Delhi-NCR, India
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10
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Badhiwala KN, Primack AS, Juliano CE, Robinson JT. Multiple neuronal networks coordinate Hydra mechanosensory behavior. eLife 2021; 10:e64108. [PMID: 34328079 PMCID: PMC8324302 DOI: 10.7554/elife.64108] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 06/17/2021] [Indexed: 12/11/2022] Open
Abstract
Hydra vulgaris is an emerging model organism for neuroscience due to its small size, transparency, genetic tractability, and regenerative nervous system; however, fundamental properties of its sensorimotor behaviors remain unknown. Here, we use microfluidic devices combined with fluorescent calcium imaging and surgical resectioning to study how the diffuse nervous system coordinates Hydra's mechanosensory response. Mechanical stimuli cause animals to contract, and we find this response relies on at least two distinct networks of neurons in the oral and aboral regions of the animal. Different activity patterns arise in these networks depending on whether the animal is contracting spontaneously or contracting in response to mechanical stimulation. Together, these findings improve our understanding of how Hydra's diffuse nervous system coordinates sensorimotor behaviors. These insights help reveal how sensory information is processed in an animal with a diffuse, radially symmetric neural architecture unlike the dense, bilaterally symmetric nervous systems found in most model organisms.
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Affiliation(s)
| | - Abby S Primack
- Department of Molecular and Cellular BiologyUniversity of California, DavisUnited States
| | - Celina E Juliano
- Department of Molecular and Cellular BiologyUniversity of California, DavisUnited States
| | - Jacob T Robinson
- Department of Bioengineering, Rice UniversityHoustonUnited States
- Department of Electrical and Computer Engineering, Rice UniversityHoustonUnited States
- Department of Neuroscience, Baylor College of MedicineHoustonUnited States
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11
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Tzouanas CN, Kim S, Badhiwala KN, Avants BW, Robinson JT. Hydra vulgaris shows stable responses to thermal stimulation despite large changes in the number of neurons. iScience 2021; 24:102490. [PMID: 34095784 PMCID: PMC8164038 DOI: 10.1016/j.isci.2021.102490] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 02/03/2021] [Accepted: 04/27/2021] [Indexed: 11/27/2022] Open
Abstract
Many animals that lose neural tissue to injury or disease can maintain behavioral repertoires by regenerating new neurons or reorganizing existing neural circuits. However, most neuroscience small model organisms lack this high degree of neural plasticity. We show that Hydra vulgaris can maintain stable sensory-motor behaviors despite 2-fold changes in neuron count, due to naturally occurring size variation or surgical resection. Specifically, we find that both behavioral and neural responses to rapid temperature changes are maintained following these perturbations. We further describe possible mechanisms for the observed neural activity and argue that Hydra's radial symmetry may allow it to maintain stable behaviors when changes in the numbers of neurons do not selectively eliminate any specific neuronal cell type. These results suggest that Hydra provides a powerful model for studying how animals maintain stable sensory-motor responses within dynamic neural circuits and may lead to the development of general principles for injury-tolerant neural architectures.
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Affiliation(s)
| | - Soonyoung Kim
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA
| | - Krishna N. Badhiwala
- Department of Bioengineering, Rice University, 6100 Main Street, Houston, TX 77005, USA
| | - Benjamin W. Avants
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA
| | - Jacob T. Robinson
- Department of Bioengineering, Rice University, 6100 Main Street, Houston, TX 77005, USA
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA
- Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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12
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Abstract
The cytochrome P450 (CYP) superfamily is a diverse and important enzyme family, playing a central role in chemical defense and in synthesis and metabolism of major biological signaling molecules. The CYPomes of four cnidarian genomes (Hydra vulgaris, Acropora digitifera, Aurelia aurita, Nematostella vectensis) were annotated; phylogenetic analyses determined the evolutionary relationships amongst the sequences and with existing metazoan CYPs. 155 functional CYPs were identified and 90 fragments. Genes were from 24 new CYP families and several new subfamilies; genes were in 9 of the 12 established metazoan CYP clans. All species had large expansions of clan 2 diversity, with H. vulgaris having reduced diversity for both clan 3 and mitochondrial clan. We identified potential candidates for xenobiotic metabolism and steroidogenesis. That each genome contained multiple, novel CYP families may reflect the large evolutionary distance within the cnidarians, unique physiology in the cnidarian classes, and/or different ecology of the individual species.
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13
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Klimovich A, Giacomello S, Björklund Å, Faure L, Kaucka M, Giez C, Murillo-Rincon AP, Matt AS, Willoweit-Ohl D, Crupi G, de Anda J, Wong GCL, D'Amato M, Adameyko I, Bosch TCG. Prototypical pacemaker neurons interact with the resident microbiota. Proc Natl Acad Sci U S A 2020; 117:17854-17863. [PMID: 32647059 PMCID: PMC7395494 DOI: 10.1073/pnas.1920469117] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Pacemaker neurons exert control over neuronal circuit function by their intrinsic ability to generate rhythmic bursts of action potential. Recent work has identified rhythmic gut contractions in human, mice, and hydra to be dependent on both neurons and the resident microbiota. However, little is known about the evolutionary origin of these neurons and their interaction with microbes. In this study, we identified and functionally characterized prototypical ANO/SCN/TRPM ion channel-expressing pacemaker cells in the basal metazoan Hydra by using a combination of single-cell transcriptomics, immunochemistry, and functional experiments. Unexpectedly, these prototypical pacemaker neurons express a rich set of immune-related genes mediating their interaction with the microbial environment. Furthermore, functional experiments gave a strong support to a model of the evolutionary emergence of pacemaker cells as neurons using components of innate immunity to interact with the microbial environment and ion channels to generate rhythmic contractions.
