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Mohajer F, Khoradmehr A, Riazalhosseini B, Zendehboudi T, Nabipour I, Baghban N. In vitro detection of marine invertebrate stem cells: utilizing molecular and cellular biology techniques and exploring markers. Front Cell Dev Biol 2024; 12:1440091. [PMID: 39239558 PMCID: PMC11374967 DOI: 10.3389/fcell.2024.1440091] [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: 05/28/2024] [Accepted: 08/07/2024] [Indexed: 09/07/2024] Open
Abstract
Marine invertebrate stem cells (MISCs) represent a distinct category of pluripotent and totipotent cells with remarkable abilities for self-renewal and differentiation into multiple germ layers, akin to their vertebrate counterparts. These unique cells persist throughout an organism's adult life and have been observed in various adult marine invertebrate phyla. MISCs play crucial roles in numerous biological processes, including developmental biology phenomena specific to marine invertebrates, such as senescence, delayed senescence, whole-body regeneration, and asexual reproduction. Furthermore, they serve as valuable models for studying stem cell biology. Despite their significance, information about MISCs remains scarce and scattered in the scientific literature. In this review, we have carefully collected and summarized valuable information about MISC detection by perusing the articles that study and detect MISCs in various marine invertebrate organisms. The review begins by defining MISCs and highlighting their unique features compared to vertebrates. It then discusses the common markers for MISC detection and in vitro techniques employed in invertebrate and vertebrates investigation. This comprehensive review provides researchers and scientists with a cohesive and succinct overview of MISC characteristics, detection methods, and associated biological phenomena in marine invertebrate organisms. We aim to offer a valuable resource to researchers and scientists interested in marine invertebrate stem cells, fostering a better understanding of their broader implications in biology. With ongoing advancements in scientific techniques and the continued exploration of marine invertebrate species, we anticipate that further discoveries will expand our knowledge of MISCs and their broader implications in biology.
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Affiliation(s)
- Fatemeh Mohajer
- Student Research and Technology Committee, Bushehr University of Medical Sciences, Bushehr, Iran
| | - Arezoo Khoradmehr
- The Persian Gulf Marine Biotechnology Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr, Iran
| | - Behnaz Riazalhosseini
- The Pharmacogenomics Laboratory, Department of Pharmacology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Tuba Zendehboudi
- Student Research and Technology Committee, Bushehr University of Medical Sciences, Bushehr, Iran
| | - Iraj Nabipour
- The Persian Gulf Marine Biotechnology Research Center, The Persian Gulf Biomedical Sciences Research Institute, Bushehr University of Medical Sciences, Bushehr, Iran
| | - Neda Baghban
- Food Control Laboratory, Food and Drug Deputy, Bushehr University of Medical Sciences, Bushehr, Iran
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Tournière O, Busengdal H, Gahan JM, Rentzsch F. Fluorescence In Situ Hybridization as a Tool for Studying the Specification and Differentiation of Cell Types in Nematostella vectensis. Methods Mol Biol 2024; 2784:59-75. [PMID: 38502478 DOI: 10.1007/978-1-0716-3766-1_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: 03/21/2024]
Abstract
The sea anemone Nematostella vectensis is a genetically tractable cnidarian species that has become a model organism for studying the evolution of developmental processes and genome regulation, resilience to fluctuations in environmental conditions, and the response to pollutants. Gene expression analyses are central to many of these studies, and in situ hybridization has been an important method for obtaining spatial information, in particular during embryonic development. Like other cnidarians, Nematostella embryos are of comparably low morphological complexity, but they possess many cell types that are dispersed throughout the tissue and originate from broad and overlapping areas. These features have made two-color fluorescence in situ hybridization an important method to determine potential co-expression of genes and to generate hypotheses for their functions in cell fate specification. We here share protocols for single and double fluorescence in situ hybridization in Nematostella and for the combination of fluorescence in situ hybridization and immunofluorescence.
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Affiliation(s)
- Océane Tournière
- Michael Sars Centre, University of Bergen, Bergen, Norway
- Institut de Biologie Valrose, Université Côte d'Azur, CNRS, INSERM, Nice, France
| | | | - James M Gahan
- Michael Sars Centre, University of Bergen, Bergen, Norway
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Fabian Rentzsch
- Department of Biological Sciences, University of Bergen, Bergen, Norway.
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Fujita S, Takahashi M, Kumano G, Kuranaga E, Miura M, Nakajima YI. Distinct stem-like cell populations facilitate functional regeneration of the Cladonema medusa tentacle. PLoS Biol 2023; 21:e3002435. [PMID: 38127832 PMCID: PMC10734932 DOI: 10.1371/journal.pbio.3002435] [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: 09/04/2023] [Accepted: 11/16/2023] [Indexed: 12/23/2023] Open
Abstract
Blastema formation is a crucial process that provides a cellular source for regenerating tissues and organs. While bilaterians have diversified blastema formation methods, its mechanisms in non-bilaterians remain poorly understood. Cnidarian jellyfish, or medusae, represent early-branching metazoans that exhibit complex morphology and possess defined appendage structures highlighted by tentacles with stinging cells (nematocytes). Here, we investigate the mechanisms of tentacle regeneration, using the hydrozoan jellyfish Cladonema pacificum. We show that proliferative cells accumulate at the tentacle amputation site and form a blastema composed of cells with stem cell morphology. Nucleoside pulse-chase experiments indicate that most repair-specific proliferative cells (RSPCs) in the blastema are distinct from resident stem cells. We further demonstrate that resident stem cells control nematogenesis and tentacle elongation during both homeostasis and regeneration as homeostatic stem cells, while RSPCs preferentially differentiate into epithelial cells in the newly formed tentacle, analogous to lineage-restricted stem/progenitor cells observed in salamander limbs. Taken together, our findings propose a regeneration mechanism that utilizes both resident homeostatic stem cells (RHSCs) and RSPCs, which in conjunction efficiently enable functional appendage regeneration, and provide novel insight into the diversification of blastema formation across animal evolution.
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Affiliation(s)
- Sosuke Fujita
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Mako Takahashi
- Asamushi Research Center for Marine Biology, Graduate School of Life Sciences, Tohoku University, Aomori, Japan
| | - Gaku Kumano
- Asamushi Research Center for Marine Biology, Graduate School of Life Sciences, Tohoku University, Aomori, Japan
| | - Erina Kuranaga
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan
| | - Masayuki Miura
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Yu-ichiro Nakajima
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan
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Puzakov MV, Puzakova LV, Shi S, Cheresiz SV. maT and mosquito transposons in cnidarians: evolutionary history and intraspecific differences. Funct Integr Genomics 2023; 23:244. [PMID: 37454326 DOI: 10.1007/s10142-023-01175-0] [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: 05/09/2023] [Revised: 07/07/2023] [Accepted: 07/10/2023] [Indexed: 07/18/2023]
Abstract
Transposable elements exert a significant effect on the size and structure of eukaryotic genomes. Tc1/mariner superfamily elements represent the widely distributed and highly variable group of DNA transposons. Tc1/mariner elements include TLE/DD34-38E, MLE/DD34D, maT/DD37D, Visitor/DD41D, Guest/DD39D, mosquito/DD37E, and L18/DD37E families, all of which are well or less scarcely studied. However, more detailed research into the patterns of prevalence and diversity of Tc1/mariner transposons enables one to better understand the coevolution of the TEs and the eukaryotic genomes. We performed a detailed analysis of the maT/DD37D family in Cnidaria. The study of 77 genomic assemblies demonstrated that maT transposons are found in a limited number of cnidarian species belonging to classes Cubozoa (1 species), Hydrozoa (3 species) и Scyphozoa (5 species) only. The identified TEs were classified into 5 clades, with the representatives from Pelagiidae (class Scyphozoa) forming a separate clade of maT transposons, which has never been described previously. The potentially functional copies of maT transposons were identified in the hydrae. The phylogenetic analysis and the studies of distribution among the taxons and the evolutionary dynamics of the elements suggest that maT transposons of the cnidarians are the descendants of several independent invasion events occurring at different periods of time. We also established that the TEs of mosquito/DD37E family are found in Hydridae (class Hydrozoa) only. A comparison of maT and mosquito prevalence in two genomic assemblies of Hydra viridissima revealed obvious differences, thus demonstrating that each individual organism might carry a unique mobilome pattern. The results of the presented research make us better understand the diversity and evolution of Tc1/mariner transposons and their effect on the eukaryotic genomes.
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Affiliation(s)
- Mikhail V Puzakov
- A.O. Kovalevsky Institute of Biology of the Southern Seas of RAS, Lenninsky Eve., 38, Moscow, Russia, 119991.
| | - Lyudmila V Puzakova
- A.O. Kovalevsky Institute of Biology of the Southern Seas of RAS, Lenninsky Eve., 38, Moscow, Russia, 119991
| | - Shasha Shi
- College of Animal Science & Technology, Yangzhou University, Yangzhou, 225009, Jiangsu, China
| | - Sergey V Cheresiz
- V. Zelman Institute for Medicine and Psychology, Novosibirsk State University, Pirogova st., 1, Novosibirsk, Russia, 630090
- State Scientific Research Institute of Physiology and Basic Medicine, P.O. Box 237, Novosibirsk, Russia, 630117
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Holstein TW. The Hydra stem cell system - Revisited. Cells Dev 2023; 174:203846. [PMID: 37121433 DOI: 10.1016/j.cdev.2023.203846] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 04/12/2023] [Accepted: 04/25/2023] [Indexed: 05/02/2023]
Abstract
Cnidarians are >600 million years old and are considered the sister group of Bilateria based on numerous molecular phylogenetic studies. Apart from Hydra, the genomes of all major clades of Cnidaria have been uncovered (e.g. Aurelia, Clytia, Nematostella and Acropora) and they reveal a remarkable completeness of the metazoan genomic toolbox. Of particular interest is Hydra, a model system of aging research, regenerative biology, and stem cell biology. With the knowledge gained from scRNA research, it is now possible to characterize the expression profiles of all cell types with great precision. In functional studies, our picture of the Hydra stem cell biology has changed, and we are in the process of obtaining a clear picture of the homeostasis and properties of the different stem cell populations. Even though Hydra is often compared to plant systems, the new data on germline and regeneration, but also on the dynamics and plasticity of the nervous system, show that Hydra with its simple body plan represents in a nutshell the prototype of an animal with stem cell lineages, whose properties correspond in many ways to Bilateria. This review provides an overview of the four stem cell lineages, the two epithelial lineages that constitute the ectoderm and the endoderm, as well as the multipotent somatic interstitial lineage (MPSC) and the germline stem cell lineage (GSC), also known as the interstitial cells of Hydra.
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Affiliation(s)
- Thomas W Holstein
- Heidelberg University, Centre for Organismal Studies (COS), Molecular Evolution and Genomics, Im Neuenheimer Feld 230, D-69120 Heidelberg, Germany.
