1
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Lee JR, Boothe T, Mauksch C, Thommen A, Rink JC. Epidermal turnover in the planarian Schmidtea mediterranea involves basal cell extrusion and intestinal digestion. Cell Rep 2024:114305. [PMID: 38906148 DOI: 10.1016/j.celrep.2024.114305] [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: 11/06/2023] [Revised: 03/21/2024] [Accepted: 05/15/2024] [Indexed: 06/23/2024] Open
Abstract
Planarian flatworms undergo continuous internal turnover, wherein old cells are replaced by the division progeny of adult pluripotent stem cells (neoblasts). How cell turnover is carried out at the organismal level remains an intriguing question in planarians and other systems. While previous studies have predominantly focused on neoblast proliferation, little is known about the processes that mediate cell loss during tissue homeostasis. Here, we use the planarian epidermis as a model to study the mechanisms of cell removal. We established a covalent dye-labeling assay and image analysis pipeline to quantify the cell turnover rate in the planarian epidermis. Our findings indicate that the ventral epidermis is highly dynamic and epidermal cells undergo internalization via basal extrusion, followed by a relocation toward the intestine and ultimately digestion by intestinal phagocytes. Overall, our study reveals a complex homeostatic process of cell clearance that may generally allow planarians to catabolize their own cells.
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Affiliation(s)
- Jun-Ru Lee
- Department of Tissue Dynamics and Regeneration, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany; Graduate Center for Neurosciences, Biophysics, and Molecular Biosciences, University of Göttingen, 37077 Göttingen, Germany
| | - Tobias Boothe
- Department of Tissue Dynamics and Regeneration, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany
| | - Clemens Mauksch
- Department of Tissue Dynamics and Regeneration, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany
| | - Albert Thommen
- Cancer Metabolism Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Jochen C Rink
- Department of Tissue Dynamics and Regeneration, Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Göttingen, Germany; Faculty of Biology and Psychology, Georg-August-University, Göttingen, Germany.
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2
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Lindsay-Mosher N, Lusk S, Pearson BJ. Planarians require ced-12/elmo-1 to clear dead cells by excretion through the gut. Cell Rep 2024; 43:113621. [PMID: 38165802 DOI: 10.1016/j.celrep.2023.113621] [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: 01/10/2023] [Revised: 10/13/2023] [Accepted: 12/08/2023] [Indexed: 01/04/2024] Open
Abstract
Cell corpse removal is a critical component of both development and homeostasis throughout the animal kingdom. Extensive research has revealed many of the mechanisms involved in corpse removal, typically involving engulfment and digestion by another cell; however, the dynamics of cell corpse clearance in adult tissues remain unclear. Here, we track cell death in the adult planarian Schmidtea mediterranea and find that, following light-induced cell death, pigment cell corpses transit to the gut and are excreted from the animal. Gut phagocytes, previously only known to phagocytose food, are required for pigment cells to enter the gut lumen. Finally, we show that the planarian ortholog of ced-12/engulfment and cell motility (ELMO) is required for corpse phagocytosis and removal through the gut. In total, we present a mechanism of cell clearance in an adult organism involving transit of dead cells to the gut, transport into the gut by phagocytes, and physical excretion of debris.
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Affiliation(s)
- Nicole Lindsay-Mosher
- The Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON M5G0A4, Canada; University of Toronto, Department of Molecular Genetics, Toronto, ON, Canada
| | - Sarah Lusk
- Papé Research Institute, Department of Pediatrics, Oregon Health & Science University, Portland, OR 97239, USA
| | - Bret J Pearson
- The Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON M5G0A4, Canada; University of Toronto, Department of Molecular Genetics, Toronto, ON, Canada; Papé Research Institute, Department of Pediatrics, Oregon Health & Science University, Portland, OR 97239, USA.