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Affiliation(s)
- Alexander Klimovich
- Department of Cell and Developmental Biology, Zoological Institute, University of Kiel, D-24118 Kiel, Germany;
| | - Stefania Giacomello
- Department of Biochemistry and Biophysics, National Infrastructure of Sweden, Science for Life Laboratory, Stockholm University, 17121 Solna, Sweden
- Department of Gene Technology, Science for Life Laboratory, Kungligia Tekniska Högskolan Royal Institute of Technology, 17121 Solna, Sweden
| | - Åsa Björklund
- Department of Cell and Molecular Biology, National Infrastructure of Sweden, Science for Life Laboratory, Uppsala University, 75237 Uppsala, Sweden
| | - Louis Faure
- Department of Molecular Neurosciences, Center for Brain Research, Medical University Vienna, 1090 Vienna, Austria
| | - Marketa Kaucka
- Department of Molecular Neurosciences, Center for Brain Research, Medical University Vienna, 1090 Vienna, Austria
- Department of Physiology and Pharmacology, Karolinska Institutet, 17177 Stockholm, Sweden
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Biology, SH 24306 Plön, Germany
| | - Christoph Giez
- Department of Cell and Developmental Biology, Zoological Institute, University of Kiel, D-24118 Kiel, Germany
| | - Andrea P Murillo-Rincon
- Department of Cell and Developmental Biology, Zoological Institute, University of Kiel, D-24118 Kiel, Germany
| | - Ann-Sophie Matt
- Department of Cell and Developmental Biology, Zoological Institute, University of Kiel, D-24118 Kiel, Germany
| | - Doris Willoweit-Ohl
- Department of Cell and Developmental Biology, Zoological Institute, University of Kiel, D-24118 Kiel, Germany
| | - Gabriele Crupi
- Department of Cell and Developmental Biology, Zoological Institute, University of Kiel, D-24118 Kiel, Germany
| | - Jaime de Anda
- Department of Bioengineering, California NanoSystems Institute, University of California, Los Angeles, CA 90095-1600
- Department of Chemistry and Biochemistry, California NanoSystems Institute, University of California, Los Angeles, CA 90095-1600
| | - Gerard C L Wong
- Department of Bioengineering, California NanoSystems Institute, University of California, Los Angeles, CA 90095-1600
- Department of Chemistry and Biochemistry, California NanoSystems Institute, University of California, Los Angeles, CA 90095-1600
| | - Mauro D'Amato
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
| | - Igor Adameyko
- Department of Molecular Neurosciences, Center for Brain Research, Medical University Vienna, 1090 Vienna, Austria
- Department of Physiology and Pharmacology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Thomas C G Bosch
- Department of Cell and Developmental Biology, Zoological Institute, University of Kiel, D-24118 Kiel, Germany;
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14
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Buzgariu W, Curchod ML, Perruchoud C, Galliot B. Combining BrdU-Labeling to Detection of Neuronal Markers to Monitor Adult Neurogenesis in Hydra. Methods Mol Biol 2020; 2047:3-24. [PMID: 31552646 DOI: 10.1007/978-1-4939-9732-9_1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The nervous system is produced and maintained in adult Hydra through the continuous production of nerve cells and mechanosensory cells (nematocytes or cnidocytes). De novo neurogenesis occurs slowly in intact animals that replace their dying nerve cells, at a faster rate in animals regenerating their head as a complete apical nervous system is built in few days. To dissect the molecular mechanisms that underlie these properties, a precise monitoring of the markers of neurogenesis and nematogenesis is required. Here we describe the conditions for an efficient BrdU-labeling coupled to an immunodetection of neuronal markers, either regulators of neurogenesis, here the homeoprotein prdl-a, or neuropeptides such as RFamide or Hym-355. This method can be performed on whole-mount animals as well as on macerated tissues when cells retain their morphology. Moreover, when antibodies are not available, BrdU-labeling can be combined with the analysis of gene expression by whole-mount in situ hybridization. This co-immunodetection procedure is well adapted to visualize and quantify the dynamics of de novo neurogenesis. Upon continuous BrdU labeling, the repeated measurements of BrdU-labeling indexes in specific cellular populations provide a precise monitoring of nematogenesis as well as neurogenesis, in homeostatic or developmental conditions.