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6
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Tursch A, Holstein TW. From injury to patterning—MAPKs and Wnt signaling in Hydra. Curr Top Dev Biol 2023; 153:381-417. [PMID: 36967201 DOI: 10.1016/bs.ctdb.2023.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Hydra has a regenerative capacity that is not limited to individual organs but encompasses the entire body. Various global and integrative genome, transcriptome and proteome approaches have shown that many of the signaling pathways and transcription factors present in vertebrates are already present in Cnidaria, the sister group of Bilateria, and are also activated in regeneration. It is now possible to investigate one of the central questions of regeneration biology, i.e., how does the patterning system become activated by the injury signals that initiate regeneration. This review will present the current data obtained in Hydra and draw parallels with regeneration in Bilateria. Important findings of this global analysis are that the Wnt signaling pathway has a dual function in the regeneration process. In the early phase Wnt is activated generically and in a second phase of pattern formation it is activated in a position specific manner. Thus, Wnt signaling is part of the generic injury response, in which mitogen-activated protein kinases (MAPKs) are initially activated via calcium and reactive oxygen species (ROS). The MAPKs, p38, c-Jun N-terminal kinases (JNKs) and extracellular signal-regulated kinases (ERK) are essential for Wnt activation in Hydra head and foot regenerates. Furthermore, the antagonism between the ERK signaling pathway and stress-induced MAPKs results in a balanced induction of apoptosis and mitosis. However, the early Wnt genes are activated by MAPK signaling rather than apoptosis. Early Wnt gene activity is differentially integrated with a stable, β-Catenin-based gradient along the primary body axis maintaining axial polarity and activating further Wnts in the regenerating head. Because MAPKs and Wnts are highly evolutionarily conserved, we hypothesize that this mechanism is also present in vertebrates but may be activated to different degrees at the level of early Wnt gene integration.
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Tournière O, Gahan JM, Busengdal H, Bartsch N, Rentzsch F. Insm1-expressing neurons and secretory cells develop from a common pool of progenitors in the sea anemone Nematostella vectensis. SCIENCE ADVANCES 2022; 8:eabi7109. [PMID: 35442742 PMCID: PMC9020782 DOI: 10.1126/sciadv.abi7109] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 03/02/2022] [Indexed: 06/01/2023]
Abstract
Neurons are highly specialized cells present in nearly all animals, but their evolutionary origin and relationship to other cell types are not well understood. We use here the sea anemone Nematostella vectensis as a model system for early-branching animals to gain fresh insights into the evolutionary history of neurons. We generated a transgenic reporter line to show that the transcription factor NvInsm1 is expressed in postmitotic cells that give rise to various types of neurons and secretory cells. Expression analyses, double transgenics, and gene knockdown experiments show that the NvInsm1-expressing neurons and secretory cells derive from a common pool of NvSoxB(2)-positive progenitor cells. These findings, together with the requirement for Insm1 for the development of neurons and endocrine cells in vertebrates, support a close evolutionary relationship of neurons and secretory cells.
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Affiliation(s)
- Océane Tournière
- Sars International Centre for Marine Molecular Biology, University of Bergen, 5006 Bergen, Norway
| | - James M. Gahan
- Sars International Centre for Marine Molecular Biology, University of Bergen, 5006 Bergen, Norway
| | - Henriette Busengdal
- Sars International Centre for Marine Molecular Biology, University of Bergen, 5006 Bergen, Norway
| | - Natascha Bartsch
- Sars International Centre for Marine Molecular Biology, University of Bergen, 5006 Bergen, Norway
- Department of Biological Sciences, University of Bergen, 5006 Bergen, Norway
| | - Fabian Rentzsch
- Sars International Centre for Marine Molecular Biology, University of Bergen, 5006 Bergen, Norway
- Department of Biological Sciences, University of Bergen, 5006 Bergen, Norway
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8
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Holstein TW. The role of cnidarian developmental biology in unraveling axis formation and Wnt signaling. Dev Biol 2022; 487:74-98. [DOI: 10.1016/j.ydbio.2022.04.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 04/07/2022] [Accepted: 04/11/2022] [Indexed: 12/12/2022]
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9
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Rinkevich B, Ballarin L, Martinez P, Somorjai I, Ben‐Hamo O, Borisenko I, Berezikov E, Ereskovsky A, Gazave E, Khnykin D, Manni L, Petukhova O, Rosner A, Röttinger E, Spagnuolo A, Sugni M, Tiozzo S, Hobmayer B. A pan-metazoan concept for adult stem cells: the wobbling Penrose landscape. Biol Rev Camb Philos Soc 2022; 97:299-325. [PMID: 34617397 PMCID: PMC9292022 DOI: 10.1111/brv.12801] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 09/20/2021] [Accepted: 09/22/2021] [Indexed: 12/17/2022]
Abstract
Adult stem cells (ASCs) in vertebrates and model invertebrates (e.g. Drosophila melanogaster) are typically long-lived, lineage-restricted, clonogenic and quiescent cells with somatic descendants and tissue/organ-restricted activities. Such ASCs are mostly rare, morphologically undifferentiated, and undergo asymmetric cell division. Characterized by 'stemness' gene expression, they can regulate tissue/organ homeostasis, repair and regeneration. By contrast, analysis of other animal phyla shows that ASCs emerge at different life stages, present both differentiated and undifferentiated phenotypes, and may possess amoeboid movement. Usually pluri/totipotent, they may express germ-cell markers, but often lack germ-line sequestering, and typically do not reside in discrete niches. ASCs may constitute up to 40% of animal cells, and participate in a range of biological phenomena, from whole-body regeneration, dormancy, and agametic asexual reproduction, to indeterminate growth. They are considered legitimate units of selection. Conceptualizing this divergence, we present an alternative stemness metaphor to the Waddington landscape: the 'wobbling Penrose' landscape. Here, totipotent ASCs adopt ascending/descending courses of an 'Escherian stairwell', in a lifelong totipotency pathway. ASCs may also travel along lower stemness echelons to reach fully differentiated states. However, from any starting state, cells can change their stemness status, underscoring their dynamic cellular potencies. Thus, vertebrate ASCs may reflect just one metazoan ASC archetype.
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Affiliation(s)
- Baruch Rinkevich
- Israel Oceanographic & Limnological ResearchNational Institute of OceanographyPOB 9753, Tel ShikmonaHaifa3109701Israel
| | - Loriano Ballarin
- Department of BiologyUniversity of PadovaVia Ugo Bassi 58/BPadova35121Italy
| | - Pedro Martinez
- Departament de Genètica, Microbiologia i EstadísticaUniversitat de BarcelonaAv. Diagonal 643Barcelona08028Spain
- Institut Català de Recerca i Estudis Avançats (ICREA)Passeig Lluís Companys 23Barcelona08010Spain
| | - Ildiko Somorjai
- School of BiologyUniversity of St AndrewsSt Andrews, FifeKY16 9ST, ScotlandUK
| | - Oshrat Ben‐Hamo
- Israel Oceanographic & Limnological ResearchNational Institute of OceanographyPOB 9753, Tel ShikmonaHaifa3109701Israel
| | - Ilya Borisenko
- Department of Embryology, Faculty of BiologySaint‐Petersburg State UniversityUniversity Embankment, 7/9Saint‐Petersburg199034Russia
| | - Eugene Berezikov
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center GroningenAntonius Deusinglaan 1Groningen9713 AVThe Netherlands
| | - Alexander Ereskovsky
- Department of Embryology, Faculty of BiologySaint‐Petersburg State UniversityUniversity Embankment, 7/9Saint‐Petersburg199034Russia
- Institut Méditerranéen de Biodiversité et d'Ecologie marine et continentale (IMBE), Aix Marseille University, CNRS, IRD, Avignon UniversityJardin du Pharo, 58 Boulevard Charles LivonMarseille13007France
- Koltzov Institute of Developmental Biology of Russian Academy of SciencesUlitsa Vavilova, 26Moscow119334Russia
| | - Eve Gazave
- Université de Paris, CNRS, Institut Jacques MonodParisF‐75006France
| | - Denis Khnykin
- Department of PathologyOslo University HospitalBygg 19, Gaustad Sykehus, Sognsvannsveien 21Oslo0188Norway
| | - Lucia Manni
- Department of BiologyUniversity of PadovaVia Ugo Bassi 58/BPadova35121Italy
| | - Olga Petukhova
- Collection of Vertebrate Cell CulturesInstitute of Cytology, Russian Academy of SciencesTikhoretsky Ave. 4St. Petersburg194064Russia
| | - Amalia Rosner
- Israel Oceanographic & Limnological ResearchNational Institute of OceanographyPOB 9753, Tel ShikmonaHaifa3109701Israel
| | - Eric Röttinger
- Université Côte d'Azur, CNRS, INSERM, Institute for Research on Cancer and Aging, Nice (IRCAN)Nice06107France
- Université Côte d'Azur, Federative Research Institute – Marine Resources (IFR MARRES)28 Avenue de ValroseNice06103France
| | - Antonietta Spagnuolo
- Department of Biology and Evolution of Marine OrganismsStazione Zoologica Anton DohrnVilla ComunaleNaples80121Italy
| | - Michela Sugni
- Department of Environmental Science and Policy (ESP)Università degli Studi di MilanoVia Celoria 26Milan20133Italy
| | - Stefano Tiozzo
- Sorbonne Université, CNRS, Laboratoire de Biologie du Développement de Villefranche‐sur‐mer (LBDV)06234 Villefranche‐sur‐MerVillefranche sur MerCedexFrance
| | - Bert Hobmayer
- Institute of Zoology and Center for Molecular Biosciences, University of InnsbruckTechnikerstrInnsbruck256020Austria
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Plessier F, Schmutz S, Novault S, Marlow H. Single-Cell Transcriptomic Analysis in the Regenerating Cnidarian Nematostella vectensis. Methods Mol Biol 2022; 2450:565-581. [PMID: 35359329 PMCID: PMC9761532 DOI: 10.1007/978-1-0716-2172-1_30] [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: 06/14/2023]
Abstract
Cnidarians have historically served as excellent laboratory models for regenerative development given their capacity to regrow large portions of the adult organism. This capacity is notably absent or poorly developed in the powerful genetic laboratory models Drosophila, C. elegans, and mouse. Increasingly, development of genetic and genomic resources and the application of next-generation sequencing-based techniques in cnidarian systems has further expanded the potential of cnidarian regenerative models. Here, we present a workflow for the characterization of the regenerative response in the sea anemone Nematostella vectensis utilizing fluorescence-activated cell sorting and a plate-based single-cell RNA-sequencing pipeline. This approach can characterize the transcriptional response during regeneration in distinct populations of cells, thus providing a quantitative view of a whole organism process at cellular resolution.