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3
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Chandra B, Voas MG, Davies EL, Roberts-Galbraith RH. Ets-1 transcription factor regulates glial cell regeneration and function in planarians. Development 2023; 150:dev201666. [PMID: 37665145 PMCID: PMC10508700 DOI: 10.1242/dev.201666] [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: 02/01/2023] [Accepted: 08/15/2023] [Indexed: 09/05/2023]
Abstract
Glia play multifaceted roles in nervous systems in response to injury. Depending on the species, extent of injury and glial cell type in question, glia can help or hinder the regeneration of neurons. Studying glia in the context of successful regeneration could reveal features of pro-regenerative glia that could be exploited for new human therapies. Planarian flatworms completely regenerate their nervous systems after injury - including glia - and thus provide a strong model system for exploring glia in the context of regeneration. Here, we report that planarian glia regenerate after neurons, and that neurons are required for correct glial numbers and localization during regeneration. We also identify the planarian transcription factor-encoding gene ets-1 as a key regulator of glial cell maintenance and regeneration. Using ets-1 (RNAi) to perturb glia, we show that glial loss is associated with altered neuronal gene expression, impeded animal movement and impaired nervous system architecture - particularly within the neuropil. Importantly, our work reveals the inter-relationships of glia and neurons in the context of robust neural regeneration.
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Affiliation(s)
- Bidushi Chandra
- Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA
| | - Matthew G. Voas
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Erin L. Davies
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
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4
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Pittendreigh M, Powers K, Cruz MV, Pellettieri J. Quantitative Analysis of Planarian Pigmentation. Methods Mol Biol 2023; 2680:253-261. [PMID: 37428383 PMCID: PMC10441274 DOI: 10.1007/978-1-0716-3275-8_16] [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] [Indexed: 07/11/2023]
Abstract
The ommochrome and porphyrin body pigments that give freshwater planarians their brown color are produced by specialized dendritic cells located just beneath the epidermis. During embryonic development and regeneration, differentiation of new pigment cells gradually darkens newly formed tissue. Conversely, prolonged light exposure ablates pigment cells through a porphyrin-based mechanism similar to the one that causes light sensitivity in rare human disorders called porphyrias. Here, we describe a novel program using image-processing algorithms to quantify relative pigment levels in live animals and apply this program to analyze changes in bodily pigmentation induced by light exposure. This tool will facilitate further characterization of genetic pathways that affect pigment cell differentiation, ommochrome and porphyrin biosynthesis, and porphyrin-based photosensitivity.
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Affiliation(s)
| | - Kaleigh Powers
- Department of Biology, Keene State College, Keene, NH, USA
| | - Meenalosini Vimal Cruz
- Department of Computer Science, Keene State College, Keene, NH, USA
- Department of Information Technology, Georgia Southern University, Statesboro, GA, USA
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5
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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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6
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Abel C, Powers K, Gurung G, Pellettieri J. Defined diets for freshwater planarians. Dev Dyn 2022; 251:390-402. [PMID: 34258816 PMCID: PMC8758798 DOI: 10.1002/dvdy.400] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 07/02/2021] [Accepted: 07/08/2021] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Planarian flatworms are popular invertebrate models for basic research on stem cell biology and regeneration. These animals are commonly maintained on a diet of homogenized calf liver or boiled egg yolk in the laboratory, introducing a source of uncontrolled experimental variability. RESULTS Here, we report the development of defined diets, prepared entirely from standardized, commercially sourced ingredients, for the freshwater species Schmidtea mediterranea, Dugesia japonica, and Girardia dorotocephala. These food sources provide an opportunity to test the effects of specific nutritional variables on biological phenomena of interest. Defined diet consumption was not sufficient for growth and only partially induced the increase in stem cell division that normally accompanies feeding, suggesting these responses are not solely determined by caloric intake. Our defined diet formulations enable delivery of double-stranded RNA for gene knockdown in a manner that provides unique advantages in some experimental contexts. We also present a new approach for preserving tissue integrity during hydrogen peroxide bleaching of liver-fed animals. CONCLUSIONS These tools will empower research on the connections between diet, metabolism, and stem cell biology in the experimentally tractable planarian system.