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Affiliation(s)
- Wanda Buzgariu
- Department of Genetics and Evolution, iGE3, Faculty of Sciences, University of Geneva, Geneva, Switzerland
| | - Marie-Laure Curchod
- Department of Genetics and Evolution, iGE3, Faculty of Sciences, University of Geneva, Geneva, Switzerland
| | - Chrystelle Perruchoud
- Department of Genetics and Evolution, iGE3, Faculty of Sciences, University of Geneva, Geneva, Switzerland
| | - Brigitte Galliot
- Department of Genetics and Evolution, iGE3, Faculty of Sciences, University of Geneva, Geneva, Switzerland.
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15
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Goel T, Wang R, Martin S, Lanphear E, Collins EMS. Linalool acts as a fast and reversible anesthetic in Hydra. PLoS One 2019; 14:e0224221. [PMID: 31648269 PMCID: PMC6812832 DOI: 10.1371/journal.pone.0224221] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 10/08/2019] [Indexed: 01/23/2023] Open
Abstract
The ability to make transgenic Hydra lines has allowed for quantitative in vivo studies of Hydra regeneration and physiology. These studies commonly include excision, grafting and transplantation experiments along with high-resolution imaging of live animals, which can be challenging due to the animal’s response to touch and light stimuli. While various anesthetics have been used in Hydra studies, they tend to be toxic over the course of a few hours or their long-term effects on animal health are unknown. Here, we show that the monoterpenoid alcohol linalool is a useful anesthetic for Hydra. Linalool is easy to use, non-toxic, fast acting, and reversible. It has no detectable long-term effects on cell viability or cell proliferation. We demonstrate that the same animal can be immobilized in linalool multiple times at intervals of several hours for repeated imaging over 2–3 days. This uniquely allows for in vivo imaging of dynamic processes such as head regeneration. We directly compare linalool to currently used anesthetics and show its superior performance. Linalool will be a useful tool for tissue manipulation and imaging in Hydra research in both research and teaching contexts.
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Affiliation(s)
- Tapan Goel
- Department of Physics, University of California San Diego, La Jolla, CA, United States of America
- Department of Biology, Swarthmore College, Swarthmore, PA, United States of America
| | - Rui Wang
- Department of Biology, Swarthmore College, Swarthmore, PA, United States of America
- Department of Bioengineering, University of California San Diego, La Jolla, CA, United States of America
| | - Sara Martin
- Department of Biology, Swarthmore College, Swarthmore, PA, United States of America
| | - Elizabeth Lanphear
- Department of Biology, Swarthmore College, Swarthmore, PA, United States of America
| | - Eva-Maria S. Collins
- Department of Physics, University of California San Diego, La Jolla, CA, United States of America
- Department of Biology, Swarthmore College, Swarthmore, PA, United States of America
- * E-mail:
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16
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Traub RD, Whittington MA, Maier N, Schmitz D, Nagy JI. Could electrical coupling contribute to the formation of cell assemblies? Rev Neurosci 2019; 31:121-141. [DOI: 10.1515/revneuro-2019-0059] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 07/07/2019] [Indexed: 12/20/2022]
Abstract
Abstract
Cell assemblies and central pattern generators (CPGs) are related types of neuronal networks: both consist of interacting groups of neurons whose collective activities lead to defined functional outputs. In the case of a cell assembly, the functional output may be interpreted as a representation of something in the world, external or internal; for a CPG, the output ‘drives’ an observable (i.e. motor) behavior. Electrical coupling, via gap junctions, is critical for the development of CPGs, as well as for their actual operation in the adult animal. Electrical coupling is also known to be important in the development of hippocampal and neocortical principal cell networks. We here argue that electrical coupling – in addition to chemical synapses – may therefore contribute to the formation of at least some cell assemblies in adult animals.
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Affiliation(s)
- Roger D. Traub
- AI Foundations, IBM T.J. Watson Research Center , Yorktown Heights, NY 10598 , USA
| | | | - Nikolaus Maier
- Charité-Universitätsmedizin Berlin , Neuroscience Research Center , Charitéplatz 1 , D-10117 Berlin , Germany
| | - Dietmar Schmitz
- Charité-Universitätsmedizin Berlin , Neuroscience Research Center , Charitéplatz 1 , D-10117 Berlin , Germany
| | - James I. Nagy
- Department of Physiology and Pathophysiology , University of Manitoba , Winnipeg R3E OJ9, MB , Canada
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17
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Siebert S, Farrell JA, Cazet JF, Abeykoon Y, Primack AS, Schnitzler CE, Juliano CE. Stem cell differentiation trajectories in Hydra resolved at single-cell resolution. Science 2019; 365:eaav9314. [PMID: 31346039 PMCID: PMC7104783 DOI: 10.1126/science.aav9314] [Citation(s) in RCA: 177] [Impact Index Per Article: 35.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 06/11/2019] [Indexed: 12/31/2022]
Abstract
The adult Hydra polyp continually renews all of its cells using three separate stem cell populations, but the genetic pathways enabling this homeostatic tissue maintenance are not well understood. We sequenced 24,985 Hydra single-cell transcriptomes and identified the molecular signatures of a broad spectrum of cell states, from stem cells to terminally differentiated cells. We constructed differentiation trajectories for each cell lineage and identified gene modules and putative regulators expressed along these trajectories, thus creating a comprehensive molecular map of all developmental lineages in the adult animal. In addition, we built a gene expression map of the Hydra nervous system. Our work constitutes a resource for addressing questions regarding the evolution of metazoan developmental processes and nervous system function.
