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Melnikov NP, Lavrov AI. Cell cycle dynamics of food-entrapping cells of sponges: an experimental approach. FEBS J 2024; 291:2405-2422. [PMID: 38401057 DOI: 10.1111/febs.17098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 12/03/2023] [Accepted: 01/30/2024] [Indexed: 02/26/2024]
Abstract
Sponges (phylum Porifera) exhibit surprisingly complex tissue dynamics, maintaining constant cell turnover and migration, rearranging internal structures, and regenerating after severe injuries. Such tissue plasticity relies on the activity of proliferating cells represented primarily by the food-entrapping cells, choanocytes. Although there are plenty of studies regarding the dynamics of regeneration and tissue rearrangement in sponges, cell cycle kinetics of choanocytes in intact tissues remains a controversial issue. This study is devoted to the comparative description of choanocyte cell cycle dynamics in intact tissues of two sponges, Halisarca dujardinii (class Demospongiae) and Leucosolenia corallorrhiza (class Calcarea). We have identified populations of proliferating cells and synchronized them in the S-phase to estimate the growth fraction of cycling cells. Using continuous exposure to labeled thymidine analog ethynyl deoxyuridine (EdU), we calculated choanocyte cell cycle duration and the length of the S phase. We also applied double labeling with EdU and antibodies against phosphorylated histone 3 to estimate the lengths of choanocyte M and G2 phases. Finally, flow-cytometry-based quantitative analysis of DNA content provided us with the lengths of G2 and G1 phases. We found that tissue growth and renewal in the studied sponges are generally maintained by a relatively large population of slowly cycling choanocytes with a total cell cycle duration of 40 h in H. dujardinii and 60 h in L. corallorrhiza. In both species, choanocytes are characterized by an extremely short M-phase and heterogeneity in the duration of the G2 phase.
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Affiliation(s)
- Nikolai P Melnikov
- Department of Invertebrate Zoology, Biological Faculty, Lomonosov Moscow State University, Russia
| | - Andrey I Lavrov
- Pertsov White Sea Biological Station, Biological Faculty, Lomonosov Moscow State University, Russia
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2
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Skorentseva KV, Bolshakov FV, Saidova AA, Lavrov AI. Regeneration in calcareous sponge relies on 'purse-string' mechanism and the rearrangements of actin cytoskeleton. Cell Tissue Res 2023; 394:107-129. [PMID: 37466725 DOI: 10.1007/s00441-023-03810-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 07/05/2023] [Indexed: 07/20/2023]
Abstract
The crucial step in any regeneration process is epithelization, i.e. the restoration of an epithelium structural and functional integrity. Epithelization requires cytoskeletal rearrangements, primarily of actin filaments and microtubules. Sponges (phylum Porifera) are early branching metazoans with pronounced regenerative abilities. Calcareous sponges have a unique step during regeneration: the formation of a temporary structure, called regenerative membrane which initially covers a wound. It forms due to the morphallactic rearrangements of exopinaco- and choanoderm epithelial-like layers. The current study quantitatively evaluates morphological changes and characterises underlying actin cytoskeleton rearrangements during regenerative membrane formation in asconoid calcareous sponge Leucosolenia variabilis through a combination of time-lapse imaging, immunocytochemistry, and confocal laser scanning microscopy. Regenerative membrane formation has non-linear stochastic dynamics with numerous fluctuations. The pinacocytes at the leading edge of regenerative membrane form a contractile actomyosin cable. Regenerative membrane formation either depends on its contraction or being coordinated through it. The cell morphology changes significantly during regenerative membrane formation. Exopinacocytes flatten, their area increases, while circularity decreases. Choanocytes transdifferentiate into endopinacocytes, losing microvillar collar and flagellum. Their area increases and circularity decreases. Subsequent redifferentiation of endopinacocytes into choanocytes is accompanied by inverse changes in cell morphology. All transformations rely on actin filament rearrangements similar to those characteristic of bilaterian animals. Altogether, we provide here a qualitative and quantitative description of cell transformations during reparative epithelial morphogenesis in a calcareous sponge.
