1
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Bray SR, Wyss LS, Chai C, Lozada ME, Wang B. Adaptive robustness through incoherent signaling mechanisms in a regenerative brain. Cell Rep 2024; 43:114580. [PMID: 39133614 DOI: 10.1016/j.celrep.2024.114580] [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: 06/15/2023] [Revised: 05/08/2024] [Accepted: 07/18/2024] [Indexed: 08/21/2024] Open
Abstract
Animal behavior emerges from collective dynamics of neurons, making it vulnerable to damage. Paradoxically, many organisms exhibit a remarkable ability to maintain significant behavior even after large-scale neural injury. Molecular underpinnings of this extreme robustness remain largely unknown. Here, we develop a quantitative pipeline to measure long-lasting latent states in planarian flatworm behaviors during whole-brain regeneration. By combining >20,000 animal trials with neural network modeling, we show that long-range volumetric peptidergic signals allow the planarian to rapidly restore coarse behavior output after large perturbations to the nervous system, while slow restoration of small-molecule neuromodulator functions refines precision. This relies on the different time and length scales of neuropeptide and small-molecule transmission to generate incoherent patterns of neural activity that competitively regulate behavior. Controlling behavior through opposing communication mechanisms creates a more robust system than either alone and may serve as a generalizable approach for constructing robust neural networks.
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Affiliation(s)
- Samuel R Bray
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Livia S Wyss
- Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Chew Chai
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Maria E Lozada
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA; Department of Biomedical Engineering, University of Miami, Coral Gables, FL 33124, USA
| | - Bo Wang
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA.
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2
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Gravato C, da Silva Barbosa R, Cavallini GS, Cruz ÁB, Pereira DH, de Souza NLGD, Carlos TD, Soares AM, Sarmento RA. Theoretical insights, degradation, and sub-lethal toxicity of thiamethoxam to the planarian Girardia tigrina. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:44068-44079. [PMID: 38922471 DOI: 10.1007/s11356-024-34067-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 06/18/2024] [Indexed: 06/27/2024]
Abstract
Advanced oxidative processes, such as Photo-Fenton, transform organic contaminants due to the attack by radicals. In this context, the lethal and sub-lethal effects of the Cruiser® 350FS (CRZ) with the active ingredient thiamethoxam (TMX) were investigated using the planarian Girardia tigrina. Degradation of thiamethoxam by the Fenton process was also assessed by using theoretical studies and the efficiency of Solar-Fenton versus Fenton. The 48 h LC50 value of CRZ for planarians was 478.6 mg L-1. The regeneration of planarians was significantly affected for concentrations ≥ 17 mg·L-1 of TMX (24 h). The Solar-Fenton showed a high degradation percentage reaching ~70%. The theoretical model showed the atoms of the TMX molecule that will suffer attacks from the formed radicals. Current results open new perspectives concerning the treatment of TMX in the aquatic environment because the 70% degradation seems to be sufficient to reach concentrations that do not induce sub-lethal effects in planarians. Further studies should determine if the by-products generated might be toxic for planaria or other organisms.
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Affiliation(s)
- Carlos Gravato
- Centre for Ecology, Evolution and Environmental Changes (cE3c) & CHANGE - Global Change and Sustainability Institute, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, Lisbon, 1749-016, Portugal
- Departamento de Biologia Animal, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, Lisbon, 1749-016, Portugal
| | - Rone da Silva Barbosa
- National Institute of Science and Technology on Terrestrial Ecotoxicology, Programa de Pós-Graduação em Produção Vegetal, Universidade Federal do Tocantins, Campus de Gurupi, Gurupi, Tocantins, 77402-970, Brazil
| | - Grasiele Soares Cavallini
- Programa de Pós-Graduação em Química, Universidade Federal do Tocantins, Campus de Gurupi, Gurupi, Tocantins, 77402-970, Brazil
| | - Állefe Barbosa Cruz
- Programa de Pós-Graduação em Química, Universidade Federal do Tocantins, Campus de Gurupi, Gurupi, Tocantins, 77402-970, Brazil
| | - Douglas Henrique Pereira
- Programa de Pós-Graduação em Química, Universidade Federal do Tocantins, Campus de Gurupi, Gurupi, Tocantins, 77402-970, Brazil
| | | | - Thayrine Dias Carlos
- Bionorte - Rede de Biodiversidade e Biotecnologia da Amazônia Legal, Universidade Federal do Tocantins, Campus de Gurupi, Gurupi, TO, 77402-970, Brazil
| | - Amadeu Mvm Soares
- CESAM & Departamento de Biologia, Universidade de Aveiro, Campus de Santiago, Aveiro, 3810-193, Portugal
| | - Renato Almeida Sarmento
- National Institute of Science and Technology on Terrestrial Ecotoxicology, Programa de Pós-Graduação em Produção Vegetal, Universidade Federal do Tocantins, Campus de Gurupi, Gurupi, Tocantins, 77402-970, Brazil.