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Affiliation(s)
- Stefan Siebert
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA.
| | - Jeffrey A Farrell
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Jack F Cazet
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA
| | - Yashodara Abeykoon
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA
| | - Abby S Primack
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA
| | - Christine E Schnitzler
- Whitney Laboratory for Marine Bioscience and Department of Biology, University of Florida, St. Augustine, FL, USA
| | - Celina E Juliano
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA.
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18
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Güiza J, Barría I, Sáez JC, Vega JL. Innexins: Expression, Regulation, and Functions. Front Physiol 2018; 9:1414. [PMID: 30364195 PMCID: PMC6193117 DOI: 10.3389/fphys.2018.01414] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 09/18/2018] [Indexed: 01/02/2023] Open
Abstract
The innexin (Inx) proteins form gap junction channels and non-junctional channels (named hemichannels) in invertebrates. These channels participate in cellular communication playing a relevant role in several physiological processes. Pioneer studies conducted mainly in worms and flies have shown that innexins participate in embryo development and behavior. However, recent studies have elucidated new functions of innexins in Arthropoda, Nematoda, Annelida, and Cnidaria, such as immune response, and apoptosis. This review describes emerging data of possible new roles of innexins and summarizes the data available to date.
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Affiliation(s)
- Juan Güiza
- Laboratorio de Fisiología Experimental, Instituto Antofagasta, Universidad de Antofagasta, Antofagasta, Chile
| | - Iván Barría
- Laboratorio de Fisiología Experimental, Instituto Antofagasta, Universidad de Antofagasta, Antofagasta, Chile
| | - Juan C Sáez
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile.,Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - José L Vega
- Laboratorio de Fisiología Experimental, Instituto Antofagasta, Universidad de Antofagasta, Antofagasta, Chile
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19
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Traub RD, Whittington MA, Gutiérrez R, Draguhn A. Electrical coupling between hippocampal neurons: contrasting roles of principal cell gap junctions and interneuron gap junctions. Cell Tissue Res 2018; 373:671-691. [PMID: 30112572 DOI: 10.1007/s00441-018-2881-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 07/03/2018] [Indexed: 11/28/2022]
Abstract
There is considerable experimental evidence, anatomical and physiological, that gap junctions exist in the hippocampus. Electrical coupling through these gap junctions may be divided into three types: between principal neurons, between interneurons and at mixed chemical (glutamatergic)/electrical synapses. An approach, combining in vitro experimental with modeling techniques, sheds some light on the functional consequences of electrical coupling, for network oscillations and for seizures. Additionally, in vivo experiments, using mouse connexin knockouts, suggest that the presence of electrical coupling is important for optimal performance on selected behavioral tasks; however, the interpretation of such data, in cellular terms, has so far proven difficult. Given that invertebrate central pattern generators so often depend on both chemical and electrical synapses, our hypothesis is that hippocampus-mediated and -influenced behaviors will act likewise. Experiments, likely hard ones, will be required to test this intuition.
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Affiliation(s)
- Roger D Traub
- Department of Physical Sciences, IBM T.J. Watson Research Center, Yorktown Heights, NY, 10598, USA.
| | | | - Rafael Gutiérrez
- Department of Pharmacobiology, Centro de Investigación y de Estudios Avanzados del IPN, Calzada de los Tenorios 235, 14330, Mexico City, Mexico.,Institut für Physiologie und Pathophysiologie, Universität Heidelberg, Im Neuenheimer Feld 326, 69120, Heidelberg, Germany
| | - Andreas Draguhn
- Institut für Physiologie und Pathophysiologie, Universität Heidelberg, Im Neuenheimer Feld 326, 69120, Heidelberg, Germany
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20
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Spontaneous body contractions are modulated by the microbiome of Hydra. Sci Rep 2017; 7:15937. [PMID: 29162937 PMCID: PMC5698334 DOI: 10.1038/s41598-017-16191-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 11/08/2017] [Indexed: 02/08/2023] Open
Abstract
Spontaneous contractile activity, such as gut peristalsis, is ubiquitous in animals and is driven by pacemaker cells. In humans, disruption of the contraction pattern leads to gastrointestinal conditions, which are also associated with gut microbiota dysbiosis. Spontaneous contractile activity is also present in animals lacking gastrointestinal tract. Here we show that spontaneous body contractions in Hydra are modulated by symbiotic bacteria. Germ-free animals display strongly reduced and less regular contraction frequencies. These effects are partially restored by reconstituting the natural microbiota. Moreover, soluble molecule(s) produced by symbiotic bacteria may be involved in contraction frequency modulation. As the absence of bacteria does not impair the contractile ability itself, a microbial effect on the pacemakers seems plausible. Our findings indicate that the influence of bacteria on spontaneous contractile activity is present in the early-branching cnidarian hydra as well as in Bilateria, and thus suggest an evolutionary ancient origin of interaction between bacteria and metazoans, opening a window into investigating the roots of human motility disorders.