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Affiliation(s)
- Kseniia V Skorentseva
- Laboratory of Morphogenesis Evolution, Koltzov Institute of Developmental Biology of Russian Academy of Sciences, 26 Vavilov Street, Moscow, 119334, Russia.
| | - Fyodor V Bolshakov
- Pertsov White Sea Biological Station, Faculty of Biology, Lomonosov Moscow State University, Leninskiye Gory, 1 Build. 12, Moscow, 119234, Russia
| | - Alina A Saidova
- Department of Cell Biology and Histology, Faculty of Biology, Lomonosov Moscow State University, Leninskiye Gory, 1 Build. 12, Moscow, 119234, Russia
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, 32 Vavilov Street, Moscow, 119991, Russia
| | - Andrey I Lavrov
- Pertsov White Sea Biological Station, Faculty of Biology, Lomonosov Moscow State University, Leninskiye Gory, 1 Build. 12, Moscow, 119234, Russia
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3
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When being flexible matters: Ecological underpinnings for the evolution of collective flexibility and task allocation. Proc Natl Acad Sci U S A 2022; 119:e2116066119. [PMID: 35486699 PMCID: PMC9170069 DOI: 10.1073/pnas.2116066119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
A central problem in evolutionary biology is explaining variation in the organization of task allocation across collective systems. Why do human cells irreversibly adopt a task during development (e.g., kidney vs. liver cell), while sponge cells switch between different cell types? And why have only some ant species evolved specialized castes of workers for particular tasks? Although it seems reasonable to suppose that such differences reflect, at least partially, the different ecological pressures that systems face, there is no general understanding of how a system’s dynamic environment shapes its task allocation. To this end, we develop a general mathematical framework that reveals how simple ecological considerations could potentially explain cross-system variation in task allocation—including in flexibility, specialization, and (in)activity. Task allocation is a central feature of collective organization. Living collective systems, such as multicellular organisms or social insect colonies, have evolved diverse ways to allocate individuals to different tasks, ranging from rigid, inflexible task allocation that is not adjusted to changing circumstances to more fluid, flexible task allocation that is rapidly adjusted to the external environment. While the mechanisms underlying task allocation have been intensely studied, it remains poorly understood whether differences in the flexibility of task allocation can be viewed as adaptive responses to different ecological contexts—for example, different degrees of temporal variability. Motivated by this question, we develop an analytically tractable mathematical framework to explore the evolution of task allocation in dynamic environments. We find that collective flexibility is not necessarily always adaptive, and fails to evolve in environments that change too slowly (relative to how long tasks can be left unattended) or too quickly (relative to how rapidly task allocation can be adjusted). We further employ the framework to investigate how environmental variability impacts the internal organization of task allocation, which allows us to propose adaptive explanations for some puzzling empirical observations, such as seemingly unnecessary task switching under constant environmental conditions, apparent task specialization without efficiency benefits, and high levels of individual inactivity. Altogether, this work provides a general framework for probing the evolved diversity of task allocation strategies in nature and reinforces the idea that considering a system’s ecology is crucial to explaining its collective organization.
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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: 17] [Impact Index Per Article: 8.5] [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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Martinez P, Ballarin L, Ereskovsky AV, Gazave E, Hobmayer B, Manni L, Rottinger E, Sprecher SG, Tiozzo S, Varela-Coelho A, Rinkevich B. Articulating the "stem cell niche" paradigm through the lens of non-model aquatic invertebrates. BMC Biol 2022; 20:23. [PMID: 35057814 PMCID: PMC8781081 DOI: 10.1186/s12915-022-01230-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 01/12/2022] [Indexed: 12/13/2022] Open
Abstract
Stem cells (SCs) in vertebrates typically reside in "stem cell niches" (SCNs), morphologically restricted tissue microenvironments that are important for SC survival and proliferation. SCNs are broadly defined by properties including physical location, but in contrast to vertebrates and other "model" organisms, aquatic invertebrate SCs do not have clearly documented niche outlines or properties. Life strategies such as regeneration or asexual reproduction may have conditioned the niche architectural variability in aquatic or marine animal groups. By both establishing the invertebrates SCNs as independent types, yet allowing inclusiveness among them, the comparative analysis will allow the future functional characterization of SCNs.
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Affiliation(s)
- 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.
| | - L Ballarin
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35100, Padova, Italy
| | - A V Ereskovsky
- Aix Marseille University, Avignon Université, CNRS, IRD, IMBE, Marseille, France
- St. Petersburg State University, Biological Faculty, Universitetskaya emb. 7/9, St. Petersburg, 199034, Russia
- N. K. Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Vavilova Street 26, Moscow, 119334, Russia
| | - E Gazave
- Université de Paris, CNRS, Institut Jacques Monod, F-75006, Paris, France
| | - B Hobmayer
- Department of Zoology and Center of Molecular Biosciences, University of Innsbruck, Technikerstr. 25, 6020, Innsbruck, Austria
| | - L Manni
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35100, Padova, Italy
| | - E Rottinger
- Université Côte d'Azur, CNRS, INSERM, Institute for Research on Cancer and Aging, Nice (IRCAN), Nice, France
- Université Côte d'Azur, Federative Research Institute - Marine Resources (IFR MARRES), Nice, France
| | - S G Sprecher
- Department of Biology, University of Fribourg, Chemin du Musee 10, 1700, Fribourg, Switzerland
| | - S Tiozzo
- Sorbonne Université, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Paris, France
| | - A Varela-Coelho
- ITQB NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Av. da República, 2780-157, Oeiras, Portugal
| | - B Rinkevich
- Israel Oceanography and Limnological Research, National Institute of Oceanography, Tel Shikmona, P.O. Box 8030, 31080, Haifa, Israel.