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3
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Vila-Farré M, Rozanski A, Ivanković M, Cleland J, Brand JN, Thalen F, Grohme MA, von Kannen S, Grosbusch AL, Vu HTK, Prieto CE, Carbayo F, Egger B, Bleidorn C, Rasko JEJ, Rink JC. Evolutionary dynamics of whole-body regeneration across planarian flatworms. Nat Ecol Evol 2023; 7:2108-2124. [PMID: 37857891 PMCID: PMC10697840 DOI: 10.1038/s41559-023-02221-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 09/14/2023] [Indexed: 10/21/2023]
Abstract
Regenerative abilities vary dramatically across animals. Even amongst planarian flatworms, well-known for complete regeneration from tiny body fragments, some species have restricted regeneration abilities while others are almost entirely regeneration incompetent. Here, we assemble a diverse live collection of 40 planarian species to probe the evolution of head regeneration in the group. Combining quantification of species-specific head-regeneration abilities with a comprehensive transcriptome-based phylogeny reconstruction, we show multiple independent transitions between robust whole-body regeneration and restricted regeneration in freshwater species. RNA-mediated genetic interference inhibition of canonical Wnt signalling in RNA-mediated genetic interference-sensitive species bypassed all head-regeneration defects, suggesting that the Wnt pathway is linked to the emergence of planarian regeneration defects. Our finding that Wnt signalling has multiple roles in the reproductive system of the model species Schmidtea mediterranea raises the possibility that a trade-off between egg-laying, asexual reproduction by fission/regeneration and Wnt signalling drives regenerative trait evolution. Although quantitative comparisons of Wnt signalling levels, yolk content and reproductive strategy across our species collection remained inconclusive, they revealed divergent Wnt signalling roles in the reproductive system of planarians. Altogether, our study establishes planarians as a model taxon for comparative regeneration research and presents a framework for the mechanistic evolution of regenerative abilities.
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Affiliation(s)
- Miquel Vila-Farré
- Department of Tissue Dynamics and Regeneration, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.
| | - Andrei Rozanski
- Department of Tissue Dynamics and Regeneration, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Mario Ivanković
- Department of Tissue Dynamics and Regeneration, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - James Cleland
- Department of Tissue Dynamics and Regeneration, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Jeremias N Brand
- Department of Tissue Dynamics and Regeneration, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Felix Thalen
- Animal Evolution and Biodiversity, Georg-August-Universität Göttingen, Göttingen, Germany
- Cardio-CARE, Medizincampus Davos, Davos, Switzerland
| | - Markus A Grohme
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | | | | | - Hanh T-K Vu
- Department of Tissue Dynamics and Regeneration, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- European Molecular Biology Laboratory, Heidelberg, Germany
| | - Carlos E Prieto
- Department of Zoology & Animal Cell Biology, University of the Basque Country (UPV/EHU), Leioa, Spain
| | - Fernando Carbayo
- Laboratório de Ecologia e Evolução. Escola de Artes, Ciências e Humanidades, Universidade de São Paulo, São Paulo, Brazil
| | - Bernhard Egger
- Department of Zoology, University of Innsbruck, Innsbruck, Austria
| | - Christoph Bleidorn
- Animal Evolution and Biodiversity, Georg-August-Universität Göttingen, Göttingen, Germany
| | - John E J Rasko
- Gene and Stem Cell Therapy Program Centenary Institute, Camperdown, New South Wales, Australia
- Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
- Cell & Molecular Therapies, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia
| | - Jochen C Rink
- Department of Tissue Dynamics and Regeneration, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.