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21
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Tran CM, Fu S, Rowe T, Collins EMS. Generation and Long-term Maintenance of Nerve-free Hydra. J Vis Exp 2017. [PMID: 28715393 DOI: 10.3791/56115] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The interstitial cell lineage of Hydra includes multipotent stem cells, and their derivatives: gland cells, nematocytes, germ cells, and nerve cells. The interstitial cells can be eliminated through two consecutive treatments with colchicine, a plant-derived toxin that kills dividing cells, thus erasing the potential for renewal of the differentiated cells that are derived from the interstitial stem cells. This allows for the generation of Hydra that lack nerve cells. A nerve-free polyp cannot open its mouth to feed, egest, or regulate osmotic pressure. Such animals, however, can survive and be cultured indefinitely in the laboratory if regularly force-fed and burped. The lack of nerve cells allows for studies of the role of the nervous system in regulating animal behavior and regeneration. Previously published protocols for nerve-free Hydra maintenance involve outdated techniques such as mouth-pipetting with hand-pulled micropipette tips to feed and clean the Hydra. Here, an improved protocol for maintenance of nerve-free Hydra is introduced. Fine-tipped forceps are used to force open the mouth and insert freshly killed Artemia. Following force-feeding, the body cavity of the animal is flushed with fresh medium using a syringe and hypodermic needle to remove undigested material, referred to here as "burping". This new method of force-feeding and burping nerve-free Hydra through the use of forceps and syringes eliminates the need for mouth-pipetting using hand-pulled micropipette tips. It thus makes the process safer and significantly more time efficient. To ensure that the nerve cells in the hypostome have been eliminated, immunohistochemistry using anti-tyrosine-tubulin is conducted.
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Affiliation(s)
| | - Sharon Fu
- Division of Biological Sciences, UC San Diego
| | | | - Eva-Maria S Collins
- Division of Biological Sciences, UC San Diego; Physics Department, UC San Diego;
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22
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Leclère L, Röttinger E. Diversity of Cnidarian Muscles: Function, Anatomy, Development and Regeneration. Front Cell Dev Biol 2017; 4:157. [PMID: 28168188 PMCID: PMC5253434 DOI: 10.3389/fcell.2016.00157] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 12/30/2016] [Indexed: 12/12/2022] Open
Abstract
The ability to perform muscle contractions is one of the most important and distinctive features of eumetazoans. As the sister group to bilaterians, cnidarians (sea anemones, corals, jellyfish, and hydroids) hold an informative phylogenetic position for understanding muscle evolution. Here, we review current knowledge on muscle function, diversity, development, regeneration and evolution in cnidarians. Cnidarian muscles are involved in various activities, such as feeding, escape, locomotion and defense, in close association with the nervous system. This variety is reflected in the large diversity of muscle organizations found in Cnidaria. Smooth epithelial muscle is thought to be the most common type, and is inferred to be the ancestral muscle type for Cnidaria, while striated muscle fibers and non-epithelial myocytes would have been convergently acquired within Cnidaria. Current knowledge of cnidarian muscle development and its regeneration is limited. While orthologs of myogenic regulatory factors such as MyoD have yet to be found in cnidarian genomes, striated muscle formation potentially involves well-conserved myogenic genes, such as twist and mef2. Although satellite cells have yet to be identified in cnidarians, muscle plasticity (e.g., de- and re-differentiation, fiber repolarization) in a regenerative context and its potential role during regeneration has started to be addressed in a few cnidarian systems. The development of novel tools to study those organisms has created new opportunities to investigate in depth the development and regeneration of cnidarian muscle cells and how they contribute to the regenerative process.
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Affiliation(s)
- Lucas Leclère
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV) Villefranche-sur-mer, France
| | - Eric Röttinger
- Université Côte d'Azur, CNRS, INSERM, Institute for Research on Cancer and Aging (IRCAN) Nice, France
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23
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Tortiglione C, Antognazza MR, Tino A, Bossio C, Marchesano V, Bauduin A, Zangoli M, Morata SV, Lanzani G. Semiconducting polymers are light nanotransducers in eyeless animals. SCIENCE ADVANCES 2017; 3:e1601699. [PMID: 28138549 PMCID: PMC5266477 DOI: 10.1126/sciadv.1601699] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 12/08/2016] [Indexed: 05/17/2023]
Abstract
Current implant technology uses electrical signals at the electrode-neural interface. This rather invasive approach presents important issues in terms of performance, tolerability, and overall safety of the implants. Inducing light sensitivity in living organisms is an alternative method that provides groundbreaking opportunities in neuroscience. Optogenetics is a spectacular demonstration of this, yet is limited by the viral transfection of exogenous genetic material. We propose a nongenetic approach toward light control of biological functions in living animals. We show that nanoparticles based on poly(3-hexylthiophene) can be internalized in eyeless freshwater polyps and are fully biocompatible. Under light, the nanoparticles modify the light response of the animals, at two different levels: (i) they enhance the contraction events of the animal body, and (ii) they change the transcriptional activation of the opsin3-like gene. This suggests the establishment of a seamless and biomimetic interface between the living organism and the polymer nanoparticles that behave as light nanotransducers, coping with or amplifying the function of primitive photoreceptors.