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Affiliation(s)
- Chris Abel
- Department of Biology, Keene State College, Keene, NH, USA
| | - Kaleigh Powers
- Department of Biology, Keene State College, Keene, NH, USA
| | - Gargi Gurung
- Department of Biology, Keene State College, Keene, NH, USA
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7
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Discovery of a body-wide photosensory array that matures in an adult-like animal and mediates eye-brain-independent movement and arousal. Proc Natl Acad Sci U S A 2021; 118:2021426118. [PMID: 33941643 DOI: 10.1073/pnas.2021426118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The ability to respond to light has profoundly shaped life. Animals with eyes overwhelmingly rely on their visual circuits for mediating light-induced coordinated movements. Building on previously reported behaviors, we report the discovery of an organized, eye-independent (extraocular), body-wide photosensory framework that allows even a head-removed animal to move like an intact animal. Despite possessing sensitive cerebral eyes and a centralized brain that controls most behaviors, head-removed planarians show acute, coordinated ultraviolet-A (UV-A) aversive phototaxis. We find this eye-brain-independent phototaxis is mediated by two noncanonical rhabdomeric opsins, the first known function for this newly classified opsin-clade. We uncover a unique array of dual-opsin-expressing photoreceptor cells that line the periphery of animal body, are proximal to a body-wide nerve net, and mediate UV-A phototaxis by engaging multiple modes of locomotion. Unlike embryonically developing cerebral eyes that are functional when animals hatch, the body-wide photosensory array matures postembryonically in "adult-like animals." Notably, apart from head-removed phototaxis, the body-wide, extraocular sensory organization also impacts physiology of intact animals. Low-dose UV-A, but not visible light (ocular-stimulus), is able to arouse intact worms that have naturally cycled to an inactive/rest-like state. This wavelength selective, low-light arousal of resting animals is noncanonical-opsin dependent but eye independent. Our discovery of an autonomous, multifunctional, late-maturing, organized body-wide photosensory system establishes a paradigm in sensory biology and evolution of light sensing.
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8
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Jaenen V, Fraguas S, Bijnens K, Heleven M, Artois T, Romero R, Smeets K, Cebrià F. Reactive oxygen species rescue regeneration after silencing the MAPK-ERK signaling pathway in Schmidtea mediterranea. Sci Rep 2021; 11:881. [PMID: 33441641 PMCID: PMC7806912 DOI: 10.1038/s41598-020-79588-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 12/08/2020] [Indexed: 02/06/2023] Open
Abstract
Despite extensive research on molecular pathways controlling the process of regeneration in model organisms, little is known about the actual initiation signals necessary to induce regeneration. Recently, the activation of ERK signaling has been shown to be required to initiate regeneration in planarians. However, how ERK signaling is activated remains unknown. Reactive Oxygen Species (ROS) are well-known early signals necessary for regeneration in several models, including planarians. Still, the probable interplay between ROS and MAPK/ERK has not yet been described. Here, by interfering with major mediators (ROS, EGFR and MAPK/ERK), we were able to identify wound-induced ROS, and specifically H2O2, as upstream cues in the activation of regeneration. Our data demonstrate new relationships between regeneration-related ROS production and MAPK/ERK activation at the earliest regeneration stages, as well as the involvement of the EGFR-signaling pathway. Our results suggest that (1) ROS and/or H2O2 have the potential to rescue regeneration after MEK-inhibition, either by H2O2-treatment or light therapy, (2) ROS and/or H2O2 are required for the activation of MAPK/ERK signaling pathway, (3) the EGFR pathway can mediate ROS production and the activation of MAPK/ERK during planarian regeneration.
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Affiliation(s)
- V Jaenen
- Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium
| | - S Fraguas
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain.,Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain
| | - K Bijnens
- Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium
| | - M Heleven
- Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium
| | - T Artois
- Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium
| | - R Romero
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain
| | - K Smeets
- Centre for Environmental Sciences, Hasselt University, Diepenbeek, Belgium. .,Department of Biology and Geology, Faculty of Sciences, Agoralaan Building D, 3590, Diepenbeek, Belgium.
| | - F Cebrià
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain. .,Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain.