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Affiliation(s)
- Flora Plessier
- Committee on Development, Regeneration and Stem Cell Biology, The University of Chicago, Chicago, IL, USA
- École Doctorale "Complexité du Vivant" ED515, Sorbonne Université, Paris, France
- Département de Biologie, École Normale Supérieure de Lyon, Lyon, France
- (Epi)genomics of Animal Development, Department of Developmental and Stem Cell Biology, Institut Pasteur, Paris, France
- Department of Organismal Biology and Anatomy, The University of Chicago, Chicago, IL, USA
| | - Sandrine Schmutz
- Cytometry and Biomarkers, Center for Technological Resources and Research, Institut Pasteur, Paris, France
| | - Sophie Novault
- Cytometry and Biomarkers, Center for Technological Resources and Research, Institut Pasteur, Paris, France
| | - Heather Marlow
- (Epi)genomics of Animal Development, Department of Developmental and Stem Cell Biology, Institut Pasteur, Paris, France.
- Department of Organismal Biology and Anatomy, The University of Chicago, Chicago, IL, USA.
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Parisi MG, Grimaldi A, Baranzini N, La Corte C, Dara M, Parrinello D, Cammarata M. Mesoglea Extracellular Matrix Reorganization during Regenerative Process in Anemonia viridis (Forskål, 1775). Int J Mol Sci 2021; 22:5971. [PMID: 34073146 PMCID: PMC8198993 DOI: 10.3390/ijms22115971] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/28/2021] [Accepted: 05/29/2021] [Indexed: 12/23/2022] Open
Abstract
Given the anatomical simplicity and the extraordinary ability to regenerate missing parts of the body, Cnidaria represent an excellent model for the study of the mechanisms regulating regenerative processes. They possess the mesoglea, an amorphous and practically acellular extracellular matrix (ECM) located between the epidermis and the gastrodermis of the body and tentacles and consists of the same molecules present in the ECM of vertebrates, such as collagen, laminin, fibronectin and proteoglycans. This feature makes cnidarians anthozoans valid models for understanding the ECM role during regenerative processes. Indeed, it is now clear that its role in animal tissues is not just tissue support, but instead plays a key role during wound healing and tissue regeneration. This study aims to explore regenerative events after tentacle amputation in the Mediterranean anemone Anemonia viridis, focusing in detail on the reorganization of the ECM mesoglea. In this context, both enzymatic, biometric and histological experiments reveal how this gelatinous connective layer plays a fundamental role in the correct restoration of the original structures by modifying its consistency and stiffness. Indeed, through the deposition of collagen I, it might act as a scaffold and as a guide for the reconstruction of missing tissues and parts, such as amputated tentacles.
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Affiliation(s)
- Maria Giovanna Parisi
- Marine Immunobiology Laboratory, Department of Earth and Sea Sciences, University of Palermo, 90123 Palermo, Italy; (C.L.C.); (M.D.); (D.P.); (M.C.)
| | - Annalisa Grimaldi
- Department of Biotechnology and Life Science, University of Insubria, Via Dunant 3, 21100 Varese, Italy;
| | - Nicolò Baranzini
- Department of Biotechnology and Life Science, University of Insubria, Via Dunant 3, 21100 Varese, Italy;
| | - Claudia La Corte
- Marine Immunobiology Laboratory, Department of Earth and Sea Sciences, University of Palermo, 90123 Palermo, Italy; (C.L.C.); (M.D.); (D.P.); (M.C.)
| | - Mariano Dara
- Marine Immunobiology Laboratory, Department of Earth and Sea Sciences, University of Palermo, 90123 Palermo, Italy; (C.L.C.); (M.D.); (D.P.); (M.C.)
| | - Daniela Parrinello
- Marine Immunobiology Laboratory, Department of Earth and Sea Sciences, University of Palermo, 90123 Palermo, Italy; (C.L.C.); (M.D.); (D.P.); (M.C.)
| | - Matteo Cammarata
- Marine Immunobiology Laboratory, Department of Earth and Sea Sciences, University of Palermo, 90123 Palermo, Italy; (C.L.C.); (M.D.); (D.P.); (M.C.)
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12
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Krasovec G, Pottin K, Rosello M, Quéinnec É, Chambon JP. Apoptosis and cell proliferation during metamorphosis of the planula larva of Clytia hemisphaerica (Hydrozoa, Cnidaria). Dev Dyn 2021; 250:1739-1758. [PMID: 34036636 DOI: 10.1002/dvdy.376] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 05/19/2021] [Accepted: 05/20/2021] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Metamorphosis in marine species is characterized by profound changes at the ecophysiological, morphological, and cellular levels. The cnidarian Clytia hemisphaerica exhibits a triphasic life cycle that includes a planula larva, a colonial polyp, and a sexually reproductive medusa. Most studies so far have focused on the embryogenesis of this species, whereas its metamorphosis has been only partially studied. RESULTS We investigated the main morphological changes of the planula larva of Clytia during the metamorphosis, and the associated cell proliferation and apoptosis. Based on our observations of planulae at successive times following artificial metamorphosis induction using GLWamide, we subdivided the Clytia's metamorphosis into a series of eight morphological stages occurring during a pre-settlement phase (from metamorphosis induction to planula ready for settlement) and the post-settlement phase (from planula settlement to primary polyp). Drastic morphological changes prior to definitive adhesion to the substrate were accompanied by specific patterns of stem-cell proliferation as well as apoptosis in both ectoderm and endoderm. Further waves of apoptosis occurring once the larva has settled were associated with morphogenesis of the primary polyp. CONCLUSION Clytia larval metamorphosis is characterized by distinct patterns of apoptosis and cell proliferation during the pre-settlement phase and the settled planula-to-polyp transformation.
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Affiliation(s)
- Gabriel Krasovec
- Sorbonne Université, CNRS, Institut de Biologie Paris Seine, IBPS, Evolution Paris Seine, Paris, France
| | - Karen Pottin
- Sorbonne Université, CNRS, Institut de Biologie Paris Seine, IBPS, Evolution Paris Seine, Paris, France
| | - Marion Rosello
- Sorbonne Université, CNRS, Institut de Biologie Paris Seine, IBPS, Evolution Paris Seine, Paris, France
| | - Éric Quéinnec
- Sorbonne Université, CNRS, Institut de Biologie Paris Seine, IBPS, Evolution Paris Seine, Paris, France.,Institut de Systématique, Evolution, Biodiversité, Sorbonne Université, Muséum National d'histoire Naturelle, Paris Cedex, France
| | - Jean-Philippe Chambon
- Sorbonne Université, CNRS, Institut de Biologie Paris Seine, IBPS, Evolution Paris Seine, Paris, France.,Centre de Recherche de Biologie Cellulaire de Montpellier (CRBM), Montpellier University, CNRS, Montpellier, France
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13
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Barve A, Galande AA, Ghaskadbi SS, Ghaskadbi S. DNA Repair Repertoire of the Enigmatic Hydra. Front Genet 2021; 12:670695. [PMID: 33995496 PMCID: PMC8117345 DOI: 10.3389/fgene.2021.670695] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 04/12/2021] [Indexed: 12/20/2022] Open
Abstract
Since its discovery by Abraham Trembley in 1744, hydra has been a popular research organism. Features like spectacular regeneration capacity, peculiar tissue dynamics, continuous pattern formation, unique evolutionary position, and an apparent lack of organismal senescence make hydra an intriguing animal to study. While a large body of work has taken place, particularly in the domain of evolutionary developmental biology of hydra, in recent years, the focus has shifted to molecular mechanisms underlying various phenomena. DNA repair is a fundamental cellular process that helps to maintain integrity of the genome through multiple repair pathways found across taxa, from archaea to higher animals. DNA repair capacity and senescence are known to be closely associated, with mutations in several repair pathways leading to premature ageing phenotypes. Analysis of DNA repair in an animal like hydra could offer clues into several aspects including hydra’s purported lack of organismal ageing, evolution of DNA repair systems in metazoa, and alternative functions of repair proteins. We review here the different DNA repair mechanisms known so far in hydra. Hydra genes from various DNA repair pathways show very high similarity with their vertebrate orthologues, indicating conservation at the level of sequence, structure, and function. Notably, most hydra repair genes are more similar to deuterostome counterparts than to common model invertebrates, hinting at ancient evolutionary origins of repair pathways and further highlighting the relevance of organisms like hydra as model systems. It appears that hydra has the full repertoire of DNA repair pathways, which are employed in stress as well as normal physiological conditions and may have a link with its observed lack of senescence. The close correspondence of hydra repair genes with higher vertebrates further demonstrates the need for deeper studies of various repair components, their interconnections, and functions in this early metazoan.
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Affiliation(s)
- Apurva Barve
- Developmental Biology Group, MACS-Agharkar Research Institute, Pune, India.,Centre of Excellence in Science and Mathematics Education, Indian Institute of Science Education and Research (IISER), Pune, India
| | - Alisha A Galande
- Developmental Biology Group, MACS-Agharkar Research Institute, Pune, India
| | - Saroj S Ghaskadbi
- Department of Zoology, Savitribai Phule Pune University, Pune, India
| | - Surendra Ghaskadbi
- Developmental Biology Group, MACS-Agharkar Research Institute, Pune, India
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14
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Schenkelaars Q, Perez-Cortes D, Perruchoud C, Galliot B. The polymorphism of Hydra microsatellite sequences provides strain-specific signatures. PLoS One 2020; 15:e0230547. [PMID: 32986740 PMCID: PMC7521734 DOI: 10.1371/journal.pone.0230547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Accepted: 09/04/2020] [Indexed: 11/18/2022] Open
Abstract
Hydra are freshwater polyps widely studied for their amazing regenerative capacity, adult stem cell populations, low senescence and value as ecotoxicological marker. Many wild-type strains of H. vulgaris have been collected worldwide and maintained effectively under laboratory conditions by asexual reproduction, while stable transgenic lines have been continuously produced since 2006. Efforts are now needed to ensure the genetic characterization of all these strains, which despite similar morphologies, show significant variability in their response to gene expression silencing procedures, pharmacological treatments or environmental conditions. Here, we established a rapid and reliable procedure at the single polyp level to produce via PCR amplification of three distinct microsatellite sequences molecular signatures that distinguish between Hydra strains and species. The TG-rich region of an uncharacterized gene (ms-c25145) helps to distinguish between Eurasian H. vulgaris-Pallas strains (Hm-105, Basel1, Basel2 and reg-16), between Eurasian and North American H. vulgaris strains (H. carnea, AEP), and between the H. vulgaris and H. oligactis species. The AT-rich microsatellite sequences located in the AIP gene (Aryl Hydrocarbon Receptor Interaction Protein, ms-AIP) also differ between Eurasian and North American H. vulgaris strains. Finally, the AT-rich microsatellite located in the Myb-Like cyclin D-binding transcription factor1 gene (ms-DMTF1) gene helps to distinguish certain transgenic AEP lines. This study shows that the analysis of microsatellite sequences, which is capable of tracing genomic variations between closely related lineages of Hydra, provides a sensitive and robust tool for characterizing the Hydra strains.
