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Srivastava M. Studying development, regeneration, stem cells, and more in the acoel Hofstenia miamia. Curr Top Dev Biol 2022; 147:153-172. [PMID: 35337448 DOI: 10.1016/bs.ctdb.2022.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Acoel worms represent an enigmatic lineage of animals (Acoelomorpha) that has danced around the tree of animal life. Morphology-based classification placed them as flatworms (Phylum Platyhelminthes), with much of their biology being interpreted as a variation on what is observed in better-studied members of that phylum. However, molecular phylogenies suggest that acoels belong to a clade (Xenacoelomorpha) that could be a sister group to other animals with bilateral symmetry (Bilateria) or could belong within deuterostomes, closely related to a group that includes sea stars (Ambulacraria). This change in phylogenetic position has led to renewed interest in the biology of acoels, which can now offer insights into the evolution of many bilaterian traits. The acoel Hofstenia miamia has emerged as a powerful new research organism that enables mechanistic studies of xenacoelomorph biology, especially of developmental and regenerative processes. This article explains the motivation for developing Hofstenia as a new model system, describes Hofstenia biology, highlights the tools and resources that make Hofstenia a good research organism, and considers the questions that Hofstenia is well-positioned to answer. Finally, looking to the future, this article serves as an invitation to new and established scientists to join the growing community of researchers studying this exciting model system.
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Affiliation(s)
- Mansi Srivastava
- Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, Cambridge, MA, United States.
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2
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Egger B. Studying Xenacoelomorpha WBR Using Isodiametra pulchra. Methods Mol Biol 2022; 2450:245-261. [PMID: 35359312 PMCID: PMC9761510 DOI: 10.1007/978-1-0716-2172-1_13] [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
Xenacoelomorpha are a phylogenetically and biologically interesting, but severely understudied group of worm-like animals. Among them, the acoel Isodiametra pulchra has been shown to be amenable to experimental work, including the study of stem cells and regeneration. The animal is capable of regenerating the posterior part of the body, but not its head. Here, methods such as nucleic acid extractions, in situ hybridisation, RNA interference, antibody and cytochemical stainings, and the general handling of the animals are presented.
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Affiliation(s)
- Bernhard Egger
- Research Unit Evolutionary and Developmental Biology, Institute of Zoology, University of Innsbruck, Innsbruck, Austria.
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3
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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 2021; 97:299-325. [PMID: 34617397 PMCID: PMC9292022 DOI: 10.1111/brv.12801] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [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 Research, National Institute of Oceanography, POB 9753, Tel Shikmona, Haifa, 3109701, Israel
| | - Loriano Ballarin
- Department of Biology, University of Padova, Via Ugo Bassi 58/B, Padova, 35121, Italy
| | - Pedro Martinez
- Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Av. Diagonal 643, Barcelona, 08028, Spain.,Institut Català de Recerca i Estudis Avançats (ICREA), Passeig Lluís Companys 23, Barcelona, 08010, Spain
| | - Ildiko Somorjai
- School of Biology, University of St Andrews, St Andrews, Fife, KY16 9ST, Scotland, UK
| | - Oshrat Ben-Hamo
- Israel Oceanographic & Limnological Research, National Institute of Oceanography, POB 9753, Tel Shikmona, Haifa, 3109701, Israel
| | - Ilya Borisenko
- Department of Embryology, Faculty of Biology, Saint-Petersburg State University, University Embankment, 7/9, Saint-Petersburg, 199034, Russia
| | - Eugene Berezikov
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Antonius Deusinglaan 1, Groningen, 9713 AV, The Netherlands
| | - Alexander Ereskovsky
- Department of Embryology, Faculty of Biology, Saint-Petersburg State University, University Embankment, 7/9, Saint-Petersburg, 199034, Russia.,Institut Méditerranéen de Biodiversité et d'Ecologie marine et continentale (IMBE), Aix Marseille University, CNRS, IRD, Avignon University, Jardin du Pharo, 58 Boulevard Charles Livon, Marseille, 13007, France.,Koltzov Institute of Developmental Biology of Russian Academy of Sciences, Ulitsa Vavilova, 26, Moscow, 119334, Russia
| | - Eve Gazave
- Université de Paris, CNRS, Institut Jacques Monod, Paris, F-75006, France
| | - Denis Khnykin
- Department of Pathology, Oslo University Hospital, Bygg 19, Gaustad Sykehus, Sognsvannsveien 21, Oslo, 0188, Norway
| | - Lucia Manni
- Department of Biology, University of Padova, Via Ugo Bassi 58/B, Padova, 35121, Italy
| | - Olga Petukhova
- Collection of Vertebrate Cell Cultures, Institute of Cytology, Russian Academy of Sciences, Tikhoretsky Ave. 4, St. Petersburg, 194064, Russia
| | - Amalia Rosner
