1
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Gambino G, Iacopetti P, Ippolito C, Salvetti A, Rossi L. Starvation resistance in planarians: multiple strategies to get a thrifty phenotype. FEBS J 2024; 291:965-985. [PMID: 38037534 DOI: 10.1111/febs.17020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 10/11/2023] [Accepted: 11/29/2023] [Indexed: 12/02/2023]
Abstract
Starvation resistance is a life-saving mechanism for many organisms facing food availability fluctuation in the natural environment. Different strategies have been episodically identified for some model organisms, the first of which was the ability to suppress metabolic rate. Among the identified strategies, the ability of planarians to shrink their body under fasting conditions and revert the process after feeding (the growth-degrowth process) represents a fascinating mechanism to face long periods of fasting. The growth-degrowth process is strictly related to the capability of planarians to continuously maintain tissue homeostasis and body proportions even in challenging conditions, thanks to the presence of a population of pluripotent stem cells. Here, we take advantage of several previous studies describing the growth-degrowth process and of recent progress in the understanding of planarian homeostasis mechanisms, to identify tissue-selective transcriptional downregulation as a driving strategy for the development of a thrifty phenotype, and the p53 transcription factor as a player in adjusting tissue homeostasis in accordance with food availability.
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Affiliation(s)
- Gaetana Gambino
- Department of Clinical and Experimental Medicine, University of Pisa, Italy
| | - Paola Iacopetti
- Department of Clinical and Experimental Medicine, University of Pisa, Italy
| | - Chiara Ippolito
- Department of Clinical and Experimental Medicine, University of Pisa, Italy
| | | | - Leonardo Rossi
- Department of Clinical and Experimental Medicine, University of Pisa, Italy
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2
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Murugan NJ, Cariba S, Abeygunawardena S, Rouleau N, Payne SL. Biophysical control of plasticity and patterning in regeneration and cancer. Cell Mol Life Sci 2023; 81:9. [PMID: 38099951 PMCID: PMC10724343 DOI: 10.1007/s00018-023-05054-6] [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: 08/18/2023] [Revised: 10/12/2023] [Accepted: 11/13/2023] [Indexed: 12/18/2023]
Abstract
Cells and tissues display a remarkable range of plasticity and tissue-patterning activities that are emergent of complex signaling dynamics within their microenvironments. These properties, which when operating normally guide embryogenesis and regeneration, become highly disordered in diseases such as cancer. While morphogens and other molecular factors help determine the shapes of tissues and their patterned cellular organization, the parallel contributions of biophysical control mechanisms must be considered to accurately predict and model important processes such as growth, maturation, injury, repair, and senescence. We now know that mechanical, optical, electric, and electromagnetic signals are integral to cellular plasticity and tissue patterning. Because biophysical modalities underly interactions between cells and their extracellular matrices, including cell cycle, metabolism, migration, and differentiation, their applications as tuning dials for regenerative and anti-cancer therapies are being rapidly exploited. Despite this, the importance of cellular communication through biophysical signaling remains disproportionately underrepresented in the literature. Here, we provide a review of biophysical signaling modalities and known mechanisms that initiate, modulate, or inhibit plasticity and tissue patterning in models of regeneration and cancer. We also discuss current approaches in biomedical engineering that harness biophysical control mechanisms to model, characterize, diagnose, and treat disease states.
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Affiliation(s)
- Nirosha J Murugan
- Department of Health Sciences, Wilfrid Laurier University, Waterloo, ON, Canada.
- Allen Discovery Center, Tufts University, Medford, MA, USA.
| | - Solsa Cariba
- Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
| | | | - Nicolas Rouleau
- Department of Health Sciences, Wilfrid Laurier University, Waterloo, ON, Canada
- Allen Discovery Center, Tufts University, Medford, MA, USA
- Department of Biomedical Engineering, Tufts University, Medford, MA, USA
| | - Samantha L Payne
- Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
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3
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Cervera J, Manzanares JA, Levin M, Mafe S. Transplantation of fragments from different planaria: A bioelectrical model for head regeneration. J Theor Biol 2023; 558:111356. [PMID: 36403806 DOI: 10.1016/j.jtbi.2022.111356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 10/16/2022] [Accepted: 11/11/2022] [Indexed: 11/18/2022]
Abstract
Head-tail planaria morphologies are influenced by the electric potential differences across the animal's primary axis, as evidenced e.g. by voltage-sensitive dyes and functional experiments that create permanent lines of 2-headed but genetically wild-type animals. However, bioelectrical and biochemical models that make predictions on what would happen in the case of spatial chimeras made by tissue transplantation from different planaria (different species and head shapes) are lacking. Here, we use a bioelectrical model to qualitatively describe the effects of tissue transplantation on the shape of the regenerated head. To this end, we assume that the cells may have distinct sets of ion channels and ascribe the system outcome to the axial distributions of average cell potentials over morphologically relevant regions. Our rationale is that the distributions of signaling ions and molecules are spatially coupled with multicellular electric potentials. Thus, long-time downstream transcriptional events should be triggered by short-time bioelectrical processes. We show that relatively small differences between the ion channel characteristics of the cells could eventually give noticeable changes in the electric potential profiles and the expected morphological deviations, which suggests that small but timely bioelectrical actions may have significant morphological effects. Our approach is based on the observed relationships between bioelectrical regionalization and biochemical gradients in body-plan studies. Such models are relevant to regenerative, developmental, and cancer biology in which cells with distinct properties and morphogenetic target states confront each other in the same tissue.
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Affiliation(s)
- Javier Cervera
- Dept. Termodinàmica, Facultat de Física, Universitat de València, E-46100 Burjassot, Spain.
| | - José A Manzanares
- 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; Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, USA
| | - Salvador Mafe
- Dept. Termodinàmica, Facultat de Física, Universitat de València, E-46100 Burjassot, Spain
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4
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Shreesha L, Levin M. Cellular Competency during Development Alters Evolutionary Dynamics in an Artificial Embryogeny Model. ENTROPY (BASEL, SWITZERLAND) 2023; 25:e25010131. [PMID: 36673272 PMCID: PMC9858125 DOI: 10.3390/e25010131] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 12/23/2022] [Accepted: 12/29/2022] [Indexed: 05/25/2023]
Abstract
Biological genotypes do not code directly for phenotypes; developmental physiology is the control layer that separates genomes from capacities ascertained by selection. A key aspect is cellular competency, since cells are not passive materials but descendants of unicellular organisms with complex context-sensitive behavioral capabilities. To probe the effects of different degrees of cellular competency on evolutionary dynamics, we used an evolutionary simulation in the context of minimal artificial embryogeny. Virtual embryos consisted of a single axis of positional information values provided by cells' 'structural genes', operated upon by an evolutionary cycle in which embryos' fitness was proportional to monotonicity of the axial gradient. Evolutionary dynamics were evaluated in two modes: hardwired development (genotype directly encodes phenotype), and a more realistic mode in which cells interact prior to evaluation by the fitness function ("regulative" development). We find that even minimal ability of cells with to improve their position in the embryo results in better performance of the evolutionary search. Crucially, we observed that increasing the behavioral competency masks the raw fitness encoded by structural genes, with selection favoring improvements to its developmental problem-solving capacities over improvements to its structural genome. This suggests the existence of a powerful ratchet mechanism: evolution progressively becomes locked in to improvements in the intelligence of its agential substrate, with reduced pressure on the structural genome. This kind of feedback loop in which evolution increasingly puts more effort into the developmental software than perfecting the hardware explains the very puzzling divergence of genome from anatomy in species like planaria. In addition, it identifies a possible driver for scaling intelligence over evolutionary time, and suggests strategies for engineering novel systems in silico and in bioengineering.
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Affiliation(s)
- Lakshwin Shreesha
- UFR Fundamental and Biomedical Sciences, Université Paris Cité, 75006 Paris, France
| | - Michael Levin
- Allen Discovery Center, Tufts University, Medford, MA 02155, USA
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5
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Petersen CP. Wnt signaling in whole-body regeneration. Curr Top Dev Biol 2023; 153:347-380. [PMID: 36967200 DOI: 10.1016/bs.ctdb.2023.01.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
Regeneration abilities are widespread among animals and select species can restore any body parts removed by wounds that sever the major body axes. This capability of whole-body regeneration as exemplified in flatworm planarians, Acoels, and Cnidarians involves initial responses to injury, the assessment of wound site polarization, determination of missing tissue and programming of blastema fate, and patterned outgrowth to restore axis content and proportionality. Wnt signaling drives many shared and conserved aspects of the biology of whole-body regeneration in the planarian species Schmidtea mediterranea and Dugesia japonica, in the Acoel Hofstenia miamia, and in Cnidarians Hydra and Nematostella. These overlapping mechanisms suggest whole-body regeneration might be an ancestral property across diverse animal taxa.
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Affiliation(s)
- Christian P Petersen
- Department of Molecular Biosciences, Northwestern University, Evanston, IL, United States; Robert Lurie Comprehensive Cancer Center, Northwestern University, Evanston, IL, United States.
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6
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Single-cell transcriptomics in planaria: new tools allow new insights into cellular and evolutionary features. Biochem Soc Trans 2022; 50:1237-1246. [DOI: 10.1042/bst20210825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 09/26/2022] [Accepted: 10/04/2022] [Indexed: 11/17/2022]
Abstract
Single-cell transcriptomics has revolutionised biology allowing the quantification of gene expression in individual cells. Since each single cell contains cell type specific mRNAs, these techniques enable the classification of cell identities. Therefore, single cell methods have been used to explore the repertoire of cell types (the single cell atlas) of different organisms, including freshwater planarians. Nowadays, planarians are one of the most prominent animal models in single cell biology. They have been studied at the single cell level for over a decade using most of the available single cell methodological approaches. These include plate-based methods, such as qPCR, nanodroplet methods and in situ barcoding methods. Because of these studies, we now have a very good picture of planarian cell types and their differentiation trajectories. Planarian regenerative properties and other characteristics, such as their developmental plasticity and their capacity to reproduce asexually, ensure that another decade of single cell biology in planarians is yet to come. Here, we review these characteristics, the new biological insights that have been obtained by single-cell transcriptomics and outline the perspectives for the future.