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Affiliation(s)
- Quentin Schenkelaars
- Department of Genetics and Evolution, Institute of Genetics and Genomics in Geneva (iGE3), University of Geneva, Geneva, Switzerland
| | - Diego Perez-Cortes
- Department of Genetics and Evolution, Institute of Genetics and Genomics in Geneva (iGE3), University of Geneva, Geneva, Switzerland
| | - Chrystelle Perruchoud
- Department of Genetics and Evolution, Institute of Genetics and Genomics in Geneva (iGE3), University of Geneva, Geneva, Switzerland
| | - Brigitte Galliot
- Department of Genetics and Evolution, Institute of Genetics and Genomics in Geneva (iGE3), University of Geneva, Geneva, Switzerland
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15
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Fields C, Levin M. Does regeneration recapitulate phylogeny? Planaria as a model of body-axis specification in ancestral eumetazoa. Commun Integr Biol 2020; 13:27-38. [PMID: 32128026 PMCID: PMC7039665 DOI: 10.1080/19420889.2020.1729601] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 02/07/2020] [Accepted: 02/09/2020] [Indexed: 12/31/2022] Open
Abstract
Metazoan body plans combine well-defined primary, secondary, and in many bilaterians, tertiary body axes with structural asymmetries at multiple scales. Despite decades of study, how axis-defining symmetries and system-defining asymmetries co-emerge during both evolution and development remain open questions. Regeneration studies in asexual planaria have demonstrated an array of viable forms with symmetrized and, in some cases, duplicated body axes. We suggest that such forms may point toward an ancestral eumetazoan form with characteristics of both cnidarians and placazoa.
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Affiliation(s)
| | - Michael Levin
- Allen Discovery Center, Tufts University, Medford, MA, USA
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16
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Fields C, Bischof J, Levin M. Morphological Coordination: A Common Ancestral Function Unifying Neural and Non-Neural Signaling. Physiology (Bethesda) 2020; 35:16-30. [DOI: 10.1152/physiol.00027.2019] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Nervous systems are traditionally thought of as providing sensing and behavioral coordination functions at the level of the whole organism. What is the evolutionary origin of the mechanisms enabling the nervous systems’ information processing ability? Here, we review evidence from evolutionary, developmental, and regenerative biology suggesting a deeper, ancestral function of both pre-neural and neural cell-cell communication systems: the long-distance coordination of cell division and differentiation required to create and maintain body-axis symmetries. This conceptualization of the function of nervous system activity sheds new light on the evolutionary transition from the morphologically rudimentary, non-neural Porifera and Placazoa to the complex morphologies of Ctenophores, Cnidarians, and Bilaterians. It further allows a sharp formulation of the distinction between long-distance axis-symmetry coordination based on external coordinates, e.g., by whole-organism scale trophisms as employed by plants and sessile animals, and coordination based on body-centered coordinates as employed by motile animals. Thus we suggest that the systems that control animal behavior evolved from ancient mechanisms adapting preexisting ionic and neurotransmitter mechanisms to regulate individual cell behaviors during morphogenesis. An appreciation of the ancient, non-neural origins of bioelectrically mediated computation suggests new approaches to the study of embryological development, including embryological dysregulation, cancer, regenerative medicine, and synthetic bioengineering.
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Affiliation(s)
- Chris Fields
- 23 Rue des Lavandières, Caunes Minervois, France
| | - Johanna Bischof
- Allen Discovery Center at Tufts University, Medford, Massachusetts
| | - Michael Levin
- Allen Discovery Center at Tufts University, Medford, Massachusetts
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17
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Abstract
Regeneration is a remarkable phenomenon that has been the subject of awe and bafflement for hundreds of years. Although regeneration competence is found in highly divergent organisms throughout the animal kingdom, recent advances in tools used for molecular and genomic characterization have uncovered common genes, molecular mechanisms, and genomic features in regenerating animals. In this review we focus on what is known about how genome regulation modulates cellular potency during regeneration. We discuss this regulation in the context of complex tissue regeneration in animals, from Hydra to humans, with reference to ex vivo-cultured cell models of pluripotency when appropriate. We emphasize the importance of a detailed molecular understanding of both the mechanisms that regulate genomic output and the functional assays that assess the biological relevance of such molecular characterizations.
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Affiliation(s)
- Elizabeth M Duncan
- Department of Biology, University of Kentucky, Lexington, Kentucky 40506, USA
| | - Alejandro Sánchez Alvarado
- Howard Hughes Medical Institute, Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA;
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18
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López EH, Palumbi SR. Somatic Mutations and Genome Stability Maintenance in Clonal Coral Colonies. Mol Biol Evol 2019; 37:828-838. [DOI: 10.1093/molbev/msz270] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
AbstractOne challenge for multicellular organisms is maintaining genome stability in the face of mutagens across long life spans. Imperfect genome maintenance leads to mutation accumulation in somatic cells, which is associated with tumors and senescence in vertebrates. Colonial reef-building corals are often large, can live for hundreds of years, rarely develop recognizable tumors, and are thought to convert somatic cells into gamete producers, so they are a pivotal group in which to understand long-term genome maintenance. To measure rates and patterns of somatic mutations, we analyzed transcriptomes from 17 to 22 branches from each of four Acropora hyacinthus colonies, determined putative single nucleotide variants, and verified them with Sanger resequencing. Unlike for human skin carcinomas, there is no signature of mutations caused by UV damage, indicating either higher efficiency of repair than in vertebrates, or strong sunscreen protection in these shallow water tropical animals. The somatic mutation frequency per nucleotide in A. hyacinthus is on the same order of magnitude (10−7) as noncancerous human somatic cells, and accumulation of mutations with age is similar. Loss of heterozygosity variants outnumber gain of heterozygosity mutations ∼2:1. Although the mutation frequency is similar in mammals and corals, the preponderance of loss of heterozygosity changes and potential selection may reduce the frequency of deleterious mutations in colonial animals like corals. This may limit the deleterious effects of somatic mutations on the coral organism as well as potential offspring.
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Affiliation(s)
- Elora H López
- Biology Department, Hopkins Marine Station, Stanford University, Pacific Grove, CA
| | - Stephen R Palumbi
- Biology Department, Hopkins Marine Station, Stanford University, Pacific Grove, CA
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19
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Mortzfeld BM, Taubenheim J, Klimovich AV, Fraune S, Rosenstiel P, Bosch TCG. Temperature and insulin signaling regulate body size in Hydra by the Wnt and TGF-beta pathways. Nat Commun 2019; 10:3257. [PMID: 31332174 PMCID: PMC6646324 DOI: 10.1038/s41467-019-11136-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 06/07/2019] [Indexed: 02/03/2023] Open
Abstract
How multicellular organisms assess and control their size is a fundamental question in biology, yet the molecular and genetic mechanisms that control organ or organism size remain largely unsolved. The freshwater polyp Hydra demonstrates a high capacity to adapt its body size to different temperatures. Here we identify the molecular mechanisms controlling this phenotypic plasticity and show that temperature-induced cell number changes are controlled by Wnt- and TGF-β signaling. Further we show that insulin-like peptide receptor (INSR) and forkhead box protein O (FoxO) are important genetic drivers of size determination controlling the same developmental regulators. Thus, environmental and genetic factors directly affect developmental mechanisms in which cell number is the strongest determinant of body size. These findings identify the basic mechanisms as to how size is regulated on an organismic level and how phenotypic plasticity is integrated into conserved developmental pathways in an evolutionary informative model organism.
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Affiliation(s)
- Benedikt M Mortzfeld
- Zoological Institute, Christian-Albrechts University Kiel, Am Botanischen Garten 1-9, 24118, Kiel, Germany
- Department of Bioengineering, University of Massachusetts Dartmouth, 285 Old Westport Rd, Dartmouth, MA, 02747, USA
| | - Jan Taubenheim
- Zoological Institute, Christian-Albrechts University Kiel, Am Botanischen Garten 1-9, 24118, Kiel, Germany
- Institute for Zoology and Organismic Interactions, Heinrich-Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Alexander V Klimovich
- Zoological Institute, Christian-Albrechts University Kiel, Am Botanischen Garten 1-9, 24118, Kiel, Germany
| | - Sebastian Fraune
- Zoological Institute, Christian-Albrechts University Kiel, Am Botanischen Garten 1-9, 24118, Kiel, Germany
- Institute for Zoology and Organismic Interactions, Heinrich-Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Philip Rosenstiel
- Institute of Clinical Molecular Biology, Christian-Albrechts University Kiel, University Hospital Schleswig-Holstein, Rosalind-Franklin-Straße 12, 24105, Kiel, Germany
| | - Thomas C G Bosch
- Zoological Institute, Christian-Albrechts University Kiel, Am Botanischen Garten 1-9, 24118, Kiel, Germany.
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20
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Sybirna A, Wong FCK, Surani MA. Genetic basis for primordial germ cells specification in mouse and human: Conserved and divergent roles of PRDM and SOX transcription factors. Curr Top Dev Biol 2019; 135:35-89. [PMID: 31155363 DOI: 10.1016/bs.ctdb.2019.04.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Primordial germ cells (PGCs) are embryonic precursors of sperm and egg that pass on genetic and epigenetic information from one generation to the next. In mammals, they are induced from a subset of cells in peri-implantation epiblast by BMP signaling from the surrounding tissues. PGCs then initiate a unique developmental program that involves comprehensive epigenetic resetting and repression of somatic genes. This is orchestrated by a set of signaling molecules and transcription factors that promote germ cell identity. Here we review significant findings on mammalian PGC biology, in particular, the genetic basis for PGC specification in mice and human, which has revealed an evolutionary divergence between the two species. We discuss the importance and potential basis for these differences and focus on several examples to illustrate the conserved and divergent roles of critical transcription factors in mouse and human germline.
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Affiliation(s)
- Anastasiya Sybirna
- Wellcome Trust Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, United Kingdom; Physiology, Development and Neuroscience Department, University of Cambridge, Cambridge, United Kingdom; Wellcome Trust/Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge, United Kingdom.
| | - Frederick C K Wong
- Wellcome Trust Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, United Kingdom; Physiology, Development and Neuroscience Department, University of Cambridge, Cambridge, United Kingdom
| | - M Azim Surani
- Wellcome Trust Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge, United Kingdom; Physiology, Development and Neuroscience Department, University of Cambridge, Cambridge, United Kingdom; Wellcome Trust/Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge, United Kingdom.
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21
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Rentzsch F, Juliano C, Galliot B. Modern genomic tools reveal the structural and cellular diversity of cnidarian nervous systems. Curr Opin Neurobiol 2019; 56:87-96. [PMID: 30654234 DOI: 10.1016/j.conb.2018.12.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 12/10/2018] [Accepted: 12/11/2018] [Indexed: 12/11/2022]
Abstract
Cnidarians shared a common ancestor with bilaterians more than 600 million years ago. This sister group relationship gives them an informative phylogenetic position for understanding the fascinating morphological and molecular cell type diversity of bilaterian nervous systems. Moreover, cnidarians display novel features such as endodermal neurogenesis and independently evolved centralizations, which provide a platform for understanding the evolution of nervous system innovations. In recent years, the application of modern genomic tools has significantly advanced our understanding of cnidarian nervous system structure and function. For example, transgenic reporter lines and gene knockdown experiments in several cnidarian species reveal a significant degree of conservation in the neurogenesis gene regulatory program, while single cell RNA sequencing projects are providing a much deeper understanding of cnidarian neural cell type diversity. At the level of neural function, the physiological properties of ion channels have been described and calcium imaging of the nervous system in whole animals has allowed for the identification of neural circuits underlying specific behaviours. Cnidarians have arrived in the modern era of molecular neurobiology and are primed to provide exciting new insights into the early evolution of nervous systems.