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4
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Bray SR, Wyss LS, Chai C, Lozada ME, Wang B. Adaptive robustness through incoherent signaling mechanisms in a regenerative brain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.20.523817. [PMID: 36711454 PMCID: PMC9882340 DOI: 10.1101/2023.01.20.523817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Animal behavior emerges from collective dynamics of interconnected neurons, making it vulnerable to connectome damage. Paradoxically, many organisms maintain significant behavioral output after large-scale neural injury. Molecular underpinnings of this extreme robustness remain largely unknown. Here, we develop a quantitative behavioral analysis pipeline to measure previously uncharacterized long-lasting latent memory states in planarian flatworms during whole-brain regeneration. By combining >20,000 animal trials with neural population dynamic modeling, we show that long-range volumetric peptidergic signals allow the planarian to rapidly reestablish latent states and restore coarse behavior after large structural perturbations to the nervous system, while small-molecule neuromodulators gradually refine the precision. The different time and length scales of neuropeptide and small-molecule transmission generate incoherent patterns of neural activity which competitively regulate behavior and memory. Controlling behavior through opposing communication mechanisms creates a more robust system than either alone and may serve as a generic approach to construct robust neural networks.
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Affiliation(s)
- Samuel R. Bray
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Livia S. Wyss
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Chew Chai
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Maria E. Lozada
- Department of Bioengineering, Stanford University, Stanford, CA, USA
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, USA
| | - Bo Wang
- Department of Bioengineering, Stanford University, Stanford, CA, USA
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5
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Cervera J, Levin M, Mafe S. Morphology changes induced by intercellular gap junction blocking: A reaction-diffusion mechanism. Biosystems 2021; 209:104511. [PMID: 34411690 DOI: 10.1016/j.biosystems.2021.104511] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 08/14/2021] [Indexed: 02/07/2023]
Abstract
Complex anatomical form is regulated in part by endogenous physiological communication between cells; however, the dynamics by which gap junctional (GJ) states across tissues regulate morphology are still poorly understood. We employed a biophysical modeling approach combining different signaling molecules (morphogens) to qualitatively describe the anteroposterior and lateral morphology changes in model multicellular systems due to intercellular GJ blockade. The model is based on two assumptions for blocking-induced patterning: (i) the local concentrations of two small antagonistic morphogens diffusing through the GJs along the axial direction, together with that of an independent, uncoupled morphogen concentration along an orthogonal direction, constitute the instructive patterns that modulate the morphological outcomes, and (ii) the addition of an external agent partially blocks the intercellular GJs between neighboring cells and modifies thus the establishment of these patterns. As an illustrative example, we study how the different connectivity and morphogen patterns obtained in presence of a GJ blocker can give rise to novel head morphologies in regenerating planaria. We note that the ability of GJs to regulate the permeability of morphogens post-translationally suggests a mechanism by which different anatomies can be produced from the same genome without the modification of gene-regulatory networks. Conceptually, our model biosystem constitutes a reaction-diffusion information processing mechanism that allows reprogramming of biological morphologies through the external manipulation of the intercellular GJs and the resulting changes in instructive biochemical signals.