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7
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Levin M. Technological Approach to Mind Everywhere: An Experimentally-Grounded Framework for Understanding Diverse Bodies and Minds. Front Syst Neurosci 2022; 16:768201. [PMID: 35401131 PMCID: PMC8988303 DOI: 10.3389/fnsys.2022.768201] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 01/24/2022] [Indexed: 12/11/2022] Open
Abstract
Synthetic biology and bioengineering provide the opportunity to create novel embodied cognitive systems (otherwise known as minds) in a very wide variety of chimeric architectures combining evolved and designed material and software. These advances are disrupting familiar concepts in the philosophy of mind, and require new ways of thinking about and comparing truly diverse intelligences, whose composition and origin are not like any of the available natural model species. In this Perspective, I introduce TAME-Technological Approach to Mind Everywhere-a framework for understanding and manipulating cognition in unconventional substrates. TAME formalizes a non-binary (continuous), empirically-based approach to strongly embodied agency. TAME provides a natural way to think about animal sentience as an instance of collective intelligence of cell groups, arising from dynamics that manifest in similar ways in numerous other substrates. When applied to regenerating/developmental systems, TAME suggests a perspective on morphogenesis as an example of basal cognition. The deep symmetry between problem-solving in anatomical, physiological, transcriptional, and 3D (traditional behavioral) spaces drives specific hypotheses by which cognitive capacities can increase during evolution. An important medium exploited by evolution for joining active subunits into greater agents is developmental bioelectricity, implemented by pre-neural use of ion channels and gap junctions to scale up cell-level feedback loops into anatomical homeostasis. This architecture of multi-scale competency of biological systems has important implications for plasticity of bodies and minds, greatly potentiating evolvability. Considering classical and recent data from the perspectives of computational science, evolutionary biology, and basal cognition, reveals a rich research program with many implications for cognitive science, evolutionary biology, regenerative medicine, and artificial intelligence.
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Affiliation(s)
- Michael Levin
- Allen Discovery Center at Tufts University, Medford, MA, United States
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Cambridge, MA, United States
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8
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Sheth M, Esfandiari L. Bioelectric Dysregulation in Cancer Initiation, Promotion, and Progression. Front Oncol 2022; 12:846917. [PMID: 35359398 PMCID: PMC8964134 DOI: 10.3389/fonc.2022.846917] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 02/21/2022] [Indexed: 12/12/2022] Open
Abstract
Cancer is primarily a disease of dysregulation – both at the genetic level and at the tissue organization level. One way that tissue organization is dysregulated is by changes in the bioelectric regulation of cell signaling pathways. At the basis of bioelectricity lies the cellular membrane potential or Vmem, an intrinsic property associated with any cell. The bioelectric state of cancer cells is different from that of healthy cells, causing a disruption in the cellular signaling pathways. This disruption or dysregulation affects all three processes of carcinogenesis – initiation, promotion, and progression. Another mechanism that facilitates the homeostasis of cell signaling pathways is the production of extracellular vesicles (EVs) by cells. EVs also play a role in carcinogenesis by mediating cellular communication within the tumor microenvironment (TME). Furthermore, the production and release of EVs is altered in cancer. To this end, the change in cell electrical state and in EV production are responsible for the bioelectric dysregulation which occurs during cancer. This paper reviews the bioelectric dysregulation associated with carcinogenesis, including the TME and metastasis. We also look at the major ion channels associated with cancer and current technologies and tools used to detect and manipulate bioelectric properties of cells.
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Affiliation(s)
- Maulee Sheth
- Department of Biomedical Engineering, University of Cincinnati, Cincinnati, OH, United States
| | - Leyla Esfandiari
- Department of Biomedical Engineering, University of Cincinnati, Cincinnati, OH, United States
- Department of Electrical Engineering and Computer Science, University of Cincinnati, Cincinnati, OH, United States
- Department of Environmental and Public Health Sciences, University of Cincinnati, Cincinnati, OH, United States
- *Correspondence: Leyla Esfandiari,
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9
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Coronel-Córdoba P, Molina MD, Cardona G, Fraguas S, Pascual-Carreras E, Saló E, Cebrià F, Adell T. FoxK1 is Required for Ectodermal Cell Differentiation During Planarian Regeneration. Front Cell Dev Biol 2022; 10:808045. [PMID: 35273960 PMCID: PMC8901602 DOI: 10.3389/fcell.2022.808045] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 01/25/2022] [Indexed: 11/24/2022] Open
Abstract
Forkhead box (Fox) genes belong to the “winged helix” transcription factor superfamily. The function of some Fox genes is well known, such as the role of foxO in controlling metabolism and longevity and foxA in controlling differentiation of endodermal tissues. However, the role of some Fox factors is not yet well characterized. Such is the case of FoxK genes, which are mainly studied in mammals and have been implicated in diverse processes including cell proliferation, tissue differentiation and carcinogenesis. Planarians are free-living flatworms, whose importance in biomedical research lies in their regeneration capacity. Planarians possess a wide population of pluripotent adult stem cells, called neoblasts, which allow them to regenerate any body part after injury. In a recent study, we identified three foxK paralogs in the genome of Schmidtea mediterranea. In this study, we demonstrate that foxK1 inhibition prevents regeneration of the ectodermal tissues, including the nervous system and the epidermis. These results correlate with foxK1 expression in neoblasts and in neural progenitors. Although the triggering of wound genes expression, polarity reestablishment and proliferation was not affected after foxK1 silencing, the apoptotic response was decreased. Altogether, these results suggest that foxK1 would be required for differentiation and maintenance of ectodermal tissues.
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Affiliation(s)
- Pablo Coronel-Córdoba
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Barcelona, Spain.,Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain
| | - M Dolores Molina
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Barcelona, Spain.,Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain
| | - Gemma Cardona
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Barcelona, Spain.,Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain
| | - Susanna Fraguas
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Barcelona, Spain.,Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain
| | - Eudald Pascual-Carreras
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Barcelona, Spain.,Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain
| | - Emili Saló
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Barcelona, Spain.,Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain
| | - Francesc Cebrià
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Barcelona, Spain.,Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain
| | - Teresa Adell
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Barcelona, Spain.,Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain
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10
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Grodstein J, Levin M. A Computational Approach to Explaining Bioelectrically Induced Persistent, Stochastic Changes of Axial Polarity in Planarian Regeneration. Bioelectricity 2022. [DOI: 10.1089/bioe.2021.0036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Joel Grodstein
- Department of Electrical and Computer Engineering, Tufts University, Medford, Massachusetts, USA
| | - Michael Levin
- Allen Discovery Center at Tufts University, Medford, Massachusetts, USA
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Boston, Massachusetts, USA
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11
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Grodstein J, Levin M. Stability and robustness properties of bioelectric networks: A computational approach. BIOPHYSICS REVIEWS 2021; 2:031305. [PMID: 38505634 PMCID: PMC10903393 DOI: 10.1063/5.0062442] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 09/07/2021] [Indexed: 03/21/2024]
Abstract
Morphogenesis during development and regeneration requires cells to communicate and cooperate toward the construction of complex anatomical structures. One important set of mechanisms for coordinating growth and form occurs via developmental bioelectricity-the dynamics of cellular networks driving changes of resting membrane potential which interface with transcriptional and biomechanical downstream cascades. While many molecular details have been elucidated about the instructive processes mediated by ion channel-dependent signaling outside of the nervous system, future advances in regenerative medicine and bioengineering require the understanding of tissue, organ, or whole body-level properties. A key aspect of bioelectric networks is their robustness, which can drive correct, invariant patterning cues despite changing cell number and anatomical configuration of the underlying tissue network. Here, we computationally analyze the minimal models of bioelectric networks and use the example of the regenerating planarian flatworm, to reveal important system-level aspects of bioelectrically derived patterns. These analyses promote an understanding of the robustness of circuits controlling regeneration and suggest design properties that can be exploited for synthetic bioengineering.
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Affiliation(s)
- Joel Grodstein
- Department of Electrical and Computer Engineering, Tufts University, Medford, Massachusetts 02155, USA
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12
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Gambino G, Ippolito C, Evangelista M, Salvetti A, Rossi L. Sub-Lethal 5-Fluorouracil Dose Challenges Planarian Stem Cells Promoting Transcriptional Profile Changes in the Pluripotent Sigma-Class Neoblasts. Biomolecules 2021; 11:biom11070949. [PMID: 34206807 PMCID: PMC8301986 DOI: 10.3390/biom11070949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 06/14/2021] [Accepted: 06/22/2021] [Indexed: 11/16/2022] Open
Abstract
Under physiological conditions, the complex planarian neoblast system is a composite of hierarchically organized stem cell sub-populations with sigma-class neoblasts, including clonogenic neoblasts, endowed with larger self-renewal and differentiation capabilities, thus generating all the other sub-populations and dominating the regenerative process. This complex system responds to differentiated tissue demands, ensuring a continuous cell turnover in a way to replace aged specialized cells and maintain tissue functionality. Potency of the neoblast system can be appreciated under challenging conditions in which these stem cells are massively depleted and the few remaining repopulate the entire body, ensuring animal resilience. These challenging conditions offer the possibility to deepen the relationships among different neoblast sub-populations, allowing to expose uncanonical properties that are negligible under physiological conditions. In this paper, we employ short, sub-lethal 5-fluorouracil treatment to specifically affect proliferating cells passing through the S phase and demonstrate that S-phase slowdown triggers a shift in the transcriptional profile of sigma neoblasts, which reduces the expression of their hallmark sox-P1. Later, some cells reactivate sox-P1 expression, suggesting that some neoblasts in the earlier steps of commitment could modulate their expression profile, reacquiring a wider differentiative potential.
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Affiliation(s)
- Gaetana Gambino
- Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy; (G.G.); (C.I.); (L.R.)
| | - Chiara Ippolito
- Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy; (G.G.); (C.I.); (L.R.)
| | | | - Alessandra Salvetti
- Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy; (G.G.); (C.I.); (L.R.)
- Correspondence: ; Tel.: +39-0502219108
| | - Leonardo Rossi
- Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy; (G.G.); (C.I.); (L.R.)
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13
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Meddeb E, Charni M, Ben Abdallah R, Raboudi F, Fattouch S. A molecular study of Tunisian populations of Dugesia sicula (Plathelminthes, Tricladida) through an identification of a set of genes. C R Biol 2019; 342:291-298. [PMID: 31786144 DOI: 10.1016/j.crvi.2019.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 10/30/2019] [Indexed: 10/25/2022]
Abstract
Cell regeneration is a natural repair of different types of tissue after an injury or a lesion, and is associated with asexual reproduction in some animals such as planarians. Its understanding and improvement could have repercussions for tissue repair and regeneration as far as humans are concerned. In this context, we have proceeded to an essential step, which is the identification of the genes involved in planarian regeneration in the model species. Dugesia sicula Lepori (D. sicula) is distributed around the Mediterranean Sea, and this population is found in most of Tunisian dams. The collection of identified genes is already known in other species. DjFoxG, DjPC2, DjotxA, and Cathepsin-D were identified by the PCR technique and their expression was confirmed by RT-PCR and in situ hybridization. DjFoxG gene, the FoxG1 homolog, is expressed throughout the planarian body, abundantly on stem cells. Consecutively, we choose a central nervous system (CNS) marker; the prohormone convertase 2 (DjPC2) gene. DjotxA was observed in the brain and especially in the region surrounding the eyes (visual cells). The regenerative cells of the gut of D. sicula were scored by the Cathepsin-D gene expression, which belongs to the aspartyl protease family. We found significant results through RT-PCR and In Situ Hybridization (ISH) techniques, confirming the expression of DjFoxG, DjPC2, DjotxA and Cathepsin-D genes in our specimens.