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Kravchuk OI, Burakov AV, Gornostaev NG, Mikhailov KV, Adameyko KI, Finoshin AD, Georgiev AA, Mikhailov VS, Yeryukova YE, Rubinovsky GA, Zayts DV, Gazizova GR, Gusev OA, Shagimardanova EI, Lyupina YV. Histone Deacetylases in the Process of Halisarca dujardini Cell Reaggregation. Russ J Dev Biol 2021. [DOI: 10.1134/s1062360421050052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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7
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Soubigou A, Ross EG, Touhami Y, Chrismas N, Modepalli V. Regeneration in the sponge Sycon ciliatum partly mimics postlarval development. Development 2020; 147:dev.193714. [PMID: 33093150 DOI: 10.1242/dev.193714] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Accepted: 10/13/2020] [Indexed: 12/20/2022]
Abstract
Somatic cells dissociated from an adult sponge can reorganize and develop into a juvenile-like sponge, a remarkable phenomenon of regeneration. However, the extent to which regeneration recapitulates embryonic developmental pathways has remained enigmatic. We have standardized and established a sponge Sycon ciliatum regeneration protocol from dissociated cells. Morphological analysis demonstrated that dissociated sponge cells follow a series of morphological events resembling postembryonic development. We performed high-throughput sequencing on regenerating samples and compared the data with that from regular postlarval development. Our comparative transcriptomic analysis revealed that sponge regeneration is as equally dynamic as embryogenesis. We found that sponge regeneration is orchestrated by recruiting pathways similar to those utilized in embryonic development. We also demonstrated that sponge regeneration is accompanied by cell death at early stages, revealing the importance of apoptosis in remodelling the primmorphs to initiate re-development. Because sponges are likely to be the first branch of extant multicellular animals, we suggest that this system can be explored to study the genetic features underlying the evolution of multicellularity and regeneration.
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Affiliation(s)
- Anael Soubigou
- Sorbonne University, Faculté de Sciences et Ingénierie, Campus Pierre et Marie Curie Jussieu, Paris 75252, France.,Marine Biological Association of the UK, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK
| | - Ethan G Ross
- Marine Biological Association of the UK, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK.,University of Southampton, School of Ocean and Earth Science, Southampton SO17 1BJ, UK
| | - Yousef Touhami
- Marine Biological Association of the UK, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK
| | - Nathan Chrismas
- Marine Biological Association of the UK, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK
| | - Vengamanaidu Modepalli
- Marine Biological Association of the UK, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK
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8
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Costa ML, de Andrade Rosa I, Andrade L, Mermelstein C, C Coutinho C. Distinct interactions between epithelial and mesenchymal cells control cell morphology and collective migration during sponge epithelial to mesenchymal transition. J Morphol 2019; 281:183-195. [PMID: 31854473 DOI: 10.1002/jmor.21090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 11/19/2019] [Accepted: 12/09/2019] [Indexed: 11/10/2022]
Abstract
Epithelial and mesenchymal cell types are basic for animal multicellularity and they have complementary functions coordinated by cellular interactions. Sponges are especially important model organisms to address the evolutionary basis of morphogenetic programs for epithelial and mesenchymal organization in animals. Evolutionary studies in sponges can contribute to the understanding of the mechanisms that control tissue maintenance and tumor progression in humans. In the present study, sponge mesenchymal and epithelial cells were isolated from the demosponge Hymeniacidon heliophila, and aggregate formation was observed by video microscopy. Epithelial-mesenchymal interaction, epithelial transition, and cell migration led to sponge cell aggregation after drastic stress. Based on their different morphologies, adhesion specificities, and motilities, we suggest a role for different sponge cell types as well as complementary functions in cell aggregation. Micromanipulation under the microscope and cell tracking were also used to promote specific grafting-host interaction, to further test the effects of cell type interaction. The loss of cell polarity and flattened shape during the epithelial to mesenchymal cell transition generated small immobile aggregates of round/amoeboid cells. The motility of these transited epithelial-cell aggregates was observed by cell tracking using fluorescent dye, but only after interaction with streams of migratory mesenchymal cells. Cell motility occurred independently of morphological changes, indicating a progressive step in the transition toward a migratory mesenchymal state. Our data suggest a two-step signaling process: (a) the lack of interaction between mesenchymal and epithelial cells triggers morphological changes; and (b) migratory mesenchymal cells instruct epithelial cells for directional cell motility. These results could have an impact on the understanding of evolutionary aspects of metastatic cancer cells. HIGHLIGHTS: Morphogenetic movements observed in modern sponges could have a common evolutionary origin with collective cell migration of human metastatic cells. A sponge regenerative model was used here to characterize epithelial and mesenchymal cells, and for the promotion of grafting/host interactions with subsequent cell tracking. The transition from epithelial to mesenchymal cell type can be observed in sponges in two steps: (a) withdrawal of epithelial/mesenchymal cell interactions to trigger morphological changes; (b) migratory mesenchymal cells to induce epithelial cells to a collective migratory state.