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9
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de Oliveira Neves AC, Galván I. Models for human porphyrias: Have animals in the wild been overlooked?: Some birds and mammals accumulate significant amounts of porphyrins in the body without showing the injurious symptoms observed in human porphyrias. Bioessays 2020; 42:e2000155. [PMID: 33155299 DOI: 10.1002/bies.202000155] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 08/27/2020] [Indexed: 11/06/2022]
Abstract
Humans accumulate porphyrins in the body mostly during the course of porphyrias, diseases caused by defects in the enzymes of the heme biosynthesis pathway and that produce acute attacks, skin lesions and liver cancer. In contrast, some wild mammals and birds are adapted to accumulate porphyrins without injurious consequences. Here we propose viewing such physiological adaptations as potential solutions to human porphyrias, and suggest certain wild animals as models. Given the enzymatic activity and/or the patterns of porphyrin excretion and accumulation, the fox squirrel, the great bustard and the Eurasian eagle owl may constitute overlooked models for different porphyrias. The Harderian gland of rodents, where large amounts of porphyrins are synthesized, presents an underexplored potential for understanding the carcinogenic/toxic effect of porphyrin accumulation. Investigating how these animals avoid porphyrin pathogenicity may complement the use of laboratory models for porphyrias and provide new insights into the treatment of these disorders.
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Affiliation(s)
| | - Ismael Galván
- Department of Evolutionary Ecology, Doñana Biological Station, CSIC, Sevilla, 41092, Spain
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10
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Figon F, Munsch T, Croix C, Viaud-Massuard MC, Lanoue A, Casas J. Uncyclized xanthommatin is a key ommochrome intermediate in invertebrate coloration. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2020; 124:103403. [PMID: 32574597 DOI: 10.1016/j.ibmb.2020.103403] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 04/23/2020] [Accepted: 04/27/2020] [Indexed: 06/11/2023]
Abstract
Ommochromes are widespread pigments that mediate multiple functions in invertebrates. The two main families of ommochromes are ommatins and ommins, which both originate from the kynurenine pathway but differ in their backbone, thereby in their coloration and function. Despite its broad significance, how the structural diversity of ommochromes arises in vivo has remained an open question since their first description. In this study, we combined organic synthesis, analytical chemistry and organelle purification to address this issue. From a set of synthesized ommatins, we derived a fragmentation pattern that helped elucidating the structure of new ommochromes. We identified uncyclized xanthommatin as the elusive biological intermediate that links the kynurenine pathway to the ommatin pathway within ommochromasomes, the ommochrome-producing organelles. Due to its unique structure, we propose that uncyclized xanthommatin functions as a key branching metabolite in the biosynthesis and structural diversification of ommatins and ommins, from insects to cephalopods.
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Affiliation(s)
- Florent Figon
- Institut de Recherche sur la Biologie de l'Insecte, UMR CNRS 7261, Université de Tours, 37200, Tours, France.