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Affiliation(s)
- Emna Meddeb
- Laboratory of Food and Molecular Biochemistry, National Institute of Applied Sciences and Technology (INSAT), University of Carthage, Zone Urbaine Nord, 1080 Tunis, Tunisia; Faculty of Sciences of Bizerte, University of Carthage, Tunis, Tunisia.
| | - Mohamed Charni
- Faculty of Sciences of Tunis, University of Tunis El Manar, Tunis, Tunisia; College of Sciences and Humanities of Dawadmi, Shaqra University, Shaqra, Kingdom of Saudi Arabia
| | - Rim Ben Abdallah
- Laboratory of Food and Molecular Biochemistry, National Institute of Applied Sciences and Technology (INSAT), University of Carthage, Zone Urbaine Nord, 1080 Tunis, Tunisia; Faculty of Sciences of Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Faten Raboudi
- ISAJC, Bir El Bey, University of Tunis, Tunis, Tunisia
| | - Sami Fattouch
- Laboratory of Food and Molecular Biochemistry, National Institute of Applied Sciences and Technology (INSAT), University of Carthage, Zone Urbaine Nord, 1080 Tunis, Tunisia
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14
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Abstract
Regeneration is the process by which lost or damaged tissue is replaced in adult organisms. Some organisms exhibit robust regenerative capabilities, while others, including humans, do not. Understanding the molecular principles governing the regenerative malleability of different organisms is of fundamental biological interest. Further, this problem has clear impact for the field of "regenerative medicine," which aspires to understand how human cells, tissues, and organs may be restored to normal function in scenarios of disease, damage, or age-related decline. This review will focus on the planarian flatworm as a powerful model system for studying the role of Ca2+ signals in regeneration. These invertebrate animals display an astounding innate regenerative capacity capable of regenerating complete organisms from tiny, excised fragments. New knowledge and methodological capabilities in this system highlight the potential for studying the role of Ca2+ signaling at multiple stages of the regenerative blueprint that controls stem cell behavior in vivo.
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Affiliation(s)
- Jonathan S Marchant
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
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15
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Goel T, Wang R, Martin S, Lanphear E, Collins EMS. Linalool acts as a fast and reversible anesthetic in Hydra. PLoS One 2019; 14:e0224221. [PMID: 31648269 PMCID: PMC6812832 DOI: 10.1371/journal.pone.0224221] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 10/08/2019] [Indexed: 01/23/2023] Open
Abstract
The ability to make transgenic Hydra lines has allowed for quantitative in vivo studies of Hydra regeneration and physiology. These studies commonly include excision, grafting and transplantation experiments along with high-resolution imaging of live animals, which can be challenging due to the animal’s response to touch and light stimuli. While various anesthetics have been used in Hydra studies, they tend to be toxic over the course of a few hours or their long-term effects on animal health are unknown. Here, we show that the monoterpenoid alcohol linalool is a useful anesthetic for Hydra. Linalool is easy to use, non-toxic, fast acting, and reversible. It has no detectable long-term effects on cell viability or cell proliferation. We demonstrate that the same animal can be immobilized in linalool multiple times at intervals of several hours for repeated imaging over 2–3 days. This uniquely allows for in vivo imaging of dynamic processes such as head regeneration. We directly compare linalool to currently used anesthetics and show its superior performance. Linalool will be a useful tool for tissue manipulation and imaging in Hydra research in both research and teaching contexts.
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Affiliation(s)
- Tapan Goel
- Department of Physics, University of California San Diego, La Jolla, CA, United States of America
- Department of Biology, Swarthmore College, Swarthmore, PA, United States of America
| | - Rui Wang
- Department of Biology, Swarthmore College, Swarthmore, PA, United States of America
- Department of Bioengineering, University of California San Diego, La Jolla, CA, United States of America
| | - Sara Martin
- Department of Biology, Swarthmore College, Swarthmore, PA, United States of America
| | - Elizabeth Lanphear
- Department of Biology, Swarthmore College, Swarthmore, PA, United States of America
| | - Eva-Maria S. Collins
- Department of Physics, University of California San Diego, La Jolla, CA, United States of America
- Department of Biology, Swarthmore College, Swarthmore, PA, United States of America
- * E-mail:
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16
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Sánchez A, Castro C, Flores DL, Gutiérrez E, Baldi P. Gap Junction Channels of Innexins and Connexins: Relations and Computational Perspectives. Int J Mol Sci 2019; 20:E2476. [PMID: 31109150 PMCID: PMC6566657 DOI: 10.3390/ijms20102476] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 05/04/2019] [Accepted: 05/14/2019] [Indexed: 12/16/2022] Open
Abstract
Gap junction (GJ) channels in invertebrates have been used to understand cell-to-cell communication in vertebrates. GJs are a common form of intercellular communication channels which connect the cytoplasm of adjacent cells. Dysregulation and structural alteration of the gap junction-mediated communication have been proven to be associated with a myriad of symptoms and tissue-specific pathologies. Animal models relying on the invertebrate nervous system have exposed a relationship between GJs and the formation of electrical synapses during embryogenesis and adulthood. The modulation of GJs as a therapeutic and clinical tool may eventually provide an alternative for treating tissue formation-related diseases and cell propagation. This review concerns the similarities between Hirudo medicinalis innexins and human connexins from nucleotide and protein sequence level perspectives. It also sets forth evidence of computational techniques applied to the study of proteins, sequences, and molecular dynamics. Furthermore, we propose machine learning techniques as a method that could be used to study protein structure, gap junction inhibition, metabolism, and drug development.
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Affiliation(s)
- Alejandro Sánchez
- Facultad de Ciencias, Universidad Autónoma de Baja California, Ensenada, Baja California 22860, Mexico.
| | - Carlos Castro
- Facultad of Ingeniería, Arquitectura y Diseño, Universidad Autónoma de Baja California, Ensenada, Baja California 22860, Mexico.
| | - Dora-Luz Flores
- Facultad of Ingeniería, Arquitectura y Diseño, Universidad Autónoma de Baja California, Ensenada, Baja California 22860, Mexico.
| | - Everardo Gutiérrez
- Facultad de Ciencias, Universidad Autónoma de Baja California, Ensenada, Baja California 22860, Mexico.
| | - Pierre Baldi
- Department of Computer Science, Institute for Genomics and Bioinformatics, and Center for Machine Learning and Intelligent Systems, University of California, Irvine, CA 92697, USA.
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17
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Pietak A, Bischof J, LaPalme J, Morokuma J, Levin M. Neural control of body-plan axis in regenerating planaria. PLoS Comput Biol 2019; 15:e1006904. [PMID: 30990801 PMCID: PMC6485777 DOI: 10.1371/journal.pcbi.1006904] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 04/26/2019] [Accepted: 02/26/2019] [Indexed: 01/01/2023] Open
Abstract
Control of axial polarity during regeneration is a crucial open question. We developed a quantitative model of regenerating planaria, which elucidates self-assembly mechanisms of morphogen gradients required for robust body-plan control. The computational model has been developed to predict the fraction of heteromorphoses expected in a population of regenerating planaria fragments subjected to different treatments, and for fragments originating from different regions along the anterior-posterior and medio-lateral axis. This allows for a direct comparison between computational and experimental regeneration outcomes. Vector transport of morphogens was identified as a fundamental requirement to account for virtually scale-free self-assembly of the morphogen gradients observed in planarian homeostasis and regeneration. The model correctly describes altered body-plans following many known experimental manipulations, and accurately predicts outcomes of novel cutting scenarios, which we tested. We show that the vector transport field coincides with the alignment of nerve axons distributed throughout the planarian tissue, and demonstrate that the head-tail axis is controlled by the net polarity of neurons in a regenerating fragment. This model provides a comprehensive framework for mechanistically understanding fundamental aspects of body-plan regulation, and sheds new light on the role of the nervous system in directing growth and form.
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Affiliation(s)
- Alexis Pietak
- Allen Discovery Center, Tufts University, Medford, Massachusetts, United States of America
| | - Johanna Bischof
- Allen Discovery Center, Tufts University, Medford, Massachusetts, United States of America
- Department of Biology, Tufts University, Medford, Massachusetts, United States of America
| | - Joshua LaPalme
- Allen Discovery Center, Tufts University, Medford, Massachusetts, United States of America
- Department of Biology, Tufts University, Medford, Massachusetts, United States of America
| | - Junji Morokuma
- Allen Discovery Center, Tufts University, Medford, Massachusetts, United States of America
- Department of Biology, Tufts University, Medford, Massachusetts, United States of America
| | - Michael Levin
- Allen Discovery Center, Tufts University, Medford, Massachusetts, United States of America
- Department of Biology, Tufts University, Medford, Massachusetts, United States of America
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18
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Tuszynski J, Tilli TM, Levin M. Ion Channel and Neurotransmitter Modulators as Electroceutical Approaches to the Control of Cancer. Curr Pharm Des 2019; 23:4827-4841. [PMID: 28554310 PMCID: PMC6340161 DOI: 10.2174/1381612823666170530105837] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 05/17/2017] [Accepted: 05/23/2017] [Indexed: 11/22/2022]
Abstract
The activities of individual cells must be tightly coordinated in order to build and maintain complex 3-dimensional body structures during embryogenesis and regeneration. Thus, one way to view cancer is within systems biology as a network disorder affecting the ability of cells to properly interact with a morphodynamic field of instructive signals that keeps proliferation and migration orchestrated toward the anatomical needs of the host or-ganism. One layer of this set of instructive microenvironmental cues is bioelectrical. Voltage gradients among all somatic cells (not just excitable nerve and muscle) control cell behavior, and the ionic coupling of cells into networks via electrochemical synapses allows them to implement tissue-level patterning decisions. These gradients have been increasingly impli-cated in the induction and suppression of tumorigenesis and metastasis, in the emerging links between developmental bioelectricity to the cancer problem. Consistent with the well-known role of neurotransmitter molecules in transducing electrical activity to downstream cascades in the brain, serotonergic signaling has likewise been implicated in cancer. Here, we review these recent data and propose new approaches for manipulating bioelectric and neurotransmitter pathways in cancer biology based on a bioelectric view of cancer. To sup-port this methodology, we present new data on the effects of the SSRI Prozac and its analog (ZINC ID = ZINC06811610) on survival of both cancer (MCF7) and normal (MCF10A) breast cells exposed to these compounds. We found an IC50 concentration (25 μM for Pro-zac and 100 μM for the Prozac analog) at which these compounds inhibited tumor cell sur-vival and proliferation. Additionally, at these concentrations, we did not observe alterations in a non-tumoral cell line. This constitutes a proof-of-concept demonstration for our hy-pothesis that the use of both existing and novel drugs as electroceuticals could serve as an alternative to highly toxic chemotherapy strategies replacing or augmenting them with less toxic alternatives. We believe this new approach forms an exciting roadmap for future bio-medical advances.