- Israel Oceanographic & Limnological Research, National Institute of Oceanography, POB 9753, Tel Shikmona, Haifa, 3109701, Israel
| | - Eric Röttinger
- Université Côte d'Azur, CNRS, INSERM, Institute for Research on Cancer and Aging, Nice (IRCAN), Nice, 06107, France.,Université Côte d'Azur, Federative Research Institute - Marine Resources (IFR MARRES), 28 Avenue de Valrose, Nice, 06103, France
| | - Antonietta Spagnuolo
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Villa Comunale, Naples, 80121, Italy
| | - Michela Sugni
- Department of Environmental Science and Policy (ESP), Università degli Studi di Milano, Via Celoria 26, Milan, 20133, Italy
| | - Stefano Tiozzo
- Sorbonne Université, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), 06234 Villefranche-sur-Mer, Villefranche sur Mer, Cedex, France
| | - Bert Hobmayer
- Institute of Zoology and Center for Molecular Biosciences, University of Innsbruck, Technikerstr, Innsbruck, 256020, Austria
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4
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Duruz J, Kaltenrieder C, Ladurner P, Bruggmann R, Martìnez P, Sprecher SG. Acoel Single-Cell Transcriptomics: Cell Type Analysis of a Deep Branching Bilaterian. Mol Biol Evol 2021; 38:1888-1904. [PMID: 33355655 PMCID: PMC8097308 DOI: 10.1093/molbev/msaa333] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Bilaterian animals display a wide variety of cell types, organized into defined anatomical structures and organ systems, which are mostly absent in prebilaterian animals. Xenacoelomorpha are an early-branching bilaterian phylum displaying an apparently relatively simple anatomical organization that have greatly diverged from other bilaterian clades. In this study, we use whole-body single-cell transcriptomics on the acoel Isodiametra pulchra to identify and characterize different cell types. Our analysis identifies the existence of ten major cell type categories in acoels all contributing to main biological functions of the organism: metabolism, locomotion and movements, behavior, defense, and development. Interestingly, although most cell clusters express core fate markers shared with other animal clades, we also describe a surprisingly large number of clade-specific marker genes, suggesting the emergence of clade-specific common molecular machineries functioning in distinct cell types. Together, these results provide novel insight into the evolution of bilaterian cell types and open the door to a better understanding of the origins of the bilaterian body plan and their constitutive cell types.
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Affiliation(s)
- Jules Duruz
- Department of Biology, Institute of Zoology, University of Fribourg, Fribourg, Switzerland
| | - Cyrielle Kaltenrieder
- Department of Biology, Institute of Zoology, University of Fribourg, Fribourg, Switzerland
| | - Peter Ladurner
- Institute of Zoology and Center of Molecular Bioscience Innsbruck, University of Innsbruck, Innsbruck, Austria
| | - Rémy Bruggmann
- Institute of Cell Biology, University of Bern, Bern, Switzerland.,Interfaculty Bioinformatics Unit, University of Bern, Bern, Switzerland
| | - Pedro Martìnez
- Departament de Genètica, Universitat de Barcelona, Barcelona, Catalonia, Spain.,Institut Català de Recerca i Estudis Avancats (ICREA), Passeig de Lluís Companys, Barcelona, Spain
| | - Simon G Sprecher
- Department of Biology, Institute of Zoology, University of Fribourg, Fribourg, Switzerland
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5
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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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6
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Gavilán B, Sprecher SG, Hartenstein V, Martinez P. The digestive system of xenacoelomorphs. Cell Tissue Res 2019; 377:369-382. [PMID: 31093756 DOI: 10.1007/s00441-019-03038-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 04/16/2019] [Indexed: 11/26/2022]
Abstract
Interest in the study of Xenacoelomorpha has recently been revived due to realization of its key phylogenetic position as the putative sister group of the remaining Bilateria. Phylogenomic studies have attracted the attention of researchers interested in the evolution of animals and the origin of novelties. However, it is clear that a proper understanding of novelties can only be gained in the context of thorough descriptions of the anatomy of the different members of this phylum. A considerable literature, based mainly on conventional histological techniques, describes different aspects of xenacoelomorphs' tissue architecture. However, the focus has been somewhat uneven; some tissues, such as the neuro-muscular system, are relatively well described in most groups, whereas others, including the digestive system, are only poorly understood. Our lack of knowledge of the xenacoelomorph digestive system is exacerbated by the assumption that, at least in Acoela, which possess a syncytial gut, the digestive system is a derived and specialized tissue with little bearing on what is observed in other bilaterian animals. Here, we try to remedy this lack of attention by revisiting the different studies of the xenacoelomorph digestive system, and we discuss the diversity present in the light of new evolutionary knowledge.