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Affiliation(s)
- Fabian Rentzsch
- Sars Centre for Marine Molecular Biology, Norway; Department for Biological Sciences, University of Bergen, Norway.
| | - Celina Juliano
- Department of Molecular and Cellular Biology, University of California Davis, CA 95616, United States.
| | - Brigitte Galliot
- Department of Genetics and Evolution, Institute of Genetics and Genomics in Geneva (iGE3), University of Geneva, Switzerland.
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22
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Golubev A, Hanson AD, Gladyshev VN. A Tale of Two Concepts: Harmonizing the Free Radical and Antagonistic Pleiotropy Theories of Aging. Antioxid Redox Signal 2018; 29:1003-1017. [PMID: 28874059 PMCID: PMC6104246 DOI: 10.1089/ars.2017.7105] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Revised: 08/09/2017] [Accepted: 08/31/2017] [Indexed: 12/18/2022]
Abstract
SIGNIFICANCE The two foremost concepts of aging are the mechanistic free radical theory (FRT) of how we age and the evolutionary antagonistic pleiotropy theory (APT) of why we age. Both date from the late 1950s. The FRT holds that reactive oxygen species (ROS) are the principal contributors to the lifelong cumulative damage suffered by cells, whereas the APT is generally understood as positing that genes that are good for young organisms can take over a population even if they are bad for the old organisms. Recent Advances: Here, we provide a common ground for the two theories by showing how aging can result from the inherent chemical reactivity of many biomolecules, not just ROS, which imposes a fundamental constraint on biological evolution. Chemically reactive metabolites spontaneously modify slowly renewable macromolecules in a continuous way over time; the resulting buildup of damage wrought by the genes coding for enzymes that generate such small molecules eventually masquerades as late-acting pleiotropic effects. In aerobic organisms, ROS are major agents of this damage but they are far from alone. CRITICAL ISSUES Being related to two sides of the same phenomenon, these theories should be compatible. However, the interface between them is obscured by the FRT mistaking a subset of damaging processes for the whole, and the APT mistaking a cumulative quantitative process for a qualitative switch. FUTURE DIRECTIONS The manifestations of ROS-mediated cumulative chemical damage at the population level may include the often-observed negative correlation between fitness and the rate of its decline with increasing age, further linking FRT and APT. Antioxid. Redox Signal. 29, 1003-1017.
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Affiliation(s)
- Alexey Golubev
- Department of Carcinogenesis and Oncogerontology, Petrov Research Institute of Oncology, Saint Petersburg, Russia
| | - Andrew D. Hanson
- Horticultural Sciences Department, University of Florida, Gainesville, Florida
| | - Vadim N. Gladyshev
- Division of Genetics, Department of Medicine, Harvard Medical School, Brigham and Women's Hospital, Boston, Massachusetts
- Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow Russia
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23
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Busengdal H, Rentzsch F. Unipotent progenitors contribute to the generation of sensory cell types in the nervous system of the cnidarian Nematostella vectensis. Dev Biol 2017; 431:59-68. [PMID: 28827097 DOI: 10.1016/j.ydbio.2017.08.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 08/08/2017] [Accepted: 08/17/2017] [Indexed: 11/18/2022]
Abstract
Nervous systems often consist of a large number of different types of neurons which are generated from neural stem and progenitor cells by a series of symmetric and asymmetric divisions. The origin and early evolution of these neural progenitor systems is not well understood. Here we use a cnidarian model organism, Nematostella vectensis, to gain insight into the generation of neural cell type diversity in a non-bilaterian animal. We identify NvFoxQ2d as a transcription factor that is expressed in a population of spatially restricted, proliferating ectodermal cells that are derived from NvSoxB(2)-expressing neural progenitor cells. Using a transgenic reporter line we show that the NvFoxQ2d cells undergo a terminal, symmetric division to generate a morphologically homogeneous population of putative sensory cells. The abundance of these cells, but not their proliferation status is affected by treatment with the γ-secretase inhibitor DAPT, suggesting regulation by Notch signalling. Our data suggest that intermediate progenitor cells and symmetric divisions contribute to the formation of the seemingly simple nervous system of a sea anemone.
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Affiliation(s)
- Henriette Busengdal
- Sars Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgt. 55, 5006 Bergen, Norway
| | - Fabian Rentzsch
- Sars Centre for Marine Molecular Biology, University of Bergen, Thormøhlensgt. 55, 5006 Bergen, Norway.
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24
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Moiseeva E, Rabinowitz C, Paz G, Rinkevich B. Histological study on maturation, fertilization and the state of gonadal region following spawning in the model sea anemone, Nematostella vectensis. PLoS One 2017; 12:e0182677. [PMID: 28796817 PMCID: PMC5552035 DOI: 10.1371/journal.pone.0182677] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 07/22/2017] [Indexed: 12/26/2022] Open
Abstract
The starlet sea-anemone Nematostella vectensis has emerged as a model organism in developmental biology. Still, our understanding of various biological features, including reproductive biology of this model species are in its infancy. Consequently, through histological sections, we study here key stages of the oogenesis (oocyte maturation/fertilization), as the state of the gonad region immediately after natural spawning. Germ cells develop in a secluded mesenterial gastrodermal zone, where the developing oocytes are surrounded by mucoid glandular cells and trophocytes (accessory cells). During vitellogenesis, the germinal vesicle in oocytes migrates towards the animal pole and the large polarized oocytes begin to mature, characterized by karyosphere formation. Then, the karyosphere breaks down, the chromosomes form the metaphase plate I and the eggs are extruded from the animal enclosed in a sticky, jelly-like mucoid mass, along with numerous nematosomes. Fertilization occurs externally at metaphase II via swimming sperm extruded by males during natural spawning. The polar bodies are ejected from the eggs and are situated within a narrow space between the egg's vitelline membrane and the adjacent edge of the jelly coat. The cortical reaction occurs only at the polar bodies' ejection site. Several spermatozoa can penetrate the same egg. Fertilization is accompanied by a strong ooplasmatic segregation. Immediately after spawning, the gonad region holds many previtellogenic and vitellogenic oocytes, though no oocytes with karyosphere. Above are the first histological descriptions for egg maturation, meiotic chromosome's status at fertilization, fertilization and the gonadal region's state following spawning, also documenting for the first time the ejection of the polar body.
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Affiliation(s)
- Elizabeth Moiseeva
- Israel Oceanography and Limnological Research, National Institute of Oceanography, Tel-Shikmona, Haifa, Israel
| | - Claudette Rabinowitz
- Israel Oceanography and Limnological Research, National Institute of Oceanography, Tel-Shikmona, Haifa, Israel
| | - Guy Paz
- Israel Oceanography and Limnological Research, National Institute of Oceanography, Tel-Shikmona, Haifa, Israel
| | - Baruch Rinkevich
- Israel Oceanography and Limnological Research, National Institute of Oceanography, Tel-Shikmona, Haifa, Israel
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25
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Rentzsch F, Layden M, Manuel M. The cellular and molecular basis of cnidarian neurogenesis. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2016; 6. [PMID: 27882698 PMCID: PMC6680159 DOI: 10.1002/wdev.257] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 08/30/2016] [Accepted: 09/21/2016] [Indexed: 12/22/2022]
Abstract
Neurogenesis initiates during early development and it continues through later developmental stages and in adult animals to enable expansion, remodeling, and homeostasis of the nervous system. The generation of nerve cells has been analyzed in detail in few bilaterian model organisms, leaving open many questions about the evolution of this process. As the sister group to bilaterians, cnidarians occupy an informative phylogenetic position to address the early evolution of cellular and molecular aspects of neurogenesis and to understand common principles of neural development. Here we review studies in several cnidarian model systems that have revealed significant similarities and interesting differences compared to neurogenesis in bilaterian species, and between different cnidarian taxa. Cnidarian neurogenesis is currently best understood in the sea anemone Nematostella vectensis, where it includes epithelial neural progenitor cells that express transcription factors of the soxB and atonal families. Notch signaling regulates the number of these neural progenitor cells, achaete‐scute and dmrt genes are required for their further development and Wnt and BMP signaling appear to be involved in the patterning of the nervous system. In contrast to many vertebrates and Drosophila, cnidarians have a high capacity to generate neurons throughout their lifetime and during regeneration. Utilizing this feature of cnidarian biology will likely allow gaining new insights into the similarities and differences of embryonic and regenerative neurogenesis. The use of different cnidarian model systems and their expanding experimental toolkits will thus continue to provide a better understanding of evolutionary and developmental aspects of nervous system formation. WIREs Dev Biol 2017, 6:e257. doi: 10.1002/wdev.257 This article is categorized under:
Gene Expression and Transcriptional Hierarchies > Cellular Differentiation Signaling Pathways > Cell Fate Signaling Comparative Development and Evolution > Organ System Comparisons Between Species
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Affiliation(s)
- Fabian Rentzsch
- Sars Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | | | - Michaël Manuel
- Sorbonne Universités, UMPC Univ Paris 06, CNRS, Evolution Paris-Seine, Institut de Biologie Paris-Seine (IBPS), Paris, France
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Barfield S, Aglyamova GV, Matz MV. Evolutionary origins of germline segregation in Metazoa: evidence for a germ stem cell lineage in the coral Orbicella faveolata (Cnidaria, Anthozoa). Proc Biol Sci 2016; 283:rspb.2015.2128. [PMID: 26763699 DOI: 10.1098/rspb.2015.2128] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The ability to segregate a committed germ stem cell (GSC) lineage distinct from somatic cell lineages is a characteristic of bilaterian Metazoans. However, the occurrence of GSC lineage specification in basally branching Metazoan phyla, such as Cnidaria, is uncertain. Without an independently segregated GSC lineage, germ cells and their precursors must be specified throughout adulthood from continuously dividing somatic stem cells, generating the risk of propagating somatic mutations within the individual and its gametes. To address the potential for existence of a GSC lineage in Anthozoa, the sister-group to all remaining Cnidaria, we identified moderate- to high-frequency somatic mutations and their potential for gametic transfer in the long-lived coral Orbicella faveolata (Anthozoa, Cnidaria) using a 2b-RAD sequencing approach. Our results demonstrate that somatic mutations can drift to high frequencies (up to 50%) and can also generate substantial intracolonial genetic diversity. However, these somatic mutations are not transferable to gametes, signifying the potential for an independently segregated GSC lineage in O. faveolata. In conjunction with previous research on germ cell development in other basally branching Metazoan species, our results suggest that the GSC system may be a Eumetazoan characteristic that evolved in association with the emergence of greater complexity in animal body plan organization and greater specificity of stem cell functions.