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Affiliation(s)
- Jack Tuszynski
- Department of Oncology, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta. Canada
| | - Tatiana M Tilli
- Laboratory of Biological System Modeling, National Institute for Science and Technology on Innovation in Neglected Diseases (INCT/IDN), Center for Technological Development in Health (CDTS), Oswaldo Cruz Foundation (Fiocruz), Rio de Janeiro. Brazil
| | - Michael Levin
- Biology Department, and Allen Discovery Center, Tufts University, Medford, MA, 02155. United States
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19
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Levin M, Pietak AM, Bischof J. Planarian regeneration as a model of anatomical homeostasis: Recent progress in biophysical and computational approaches. Semin Cell Dev Biol 2019; 87:125-144. [PMID: 29635019 PMCID: PMC6234102 DOI: 10.1016/j.semcdb.2018.04.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 04/03/2018] [Accepted: 04/06/2018] [Indexed: 12/22/2022]
Abstract
Planarian behavior, physiology, and pattern control offer profound lessons for regenerative medicine, evolutionary biology, morphogenetic engineering, robotics, and unconventional computation. Despite recent advances in the molecular genetics of stem cell differentiation, this model organism's remarkable anatomical homeostasis provokes us with truly fundamental puzzles about the origin of large-scale shape and its relationship to the genome. In this review article, we first highlight several deep mysteries about planarian regeneration in the context of the current paradigm in this field. We then review recent progress in understanding of the physiological control of an endogenous, bioelectric pattern memory that guides regeneration, and how modulating this memory can permanently alter the flatworm's target morphology. Finally, we focus on computational approaches that complement reductive pathway analysis with synthetic, systems-level understanding of morphological decision-making. We analyze existing models of planarian pattern control and highlight recent successes and remaining knowledge gaps in this interdisciplinary frontier field.
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Affiliation(s)
- Michael Levin
- Allen Discovery Center at Tufts University, Medford, MA 02155, United States; Biology Department, Tufts University, Medford, MA 02155, United States.
| | - Alexis M Pietak
- Allen Discovery Center at Tufts University, Medford, MA 02155, United States
| | - Johanna Bischof
- Allen Discovery Center at Tufts University, Medford, MA 02155, United States; Biology Department, Tufts University, Medford, MA 02155, United States
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20
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Sureda-Gomez M, Adell T. Planarian organizers. Semin Cell Dev Biol 2019; 87:95-104. [DOI: 10.1016/j.semcdb.2018.05.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 05/09/2018] [Accepted: 05/18/2018] [Indexed: 12/27/2022]
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21
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Durant F, Bischof J, Fields C, Morokuma J, LaPalme J, Hoi A, Levin M. The Role of Early Bioelectric Signals in the Regeneration of Planarian Anterior/Posterior Polarity. Biophys J 2019; 116:948-961. [PMID: 30799071 DOI: 10.1016/j.bpj.2019.01.029] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 01/11/2019] [Accepted: 01/16/2019] [Indexed: 01/14/2023] Open
Abstract
Axial patterning during planarian regeneration relies on a transcriptional circuit that confers distinct positional information on the two ends of an amputated fragment. The earliest known elements of this system begin demarcating differences between anterior and posterior wounds by 6 h postamputation. However, it is still unknown what upstream events break the axial symmetry, allowing a mutual repressor system to establish invariant, distinct biochemical states at the anterior and posterior ends. Here, we show that bioelectric signaling at 3 h is crucial for the formation of proper anterior-posterior polarity in planaria. Briefly manipulating the endogenous bioelectric state by depolarizing the injured tissue during the first 3 h of regeneration alters gene expression by 6 h postamputation and leads to a double-headed phenotype upon regeneration despite confirmed washout of ionophores from tissue. These data reveal a primary functional role for resting membrane potential taking place within the first 3 h after injury and kick-starting the downstream pattern of events that elaborate anatomy over the following 10 days. We propose a simple model of molecular-genetic mechanisms to explain how physiological events taking place immediately after injury regulate the spatial distribution of downstream gene expression and anatomy of regenerating planaria.
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Affiliation(s)
- Fallon Durant
- Allen Discovery Center at Tufts University, Department of Biology, Tufts University, Medford, Massachusetts
| | - Johanna Bischof
- Allen Discovery Center at Tufts University, Department of Biology, Tufts University, Medford, Massachusetts
| | - Chris Fields
- Allen Discovery Center at Tufts University, Department of Biology, Tufts University, Medford, Massachusetts
| | - Junji Morokuma
- Allen Discovery Center at Tufts University, Department of Biology, Tufts University, Medford, Massachusetts
| | - Joshua LaPalme
- Allen Discovery Center at Tufts University, Department of Biology, Tufts University, Medford, Massachusetts
| | - Alison Hoi
- Allen Discovery Center at Tufts University, Department of Biology, Tufts University, Medford, Massachusetts
| | - Michael Levin
- Allen Discovery Center at Tufts University, Department of Biology, Tufts University, Medford, Massachusetts.
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22
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Schmidt D, Reuter H, Hüttner K, Ruhe L, Rabert F, Seebeck F, Irimia M, Solana J, Bartscherer K. The Integrator complex regulates differential snRNA processing and fate of adult stem cells in the highly regenerative planarian Schmidtea mediterranea. PLoS Genet 2018; 14:e1007828. [PMID: 30557303 PMCID: PMC6312358 DOI: 10.1371/journal.pgen.1007828] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 12/31/2018] [Accepted: 11/12/2018] [Indexed: 02/07/2023] Open
Abstract
In multicellular organisms, cell type diversity and fate depend on specific sets of transcript isoforms generated by post-transcriptional RNA processing. Here, we used Schmidtea mediterranea, a flatworm with extraordinary regenerative abilities and a large pool of adult stem cells, as an in vivo model to study the role of Uridyl-rich small nuclear RNAs (UsnRNAs), which participate in multiple RNA processing reactions including splicing, in stem cell regulation. We characterized the planarian UsnRNA repertoire, identified stem cell-enriched variants and obtained strong evidence for an increased rate of UsnRNA 3'-processing in stem cells compared to their differentiated counterparts. Consistently, components of the Integrator complex showed stem cell-enriched expression and their depletion by RNAi disrupted UsnRNA processing resulting in global changes of splicing patterns and reduced processing of histone mRNAs. Interestingly, loss of Integrator complex function disrupted both stem cell maintenance and regeneration of tissues. Our data show that the function of the Integrator complex in UsnRNA 3'-processing is conserved in planarians and essential for maintaining their stem cell pool. We propose that cell type-specific modulation of UsnRNA composition and maturation contributes to in vivo cell fate choices, such as stem cell self-renewal in planarians.
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Affiliation(s)
- David Schmidt
- Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Medical Faculty, University of Münster, Münster, Germany
- * E-mail: (DS); (KB)
| | - Hanna Reuter
- Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Medical Faculty, University of Münster, Münster, Germany
| | - Katja Hüttner
- Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Medical Faculty, University of Münster, Münster, Germany
| | - Larissa Ruhe
- Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Medical Faculty, University of Münster, Münster, Germany
| | - Franziska Rabert
- Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Medical Faculty, University of Münster, Münster, Germany
| | - Florian Seebeck
- Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Medical Faculty, University of Münster, Münster, Germany
| | - Manuel Irimia
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
- Universitat Pompeu Fabra, Barcelona, Spain
| | - Jordi Solana
- Systems Biology of Gene Regulatory Elements, Berlin Institute for Medical Systems Biology, Max-Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Kerstin Bartscherer
- Max Planck Institute for Molecular Biomedicine, Münster, Germany
- Medical Faculty, University of Münster, Münster, Germany
- Hubrecht Institute for Developmental Biology and Stem Cell Research, CT Utrecht, The Netherlands
- * E-mail: (DS); (KB)
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23
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Güiza J, Barría I, Sáez JC, Vega JL. Innexins: Expression, Regulation, and Functions. Front Physiol 2018; 9:1414. [PMID: 30364195 PMCID: PMC6193117 DOI: 10.3389/fphys.2018.01414] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 09/18/2018] [Indexed: 01/02/2023] Open
Abstract
The innexin (Inx) proteins form gap junction channels and non-junctional channels (named hemichannels) in invertebrates. These channels participate in cellular communication playing a relevant role in several physiological processes. Pioneer studies conducted mainly in worms and flies have shown that innexins participate in embryo development and behavior. However, recent studies have elucidated new functions of innexins in Arthropoda, Nematoda, Annelida, and Cnidaria, such as immune response, and apoptosis. This review describes emerging data of possible new roles of innexins and summarizes the data available to date.
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Affiliation(s)
- Juan Güiza
- Laboratorio de Fisiología Experimental, Instituto Antofagasta, Universidad de Antofagasta, Antofagasta, Chile
| | - Iván Barría
- Laboratorio de Fisiología Experimental, Instituto Antofagasta, Universidad de Antofagasta, Antofagasta, Chile
| | - Juan C Sáez
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile.,Instituto de Neurociencias, Centro Interdisciplinario de Neurociencias de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - José L Vega
- Laboratorio de Fisiología Experimental, Instituto Antofagasta, Universidad de Antofagasta, Antofagasta, Chile
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24
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Bioelectrical coupling in multicellular domains regulated by gap junctions: A conceptual approach. Bioelectrochemistry 2018; 123:45-61. [DOI: 10.1016/j.bioelechem.2018.04.013] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 04/13/2018] [Accepted: 04/17/2018] [Indexed: 12/16/2022]
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25
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Birkholz TR, Van Huizen AV, Beane WS. Staying in shape: Planarians as a model for understanding regenerative morphology. Semin Cell Dev Biol 2018; 87:105-115. [PMID: 29738883 DOI: 10.1016/j.semcdb.2018.04.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 04/23/2018] [Accepted: 04/30/2018] [Indexed: 01/18/2023]
Abstract
A key requirement of tissue/organ regeneration is the ability to induce appropriate shape in situ. Regenerated structures need to be integrated with pre-existing ones, through the combined regulation of new tissue growth and the scaling of surrounding tissues. This requires a tightly coordinated control of individual cell functions such as proliferation and stem cell differentiation. While great strides have been made in elucidating cell growth and differentiation mechanisms, how overall shape is generated during regeneration remains unknown. This is because a significant gap remains in our understanding of how cell behaviors are coordinated at the level of tissues and organs. The highly regenerative planarian flatworm has emerged as an important model for defining and understanding regenerative shape mechanisms. This review provides an overview of the main processes known to regulate tissue and animal shape during planarian regeneration: adult stem cell regulation, the reestablishment of body axes, tissue remodeling in pre-existing structures, organ scaling and the maintenance of body proportion, and the bioelectrical regulation of animal morphology. In order for the field to move forward, it will be necessary to identify shape mutants as a means to uncover the molecular mechanisms that synchronize all these separate processes to produce the worm's final regenerative shape. This knowledge will also aid efforts to define the mechanisms that control the termination of regenerative processes.