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Affiliation(s)
- Claudia Tortiglione
- Istituto di Scienze Applicate e Sistemi Intelligenti “Eduardo Caianiello,” Consiglio Nazionale delle Ricerche, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
| | - Maria Rosa Antognazza
- Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano, Italy
| | - Angela Tino
- Istituto di Scienze Applicate e Sistemi Intelligenti “Eduardo Caianiello,” Consiglio Nazionale delle Ricerche, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
| | - Caterina Bossio
- Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano, Italy
| | - Valentina Marchesano
- Istituto di Scienze Applicate e Sistemi Intelligenti “Eduardo Caianiello,” Consiglio Nazionale delle Ricerche, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
| | - Antonella Bauduin
- Istituto di Scienze Applicate e Sistemi Intelligenti “Eduardo Caianiello,” Consiglio Nazionale delle Ricerche, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
| | - Mattia Zangoli
- Istituto per la Sintesi Organica e la Fotoreattività, Consiglio Nazionale delle Ricerche, Via P. Gobetti 101, 40129 Bologna, Italy
| | - Susana Vaquero Morata
- Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano, Italy
| | - Guglielmo Lanzani
- Center for Nano Science and Technology @PoliMi, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano, Italy
- Department of Physics, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
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24
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Bosch TCG, Klimovich A, Domazet-Lošo T, Gründer S, Holstein TW, Jékely G, Miller DJ, Murillo-Rincon AP, Rentzsch F, Richards GS, Schröder K, Technau U, Yuste R. Back to the Basics: Cnidarians Start to Fire. Trends Neurosci 2016; 40:92-105. [PMID: 28041633 DOI: 10.1016/j.tins.2016.11.005] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 11/22/2016] [Accepted: 11/23/2016] [Indexed: 12/15/2022]
Abstract
The nervous systems of cnidarians, pre-bilaterian animals that diverged close to the base of the metazoan radiation, are structurally simple and thus have great potential to reveal fundamental principles of neural circuits. Unfortunately, cnidarians have thus far been relatively intractable to electrophysiological and genetic techniques and consequently have been largely passed over by neurobiologists. However, recent advances in molecular and imaging methods are fueling a renaissance of interest in and research into cnidarians nervous systems. Here, we review current knowledge on the nervous systems of cnidarian species and propose that researchers should seize this opportunity and undertake the study of members of this phylum as strategic experimental systems with great basic and translational relevance for neuroscience.
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Affiliation(s)
| | | | - Tomislav Domazet-Lošo
- Ruđer Bošković Institute, Zagreb, Croatia; Catholic University of Croatia, Zagreb, Croatia
| | - Stefan Gründer
- Institute of Physiology, RWTH Aachen University, Germany
| | | | - Gáspár Jékely
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - David J Miller
- ARC Centre of Excellence for Coral Reef Studies, Townsville, Australia
| | | | - Fabian Rentzsch
- Sars International Centre for Marine Molecular Biology, University of Bergen, Norway
| | - Gemma S Richards
- Sars International Centre for Marine Molecular Biology, University of Bergen, Norway; University of Queensland, Brisbane, Australia
| | | | | | - Rafael Yuste
- Neurotechnology Center, Columbia University, New York, NY, USA.
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25
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Wenger Y, Buzgariu W, Galliot B. Loss of neurogenesis in Hydra leads to compensatory regulation of neurogenic and neurotransmission genes in epithelial cells. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150040. [PMID: 26598723 PMCID: PMC4685579 DOI: 10.1098/rstb.2015.0040] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Hydra continuously differentiates a sophisticated nervous system made of mechanosensory cells (nematocytes) and sensory-motor and ganglionic neurons from interstitial stem cells. However, this dynamic adult neurogenesis is dispensable for morphogenesis. Indeed animals depleted of their interstitial stem cells and interstitial progenitors lose their active behaviours but maintain their developmental fitness, and regenerate and bud when force-fed. To characterize the impact of the loss of neurogenesis in Hydra, we first performed transcriptomic profiling at five positions along the body axis. We found neurogenic genes predominantly expressed along the central body column, which contains stem cells and progenitors, and neurotransmission genes predominantly expressed at the extremities, where the nervous system is dense. Next, we performed transcriptomics on animals depleted of their interstitial cells by hydroxyurea, colchicine or heat-shock treatment. By crossing these results with cell-type-specific transcriptomics, we identified epithelial genes up-regulated upon loss of neurogenesis: transcription factors (Dlx, Dlx1, DMBX1/Manacle, Ets1, Gli3, KLF11, LMX1A, ZNF436, Shox1), epitheliopeptides (Arminins, PW peptide), neurosignalling components (CAMK1D, DDCl2, Inx1), ligand-ion channel receptors (CHRNA1, NaC7), G-Protein Coupled Receptors and FMRFRL. Hence epitheliomuscular cells seemingly enhance their sensing ability when neurogenesis is compromised. This unsuspected plasticity might reflect the extended multifunctionality of epithelial-like cells in early eumetazoan evolution.