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Affiliation(s)
- Sarah Barfield
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Galina V Aglyamova
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Mikhail V Matz
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA
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Grillo M, Konstantinides N, Averof M. Old questions, new models: unraveling complex organ regeneration with new experimental approaches. Curr Opin Genet Dev 2016; 40:23-31. [DOI: 10.1016/j.gde.2016.05.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Revised: 05/12/2016] [Accepted: 05/13/2016] [Indexed: 10/21/2022]
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A transcriptional time-course analysis of oral vs. aboral whole-body regeneration in the Sea anemone Nematostella vectensis. BMC Genomics 2016; 17:718. [PMID: 27605362 PMCID: PMC5015328 DOI: 10.1186/s12864-016-3027-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 08/20/2016] [Indexed: 02/07/2023] Open
Abstract
Background The ability of regeneration is essential for the homeostasis of all animals as it allows the repair and renewal of tissues and body parts upon normal turnover or injury. The extent of this ability varies greatly in different animals with the sea anemone Nematostella vectensis, a basal cnidarian model animal, displaying remarkable whole-body regeneration competence. Results In order to study this process in Nematostella we performed an RNA-Seq screen wherein we analyzed and compared the transcriptional response to bisection in the wound-proximal body parts undergoing oral (head) or aboral (tail) regeneration at several time points up to the initial restoration of the basic body shape. The transcriptional profiles of regeneration responsive genes were analyzed so as to define the temporal pattern of differential gene expression associated with the tissue-specific oral and aboral regeneration. The identified genes were characterized according to their GO (gene ontology) assignations revealing groups that were enriched in the regeneration process with particular attention to their affiliation to the major developmental signaling pathways. While some of the genes and gene groups thus analyzed were previously known to be active in regeneration, we have also revealed novel and surprising candidate genes such as cilia-associated genes that likely participate in this important developmental program. Conclusions This work highlighted the main groups of genes which showed polarization upon regeneration, notably the proteinases, multiple transcription factors and the Wnt pathway genes that were highly represented, all displaying an intricate temporal balance between the two sides. In addition, the evolutionary comparison performed between regeneration in different animal model systems may reveal the basic mechanisms playing a role in this fascinating process. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-3027-1) contains supplementary material, which is available to authorized users.
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Considine MJ, Considine JA. On the language and physiology of dormancy and quiescence in plants. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:3189-203. [PMID: 27053719 DOI: 10.1093/jxb/erw138] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The language of dormancy is rich and poetic, as researchers spanning disciplines and decades have attempted to understand the spell that entranced 'Sleeping Beauty', and how she was gently awoken. The misleading use of 'dormancy', applied to annual axillary buds, for example, has confounded progress. Language is increasingly important as genetic and genomic approaches become more accessible to species of agricultural and ecological importance. Here we examine how terminology has been applied to different eco-physiological states in plants, and with pertinent reference to quiescent states described in other domains of life, in order to place plant quiescence and dormancy in a more complete context than previously described. The physiological consensus defines latency or quiescence as opportunistic avoidance states, where growth resumes in favourable conditions. In contrast, the dormant state in higher plants is entrained in the life history of the organism. Competence to resume growth requires quantitative and specific conditioning. This definition applies only to the embryo of seeds and specialized meristems in higher plants; however, mechanistic control of dormancy extends to mobile signals from peripheral tissues and organs, such as the endosperm of seed or subtending leaf of buds. The distinction between dormancy, quiescence, and stress-hardiness remains poorly delineated, most particularly in buds of winter perennials, which comprise multiple meristems of differing organogenic states. Studies in seeds have shown that dormancy is not a monogenic trait, and limited study has thus far failed to canalize dormancy as seen in seeds and buds. We argue that a common language, based on physiology, is central to enable further dissection of the quiescent and dormant states in plants. We direct the topic largely to woody species showing a single cycle of growth and reproduction per year, as these bear the majority of global timber, fruit, and nut production, as well being of great ecological value. However, for context and hypotheses, we draw on knowledge from annuals and other specialized plant conditions, from a perspective of the major physical, metabolic, and molecular cues that regulate cellular activity.
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Affiliation(s)
- Michael J Considine
- School of Plant Biology, and The Institute of Agriculture, The University of Western Australia, Perth, WA 6009 Australia Department of Agriculture and Food Western Australia, South Perth, WA 6151 Australia Centre for Plant Sciences, University of Leeds, Leeds, Yorkshire LS2 9JT, UK
| | - John A Considine
- School of Plant Biology, and The Institute of Agriculture, The University of Western Australia, Perth, WA 6009 Australia
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Yun MH. Changes in Regenerative Capacity through Lifespan. Int J Mol Sci 2015; 16:25392-432. [PMID: 26512653 PMCID: PMC4632807 DOI: 10.3390/ijms161025392] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 09/30/2015] [Accepted: 09/30/2015] [Indexed: 12/14/2022] Open
Abstract
Most organisms experience changes in regenerative abilities through their lifespan. During aging, numerous tissues exhibit a progressive decline in homeostasis and regeneration that results in tissue degeneration, malfunction and pathology. The mechanisms responsible for this decay are both cell intrinsic, such as cellular senescence, as well as cell-extrinsic, such as changes in the regenerative environment. Understanding how these mechanisms impact on regenerative processes is essential to devise therapeutic approaches to improve tissue regeneration and extend healthspan. This review offers an overview of how regenerative abilities change through lifespan in various organisms, the factors that underlie such changes and the avenues for therapeutic intervention. It focuses on established models of mammalian regeneration as well as on models in which regenerative abilities do not decline with age, as these can deliver valuable insights for our understanding of the interplay between regeneration and aging.
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Affiliation(s)
- Maximina H Yun
- Institute of Structural and Molecular Biology, Division of Biosciences, University College London, Gower Street, London WC1E 6BT, UK.
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Schwentner M, Bosch TC. Revisiting the age, evolutionary history and species level diversity of the genus Hydra (Cnidaria: Hydrozoa). Mol Phylogenet Evol 2015; 91:41-55. [DOI: 10.1016/j.ympev.2015.05.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 05/13/2015] [Accepted: 05/15/2015] [Indexed: 12/21/2022]
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Arenas-Mena C, Coffman JA. Developmental control of transcriptional and proliferative potency during the evolutionary emergence of animals. Dev Dyn 2015; 244:1193-201. [PMID: 26173445 PMCID: PMC4705838 DOI: 10.1002/dvdy.24305] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Revised: 06/18/2015] [Accepted: 07/07/2015] [Indexed: 12/13/2022] Open
Abstract
It is proposed that the evolution of complex animals required repressive genetic mechanisms for controlling the transcriptional and proliferative potency of cells. Unicellular organisms are transcriptionally potent, able to express their full genetic complement as the need arises through their life cycle, whereas differentiated cells of multicellular organisms can only express a fraction of their genomic potential. Likewise, whereas cell proliferation in unicellular organisms is primarily limited by nutrient availability, cell proliferation in multicellular organisms is developmentally regulated. Repressive genetic controls limiting the potency of cells at the end of ontogeny would have stabilized the gene expression states of differentiated cells and prevented disruptive proliferation, allowing the emergence of diverse cell types and functional shapes. We propose that distal cis-regulatory elements represent the primary innovations that set the stage for the evolution of developmental gene regulatory networks and the repressive control of key multipotency and cell-cycle control genes. The testable prediction of this model is that the genomes of extant animals, unlike those of our unicellular relatives, encode gene regulatory circuits dedicated to the developmental control of transcriptional and proliferative potency.
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Affiliation(s)
- Cesar Arenas-Mena
- Department of Biology, College of Staten Island and Graduate Center, The City University of New York (CUNY), Staten Island, New York
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Sturm Á, Ivics Z, Vellai T. The mechanism of ageing: primary role of transposable elements in genome disintegration. Cell Mol Life Sci 2015; 72:1839-47. [PMID: 25837999 PMCID: PMC11113528 DOI: 10.1007/s00018-015-1896-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 03/16/2015] [Accepted: 03/25/2015] [Indexed: 01/11/2023]
Abstract
Understanding the molecular basis of ageing remains a fundamental problem in biology. In multicellular organisms, while the soma undergoes a progressive deterioration over the lifespan, the germ line is essentially immortal as it interconnects the subsequent generations. Genomic instability in somatic cells increases with age, and accumulating evidence indicates that the disintegration of somatic genomes is accompanied by the mobilisation of transposable elements (TEs) that, when mobilised, can be mutagenic by disrupting coding or regulatory sequences. In contrast, TEs are effectively silenced in the germ line by the Piwi-piRNA system. Here, we propose that TE repression transmits the persistent proliferation capacity and the non-ageing phenotype (e.g., preservation of genomic integrity) of the germ line. The Piwi-piRNA pathway also operates in tumorous cells and in somatic cells of certain organisms, including hydras, which likewise exhibit immortality. However, in somatic cells lacking the Piwi-piRNA pathway, gradual chromatin decondensation increasingly allows the mobilisation of TEs as the organism ages. This can explain why the mortality rate rises exponentially throughout the adult life in most animal species, including humans.
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Affiliation(s)
- Ádám Sturm
- Department of Genetics, Eötvös Loránd University, Pázmány Péter stny. 1/C, Budapest, Hungary
| | - Zoltán Ivics
- Division of Medical Biotechnology, Paul Ehrlich Institute, 63225 Langen, Germany
| | - Tibor Vellai
- Department of Genetics, Eötvös Loránd University, Pázmány Péter stny. 1/C, Budapest, Hungary
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Abstract
Adult stem cells face the challenge of maintaining tissue homeostasis by self-renewal while maintaining their proliferation potential over the lifetime of an organism. Continuous proliferation can cause genotoxic/metabolic stress that can compromise the genomic integrity of stem cells. To prevent stem cell exhaustion, highly proliferative adult tissues maintain a pool of quiescent stem cells that divide only in response to injury and thus remain protected from genotoxic stress. Hydra is a remarkable organism with highly proliferative stem cells and ability to regenerate at whole animal level. Intriguingly, hydra does not display consequences of high proliferation, such as senescence or tumour formation. In this study, we investigate if hydra harbours a pool of slow-cycling stem cells that could help prevent undesirable consequences of continuous proliferation. Hydra were pulsed with the thymidine analogue 5-ethynyl-2′-deoxyuridine (EdU) and then chased in the absence of EdU to monitor the presence of EdU-retaining cells. A significant number of undifferentiated cells of all three lineages in hydra retained EdU for about 8–10 cell cycles, indicating that these cells did not enter cell cycle. These label-retaining cells were resistant to hydroxyurea treatment and were predominantly in the G2 phase of cell cycle. Most significantly, similar to mammalian quiescent stem cells, these cells rapidly entered cell division during head regeneration. This study shows for the first time that, contrary to current beliefs, cells in hydra display heterogeneity in their cell cycle potential and the slow-cycling cells in this population enter cell cycle during head regeneration. These results suggest an early evolution of slow-cycling stem cells in multicellular animals.