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Affiliation(s)
- Taylor R Birkholz
- Department of Biological Sciences, Western Michigan University, 1903 W. Michigan Avenue, Kalamazoo, MI, 49008, USA
| | - Alanna V Van Huizen
- Department of Biological Sciences, Western Michigan University, 1903 W. Michigan Avenue, Kalamazoo, MI, 49008, USA
| | - Wendy S Beane
- Department of Biological Sciences, Western Michigan University, 1903 W. Michigan Avenue, Kalamazoo, MI, 49008, USA.
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26
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Dong Z, Yang Y, Chen G, Liu D. Identification of runt family genes involved in planarian regeneration and tissue homeostasis. Gene Expr Patterns 2018; 29:24-31. [PMID: 29649632 DOI: 10.1016/j.gep.2018.04.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 03/21/2018] [Accepted: 04/06/2018] [Indexed: 01/04/2023]
Abstract
The runt family genes play important roles in physiological processes in eukaryotic organisms by regulation of protein transcription, such as hematopoietic system, proliferation of gastric epithelial cells and neural development. However, it remains unclear about the specific functions of these genes. In this study, the full-length cDNA sequences of two runt genes are first cloned from Dugesia japonica, and their roles are investigated by WISH and RNAi. The results show that: (1) the Djrunts are conserved during evolution; (2) the Djrunts mRNA are widely expressed in intact and regenerative worms, and their expression levels are up-regulated significantly on day 1 after amputation; (3) loss of Djrunts function lead to lysis or regeneration failure in the intact and regenerating worms. Overall, the data suggests that Djrunts play important roles in regeneration and homeostatic maintenance in planarians.
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Affiliation(s)
- Zimei Dong
- College of Life Science, Henan Normal University, Xinxiang, 453007 Henan, China
| | - Yibo Yang
- College of Life Science, Henan Normal University, Xinxiang, 453007 Henan, China
| | - Guangwen Chen
- College of Life Science, Henan Normal University, Xinxiang, 453007 Henan, China.
| | - Dezeng Liu
- College of Life Science, Henan Normal University, Xinxiang, 453007 Henan, China
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27
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Fields C, Levin M. Are Planaria Individuals? What Regenerative Biology is Telling Us About the Nature of Multicellularity. Evol Biol 2018. [DOI: 10.1007/s11692-018-9448-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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28
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Silver BB, Nelson CM. The Bioelectric Code: Reprogramming Cancer and Aging From the Interface of Mechanical and Chemical Microenvironments. Front Cell Dev Biol 2018; 6:21. [PMID: 29560350 PMCID: PMC5845671 DOI: 10.3389/fcell.2018.00021] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 02/15/2018] [Indexed: 12/12/2022] Open
Abstract
Cancer is a complex, heterogeneous group of diseases that can develop through many routes. Broad treatments such as chemotherapy destroy healthy cells in addition to cancerous ones, but more refined strategies that target specific pathways are usually only effective for a limited number of cancer types. This is largely due to the multitude of physiological variables that differ between cells and their surroundings. It is therefore important to understand how nature coordinates these variables into concerted regulation of growth at the tissue scale. The cellular microenvironment might then be manipulated to drive cells toward a desired outcome at the tissue level. One unexpected parameter, cellular membrane voltage (Vm), has been documented to exert control over cellular behavior both in culture and in vivo. Manipulating this fundamental cellular property influences a remarkable array of organism-wide patterning events, producing striking outcomes in both tumorigenesis as well as regeneration. These studies suggest that Vm is not only a key intrinsic cellular property, but also an integral part of the microenvironment that acts in both space and time to guide cellular behavior. As a result, there is considerable interest in manipulating Vm both to treat cancer as well as to regenerate organs damaged or deteriorated during aging. However, such manipulations have produced conflicting outcomes experimentally, which poses a substantial barrier to understanding the fundamentals of bioelectrical reprogramming. Here, we summarize these inconsistencies and discuss how the mechanical microenvironment may impact bioelectric regulation.
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Affiliation(s)
- Brian B Silver
- Department of Molecular Biology, Princeton University, Princeton, NJ, United States
| | - Celeste M Nelson
- Department of Molecular Biology, Princeton University, Princeton, NJ, United States.,Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, United States
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29
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Levin M, Martyniuk CJ. The bioelectric code: An ancient computational medium for dynamic control of growth and form. Biosystems 2018; 164:76-93. [PMID: 28855098 PMCID: PMC10464596 DOI: 10.1016/j.biosystems.2017.08.009] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 08/20/2017] [Accepted: 08/22/2017] [Indexed: 12/19/2022]
Abstract
What determines large-scale anatomy? DNA does not directly specify geometrical arrangements of tissues and organs, and a process of encoding and decoding for morphogenesis is required. Moreover, many species can regenerate and remodel their structure despite drastic injury. The ability to obtain the correct target morphology from a diversity of initial conditions reveals that the morphogenetic code implements a rich system of pattern-homeostatic processes. Here, we describe an important mechanism by which cellular networks implement pattern regulation and plasticity: bioelectricity. All cells, not only nerves and muscles, produce and sense electrical signals; in vivo, these processes form bioelectric circuits that harness individual cell behaviors toward specific anatomical endpoints. We review emerging progress in reading and re-writing anatomical information encoded in bioelectrical states, and discuss the approaches to this problem from the perspectives of information theory, dynamical systems, and computational neuroscience. Cracking the bioelectric code will enable much-improved control over biological patterning, advancing basic evolutionary developmental biology as well as enabling numerous applications in regenerative medicine and synthetic bioengineering.
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Affiliation(s)
- Michael Levin
- Allen Discovery Center at Tufts University, Biology Department, Tufts University, 200 Boston Avenue, Suite 4600 Medford, MA 02155, USA.
| | - Christopher J Martyniuk
- Department of Physiological Sciences and Center for Environmental and Human Toxicology, University of Florida Genetics Institute, Interdisciplinary Program in Biomedical Sciences Neuroscience, College of Veterinary Medicine, University of Florida, Gainesville, FL, 32611, USA
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30
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Rink JC. Stem Cells, Patterning and Regeneration in Planarians: Self-Organization at the Organismal Scale. Methods Mol Biol 2018; 1774:57-172. [PMID: 29916155 DOI: 10.1007/978-1-4939-7802-1_2] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The establishment of size and shape remains a fundamental challenge in biological research that planarian flatworms uniquely epitomize. Planarians can regenerate complete and perfectly proportioned animals from tiny and arbitrarily shaped tissue pieces; they continuously renew all organismal cell types from abundant pluripotent stem cells, yet maintain shape and anatomy in the face of constant turnover; they grow when feeding and literally degrow when starving, while scaling form and function over as much as a 40-fold range in body length or an 800-fold change in total cell numbers. This review provides a broad overview of the current understanding of the planarian stem cell system, the mechanisms that pattern the planarian body plan and how the interplay between patterning signals and cell fate choices orchestrates regeneration. What emerges is a conceptual framework for the maintenance and regeneration of the planarian body plan on basis of the interplay between pluripotent stem cells and self-organizing patterns and further, the general utility of planarians as model system for the mechanistic basis of size and shape.
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Affiliation(s)
- Jochen C Rink
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.
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31
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Abstract
RNA in situ hybridization techniques are an important tool for the study of gene expression patterns in freshwater planarians. Here I describe a RNA in situ hybridization method on histological paraffin sections of planarian tissue. This protocol allows the visualization of gene expression at cellular or subcellular resolution. Following paraffin-embedding and sectioning of planarians, the resulting sections are hybridized with hapten-labeled RNA probes. Subsequent immunological probe detection is carried out with either chromogenic or fluorescent development. This protocol can be performed alone, or in combination with other immunodetection techniques, and represents a useful alternative to whole-mount protocols more commonly used in the community.
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Affiliation(s)
- Jordi Solana
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, UK.
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Ma K, Zhang H, Zhang Y, Song G, Wu M, Chen G. Identification of a HSP40 gene involved in planarian regeneration. Biologia (Bratisl) 2017. [DOI: 10.1515/biolog-2017-0157] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Moore D, Walker SI, Levin M. Cancer as a disorder of patterning information: computational and biophysical perspectives on the cancer problem. CONVERGENT SCIENCE PHYSICAL ONCOLOGY 2017. [DOI: 10.1088/2057-1739/aa8548] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Pietak A, Levin M. Bioelectric gene and reaction networks: computational modelling of genetic, biochemical and bioelectrical dynamics in pattern regulation. J R Soc Interface 2017; 14:20170425. [PMID: 28954851 PMCID: PMC5636277 DOI: 10.1098/rsif.2017.0425] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 08/31/2017] [Indexed: 12/17/2022] Open
Abstract
Gene regulatory networks (GRNs) describe interactions between gene products and transcription factors that control gene expression. In combination with reaction-diffusion models, GRNs have enhanced comprehension of biological pattern formation. However, although it is well known that biological systems exploit an interplay of genetic and physical mechanisms, instructive factors such as transmembrane potential (Vmem) have not been integrated into full GRN models. Here we extend regulatory networks to include bioelectric signalling, developing a novel synthesis: the bioelectricity-integrated gene and reaction (BIGR) network. Using in silico simulations, we highlight the capacity for Vmem to alter steady-state concentrations of key signalling molecules inside and out of cells. We characterize fundamental feedbacks where Vmem both controls, and is in turn regulated by, biochemical signals and thereby demonstrate Vmem homeostatic control, Vmem memory and Vmem controlled state switching. BIGR networks demonstrating hysteresis are identified as a mechanisms through which more complex patterns of stable Vmem spots and stripes, along with correlated concentration patterns, can spontaneously emerge. As further proof of principle, we present and analyse a BIGR network model that mechanistically explains key aspects of the remarkable regenerative powers of creatures such as planarian flatworms. The functional properties of BIGR networks generate the first testable, quantitative hypotheses for biophysical mechanisms underlying the stability and adaptive regulation of anatomical bioelectric pattern.