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Affiliation(s)
- Javier Cervera
- Dept. Termodinàmica, Facultat de Física, Universitat de València, E-46100, Burjassot, Spain.
| | - Michael Levin
- Dept. of Biology and Allen Discovery Center at Tufts University, Medford, MA, 02155-4243, USA
| | - Salvador Mafe
- Dept. Termodinàmica, Facultat de Física, Universitat de València, E-46100, Burjassot, Spain
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Cigliola V, Ghila L, Chera S, Herrera PL. Tissue repair brakes: A common paradigm in the biology of regeneration. Stem Cells 2019; 38:330-339. [PMID: 31722129 DOI: 10.1002/stem.3118] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 10/09/2019] [Accepted: 10/20/2019] [Indexed: 12/12/2022]
Abstract
To date, most attention on tissue regeneration has focused on the exploration of positive cues promoting or allowing the engagement of natural cellular restoration upon injury. In contrast, the signals fostering cell identity maintenance in the vertebrate body have been poorly investigated; yet they are crucial, for their counteraction could become a powerful method to induce and modulate regeneration. Here we review the mechanisms inhibiting pro-regenerative spontaneous adaptive cell responses in different model organisms and organs. The pharmacological or genetic/epigenetic modulation of such regenerative brakes could release a dormant but innate adaptive competence of certain cell types and therefore boost tissue regeneration in different situations.
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Affiliation(s)
- Valentina Cigliola
- Department of Cell Biology, Regeneration Next, Duke University Medical Center, Durham, North Carolina
| | - Luiza Ghila
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Simona Chera
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Pedro L Herrera
- Department of Genetic Medicine & Development, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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7
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Ross KG, Currie KW, Pearson BJ, Zayas RM. Nervous system development and regeneration in freshwater planarians. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2017; 6. [DOI: 10.1002/wdev.266] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 01/10/2017] [Accepted: 01/20/2017] [Indexed: 01/22/2023]
Affiliation(s)
- Kelly G. Ross
- Department of Biology San Diego State University San Diego CA USA
| | - Ko W. Currie
- Program in Developmental and Stem Cell Biology The Hospital for Sick Children Toronto Canada
- Department of Molecular Genetics University of Toronto Toronto Canada
- Ontario Institute for Cancer Research Toronto Canada
| | - Bret J. Pearson
- Program in Developmental and Stem Cell Biology The Hospital for Sick Children Toronto Canada
- Department of Molecular Genetics University of Toronto Toronto Canada
- Ontario Institute for Cancer Research Toronto Canada
| | - Ricardo M. Zayas
- Department of Biology San Diego State University San Diego CA USA
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8
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Owlarn S, Bartscherer K. Go ahead, grow a head! A planarian's guide to anterior regeneration. ACTA ACUST UNITED AC 2016; 3:139-55. [PMID: 27606065 PMCID: PMC5011478 DOI: 10.1002/reg2.56] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 04/08/2016] [Accepted: 04/15/2016] [Indexed: 12/12/2022]
Abstract
The unique ability of some planarian species to regenerate a head de novo, including a functional brain, provides an experimentally accessible system in which to study the mechanisms underlying regeneration. Here, we summarize the current knowledge on the key steps of planarian head regeneration (head‐versus‐tail decision, anterior pole formation and head patterning) and their molecular and cellular basis. Moreover, instructive properties of the anterior pole as a putative organizer and in coordinating anterior midline formation are discussed. Finally, we highlight that regeneration initiation occurs in a two‐step manner and hypothesize that wound‐induced and existing positional cues interact to detect tissue loss and together determine the appropriate regenerative outcomes.