| | - Thibaut Munsch
- Biomolécules et Biotechnologies Végétales, EA 2106, Université de Tours, 37200, Tours, France
| | - Cécile Croix
- Génétique, Immunothérapie, Chimie et Cancer, UMR CNRS 7292, Université de Tours, 37200, Tours, France
| | | | - Arnaud Lanoue
- Biomolécules et Biotechnologies Végétales, EA 2106, Université de Tours, 37200, Tours, France
| | - Jérôme Casas
- Institut de Recherche sur la Biologie de l'Insecte, UMR CNRS 7261, Université de Tours, 37200, Tours, France
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11
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Lewallen M, Burggren W. Metabolic physiology of the freshwater planaria Girardia dorotocephela and Schmidtea mediterranea: reproductive mode, specific dynamic action, and temperature. Am J Physiol Regul Integr Comp Physiol 2020; 319:R428-R438. [PMID: 32783687 DOI: 10.1152/ajpregu.00099.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Planarians are widely used animal models for studies in regeneration, developmental biology, neurobiology, and behavior. However, surprisingly little is known about other aspects of their basic biology, even though such information might help validate these flatworms as a general animal model. We hypothesized that planaria, although dependent on simple diffusion of O2 across the integument for O2 uptake, would nonetheless show changes in oxygen consumption (V̇o2) associated with reproductive mode (sexual or asexual), feeding (specific dynamic action; SDA), temperature (Q10 values), and photoperiod typical of those responses of more complex invertebrates. In the current experiments, routine V̇o2 was measured over the range of 13-28°C in Schmidtea mediterranea and Girardia dorotocephala. At the long-term maintenance temperature of 18°C, routine V̇o2 was ~13 µL O2·g-1·h-1 in the two asexual strains, but approximately twice as high (27 µL O2·g-1·h-1) in the sexual strain of S. mediterranea, suggesting a metabolic cost for sexual reproduction. Metabolic temperature sensitivity, measured by Q10, was about one to three for all three groups. All three groups showed a large (~2- to 3-fold) increase in V̇o2 within a day following feeding, suggesting a large SDA effect. Starvation, causing "degrowth" in some planaria, resulted in a loss of one-third of body mass in sexual S. mediterranea but no body mass loss in either asexual strains. Collectively, these data indicate that, while being a relatively simple flatworm with no dedicated respiratory or circulatory system, their metabolic physiological responses are quite similar to those shown by more complex invertebrates and vertebrates, contributing to their validation as an animal model.
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Affiliation(s)
- Melissa Lewallen
- Developmental Integrative Biology, Department of Biological Sciences, University of North Texas, Denton, Texas
| | - Warren Burggren
- Developmental Integrative Biology, Department of Biological Sciences, University of North Texas, Denton, Texas
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12
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Planarian EGF repeat-containing genes megf6 and hemicentin are required to restrict the stem cell compartment. PLoS Genet 2020; 16:e1008613. [PMID: 32078629 PMCID: PMC7059952 DOI: 10.1371/journal.pgen.1008613] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 03/06/2020] [Accepted: 01/16/2020] [Indexed: 12/17/2022] Open
Abstract
The extracellular matrix (ECM) is important for maintaining the boundaries between tissues. This role is particularly critical in the stem cell niche, as pre-neoplastic or cancerous stem cells must pass these boundaries in order to invade into the surrounding tissue. Here, we examine the role of the ECM as a regulator of the stem cell compartment in the planarian Schmidtea mediterranea, a highly regenerative, long-lived organism with a large population of adult stem cells. We identify two EGF repeat-containing genes, megf6 and hemicentin, with identical knockdown phenotypes. We find that megf6 and hemicentin are needed to maintain the structure of the basal lamina, and in the absence of either gene, pluripotent stem cells migrate ectopically outside of their compartment and hyper-proliferate, causing lesions in the body wall muscle. These muscle lesions and ectopic stem cells are also associated with ectopic gut branches, which protrude from the normal gut towards the dorsal side of the animal. Interestingly, both megf6 and hemicentin knockdown worms are capable of regenerating tissue free of both muscle lesions and ectopic cells, indicating that these genes are dispensable for regeneration. These results provide insight into the role of planarian ECM in restricting the stem cell compartment, and suggest that signals within the compartment may act to suppress stem cell hyperproliferation. The freshwater planarian maintains a large population of adult stem cells throughout its long lifespan. Although these stem cells are constantly dividing, the rate of division is tightly controlled to such a degree that planarians almost never develop neoplastic growths. In addition, the stem cells are located in a specific spatial compartment within the animal, although no known physical boundary keeps them in place. What mechanisms do planarians use to control the number, rate of division, and location of their stem cells? Here, we find that two EGF repeat-containing genes, megf6 and hemicentin, are required to keep stem cells within their compartment. Although these two genes are expressed in different cell populations, we find that both are required to maintain the epithelial basal lamina. In the absence of either gene, stem cells can escape their compartment and migrate towards the skin of the animal, where they divide at an accelerated rate and cause lesions in the muscle. These results show that the extracellular matrix plays a role in limiting the boundaries of the stem cell compartment.