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Affiliation(s)
- Y Wenger
- Department of Genetics and Evolution, Institute of Genetics and Genomics in Geneva (IGe3), Faculty of Sciences, University of Geneva, 30 quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
| | - W Buzgariu
- Department of Genetics and Evolution, Institute of Genetics and Genomics in Geneva (IGe3), Faculty of Sciences, University of Geneva, 30 quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
| | - B Galliot
- Department of Genetics and Evolution, Institute of Genetics and Genomics in Geneva (IGe3), Faculty of Sciences, University of Geneva, 30 quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
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26
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Moroz LL, Kohn AB. Independent origins of neurons and synapses: insights from ctenophores. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150041. [PMID: 26598724 PMCID: PMC4685580 DOI: 10.1098/rstb.2015.0041] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/18/2015] [Indexed: 12/29/2022] Open
Abstract
There is more than one way to develop neuronal complexity, and animals frequently use different molecular toolkits to achieve similar functional outcomes. Genomics and metabolomics data from basal metazoans suggest that neural signalling evolved independently in ctenophores and cnidarians/bilaterians. This polygenesis hypothesis explains the lack of pan-neuronal and pan-synaptic genes across metazoans, including remarkable examples of lineage-specific evolution of neurogenic and signalling molecules as well as synaptic components. Sponges and placozoans are two lineages without neural and muscular systems. The possibility of secondary loss of neurons and synapses in the Porifera/Placozoa clades is a highly unlikely and less parsimonious scenario. We conclude that acetylcholine, serotonin, histamine, dopamine, octopamine and gamma-aminobutyric acid (GABA) were recruited as transmitters in the neural systems in cnidarian and bilaterian lineages. By contrast, ctenophores independently evolved numerous secretory peptides, indicating extensive adaptations within the clade and suggesting that early neural systems might be peptidergic. Comparative analysis of glutamate signalling also shows numerous lineage-specific innovations, implying the extensive use of this ubiquitous metabolite and intercellular messenger over the course of convergent and parallel evolution of mechanisms of intercellular communication. Therefore: (i) we view a neuron as a functional character but not a genetic character, and (ii) any given neural system cannot be considered as a single character because it is composed of different cell lineages with distinct genealogies, origins and evolutionary histories. Thus, when reconstructing the evolution of nervous systems, we ought to start with the identification of particular cell lineages by establishing distant neural homologies or examples of convergent evolution. In a corollary of the hypothesis of the independent origins of neurons, our analyses suggest that both electrical and chemical synapses evolved more than once.
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Affiliation(s)
- Leonid L Moroz
- The Whitney Laboratory for Marine Bioscience, 9505 Ocean Shore Boulevard, St Augustine, FL 32080, USA Department of Neuroscience and McKnight Brain Institute, University of Florida, Gainesville, FL 32611, USA
| | - Andrea B Kohn
- The Whitney Laboratory for Marine Bioscience, 9505 Ocean Shore Boulevard, St Augustine, FL 32080, USA
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27
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Gründer S, Assmann M. Peptide-gated ion channels and the simple nervous system of Hydra. ACTA ACUST UNITED AC 2015; 218:551-61. [PMID: 25696818 DOI: 10.1242/jeb.111666] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Neurons either use electrical or chemical synapses to communicate with each other. Transmitters at chemical synapses are either small molecules or neuropeptides. After binding to their receptors, transmitters elicit postsynaptic potentials, which can either be fast and transient or slow and longer lasting, depending on the type of receptor. Fast transient potentials are mediated by ionotropic receptors and slow long-lasting potentials by metabotropic receptors. Transmitters and receptors are well studied for animals with a complex nervous system such as vertebrates and insects, but much less is known for animals with a simple nervous system like Cnidaria. As cnidarians arose early in animal evolution, nervous systems might have first evolved within this group and the study of neurotransmission in cnidarians might reveal an ancient mechanism of neuronal communication. The simple nervous system of the cnidarian Hydra extensively uses neuropeptides and, recently, we cloned and functionally characterized an ion channel that is directly activated by neuropeptides of the Hydra nervous system. These results demonstrate the existence of peptide-gated ion channels in Hydra, suggesting they mediate fast transmission in its nervous system. As related channels are also present in the genomes of the cnidarian Nematostella, of placozoans and of ctenophores, it should be considered that the early nervous systems of cnidarians and ctenophores have co-opted neuropeptides for fast transmission at chemical synapses.