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Affiliation(s)
- Suthira Owlarn
- Max Planck Research Group Stem Cells and Regeneration Max Planck Institute for Molecular Biomedicine Von-Esmarch-Str. 5448149 Münster Germany; Medical Faculty University of Münster Albert-Schweitzer-Campus 148149 Münster Germany; CiM-IMPRS Graduate School Schlossplatz 548149 Münster Germany
| | - Kerstin Bartscherer
- Max Planck Research Group Stem Cells and Regeneration Max Planck Institute for Molecular Biomedicine Von-Esmarch-Str. 5448149 Münster Germany; Medical Faculty University of Münster Albert-Schweitzer-Campus 148149 Münster Germany
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9
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Tejada-Romero B, Carter JM, Mihaylova Y, Neumann B, Aboobaker AA. JNK signalling is necessary for a Wnt- and stem cell-dependent regeneration programme. Development 2015; 142:2413-24. [PMID: 26062938 DOI: 10.1242/dev.115139] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Accepted: 06/03/2015] [Indexed: 12/23/2022]
Abstract
Regeneration involves the integration of new and old tissues in the context of an adult life history. It is clear that the core conserved signalling pathways that orchestrate development also play central roles in regeneration, and further study of conserved signalling pathways is required. Here we have studied the role of the conserved JNK signalling cascade during planarian regeneration. Abrogation of JNK signalling by RNAi or pharmacological inhibition blocks posterior regeneration and animals fail to express posterior markers. While the early injury-induced expression of polarity markers is unaffected, the later stem cell-dependent phase of posterior Wnt expression is not established. This defect can be rescued by overactivation of the Hh or Wnt signalling pathway to promote posterior Wnt activity. Together, our data suggest that JNK signalling is required to establish stem cell-dependent Wnt expression after posterior injury. Given that Jun is known to be required in vertebrates for the expression of Wnt and Wnt target genes, we propose that this interaction may be conserved and is an instructive part of planarian posterior regeneration.
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Affiliation(s)
- Belen Tejada-Romero
- Department of Zoology, Tinbergen Building, South Parks Road, University of Oxford, Oxford OX1 3PS, UK
| | - Jean-Michel Carter
- Department of Zoology, Tinbergen Building, South Parks Road, University of Oxford, Oxford OX1 3PS, UK
| | - Yuliana Mihaylova
- Department of Zoology, Tinbergen Building, South Parks Road, University of Oxford, Oxford OX1 3PS, UK
| | - Bjoern Neumann
- Department of Zoology, Tinbergen Building, South Parks Road, University of Oxford, Oxford OX1 3PS, UK
| | - A Aziz Aboobaker
- Department of Zoology, Tinbergen Building, South Parks Road, University of Oxford, Oxford OX1 3PS, UK
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10
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11
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Wheeler NJ, Agbedanu PN, Kimber MJ, Ribeiro P, Day TA, Zamanian M. Functional analysis of Girardia tigrina transcriptome seeds pipeline for anthelmintic target discovery. Parasit Vectors 2015; 8:34. [PMID: 25600302 PMCID: PMC4304616 DOI: 10.1186/s13071-014-0622-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 12/23/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Neglected diseases caused by helminth infections impose a massive hindrance to progress in the developing world. While basic research on parasitic flatworms (platyhelminths) continues to expand, researchers have yet to broadly adopt a free-living model to complement the study of these important parasites. METHODS We report the high-coverage sequencing (RNA-Seq) and assembly of the transcriptome of the planarian Girardia tigrina across a set of dynamic conditions. The assembly was annotated and extensive orthology analysis was used to seed a pipeline for the rational prioritization and validation of putative anthelmintic targets. A small number of targets conserved between parasitic and free-living flatworms were comparatively interrogated. RESULTS 240 million paired-end reads were assembled de novo to produce a strictly filtered predicted proteome consisting of over 22,000 proteins. Gene Ontology annotations were extended to 16,467 proteins. 2,693 sequences were identified in orthology groups spanning flukes, tapeworms and planaria, with 441 highlighted as belonging to druggable protein families. Chemical inhibitors were used on three targets in pharmacological screens using both planaria and schistosomula, revealing distinct motility phenotypes that were shown to correlate with planarian RNAi phenotypes. CONCLUSIONS This work provides the first comprehensive and annotated sequence resource for the model planarian G. tigrina, alongside a prioritized list of candidate drug targets conserved among parasitic and free-living flatworms. As proof of principle, we show that a simple RNAi and pharmacology pipeline in the more convenient planarian model system can inform parasite biology and serve as an efficient screening tool for the identification of lucrative anthelmintic targets.