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Affiliation(s)
- Alexis Pietak
- Allen Discovery Center, Tufts University, Medford, MA, USA
| | - Michael Levin
- Allen Discovery Center, Tufts University, Medford, MA, USA
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Cassella L, Salvetti A, Iacopetti P, Ippolito C, Ghezzani C, Gimenez G, Ghigo E, Rossi L. Putrescine independent wound response phenotype is produced by ODC-like RNAi in planarians. Sci Rep 2017; 7:9736. [PMID: 28851936 PMCID: PMC5574924 DOI: 10.1038/s41598-017-09567-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 07/26/2017] [Indexed: 01/18/2023] Open
Abstract
Despite increasing evidence indicates polyamines as a convergence point for signaling pathways, including cell growth and differentiation, a unifying concept to interpret their role is still missing. The activity of ornithine decarboxylase (ODC), the rate-limiting enzyme in polyamine biosynthesis, is tightly regulated by a complex molecular machinery, and the demonstration of the existence of multiple ODC paralogs, lacking decarboxylation activity, suggests additional layers of complexity to the intricate ODC regulatory pathway. Because of their extraordinary regenerative abilities and abundance of stem cells, planarians have potential to contribute to our understanding of polyamine function in an in vivo context. We undertook a study on ODC function in planarians and we found six planarian ODCs (ODC1-6). Five out of six ODC homologs carry substitutions of key aminoacids for enzymatic activity, which makes them theoretically unable to decarboxylate ornithine. Silencing of ODC5 and 6 produced a complex phenotype, by prompting animals to an aberrant response, following chronic injury without tissue removal. Phenotype is neither rescued by putrescine, nor mimicked by difluoromethylornithine treatment. Moreover, the co-silencing of other genes of the ODC regulatory pathway did not modulate phenotype outcome or severity, thus suggesting that the function/s of these ODC-like proteins might be unrelated to decarboxylase activity and putrescine production.
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Affiliation(s)
- Lucia Cassella
- Department of Clinical and Experimental Medicine, University of Pisa, via Volta 4, 56126, Pisa, Italy
| | - Alessandra Salvetti
- Department of Clinical and Experimental Medicine, University of Pisa, via Volta 4, 56126, Pisa, Italy
| | - Paola Iacopetti
- Department of Clinical and Experimental Medicine, University of Pisa, via Volta 4, 56126, Pisa, Italy
| | - Chiara Ippolito
- Department of Clinical and Experimental Medicine, University of Pisa, via Volta 4, 56126, Pisa, Italy
| | - Claudio Ghezzani
- Department of Clinical and Experimental Medicine, University of Pisa, via Volta 4, 56126, Pisa, Italy
| | - Gregory Gimenez
- Otago Genomics & Bioinformatics Facility, Department of Biochemistry, University of Otago, PO Box 56, 710 Cumberland Street, Dunedin, 9054, New Zealand
| | - Eric Ghigo
- CNRS UMR 7278, IRD198, INSERM U1095, APHM, Institut Hospitalier Universitaire Méditerranée-Infection, Aix-Marseille Université, 19-21 Bd Jean Moulin, 13385, Marseille Cedex 05, France
| | - Leonardo Rossi
- Department of Clinical and Experimental Medicine, University of Pisa, via Volta 4, 56126, Pisa, Italy.
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Levin M, Morokuma J, Finkelstein J. Space travel has effects on planarian regeneration that cannot be explained by a null hypothesis. REGENERATION (OXFORD, ENGLAND) 2017; 4:156-158. [PMID: 29299321 PMCID: PMC5743785 DOI: 10.1002/reg2.89] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 10/03/2017] [Indexed: 06/07/2023]
Affiliation(s)
- Michael Levin
- Allen Discovery CenterTufts University200 Boston AveMedfordMA 02155–4243USA
| | - Junji Morokuma
- Allen Discovery CenterTufts University200 Boston AveMedfordMA 02155–4243USA
| | - Joshua Finkelstein
- Allen Discovery CenterTufts University200 Boston AveMedfordMA 02155–4243USA
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Stückemann T, Cleland JP, Werner S, Thi-Kim Vu H, Bayersdorf R, Liu SY, Friedrich B, Jülicher F, Rink JC. Antagonistic Self-Organizing Patterning Systems Control Maintenance and Regeneration of the Anteroposterior Axis in Planarians. Dev Cell 2017; 40:248-263.e4. [PMID: 28171748 DOI: 10.1016/j.devcel.2016.12.024] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Revised: 11/05/2016] [Accepted: 12/30/2016] [Indexed: 11/27/2022]
Abstract
Planarian flatworms maintain their body plan in the face of constant internal turnover and can regenerate from arbitrary tissue fragments. Both phenomena require self-maintaining and self-organizing patterning mechanisms, the molecular mechanisms of which remain poorly understood. We show that a morphogenic gradient of canonical Wnt signaling patterns gene expression along the planarian anteroposterior (A/P) axis. Our results demonstrate that gradient formation likely occurs autonomously in the tail and that an autoregulatory module of Wnt-mediated Wnt expression both shapes the gradient at steady state and governs its re-establishment during regeneration. Functional antagonism between the tail Wnt gradient and an unknown head patterning system further determines the spatial proportions of the planarian A/P axis and mediates mutually exclusive molecular fate choices during regeneration. Overall, our results suggest that the planarian A/P axis is patterned by self-organizing patterning systems deployed from either end that are functionally coupled by mutual antagonism.
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Affiliation(s)
- Tom Stückemann
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - James Patrick Cleland
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Steffen Werner
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Straße 38, 01187 Dresden, Germany; Center for Advancing Electronics Dresden, Technische Universität Dresden, 01062 Dresden, Germany
| | - Hanh Thi-Kim Vu
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Robert Bayersdorf
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Shang-Yun Liu
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
| | - Benjamin Friedrich
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Straße 38, 01187 Dresden, Germany; Center for Advancing Electronics Dresden, Technische Universität Dresden, 01062 Dresden, Germany
| | - Frank Jülicher
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Straße 38, 01187 Dresden, Germany
| | - Jochen Christian Rink
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany.
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Levin M, Pezzulo G, Finkelstein JM. Endogenous Bioelectric Signaling Networks: Exploiting Voltage Gradients for Control of Growth and Form. Annu Rev Biomed Eng 2017; 19:353-387. [PMID: 28633567 PMCID: PMC10478168 DOI: 10.1146/annurev-bioeng-071114-040647] [Citation(s) in RCA: 142] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Living systems exhibit remarkable abilities to self-assemble, regenerate, and remodel complex shapes. How cellular networks construct and repair specific anatomical outcomes is an open question at the heart of the next-generation science of bioengineering. Developmental bioelectricity is an exciting emerging discipline that exploits endogenous bioelectric signaling among many cell types to regulate pattern formation. We provide a brief overview of this field, review recent data in which bioelectricity is used to control patterning in a range of model systems, and describe the molecular tools being used to probe the role of bioelectrics in the dynamic control of complex anatomy. We suggest that quantitative strategies recently developed to infer semantic content and information processing from ionic activity in the brain might provide important clues to cracking the bioelectric code. Gaining control of the mechanisms by which large-scale shape is regulated in vivo will drive transformative advances in bioengineering, regenerative medicine, and synthetic morphology, and could be used to therapeutically address birth defects, traumatic injury, and cancer.
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Affiliation(s)
- Michael Levin
- Biology Department, Tufts University, Medford, Massachusetts 02155-4243;
- Allen Discovery Center, Tufts University, Medford, Massachusetts 02155;
| | - Giovanni Pezzulo
- Institute of Cognitive Sciences and Technologies, National Research Council, Rome 00185, Italy;
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Morokuma J, Durant F, Williams KB, Finkelstein JM, Blackiston DJ, Clements T, Reed DW, Roberts M, Jain M, Kimel K, Trauger SA, Wolfe BE, Levin M. Planarian regeneration in space: Persistent anatomical, behavioral, and bacteriological changes induced by space travel. ACTA ACUST UNITED AC 2017; 4:85-102. [PMID: 28616247 PMCID: PMC5469732 DOI: 10.1002/reg2.79] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 03/27/2017] [Accepted: 04/21/2017] [Indexed: 12/14/2022]
Abstract
Regeneration is regulated not only by chemical signals but also by physical processes, such as bioelectric gradients. How these may change in the absence of the normal gravitational and geomagnetic fields is largely unknown. Planarian flatworms were moved to the International Space Station for 5 weeks, immediately after removing their heads and tails. A control group in spring water remained on Earth. No manipulation of the planaria occurred while they were in orbit, and space‐exposed worms were returned to our laboratory for analysis. One animal out of 15 regenerated into a double‐headed phenotype—normally an extremely rare event. Remarkably, amputating this double‐headed worm again, in plain water, resulted again in the double‐headed phenotype. Moreover, even when tested 20 months after return to Earth, the space‐exposed worms displayed significant quantitative differences in behavior and microbiome composition. These observations may have implications for human and animal space travelers, but could also elucidate how microgravity and hypomagnetic environments could be used to trigger desired morphological, neurological, physiological, and bacteriomic changes for various regenerative and bioengineering applications.