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Affiliation(s)
- Stefan Gründer
- Institute of Physiology, RWTH Aachen University, D-52074 Aachen, Germany
| | - Marc Assmann
- Institute of Physiology, RWTH Aachen University, D-52074 Aachen, Germany
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28
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Technau U, Schwaiger M. Recent advances in genomics and transcriptomics of cnidarians. Mar Genomics 2015; 24 Pt 2:131-8. [PMID: 26421490 DOI: 10.1016/j.margen.2015.09.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 09/20/2015] [Accepted: 09/21/2015] [Indexed: 01/05/2023]
Abstract
The advent of the genomic era has provided important and surprising insights into the deducted genetic composition of the common ancestor of cnidarians and bilaterians. This has changed our view of how genomes of metazoans evolve and when crucial gene families arose and diverged in animal evolution. Sequencing of several cnidarian genomes showed that cnidarians share a great part of their gene repertoire as well as genome synteny with vertebrates, with less gene losses in the anthozoan cnidarian lineage than for example in ecdysozoans like Drosophila melanogaster or Caenorhabditis elegans. The Hydra genome on the other hand has evolved more rapidly indicated by more divergent sequences, more cases of gene losses and many taxonomically restricted genes. Cnidarian genomes also contain a rich repertoire of transcription factors, including those that in bilaterian model organisms regulate the development of key bilaterian traits such as mesoderm, nervous system development and bilaterality. The sea anemone Nematostella vectensis, and possibly cnidarians in general, does not only share its complex gene repertoire with bilaterians, but also the regulation of crucial developmental regulatory genes via distal enhancer elements. In addition, epigenetic modifications on DNA and chromatin are shared among eumetazoans. This suggests that most conserved genes present in our genomes today, as well as the mechanisms guiding their expression, evolved before the divergence of cnidarians and bilaterians about 600 Myr ago.
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Affiliation(s)
- Ulrich Technau
- Department of Molecular Evolution and Development, Centre of Organismal Systems Biology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria.
| | - Michaela Schwaiger
- Department of Molecular Evolution and Development, Centre of Organismal Systems Biology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria
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29
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Buzgariu W, Al Haddad S, Tomczyk S, Wenger Y, Galliot B. Multi-functionality and plasticity characterize epithelial cells in Hydra. Tissue Barriers 2015; 3:e1068908. [PMID: 26716072 PMCID: PMC4681288 DOI: 10.1080/21688370.2015.1068908] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 06/23/2015] [Accepted: 06/27/2015] [Indexed: 01/09/2023] Open
Abstract
Epithelial sheets, a synapomorphy of all metazoans but porifers, are present as 2 layers in cnidarians, ectoderm and endoderm, joined at their basal side by an extra-cellular matrix named mesoglea. In the Hydra polyp, epithelial cells of the body column are unipotent stem cells that continuously self-renew and concomitantly express their epitheliomuscular features. These multifunctional contractile cells maintain homeostasis by providing a protective physical barrier, by digesting nutrients, by selecting a stable microbiota, and by rapidly closing wounds. In addition, epithelial cells are highly plastic, supporting the adaptation of Hydra to physiological and environmental changes, such as long starvation periods where survival relies on a highly dynamic autophagy flux. Epithelial cells also play key roles in developmental processes as evidenced by the organizer activity they develop to promote budding and regeneration. We propose here an integrative view of the homeostatic and developmental aspects of epithelial plasticity in Hydra.
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Affiliation(s)
- W Buzgariu
- Department of Genetics and Evolution; Institute of Genetics and Genomics in Geneva (IGe3); Faculty of Sciences; University of Geneva; Geneva, Switzerland
| | - S Al Haddad
- Department of Genetics and Evolution; Institute of Genetics and Genomics in Geneva (IGe3); Faculty of Sciences; University of Geneva; Geneva, Switzerland
| | - S Tomczyk
- Department of Genetics and Evolution; Institute of Genetics and Genomics in Geneva (IGe3); Faculty of Sciences; University of Geneva; Geneva, Switzerland
| | - Y Wenger
- Department of Genetics and Evolution; Institute of Genetics and Genomics in Geneva (IGe3); Faculty of Sciences; University of Geneva; Geneva, Switzerland
| | - B Galliot
- Department of Genetics and Evolution; Institute of Genetics and Genomics in Geneva (IGe3); Faculty of Sciences; University of Geneva; Geneva, Switzerland
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30
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Jékely G, Paps J, Nielsen C. The phylogenetic position of ctenophores and the origin(s) of nervous systems. EvoDevo 2015; 6:1. [PMID: 25905000 PMCID: PMC4406211 DOI: 10.1186/2041-9139-6-1] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 12/17/2014] [Indexed: 12/19/2022] Open
Abstract
Ctenophores have traditionally been treated as eumetazoans, but some recent whole genome studies have revived the idea that they are, rather, the sister group to all other metazoans. This deep branching position implies either that nervous systems have evolved twice, in Ctenophora and in Eumetazoa, or that an ancestral metazoan nervous system has been lost in sponges and placozoans. We caution, however, that phylogenetic-tree construction artifacts may have placed ctenophores too deep in the metazoan tree. We discuss nervous system origins under these alternative phylogenies and in light of comparative data of ctenophore and eumetazoan nervous systems. We argue that characters like neuropeptide signaling, ciliary photoreceptors, gap junctions and presynaptic molecules are consistent with a shared ancestry of nervous systems. However, if ctenophores are the sister group to all other metazoans, this ancestral nervous system was likely very simple. Further studies are needed to resolve the deep phylogeny of metazoans and to have a better understanding of the early steps of nervous system evolution.
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Affiliation(s)
- Gáspár Jékely
- Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany
| | - Jordi Paps
- Department of Zoology, University of Oxford, South Parks Rd, Oxford, OX13PS UK
| | - Claus Nielsen
- The Natural History Museum of Denmark, University of Copenhagen, Universitetsparken 15, DK-2100 Copenhagen, Denmark
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