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Affiliation(s)
- Nicolas J Wheeler
- Department of Biomedical Sciences, Iowa State University, Ames, IA, 50010, USA.
| | - Prince N Agbedanu
- Department of Biomedical Sciences, Iowa State University, Ames, IA, 50010, USA.
| | - Michael J Kimber
- Department of Biomedical Sciences, Iowa State University, Ames, IA, 50010, USA.
| | - Paula Ribeiro
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, QC, H9X 3V9, Canada.
| | - Tim A Day
- Department of Biomedical Sciences, Iowa State University, Ames, IA, 50010, USA.
| | - Mostafa Zamanian
- Department of Biomedical Sciences, Iowa State University, Ames, IA, 50010, USA. .,Institute of Parasitology, McGill University, Ste. Anne de Bellevue, QC, H9X 3V9, Canada.
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12
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Optical coherence tomography: a new strategy to image planarian regeneration. Sci Rep 2014; 4:6316. [PMID: 25204535 PMCID: PMC4159628 DOI: 10.1038/srep06316] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 08/11/2014] [Indexed: 02/02/2023] Open
Abstract
The planarian is widely used as a model for studying tissue regeneration. In this study, we used optical coherence tomography (OCT) for the real-time, high-resolution imaging of planarian tissue regeneration. Five planaria were sliced transversely to produce 5 head and 5 tail fragments. During a 2-week regeneration period, OCT images of the planaria were acquired to analyze the signal attenuation rates, intensity ratios, and image texture features (including contrast, correlation, homogeneity, energy, and entropy) to compare the primitive and regenerated tissues. In the head and tail fragments, the signal attenuation rates of the regenerated fragments decreased from −0.2 dB/μm to −0.05 dB/μm, between Day 1 and Day 6, and then increased to −0.2 dB/μm on Day 14. The intensity ratios decreased to approximately 0.8 on Day 6, and increased to between 0.8 and 0.9 on Day 14. The texture parameters of contrast, correlation, and homogeneity exhibited trends similar to the signal attenuation rates and intensity ratios during the planarian regeneration. The proposed OCT parameters might provide biological information regarding cell apoptosis and the formation of a mass of new cells during planarian regeneration. Therefore, OCT imaging is a potentially effective method for planarian studies.
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13
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Fraguas S, Barberán S, Iglesias M, Rodríguez-Esteban G, Cebrià F. egr-4, a target of EGFR signaling, is required for the formation of the brain primordia and head regeneration in planarians. Development 2014; 141:1835-47. [PMID: 24700819 DOI: 10.1242/dev.101345] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
During the regeneration of freshwater planarians, polarity and patterning programs play essential roles in determining whether a head or a tail regenerates at anterior or posterior-facing wounds. This decision is made very soon after amputation. The pivotal role of the Wnt/β-catenin and Hh signaling pathways in re-establishing anterior-posterior (AP) polarity has been well documented. However, the mechanisms that control the growth and differentiation of the blastema in accordance with its AP identity are less well understood. Previous studies have described a role of Smed-egfr-3, a planarian epidermal growth factor receptor, in blastema growth and differentiation. Here, we identify Smed-egr-4, a zinc-finger transcription factor belonging to the early growth response gene family, as a putative downstream target of Smed-egfr-3. Smed-egr-4 is mainly expressed in the central nervous system and its silencing inhibits anterior regeneration without affecting the regeneration of posterior regions. Single and combinatorial RNA interference to target different elements of the Wnt/β-catenin pathway, together with expression analysis of brain- and anterior-specific markers, revealed that Smed-egr-4: (1) is expressed in two phases - an early Smed-egfr-3-independent phase and a late Smed-egfr-3-dependent phase; (2) is necessary for the differentiation of the brain primordia in the early stages of regeneration; and (3) that it appears to antagonize the activity of the Wnt/β-catenin pathway to allow head regeneration. These results suggest that a conserved EGFR/egr pathway plays an important role in cell differentiation during planarian regeneration and indicate an association between early brain differentiation and the proper progression of head regeneration.