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Affiliation(s)
- Junji Morokuma
- Allen Discovery Center at Tufts University Biology Department Tufts University 200 Boston Ave., Suite 4600 Medford MA 02155-4243 USA
| | - Fallon Durant
- Allen Discovery Center at Tufts University Biology Department Tufts University 200 Boston Ave., Suite 4600 Medford MA 02155-4243 USA
| | - Katherine B Williams
- Allen Discovery Center at Tufts University Biology Department Tufts University 200 Boston Ave., Suite 4600 Medford MA 02155-4243 USA
| | - Joshua M Finkelstein
- Allen Discovery Center at Tufts University Biology Department Tufts University 200 Boston Ave., Suite 4600 Medford MA 02155-4243 USA
| | - Douglas J Blackiston
- Allen Discovery Center at Tufts University Biology Department Tufts University 200 Boston Ave., Suite 4600 Medford MA 02155-4243 USA
| | - Twyman Clements
- Kentucky Space LLC, 200 West Vine St., Suite 420 Lexington KY 40507 USA
| | - David W Reed
- NASA Kennedy Space Center Space Station Processing Facility Building M7-0360, Kennedy Space Center FL 32899 USA
| | - Michael Roberts
- Center for the Advancement of Science in Space (CASIS) 6905 N. Wickham Rd., Suite 500 Melbourne FL 32940 USA
| | - Mahendra Jain
- Kentucky Space LLC, 200 West Vine St., Suite 420 Lexington KY 40507 USA
| | - Kris Kimel
- Exomedicine Institute 200 West Vine St. Lexington KY 40507 USA
| | - Sunia A Trauger
- Harvard University Small Molecule Mass Spectrometry Facility 52 Oxford St. Cambridge MA 02138 USA
| | - Benjamin E Wolfe
- Allen Discovery Center at Tufts University Biology Department Tufts University 200 Boston Ave., Suite 4600 Medford MA 02155-4243 USA
| | - Michael Levin
- Allen Discovery Center at Tufts University Biology Department Tufts University 200 Boston Ave., Suite 4600 Medford MA 02155-4243 USA
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Durant F, Morokuma J, Fields C, Williams K, Adams DS, Levin M. Long-Term, Stochastic Editing of Regenerative Anatomy via Targeting Endogenous Bioelectric Gradients. Biophys J 2017; 112:2231-2243. [PMID: 28538159 PMCID: PMC5443973 DOI: 10.1016/j.bpj.2017.04.011] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 03/30/2017] [Accepted: 04/14/2017] [Indexed: 12/22/2022] Open
Abstract
We show that regenerating planarians' normal anterior-posterior pattern can be permanently rewritten by a brief perturbation of endogenous bioelectrical networks. Temporary modulation of regenerative bioelectric dynamics in amputated trunk fragments of planaria stochastically results in a constant ratio of regenerates with two heads to regenerates with normal morphology. Remarkably, this is shown to be due not to partial penetrance of treatment, but a profound yet hidden alteration to the animals' patterning circuitry. Subsequent amputations of the morphologically normal regenerates in water result in the same ratio of double-headed to normal morphology, revealing a cryptic phenotype that is not apparent unless the animals are cut. These animals do not differ from wild-type worms in histology, expression of key polarity genes, or neoblast distribution. Instead, the altered regenerative bodyplan is stored in seemingly normal planaria via global patterns of cellular resting potential. This gradient is functionally instructive, and represents a multistable, epigenetic anatomical switch: experimental reversals of bioelectric state reset subsequent regenerative morphology back to wild-type. Hence, bioelectric properties can stably override genome-default target morphology, and provide a tractable control point for investigating cryptic phenotypes and the stochasticity of large-scale epigenetic controls.
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Affiliation(s)
- Fallon Durant
- Allen Discovery Center at Tufts University, and Department of Biology, Tufts University, Medford, Massachusetts
| | - Junji Morokuma
- Allen Discovery Center at Tufts University, and Department of Biology, Tufts University, Medford, Massachusetts
| | | | - Katherine Williams
- Allen Discovery Center at Tufts University, and Department of Biology, Tufts University, Medford, Massachusetts
| | - Dany Spencer Adams
- Allen Discovery Center at Tufts University, and Department of Biology, Tufts University, Medford, Massachusetts
| | - Michael Levin
- Allen Discovery Center at Tufts University, and Department of Biology, Tufts University, Medford, Massachusetts.
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Mathews J, Levin M. Gap junctional signaling in pattern regulation: Physiological network connectivity instructs growth and form. Dev Neurobiol 2017; 77:643-673. [PMID: 27265625 PMCID: PMC10478170 DOI: 10.1002/dneu.22405] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 05/27/2016] [Accepted: 05/31/2016] [Indexed: 12/19/2022]
Abstract
Gap junctions (GJs) are aqueous channels that allow cells to communicate via physiological signals directly. The role of gap junctional connectivity in determining single-cell functions has long been recognized. However, GJs have another important role: the regulation of large-scale anatomical pattern. GJs are not only versatile computational elements that allow cells to control which small molecule signals they receive and emit, but also establish connectivity patterns within large groups of cells. By dynamically regulating the topology of bioelectric networks in vivo, GJs underlie the ability of many tissues to implement complex morphogenesis. Here, a review of recent data on patterning roles of GJs in growth of the zebrafish fin, the establishment of left-right patterning, the developmental dysregulation known as cancer, and the control of large-scale head-tail polarity, and head shape in planarian regeneration has been reported. A perspective in which GJs are not only molecular features functioning in single cells, but also enable global neural-like dynamics in non-neural somatic tissues has been proposed. This view suggests a rich program of future work which capitalizes on the rapid advances in the biophysics of GJs to exploit GJ-mediated global dynamics for applications in birth defects, regenerative medicine, and morphogenetic bioengineering. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 643-673, 2017.
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Affiliation(s)
- Juanita Mathews
- Department of Biology, Tufts Center for Regenerative and Developmental Biology, Tufts University, Medford, MA
| | - Michael Levin
- Department of Biology, Tufts Center for Regenerative and Developmental Biology, Tufts University, Medford, MA
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42
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Hall DH. Gap junctions in C. elegans: Their roles in behavior and development. Dev Neurobiol 2017; 77:587-596. [PMID: 27294317 PMCID: PMC5412865 DOI: 10.1002/dneu.22408] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 06/08/2016] [Accepted: 06/08/2016] [Indexed: 01/07/2023]
Abstract
The nematode Caenorhabditis elegans utilizes gap junctions in different fashions in virtually all of its cells. This model animal has a surprisingly large number of innexin genes within its genome, and many nematode cell types can express multiple innexins at once, leading to the formation of diverse junction types and enough redundancy to limit the effect of single gene knockdowns on animal development or behavioral phenotypes. Here, we review the general properties of these junctions, their expression patterns, and their known roles in tissue development and in the animal's connectome. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 587-596, 2017.
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Affiliation(s)
- David H Hall
- Department of Neuroscience, Center for C. elegans Anatomy, Albert Einstein College of Medicine, Bronx, New York, 10461
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43
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García-Quismondo M, Levin M, Lobo D. Modeling regenerative processes with membrane computing. Inf Sci (N Y) 2017. [DOI: 10.1016/j.ins.2016.11.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Gao L, Han Y, Deng H, Hu W, Zhen H, Li N, Qin N, Yan M, Wu W, Liu B, Zhao B, Pang Q. The role of a novel C-type lectin-like protein from planarian in innate immunity and regeneration. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2017; 67:413-426. [PMID: 27565408 DOI: 10.1016/j.dci.2016.08.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 08/22/2016] [Accepted: 08/22/2016] [Indexed: 06/06/2023]
Abstract
Planarian, a representative of platyhelminthes, has strong regeneration ability and less complicated innate immune system. However, planarian immune system remains poorly understood. In this paper, a novel C-type lectin-like protein, namely, DjCTL was identified and characterized in Dugesia japonica. DjCTL was mainly expressed in the pharyngeal and epidermis and up-regulated upon the induction of lipopolysaccharide (LPS), peptidoglycan (PGN), Gram-positive and Gram-negative bacteria indicating that DjCTL may be involved in the immune responses. Recombination DjCTL protein agglomerated rabbit red blood cells and interacted with LPS, PGN, mannose and galactose as well as both Gram-positive and Gram-negative bacteria, but it can only cause the agglutination of Gram-negative bacteria. Importantly, in the early periods of regeneration, DjCTL had a significantly high expression and was mainly expressed in early blastemas. RNA interference of DjCTL by dsRNA-DjCTL led to a slow wound healing during regeneration. These findings suggest that DjCTL participates in the innate immune response and plays an important role in early stages of regeneration.
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Affiliation(s)
- Lili Gao
- Laboratory of Developmental and Evolutionary Biology, School of Life Sciences, Shandong University of Technology, Zibo, 255049, PR China; Anti-Aging & Regenerative Medicine Research Institution, School of Life Sciences, Shandong University of Technology, Zibo, 255049, PR China
| | - Yu Han
- Laboratory of Developmental and Evolutionary Biology, School of Life Sciences, Shandong University of Technology, Zibo, 255049, PR China; Anti-Aging & Regenerative Medicine Research Institution, School of Life Sciences, Shandong University of Technology, Zibo, 255049, PR China
| | - Hongkuan Deng
- Laboratory of Developmental and Evolutionary Biology, School of Life Sciences, Shandong University of Technology, Zibo, 255049, PR China
| | - Wenjing Hu
- Laboratory of Developmental and Evolutionary Biology, School of Life Sciences, Shandong University of Technology, Zibo, 255049, PR China; Anti-Aging & Regenerative Medicine Research Institution, School of Life Sciences, Shandong University of Technology, Zibo, 255049, PR China
| | - Hui Zhen
- Laboratory of Developmental and Evolutionary Biology, School of Life Sciences, Shandong University of Technology, Zibo, 255049, PR China
| | - Na Li
- Laboratory of Developmental and Evolutionary Biology, School of Life Sciences, Shandong University of Technology, Zibo, 255049, PR China; Anti-Aging & Regenerative Medicine Research Institution, School of Life Sciences, Shandong University of Technology, Zibo, 255049, PR China
| | - Nianci Qin
- Laboratory of Developmental and Evolutionary Biology, School of Life Sciences, Shandong University of Technology, Zibo, 255049, PR China
| | - Meihui Yan
- Laboratory of Developmental and Evolutionary Biology, School of Life Sciences, Shandong University of Technology, Zibo, 255049, PR China
| | - Weiwei Wu
- Anti-Aging & Regenerative Medicine Research Institution, School of Life Sciences, Shandong University of Technology, Zibo, 255049, PR China
| | - Baohua Liu
- Anti-Aging & Regenerative Medicine Research Institution, School of Life Sciences, Shandong University of Technology, Zibo, 255049, PR China; Shenzhen University of Health Science Center, District Shenzhen, 518060, PR China.
| | - Bosheng Zhao
- Laboratory of Developmental and Evolutionary Biology, School of Life Sciences, Shandong University of Technology, Zibo, 255049, PR China.
| | - Qiuxiang Pang
- Laboratory of Developmental and Evolutionary Biology, School of Life Sciences, Shandong University of Technology, Zibo, 255049, PR China; Anti-Aging & Regenerative Medicine Research Institution, School of Life Sciences, Shandong University of Technology, Zibo, 255049, PR China.
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Seebeck F, März M, Meyer AW, Reuter H, Vogg MC, Stehling M, Mildner K, Zeuschner D, Rabert F, Bartscherer K. Integrins are required for tissue organization and restriction of neurogenesis in regenerating planarians. Development 2017; 144:795-807. [PMID: 28137894 PMCID: PMC5374344 DOI: 10.1242/dev.139774] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 01/11/2017] [Indexed: 12/13/2022]
Abstract
Tissue regeneration depends on proliferative cells and on cues that regulate cell division, differentiation, patterning and the restriction of these processes once regeneration is complete. In planarians, flatworms with high regenerative potential, muscle cells express some of these instructive cues. Here, we show that members of the integrin family of adhesion molecules are required for the integrity of regenerating tissues, including the musculature. Remarkably, in regenerating β1-integrin RNAi planarians, we detected increased numbers of mitotic cells and progenitor cell types, as well as a reduced ability of stem cells and lineage-restricted progenitor cells to accumulate at wound sites. These animals also formed ectopic spheroid structures of neural identity in regenerating heads. Interestingly, those polarized assemblies comprised a variety of neural cells and underwent continuous growth. Our study indicates that integrin-mediated cell adhesion is required for the regenerative formation of organized tissues and for restricting neurogenesis during planarian regeneration. Highlighted article: Integrin signaling acts to recruit and localize progenitor cells following injury, thereby promoting the correct organization of regenerating planarian tissue.