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Affiliation(s)
- Niraimathi Govindasamy
- Institute for Stem Cell Biology and Regenerative Medicine (inStem), National Centre for Biological Sciences, GKVK Campus, Bellary Road, Bangalore 560065, India
| | - Supriya Murthy
- Institute for Stem Cell Biology and Regenerative Medicine (inStem), National Centre for Biological Sciences, GKVK Campus, Bellary Road, Bangalore 560065, India
| | - Yashoda Ghanekar
- Institute for Stem Cell Biology and Regenerative Medicine (inStem), National Centre for Biological Sciences, GKVK Campus, Bellary Road, Bangalore 560065, India
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Petralia RS, Mattson MP, Yao PJ. Aging and longevity in the simplest animals and the quest for immortality. Ageing Res Rev 2014; 16:66-82. [PMID: 24910306 DOI: 10.1016/j.arr.2014.05.003] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 05/08/2014] [Accepted: 05/22/2014] [Indexed: 12/12/2022]
Abstract
Here we review the examples of great longevity and potential immortality in the earliest animal types and contrast and compare these to humans and other higher animals. We start by discussing aging in single-celled organisms such as yeast and ciliates, and the idea of the immortal cell clone. Then we describe how these cell clones could become organized into colonies of different cell types that lead to multicellular animal life. We survey aging and longevity in all of the basal metazoan groups including ctenophores (comb jellies), sponges, placozoans, cnidarians (hydras, jellyfish, corals and sea anemones) and myxozoans. Then we move to the simplest bilaterian animals (with a head, three body cell layers, and bilateral symmetry), the two phyla of flatworms. A key determinant of longevity and immortality in most of these simple animals is the large numbers of pluripotent stem cells that underlie the remarkable abilities of these animals to regenerate and rejuvenate themselves. Finally, we discuss briefly the evolution of the higher bilaterians and how longevity was reduced and immortality lost due to attainment of greater body complexity and cell cycle strategies that protect these complex organisms from developing tumors. We also briefly consider how the evolution of multiple aging-related mechanisms/pathways hinders our ability to understand and modify the aging process in higher organisms.
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Impairment of regeneration in aging: appropriateness or stochastics? Biogerontology 2013; 14:703-8. [DOI: 10.1007/s10522-013-9468-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 09/17/2013] [Indexed: 01/14/2023]
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Boehm AM, Rosenstiel P, Bosch TCG. Stem cells and aging from a quasi-immortal point of view. Bioessays 2013; 35:994-1003. [PMID: 24037777 DOI: 10.1002/bies.201300075] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Understanding aging and how it affects an organism's lifespan is a fundamental problem in biology. A hallmark of aging is stem cell senescence, the decline of functionality, and number of somatic stem cells, resulting in an impaired regenerative capacity and reduced tissue function. In addition, aging is characterized by profound remodeling of the immune system and a quantitative decline of adequate immune responses, a phenomenon referred to as immune-senescence. Yet, what is causing stem cell and immune-senescence? This review discusses experimental studies of potentially immortal Hydra which have made contributions to answering this question. Hydra transcription factor FoxO has been shown to modulate both stem cell proliferation and innate immunity, lending strong support to a role of FoxO as critical rate-of-aging regulator from Hydra to human. Constructing a model of how FoxO responds to diverse environmental factors provides a framework for how stem cell factors might contribute to aging.
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Affiliation(s)
- Anna-Marei Boehm
- Zoological Institute, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
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Zhang QJ, Luo YJ, Wu HR, Chen YT, Yu JK. Expression of germline markers in three species of amphioxus supports a preformation mechanism of germ cell development in cephalochordates. EvoDevo 2013; 4:17. [PMID: 23777831 PMCID: PMC3735472 DOI: 10.1186/2041-9139-4-17] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 04/22/2013] [Indexed: 12/21/2022] Open
Abstract
Background In a previous study, we showed that the cephalochordate amphioxus Branchiostoma floridae has localized maternal transcripts of conserved germ cell markers Vasa and Nanos in its early embryos. These results provided strong evidence to support a preformation mechanism for primordial germ cell (PGC) development in B. floridae. Results In this study, we further characterize the expression of B. floridae homologs of Piwi and Tudor, which play important roles in germline development in diverse metazoan animals. We show that maternal mRNA of one of the identified Piwi-like homologs, Bf-Piwil1, also colocalizes with Vasa in the vegetal germ plasm and has zygotic expression in both the putative PGCs and the tail bud, suggesting it may function in both germline and somatic stem cells. More interestingly, one Tudor family gene, Bf-Tdrd7, is only expressed maternally and colocalizes with Vasa in germ plasm, suggesting that it may function exclusively in germ cell specification. To evaluate the conservation of the preformation mechanism among amphioxus species, we further analyze Vasa, Nanos, Piwil1, and Tdrd7 expression in two Asian amphioxus species, B. belcheri and B. japonicum. Their maternal transcripts all localize in similar patterns to those seen in B. floridae. In addition, we labeled putative PGCs with Vasa antibody to trace their dynamic distribution in developing larvae. Conclusions We identify additional germ plasm components in amphioxus and demonstrate the molecular distinction between the putative germline stem cells and somatic stem cells. Moreover, our results suggest that preformation may be a conserved mechanism for PGC specification among Branchiostoma species. Our Vasa antibody staining results suggest that after the late neurula stage, amphioxus PGCs probably proliferate with the tail bud cells during posterior elongation and are deposited near the forming myomere boundaries. Subsequently, these PGCs would concentrate at the ventral tip of the myoseptal walls to form the gonad anlagen.
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Affiliation(s)
- Qiu-Jin Zhang
- Institute of Cellular and Organismic Biology, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei, 11529, Taiwan.,Fujian Key Laboratory of Developmental and Neuro Biology, College of Life Sciences, Fujian Normal University, Fuzhou, 350108, People's Republic of China
| | - Yi-Jyun Luo
- Institute of Cellular and Organismic Biology, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei, 11529, Taiwan
| | - Hui-Ru Wu
- Institute of Cellular and Organismic Biology, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei, 11529, Taiwan
| | - Yen-Ta Chen
- Institute of Cellular and Organismic Biology, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei, 11529, Taiwan
| | - Jr-Kai Yu
- Institute of Cellular and Organismic Biology, Academia Sinica, 128 Academia Road, Section 2, Nankang, Taipei, 11529, Taiwan.,Institute of Oceanography, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei, 10617, Taiwan
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Giangrande A, Licciano M. Regeneration and clonality in Metazoa. The price to pay for evolving complexity. INVERTEBR REPROD DEV 2013. [DOI: 10.1080/07924259.2013.793622] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Gold DA, Jacobs DK. Stem cell dynamics in Cnidaria: are there unifying principles? Dev Genes Evol 2013; 223:53-66. [PMID: 23179637 PMCID: PMC7211294 DOI: 10.1007/s00427-012-0429-1] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 10/26/2012] [Indexed: 10/27/2022]
Abstract
The study of stem cells in cnidarians has a history spanning hundreds of years, but it has primarily focused on the hydrozoan genus Hydra. While Hydra has a number of self-renewing cell types that act much like stem cells--in particular the interstitial cell line--finding cellular homologues outside of the Hydrozoa has been complicated by the morphological simplicity of stem cells and inconclusive gene expression data. In non-hydrozoan cnidarians, an enigmatic cell type known as the amoebocyte might play a similar role to interstitial cells, but there is little evidence that I-cells and amoebocytes are homologous. Instead, self-renewal and transdifferentiation of epithelial cells was probably more important to ancestral cnidarian development than any undifferentiated cell lineage, and only later in evolution did one or more cell types come under the regulation of a "stem" cell line. Ultimately, this hypothesis and competing ones will need to be tested by expanding genetic and developmental studies on a variety of cnidarian model systems.
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Affiliation(s)
- David A Gold
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 2154 Terasaki Life Science Building, Los Angeles, CA 90095, USA
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Labbé RM, Irimia M, Currie KW, Lin A, Zhu SJ, Brown DDR, Ross EJ, Voisin V, Bader GD, Blencowe BJ, Pearson BJ. A comparative transcriptomic analysis reveals conserved features of stem cell pluripotency in planarians and mammals. Stem Cells 2013; 30:1734-45. [PMID: 22696458 DOI: 10.1002/stem.1144] [Citation(s) in RCA: 149] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Many long-lived species of animals require the function of adult stem cells throughout their lives. However, the transcriptomes of stem cells in invertebrates and vertebrates have not been compared, and consequently, ancestral regulatory circuits that control stem cell populations remain poorly defined. In this study, we have used data from high-throughput RNA sequencing to compare the transcriptomes of pluripotent adult stem cells from planarians with the transcriptomes of human and mouse pluripotent embryonic stem cells. From a stringently defined set of 4,432 orthologs shared between planarians, mice and humans, we identified 123 conserved genes that are ≥5-fold differentially expressed in stem cells from all three species. Guided by this gene set, we used RNAi screening in adult planarians to discover novel stem cell regulators, which we found to affect the stem cell-associated functions of tissue homeostasis, regeneration, and stem cell maintenance. Examples of genes that disrupted these processes included the orthologs of TBL3, PSD12, TTC27, and RACK1. From these analyses, we concluded that by comparing stem cell transcriptomes from diverse species, it is possible to uncover conserved factors that function in stem cell biology. These results provide insights into which genes comprised the ancestral circuitry underlying the control of stem cell self-renewal and pluripotency.