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Affiliation(s)
- Susanna Fraguas
- Departament de Genètica de la Universitat de Barcelona and Institut de Biomedicina de la Universitat de Barcelona (IBUB), Avenida Diagonal 643, Edifici Prevosti planta 1, Barcelona 08028, Spain
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Kao D, Felix D, Aboobaker A. The planarian regeneration transcriptome reveals a shared but temporally shifted regulatory program between opposing head and tail scenarios. BMC Genomics 2013; 14:797. [PMID: 24238224 PMCID: PMC4046745 DOI: 10.1186/1471-2164-14-797] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2013] [Accepted: 11/11/2013] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Planarians can regenerate entire animals from a small fragment of the body. The regenerating fragment is able to create new tissues and remodel existing tissues to form a complete animal. Thus different fragments with very different starting components eventually converge on the same solution. In this study, we performed an extensive RNA-seq time-course on regenerating head and tail fragments to observe the differences and similarities of the transcriptional landscape between head and tail fragments during regeneration. RESULTS We have consolidated existing transcriptomic data for S. mediterranea to generate a high confidence set of transcripts for use in genome wide expression studies. We performed a RNA-seq time-course on regenerating head and tail fragments from 0 hours to 3 days. We found that the transcriptome profiles of head and tail regeneration were very different at the start of regeneration; however, an unexpected convergence of transcriptional profiles occurred at 48 hours when head and tail fragments are still morphologically distinct. By comparing differentially expressed transcripts at various time-points, we revealed that this divergence/convergence pattern is caused by a shared regulatory program that runs early in heads and later in tails.Additionally, we also performed RNA-seq on smed-prep(RNAi) tail fragments which ultimately fail to regenerate anterior structures. We find the gene regulation program in response to smed-prep(RNAi) to display the opposite regulatory trend compared to the previously mentioned share regulatory program during regeneration. Using annotation data and comparative approaches, we also identified a set of approximately 4,800 triclad specific transcripts that were enriched amongst the genes displaying differential expression during the regeneration time-course. CONCLUSION The regeneration transcriptome of head and tail regeneration provides us with a rich resource for investigating the global expression changes that occurs during regeneration. We show that very different regenerative scenarios utilize a shared core regenerative program. Furthermore, our consolidated transcriptome and annotations allowed us to identity triclad specific transcripts that are enriched within this core regulatory program. Our data support the hypothesis that both conserved aspects of animal developmental programs and recent evolutionarily innovations work in concert to control regeneration.
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Affiliation(s)
- Damian Kao
- />School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD UK
| | - Daniel Felix
- />Fundación CNIC Carlos III- Centro Nacional de Investigaciones Cardiovasculares, Melchor Fernández Almagro, 3, Madrid, Código Postal 28029 Spain
| | - Aziz Aboobaker
- />Department of Zoology, University of Oxford, The Tinbergen Building, South Parks Road, Oxford, OX1 3PS UK
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Elliott SA, Sánchez Alvarado A. The history and enduring contributions of planarians to the study of animal regeneration. WILEY INTERDISCIPLINARY REVIEWS. DEVELOPMENTAL BIOLOGY 2013; 2:301-26. [PMID: 23799578 PMCID: PMC3694279 DOI: 10.1002/wdev.82] [Citation(s) in RCA: 132] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Having an almost unlimited capacity to regenerate tissues lost to age and injury, planarians have long fascinated naturalists. In the Western hemisphere alone, their documented history spans more than 200 years. Planarians were described in the early 19th century as being 'immortal under the edge of the knife', and initial investigation of these remarkable animals was significantly influenced by studies of regeneration in other organisms and from the flourishing field of experimental embryology in the late 19th and early 20th centuries. This review strives to place the study of planarian regeneration into a broader historical context by focusing on the significance and evolution of knowledge in this field. It also synthesizes our current molecular understanding of the mechanisms of planarian regeneration uncovered since this animal's relatively recent entrance into the molecular-genetic age.
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Affiliation(s)
- Sarah A Elliott
- Howard Hughes Medical Institute and Stowers Institute for Medical Research, Kansas City, MO, USA.