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Affiliation(s)
- Florian Seebeck
- Max Planck Research Group Stem Cells & Regeneration, Max Planck Institute for Molecular Biomedicine, Von-Esmarch-Str. 54, Münster 48149, Germany.,Medical Faculty, University of Münster, Albert-Schweitzer-Campus 1, 48149 Münster, Germany
| | - Martin März
- Max Planck Research Group Stem Cells & Regeneration, Max Planck Institute for Molecular Biomedicine, Von-Esmarch-Str. 54, Münster 48149, Germany.,Medical Faculty, University of Münster, Albert-Schweitzer-Campus 1, 48149 Münster, Germany
| | - Anna-Wiebke Meyer
- Max Planck Research Group Stem Cells & Regeneration, Max Planck Institute for Molecular Biomedicine, Von-Esmarch-Str. 54, Münster 48149, Germany.,Medical Faculty, University of Münster, Albert-Schweitzer-Campus 1, 48149 Münster, Germany
| | - Hanna Reuter
- Max Planck Research Group Stem Cells & Regeneration, Max Planck Institute for Molecular Biomedicine, Von-Esmarch-Str. 54, Münster 48149, Germany.,Medical Faculty, University of Münster, Albert-Schweitzer-Campus 1, 48149 Münster, Germany
| | - Matthias C Vogg
- Max Planck Research Group Stem Cells & Regeneration, Max Planck Institute for Molecular Biomedicine, Von-Esmarch-Str. 54, Münster 48149, Germany.,Medical Faculty, University of Münster, Albert-Schweitzer-Campus 1, 48149 Münster, Germany
| | - Martin Stehling
- Flow Cytometry Unit, Max Planck Institute for Molecular Biomedicine, Röntgenstrasse 20, Münster 48149, Germany
| | - Karina Mildner
- Electron Microscopy Unit, Max Planck Institute for Molecular Biomedicine, Röntgenstrasse 20, Münster 48149, Germany
| | - Dagmar Zeuschner
- Electron Microscopy Unit, Max Planck Institute for Molecular Biomedicine, Röntgenstrasse 20, Münster 48149, Germany
| | - Franziska Rabert
- Max Planck Research Group Stem Cells & Regeneration, Max Planck Institute for Molecular Biomedicine, Von-Esmarch-Str. 54, Münster 48149, Germany.,Medical Faculty, University of Münster, Albert-Schweitzer-Campus 1, 48149 Münster, Germany
| | - Kerstin Bartscherer
- Max Planck Research Group Stem Cells & Regeneration, Max Planck Institute for Molecular Biomedicine, Von-Esmarch-Str. 54, Münster 48149, Germany .,Medical Faculty, University of Münster, Albert-Schweitzer-Campus 1, 48149 Münster, Germany
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Chan JD, Zhang D, Liu X, Zarowiecki M, Berriman M, Marchant JS. Utilizing the planarian voltage-gated ion channel transcriptome to resolve a role for a Ca 2+ channel in neuromuscular function and regeneration. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1864:1036-1045. [PMID: 27771293 DOI: 10.1016/j.bbamcr.2016.10.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 10/13/2016] [Accepted: 10/17/2016] [Indexed: 12/22/2022]
Abstract
The robust regenerative capacity of planarian flatworms depends on the orchestration of signaling events from early wounding responses through the stem cell enacted differentiative outcomes that restore appropriate tissue types. Acute signaling events in excitable cells play an important role in determining regenerative polarity, rationalized by the discovery that sub-epidermal muscle cells express critical patterning genes known to control regenerative outcomes. These data imply a dual conductive (neuromuscular signaling) and instructive (anterior-posterior patterning) role for Ca2+ signaling in planarian regeneration. Here, to facilitate study of acute signaling events in the excitable cell niche, we provide a de novo transcriptome assembly from the planarian Dugesia japonica allowing characterization of the diverse ionotropic portfolio of this model organism. We demonstrate the utility of this resource by proceeding to characterize the individual role of each of the planarian voltage-operated Ca2+ channels during regeneration, and demonstrate that knockdown of a specific voltage operated Ca2+ channel (Cav1B) that impairs muscle function uniquely creates an environment permissive for anteriorization. Provision of the full transcriptomic dataset should facilitate further investigations of molecules within the planarian voltage-gated channel portfolio to explore the role of excitable cell physiology on regenerative outcomes. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.
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Affiliation(s)
- John D Chan
- Department of Pharmacology, University of Minnesota Medical School, MN 55455, United States
| | - Dan Zhang
- Department of Pharmacology, University of Minnesota Medical School, MN 55455, United States
| | - Xiaolong Liu
- Department of Pharmacology, University of Minnesota Medical School, MN 55455, United States
| | - Magdalena Zarowiecki
- Parasite Genomics Group, Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Matthew Berriman
- Parasite Genomics Group, Wellcome Trust Sanger Institute, Hinxton, United Kingdom
| | - Jonathan S Marchant
- Department of Pharmacology, University of Minnesota Medical School, MN 55455, United States; The Stem Cell Institute, University of Minnesota Medical School, MN 55455, United States.
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Neuhof M, Levin M, Rechavi O. Vertically- and horizontally-transmitted memories - the fading boundaries between regeneration and inheritance in planaria. Biol Open 2016; 5:1177-88. [PMID: 27565761 PMCID: PMC5051648 DOI: 10.1242/bio.020149] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The Weismann barrier postulates that genetic information passes only from the germline to the soma and not in reverse, thus providing an obstacle to the inheritance of acquired traits. Certain organisms such as planaria – flatworms that can reproduce through asymmetric fission – avoid the limitations of this barrier, thus blurring the distinction between the processes of inheritance and development. In this paper, we re-evaluate canonical ideas about the interaction between developmental, genetic and evolutionary processes through the lens of planaria. Biased distribution of epigenetic effects in asymmetrically produced parts of a regenerating organism could increase variation and therefore affect the species' evolution. The maintenance and fixing of somatic experiences, encoded via stable biochemical or physiological states, may contribute to evolutionary processes in the absence of classically defined generations. We discuss different mechanisms that could induce asymmetry between the two organisms that eventually develop from the regenerating parts, including one particularly fascinating source – the potential capacity of the brain to produce long-lasting epigenetic changes. Summary: In this hypothesis paper we re-evaluate canonical ideas about the interaction between developmental, genetic and evolutionary processes through the lens of planaria, an invertebrate model organism which challenges fundamental assumptions regarding reproduction.
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Affiliation(s)
- Moran Neuhof
- Department of Neurobiology, Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
| | - Michael Levin
- Allen Discovery Center, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155, USA
| | - Oded Rechavi
- Department of Neurobiology, Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel Allen Discovery Center, Tufts University, 200 Boston Avenue, Suite 4600, Medford, MA 02155, USA Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
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Teramoto M, Kudome-Takamatsu T, Nishimura O, An Y, Kashima M, Shibata N, Agata K. Molecular markers for X-ray-insensitive differentiated cells in the Inner and outer regions of the mesenchymal space in planarian Dugesia japonica. Dev Growth Differ 2016; 58:609-19. [PMID: 27530596 DOI: 10.1111/dgd.12309] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 05/24/2016] [Accepted: 06/05/2016] [Indexed: 12/01/2022]
Abstract
Planarian's strong regenerative ability is dependent on stem cells (called neoblasts) that are X-ray-sensitive and proliferative stem cells. In addition to neoblasts, another type of X-ray-sensitive cells was newly identified by recent research. Thus, planarian's X-ray-sensitive cells can be divided into at least two populations, Type 1 and Type 2, the latter corresponding to planarian's classically defined "neoblasts". Here, we show that Type 1 cells were distributed in the outer region (OR) immediately underneath the muscle layer at all axial levels from head to tail, while the Type 2 cells were distributed in a more internal region (IR) of the mesenchymal space at the axial levels from neck to tail. To elucidate the biological significance of these two regions, we searched for genes expressed in differentiated cells that were locate close to these X-ray-sensitive cell populations in the mesenchymal space, and identified six genes mainly expressed in the OR or IR, named OR1, OR2, OR3, IR1, IR2 and IR3. The predicted amino acid sequences of these genes suggested that differentiated cells expressing OR1, OR3, IR1, or IR2 provide Type 1 and Type 2 cells with specific extracellular matrix (ECM) environments.
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Affiliation(s)
- Machiko Teramoto
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | | | - Osamu Nishimura
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan.,Global COE Program: Evolution and Biodiversity, Graduate School of Science, Kyoto University, Kyoto, Japan.,Center for Life Science Technologies, RIKEN, Kobe, Hyogo, Japan
| | - Yang An
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan.,Immolife-biotech Co. Ltd., Nanking, China
| | - Makoto Kashima
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Norito Shibata
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan.,Department of Integrated Science and Technology, National Institute of Technology, Tsuyama College 624-1, Tsuyama-City, Okayama, Japan
| | - Kiyokazu Agata
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan. .,Center for Developmental Biology, RIKEN, Kobe, Hyogo, Japan. .,Global COE Program: Evolution and Biodiversity, Graduate School of Science, Kyoto University, Kyoto, Japan.
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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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Abstract
The central nervous system (CNS) underlies memory, perception, decision-making, and behavior in numerous organisms. However, neural networks have no monopoly on the signaling functions that implement these remarkable algorithms. It is often forgotten that neurons optimized cellular signaling modes that existed long before the CNS appeared during evolution, and were used by somatic cellular networks to orchestrate physiology, embryonic development, and behavior. Many of the key dynamics that enable information processing can, in fact, be implemented by different biological hardware. This is widely exploited by organisms throughout the tree of life. Here, we review data on memory, learning, and other aspects of cognition in a range of models, including single celled organisms, plants, and tissues in animal bodies. We discuss current knowledge of the molecular mechanisms at work in these systems, and suggest several hypotheses for future investigation. The study of cognitive processes implemented in aneural contexts is a fascinating, highly interdisciplinary topic that has many implications for evolution, cell biology, regenerative medicine, computer science, and synthetic bioengineering.
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Affiliation(s)
- František Baluška
- Department of Plant Cell Biology, IZMB, University of Bonn Bonn, Germany
| | - Michael Levin
- Biology Department, Tufts Center for Regenerative and Developmental Biology, Tufts University Medford, MA, USA
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