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Affiliation(s)
- Roselyne M Labbé
- The Hospital for Sick Children, Program in Developmental and Stem Cell Biology, University of Toronto, Toronto, Ontario, Canada
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Franco C, Soares R, Pires E, Koci K, Almeida AM, Santos R, Coelho AV. Understanding regeneration through proteomics. Proteomics 2013; 13:686-709. [DOI: 10.1002/pmic.201200397] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 10/31/2012] [Accepted: 11/06/2012] [Indexed: 12/29/2022]
Affiliation(s)
- Catarina Franco
- Instituto de Tecnologia Química e Biológica; Universidade Nova de Lisboa; Oeiras Portugal
| | - Renata Soares
- Instituto de Tecnologia Química e Biológica; Universidade Nova de Lisboa; Oeiras Portugal
| | - Elisabete Pires
- Instituto de Tecnologia Química e Biológica; Universidade Nova de Lisboa; Oeiras Portugal
| | - Kamila Koci
- Instituto de Tecnologia Química e Biológica; Universidade Nova de Lisboa; Oeiras Portugal
| | - André M. Almeida
- Instituto de Tecnologia Química e Biológica; Universidade Nova de Lisboa; Oeiras Portugal
- Instituto de Investigação Científica Tropical; Lisboa Portugal
| | - Romana Santos
- Unidade de Investigação em Ciências Orais e Biomédicas, Faculdade de Medicina Dentária; Universidade de Lisboa; Portugal
| | - Ana Varela Coelho
- Instituto de Tecnologia Química e Biológica; Universidade Nova de Lisboa; Oeiras Portugal
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Hemmrich G, Khalturin K, Boehm AM, Puchert M, Anton-Erxleben F, Wittlieb J, Klostermeier UC, Rosenstiel P, Oberg HH, Domazet-Loso T, Sugimoto T, Niwa H, Bosch TCG. Molecular signatures of the three stem cell lineages in hydra and the emergence of stem cell function at the base of multicellularity. Mol Biol Evol 2012; 29:3267-80. [PMID: 22595987 DOI: 10.1093/molbev/mss134] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
How distinct stem cell populations originate and whether there is a clear stem cell "genetic signature" remain poorly understood. Understanding the evolution of stem cells requires molecular profiling of stem cells in an animal at a basal phylogenetic position. In this study, using transgenic Hydra polyps, we reveal for each of the three stem cell populations a specific signature set of transcriptions factors and of genes playing key roles in cell type-specific function and interlineage communication. Our data show that principal functions of stem cell genes, such as maintenance of stemness and control of stem cell self-renewal and differentiation, arose very early in metazoan evolution. They are corroborating the view that stem cell types shared common, multifunctional ancestors, which achieved complexity through a stepwise segregation of function in daughter cells.
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Affiliation(s)
- Georg Hemmrich
- Zoological Institute, Christian-Albrechts University, Kiel, Germany
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Somorjai IML, Lohmann JU, Holstein TW, Zhao Z. Stem cells: a view from the roots. Biotechnol J 2012; 7:704-22. [PMID: 22581706 DOI: 10.1002/biot.201100349] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Revised: 03/15/2012] [Accepted: 04/12/2012] [Indexed: 12/22/2022]
Abstract
In both plants and animals, regeneration requires the activation of stem cells. This is possibly related to the origin and requirements of multicellularity. Although long diverged from a common ancestry, plant and animal models such as Arabidopsis, Drosophila and mouse share considerable similarities in stem cell regulation. This includes stem cell niche organisation, epigenetic modification of DNA and histones, and the role of small RNA machinery in differentiation and pluripotency states. Dysregulation of any of these can lead to premature ageing, patterning and specification defects, as well as cancers. Moreover, emerging basal animal and plant systems are beginning to provide important clues concerning the diversity and evolutionary history of stem cell regulatory mechanisms in eukaryotes. This review provides a comparative framework, highlighting both the commonalities and differences among groups, which should promote the intelligent design of artificial stem cell systems, and thereby fuel the field of biomaterials science.
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Affiliation(s)
- Ildiko M L Somorjai
- Centre for Organismal Studies (COS), University of Heidelberg, Heidelberg, Germany.
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Maternally localized germ plasm mRNAs and germ cell/stem cell formation in the cnidarian Clytia. Dev Biol 2012; 364:236-48. [DOI: 10.1016/j.ydbio.2012.01.018] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Revised: 01/11/2012] [Accepted: 01/20/2012] [Indexed: 01/07/2023]
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Telomere maintenance and telomerase activity are differentially regulated in asexual and sexual worms. Proc Natl Acad Sci U S A 2012; 109:4209-14. [PMID: 22371573 DOI: 10.1073/pnas.1118885109] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
In most sexually reproducing animals, replication and maintenance of telomeres occurs in the germ line and during early development in embryogenesis through the use of telomerase. Somatic cells generally do not maintain telomere sequences, and these cells become senescent in adults as telomeres shorten to a critical length. Some animals reproduce clonally and must therefore require adult somatic mechanisms for maintaining their chromosome ends. Here we study the telomere biology of planarian flatworms with apparently limitless regenerative capacity fueled by a population of highly proliferative adult stem cells. We show that somatic telomere maintenance is different in asexual and sexual animals. Asexual animals maintain telomere length somatically during reproduction by fission or when regeneration is induced by amputation, whereas sexual animals only achieve telomere elongation through sexual reproduction. We demonstrate that this difference is reflected in the expression and alternate splicing of the protein subunit of the telomerase enzyme. Asexual adult planarian stem cells appear to maintain telomere length over evolutionary timescales without passage through a germ-line stage. The adaptations we observe demonstrate indefinite somatic telomerase activity in proliferating stem cells during regeneration or reproduction by fission, and establish planarians as a pertinent model for studying telomere structure, function, and maintenance.
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Ambrosone A, Marchesano V, Tino A, Hobmayer B, Tortiglione C. Hymyc1 downregulation promotes stem cell proliferation in Hydra vulgaris. PLoS One 2012; 7:e30660. [PMID: 22292012 PMCID: PMC3264606 DOI: 10.1371/journal.pone.0030660] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Accepted: 12/20/2011] [Indexed: 12/13/2022] Open
Abstract
Hydra is a unique model for studying the mechanisms underlying stem cell biology. The activity of the three stem cell lineages structuring its body constantly replenishes mature cells lost due to normal tissue turnover. By a poorly understood mechanism, stem cells are maintained through self-renewal while concomitantly producing differentiated progeny. In vertebrates, one of many genes that participate in regulating stem cell homeostasis is the protooncogene c-myc, which has been recently identified also in Hydra, and found expressed in the interstitial stem cell lineage. In the present paper, by developing a novel strategy of RNA interference-mediated gene silencing (RNAi) based on an enhanced uptake of small interfering RNAi (siRNA), we provide molecular and biological evidence for an unexpected function of the Hydra myc gene (Hymyc1) in the homeostasis of the interstitial stem cell lineage. We found that Hymyc1 inhibition impairs the balance between stem cell self renewal/differentiation, as shown by the accumulation of stem cell intermediate and terminal differentiation products in genetically interfered animals. The identical phenotype induced by the 10058-F4 inhibitor, a disruptor of c-Myc/Max dimerization, demonstrates the specificity of the RNAi approach. We show the kinetic and the reversible feature of Hymyc1 RNAi, together with the effects displayed on regenerating animals. Our results show the involvement of Hymyc1 in the control of interstitial stem cell dynamics, provide new clues to decipher the molecular control of the cell and tissue plasticity in Hydra, and also provide further insights into the complex myc network in higher organisms. The ability of Hydra cells to uptake double stranded RNA and to trigger a RNAi response lays the foundations of a comprehensive analysis of the RNAi response in Hydra allowing us to track back in the evolution and the origin of this process.
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Affiliation(s)
- Alfredo Ambrosone
- Istituto di Cibernetica “E Caianiello,” Consiglio Nazionale delle Ricerche, Pozzuoli, Italy
| | - Valentina Marchesano
- Istituto di Cibernetica “E Caianiello,” Consiglio Nazionale delle Ricerche, Pozzuoli, Italy
| | - Angela Tino
- Istituto di Cibernetica “E Caianiello,” Consiglio Nazionale delle Ricerche, Pozzuoli, Italy
| | - Bert Hobmayer
- Zoological Institute and Center for Molecular Biosciences, University of Innsbruck, Innsbruck, Austria
| | - Claudia Tortiglione
- Istituto di Cibernetica “E Caianiello,” Consiglio Nazionale delle Ricerche, Pozzuoli, Italy
- * E-mail:
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Genikhovich G, Technau U. Complex functions of Mef2 splice variants in the differentiation of endoderm and of a neuronal cell type in a sea anemone. Development 2011; 138:4911-9. [PMID: 22007131 DOI: 10.1242/dev.068122] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In triploblastic animals, mesoderm gives rise to many tissues and organs, including muscle. By contrast, the representatives of the diploblastic phylum Cnidaria (corals, sea anemones, jellyfish and hydroids) lack mesoderm but possess muscle. In vertebrates and insects, the transcription factor Mef2 plays a pivotal role in muscle differentiation; however, it is also an important regulator of neuron differentiation and survival. In the sea anemone Nematostella vectensis, an organism that lacks mesoderm but has muscles and neurons, Mef2 (Nvmef2) has been reported in single ectodermal cells of likely neural origin. To our surprise, we found that Nvmef2 is alternatively spliced, forming differentially expressed variants. Using morpholino-mediated knockdown and mRNA injection, we demonstrate that specific splice variants of Nvmef2 are required for the proliferation and differentiation of endodermal cells and for the development of ectodermal nematocytes, a neuronal cell type. Moreover, we identified a small conserved motif in the transactivation domain that is crucially involved in the endodermal function of Nvmef2. The identification of a crucial and conserved motif in the transactivation domain predicts a similarly important role in vertebrate Mef2 function. This is the first functional study of a determinant of several mesodermal derivatives in a diploblastic animal. Our data suggest that the involvement of alternative splice variants of Mef2 in endomesoderm and neuron differentiation predates the cnidarian-bilaterian split.
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Affiliation(s)
- Grigory Genikhovich
- Department for Molecular Evolution and Development, Centre of Organismal Systems Biology, University of Vienna, Althanstraße 14, A-1090 Vienna, Austria
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Martino G, Pluchino S, Bonfanti L, Schwartz M. Brain regeneration in physiology and pathology: the immune signature driving therapeutic plasticity of neural stem cells. Physiol Rev 2011; 91:1281-304. [PMID: 22013212 PMCID: PMC3552310 DOI: 10.1152/physrev.00032.2010] [Citation(s) in RCA: 171] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Regenerative processes occurring under physiological (maintenance) and pathological (reparative) conditions are a fundamental part of life and vary greatly among different species, individuals, and tissues. Physiological regeneration occurs naturally as a consequence of normal cell erosion, or as an inevitable outcome of any biological process aiming at the restoration of homeostasis. Reparative regeneration occurs as a consequence of tissue damage. Although the central nervous system (CNS) has been considered for years as a "perennial" tissue, it has recently become clear that both physiological and reparative regeneration occur also within the CNS to sustain tissue homeostasis and repair. Proliferation and differentiation of neural stem/progenitor cells (NPCs) residing within the healthy CNS, or surviving injury, are considered crucial in sustaining these processes. Thus a large number of experimental stem cell-based transplantation systems for CNS repair have recently been established. The results suggest that transplanted NPCs promote tissue repair not only via cell replacement but also through their local contribution to changes in the diseased tissue milieu. This review focuses on the remarkable plasticity of endogenous and exogenous (transplanted) NPCs in promoting repair. Special attention will be given to the cross-talk existing between NPCs and CNS-resident microglia as well as CNS-infiltrating immune cells from the circulation, as a crucial event sustaining NPC-mediated neuroprotection. Finally, we will propose the concept of the context-dependent potency of transplanted NPCs (therapeutic plasticity) to exert multiple therapeutic actions, such as cell replacement, neurotrophic support, and immunomodulation, in CNS repair.
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Affiliation(s)
- Gianvito Martino
- Institute of Experimental Neurology, Division of Neuroscience, San Raffaele Scientific Institute, Milan, Italy.
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