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Affiliation(s)
- B Gavilán
- Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
| | - S G Sprecher
- Department of Biology, University of Fribourg, 10, ch. Du Musée, 1700, Fribourg, Switzerland
| | - V Hartenstein
- Department of Biology, University of California, Los Angeles, CA, USA.
| | - P Martinez
- Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain.
- Institut Català de Recerca i Estudis Avançats (ICREA), Barcelona, Spain.
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7
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Ricci L, Srivastava M. Wound-induced cell proliferation during animal regeneration. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2018; 7:e321. [PMID: 29719123 DOI: 10.1002/wdev.321] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 03/20/2018] [Accepted: 03/20/2018] [Indexed: 12/19/2022]
Abstract
Many animal species are capable of replacing missing tissues that are lost upon injury or amputation through the process of regeneration. Although the extent of regeneration is variable across animals, that is, some animals can regenerate any missing cell type whereas some can only regenerate certain organs or tissues, regulated cell proliferation underlies the formation of new tissues in most systems. Notably, many species display an increase in proliferation within hours or days upon wounding. While different cell types proliferate in response to wounding in various animal taxa, comparative molecular data are beginning to point to shared wound-induced mechanisms that regulate cell division during regeneration. Here, we synthesize current insights about early molecular pathways of regeneration from diverse model and emerging systems by considering these species in their evolutionary contexts. Despite the great diversity of mechanisms underlying injury-induced cell proliferation across animals, and sometimes even in the same species, similar pathways for proliferation have been implicated in distantly related species (e.g., small diffusible molecules, signaling from apoptotic cells, growth factor signaling, mTOR and Hippo signaling, and Wnt and Bmp pathways). Studies that explicitly interrogate molecular and cellular regenerative mechanisms in understudied animal phyla will reveal the extent to which early pathways in the process of regeneration are conserved or independently evolved. This article is categorized under: Comparative Development and Evolution > Body Plan Evolution Adult Stem Cells, Tissue Renewal, and Regeneration > Regeneration Comparative Development and Evolution > Model Systems.
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Affiliation(s)
- Lorenzo Ricci
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts
| | - Mansi Srivastava
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts
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8
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Lai AG, Aboobaker AA. EvoRegen in animals: Time to uncover deep conservation or convergence of adult stem cell evolution and regenerative processes. Dev Biol 2018; 433:118-131. [PMID: 29198565 DOI: 10.1016/j.ydbio.2017.10.010] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 10/09/2017] [Accepted: 10/10/2017] [Indexed: 01/08/2023]
Abstract
How do animals regenerate specialised tissues or their entire body after a traumatic injury, how has this ability evolved and what are the genetic and cellular components underpinning this remarkable feat? While some progress has been made in understanding mechanisms, relatively little is known about the evolution of regenerative ability. Which elements of regeneration are due to lineage specific evolutionary novelties or have deeply conserved roots within the Metazoa remains an open question. The renaissance in regeneration research, fuelled by the development of modern functional and comparative genomics, now enable us to gain a detailed understanding of both the mechanisms and evolutionary forces underpinning regeneration in diverse animal phyla. Here we review existing and emerging model systems, with the focus on invertebrates, for studying regeneration. We summarize findings across these taxa that tell us something about the evolution of adult stem cell types that fuel regeneration and the growing evidence that many highly regenerative animals harbor adult stem cells with a gene expression profile that overlaps with germline stem cells. We propose a framework in which regenerative ability broadly evolves through changes in the extent to which stem cells generated through embryogenesis are maintained into the adult life history.
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Affiliation(s)
- Alvina G Lai
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, United Kingdom
| | - A Aziz Aboobaker
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, United Kingdom.