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16
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Abstract
Planarians are flatworms capable of regenerating all body parts. Planarian regeneration requires neoblasts, a population of dividing cells that has been studied for over a century. Neoblast progeny generate new cells of blastemas, which are the regenerative outgrowths at wounds. If the neoblasts comprise a uniform population of cells during regeneration (e.g. they are all uncommitted and pluripotent), then specialization of new cell types should occur in multipotent, non-dividing neoblast progeny cells. By contrast, recent data indicate that some neoblasts express lineage-specific transcription factors during regeneration and in uninjured animals. These observations raise the possibility that an important early step in planarian regeneration is the specialization of neoblasts to produce specified rather than naïve blastema cells.
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Affiliation(s)
- Peter W Reddien
- Howard Hughes Medical Institute, MIT Biology, Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA 02142, USA.
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Lobo D, Malone TJ, Levin M. Towards a bioinformatics of patterning: a computational approach to understanding regulative morphogenesis. Biol Open 2013; 2:156-69. [PMID: 23429669 PMCID: PMC3575650 DOI: 10.1242/bio.20123400] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Accepted: 11/01/2012] [Indexed: 12/25/2022] Open
Abstract
The mechanisms underlying the regenerative abilities of certain model species are of central importance to the basic understanding of pattern formation. Complex organisms such as planaria and salamanders exhibit an exceptional capacity to regenerate complete body regions and organs from amputated pieces. However, despite the outstanding bottom-up efforts of molecular biologists and bioinformatics focused at the level of gene sequence, no comprehensive mechanistic model exists that can account for more than one or two aspects of regeneration. The development of computational approaches that help scientists identify constructive models of pattern regulation is held back by the lack of both flexible morphological representations and a repository for the experimental procedures and their results (altered pattern formation). No formal representation or computational tools exist to efficiently store, search, or mine the available knowledge from regenerative experiments, inhibiting fundamental insights from this huge dataset. To overcome these problems, we present here a new class of ontology to encode formally and unambiguously a very wide range of possible morphologies, manipulations, and experiments. This formalism will pave the way for top-down approaches for the discovery of comprehensive models of regeneration. We chose the planarian regeneration dataset to illustrate a proof-of-principle of this novel bioinformatics of shape; we developed a software tool to facilitate the formalization and mining of the planarian experimental knowledge, and cured a database containing all of the experiments from the principal publications on planarian regeneration. These resources are freely available for the regeneration community and will readily assist researchers in identifying specific functional data in planarian experiments. More importantly, these applications illustrate the presented framework for formalizing knowledge about functional perturbations of morphogenesis, which is widely applicable to numerous model systems beyond regenerating planaria, and can be extended to many aspects of functional developmental, regenerative, and evolutionary biology.
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Affiliation(s)
| | | | - Michael Levin
- Tufts Center for Regenerative and Developmental Biology, and Department of Biology, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155, USA
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Blassberg RA, Felix DA, Tejada-Romero B, Aboobaker AA. PBX/extradenticle is required to re-establish axial structures and polarity during planarian regeneration. Development 2013; 140:730-9. [PMID: 23318635 DOI: 10.1242/dev.082982] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Recent advances in a number of systems suggest many genes involved in orchestrating regeneration are redeployed from similar processes in development, with others being novel to the regeneration process in particular lineages. Of particular importance will be understanding the architecture of regenerative genetic regulatory networks and whether they are conserved across broad phylogenetic distances. Here, we describe the role of the conserved TALE class protein PBX/Extradenticle in planarians, a representative member of the Lophotrocozoa. PBX/Extradenticle proteins play central roles in both embryonic and post-embryonic developmental patterning in both vertebrates and insects, and we demonstrate a broad requirement during planarian regeneration. We observe that Smed-pbx has pleiotropic functions during regeneration, with a primary role in patterning the anterior-posterior (AP) axis and AP polarity. Smed-pbx is required for expression of polarity determinants notum and wnt1 and for correct patterning of the structures polarized along the AP axis, such as the brain, pharynx and gut. Overall, our data suggest that Smed-pbx functions as a central integrator of positional information to drive patterning of regeneration along the body axis.
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Affiliation(s)
- Robert A Blassberg
- Department of Zoology, Tinbergen Building, University of Oxford, South Parks Road, Oxford OX1 3PS, UK.
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