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Affiliation(s)
- Manoel L Costa
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro - UFRJ, Rio de Janeiro, RJ, Brazil
| | - Ivone de Andrade Rosa
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro - UFRJ, Rio de Janeiro, RJ, Brazil
| | - Leonardo Andrade
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro - UFRJ, Rio de Janeiro, RJ, Brazil
| | - Claudia Mermelstein
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro - UFRJ, Rio de Janeiro, RJ, Brazil
| | - Cristiano C Coutinho
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro - UFRJ, Rio de Janeiro, RJ, Brazil
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9
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Ereskovsky AV, Tokina DB, Saidov DM, Baghdiguian S, Le Goff E, Lavrov AI. Transdifferentiation and mesenchymal-to-epithelial transition during regeneration in Demospongiae (Porifera). JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2019; 334:37-58. [PMID: 31725194 DOI: 10.1002/jez.b.22919] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 10/15/2019] [Accepted: 10/25/2019] [Indexed: 12/18/2022]
Abstract
Origin and early evolution of regeneration mechanisms remain among the most pressing questions in animal regeneration biology. Porifera have exceptional regenerative capacities and, as early Metazoan lineage, are a promising model for studying evolutionary aspects of regeneration. Here, we focus on reparative regeneration of the body wall in the Mediterranean demosponge Aplysina cavernicola. The epithelialization of the wound surface is completed within 2 days, and the wound is completely healed within 2 weeks. The regeneration is accompanied with the formation of a mass of undifferentiated cells (blastema), which consists of archaeocytes, dedifferentiated choanocytes, anucleated amoebocytes, and differentiated spherulous cells. The main mechanisms of A. cavernicola regeneration are cell dedifferentiation with active migration and subsequent redifferentiation or transdifferentiation of polypotent cells through the mesenchymal-to-epithelial transformation. The main cell sources of the regeneration are archaeocytes and choanocytes. At early stages of the regeneration, the blastema almost devoid of cell proliferation, but after 24 hr postoperation (hpo) and up to 72 hpo numerous DNA-synthesizing cells appear there. In contrast to intact tissues, where vast majority of DNA-synthesizing cells are choanocytes, all 5-ethynyl-2'-deoxyuridine-labeled cells in the blastema are mesohyl cells. Intact tissues, distant from the wound, retains intact level of cell proliferation during whole regeneration process. For the first time, the apoptosis was studied during the regeneration of sponges. Two waves of apoptosis were detected during A. cavernicola regeneration: The first wave at 6-12 hpo and the second wave at 48-72 hpo.
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Affiliation(s)
- Alexander V Ereskovsky
- Institut Méditerranéen de Biodiversité et d'Ecologie Marine et Continentale (IMBE), Aix Marseille University, CNRS, IRD, Station Marine d'Endoume, Rue de la Batterie des Lions, Avignon University, Marseille, France.,Department of Embryology, Faculty of Biology, Saint-Petersburg State University, Saint-Petersburg, Russia.,Evolution of Morphogenesis Laboratory, Koltzov Institute of Developmental Biology of Russian Academy of Sciences, Moscow, Russia
| | - Daria B Tokina
- Institut Méditerranéen de Biodiversité et d'Ecologie Marine et Continentale (IMBE), Aix Marseille University, CNRS, IRD, Station Marine d'Endoume, Rue de la Batterie des Lions, Avignon University, Marseille, France
| | - Danial M Saidov
- Department of Invertebrate Zoology, Biological Faculty, Lomonosov Moscow State University, Moscow, Russia
| | | | - Emilie Le Goff
- ISEM, CNRS, EPHE, IRD, Université de Montpellier, Montpellier, France
| | - Andrey I Lavrov
- Department of Embryology, Faculty of Biology, Saint-Petersburg State University, Saint-Petersburg, Russia.,Pertsov White Sea Biological Station, Biological Faculty, Lomonosov Moscow State University, Moscow, Russia
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