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9
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Gehrke AR, Srivastava M. Neoblasts and the evolution of whole-body regeneration. Curr Opin Genet Dev 2016; 40:131-137. [PMID: 27498025 DOI: 10.1016/j.gde.2016.07.009] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Revised: 07/02/2016] [Accepted: 07/13/2016] [Indexed: 11/26/2022]
Abstract
The molecular mechanisms underlying whole-body regeneration are best understood in the planarian flatworm Schmidtea mediterranea, where a heterogeneous population of somatic stem cells called neoblasts provides new tissue for regeneration of essentially any missing body part. Studies on Schmidtea have provided a detailed description of neoblasts and their role in regeneration, but comparatively little is known about the evolutionary history of these cells and their underlying developmental programs. Acoels, an understudied group of aquatic worms that are also capable of extensive whole-body regeneration, have arisen as an attractive group to study the evolution of regenerative processes due to their phylogenetically distant position relative to flatworms. Here, we review the phylogenetic distribution of neoblast cells and compare their anatomical locations, transcriptional profiles, and roles during regeneration in flatworms and acoels to understand the evolution of whole-body regeneration. While the general role of neoblasts appears conserved in species separated by 550 million years of evolution, the extrinsic inputs they receive during regeneration can vary, making the distinction between homology and convergence of mechanism unclear. A more detailed understanding of the precise mechanisms behind whole-body regeneration in diverse phyla is necessary to understand the evolutionary history of this powerful process.
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Affiliation(s)
- Andrew R Gehrke
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - Mansi Srivastava
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA.
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10
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Haszprunar G. Review of data for a morphological look on Xenacoelomorpha (Bilateria incertae sedis). ORG DIVERS EVOL 2015. [DOI: 10.1007/s13127-015-0249-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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11
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Sprecher SG, Bernardo-Garcia FJ, van Giesen L, Hartenstein V, Reichert H, Neves R, Bailly X, Martinez P, Brauchle M. Functional brain regeneration in the acoel worm Symsagittifera roscoffensis. Biol Open 2015; 4:1688-95. [PMID: 26581588 PMCID: PMC4736034 DOI: 10.1242/bio.014266] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The ability of some animals to regrow their head and brain after decapitation provides a striking example of the regenerative capacity within the animal kingdom. The acoel worm Symsagittifera roscoffensis can regrow its head, brain and sensory head organs within only a few weeks after decapitation. How rapidly and to what degree it also reacquires its functionality to control behavior however remains unknown. We provide here a neuroanatomical map of the brain neuropils of the adult S. roscoffensis and show that after decapitation a normal neuroanatomical organization of the brain is restored in the majority of animals. By testing different behaviors we further show that functionality of both sensory perception and the underlying brain architecture are restored within weeks after decapitation. Interestingly not all behaviors are restored at the same speed and to the same extent. While we find that phototaxis recovered rapidly, geotaxis is not restored within 7 weeks. Our findings show that regeneration of the head, sensory organs and brain result in the restoration of directed navigation behavior, suggesting a tight coordination in the regeneration of certain sensory organs with that of their underlying neural circuits. Thus, at least in S. roscoffensis, the regenerative capacity of different sensory modalities follows distinct paths. Summary: Brain and head regeneration in the acoel Symsagittifera roscoffensis is coordinated with restoration of directed navigation behavior, suggesting that the regenerative capacity of different sensory modalities follows distinct paths.
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Affiliation(s)
- Simon G Sprecher
- Institute of Developmental and Cell Biology, Department of Biology, University of Fribourg, Chemin du Musée 10, Fribourg 1700, Switzerland
| | - F Javier Bernardo-Garcia
- Institute of Developmental and Cell Biology, Department of Biology, University of Fribourg, Chemin du Musée 10, Fribourg 1700, Switzerland
| | - Lena van Giesen
- Institute of Developmental and Cell Biology, Department of Biology, University of Fribourg, Chemin du Musée 10, Fribourg 1700, Switzerland
| | - Volker Hartenstein
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, 621 Charles E. Young Drive, East Boyer Hall 559, Los Angeles, CA 90095-1606, USA
| | - Heinrich Reichert
- Biozentrum, University of Basel, Klingelbergstrasse 50, Basel 4056, Switzerland
| | - Ricardo Neves
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, 621 Charles E. Young Drive, East Boyer Hall 559, Los Angeles, CA 90095-1606, USA
| | - Xavier Bailly
- UPMC-CNRS, FR2424, Station Biologique de Roscoff, Roscoff 29680, France
| | - Pedro Martinez
- Departament de Genètica, Universitat de Barcelona, A v. Diagonal, 643, Barcelona, Catalonia 08028, Spain Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluís Companys, Barcelona, Catalonia 23 08010, Spain
| | - Michael Brauchle
- Institute of Developmental and Cell Biology, Department of Biology, University of Fribourg, Chemin du Musée 10, Fribourg 1700, Switzerland
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