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13
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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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14
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Ochoa SD, Dores MR, Allen JM, Tran T, Osman M, Vázquez Castellanos NP, Trejo J, Zayas RM. A modular laboratory course using planarians to study genes involved in tissue regeneration. BIOCHEMISTRY AND MOLECULAR BIOLOGY EDUCATION : A BIMONTHLY PUBLICATION OF THE INTERNATIONAL UNION OF BIOCHEMISTRY AND MOLECULAR BIOLOGY 2019; 47:547-559. [PMID: 31194289 PMCID: PMC6731126 DOI: 10.1002/bmb.21259] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 04/10/2019] [Accepted: 05/15/2019] [Indexed: 05/02/2023]
Abstract
Undergraduate research experiences are excellent opportunities to engage students in science alongside experienced scientists, but at large institutions, it is challenging to accommodate all students. To address and engage a larger number of students, we developed a modular laboratory course based on the course-based undergraduate research experiences model. This new course was integrated with the scientific aims of a research laboratory studying the cellular and molecular mechanisms underlying tissue regeneration in planarians. In this course, students were asked to identify genes with roles in planarian biology. Students analyzed and cloned an assigned gene, determined its expression pattern in situ and examined its function in regeneration. Additionally, we developed critical thinking and scientific communication skills by incorporating activities focused on critical concepts. Students obtained high quality primary data and were successful in completing and mastering the course learning outcomes. They benefitted by developing basic research skills, learning to perform, trouble-shooting experiments, reading and critically analyzing primary literature, and using the information to defend and explain their experimental results. Through this course, students also increased their confidence and ability to perform independent scientific research. The course was designed to make it accessible to the community to implement and adapt as appropriate in diverse institutions. © 2019 International Union of Biochemistry and Molecular Biology, 47(5):547-559, 2019.
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Affiliation(s)
- Stacy D Ochoa
- Department of Biology, San Diego State University, San Diego, California
- Department of Pharmacology, University of California San Diego, La Jolla, California
| | - Michael R Dores
- Department of Pharmacology, University of California San Diego, La Jolla, California
- Department of Biology, Hofstra University, Hempstead, New York
| | - John M Allen
- Department of Biology, San Diego State University, San Diego, California
| | - Tuan Tran
- Department of Biology, San Diego State University, San Diego, California
| | - Maryan Osman
- Department of Biology, San Diego State University, San Diego, California
| | | | - JoAnn Trejo
- Department of Pharmacology, University of California San Diego, La Jolla, California
| | - Ricardo M Zayas
- Department of Biology, San Diego State University, San Diego, California
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15
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Falcon T, Pinheiro DG, Ferreira-Caliman MJ, Turatti ICC, de Abreu FCP, Galaschi-Teixeira JS, Martins JR, Elias-Neto M, Soares MPM, Laure MB, Figueiredo VLC, Lopes NP, Simões ZLP, Garófalo CA, Bitondi MMG. Exploring integument transcriptomes, cuticle ultrastructure, and cuticular hydrocarbons profiles in eusocial and solitary bee species displaying heterochronic adult cuticle maturation. PLoS One 2019; 14:e0213796. [PMID: 30870522 PMCID: PMC6417726 DOI: 10.1371/journal.pone.0213796] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 02/28/2019] [Indexed: 12/26/2022] Open
Abstract
Differences in the timing of exoskeleton melanization and sclerotization are evident when comparing eusocial and solitary bees. This cuticular maturation heterochrony may be associated with life style, considering that eusocial bees remain protected inside the nest for many days after emergence, while the solitary bees immediately start outside activities. To address this issue, we characterized gene expression using large-scale RNA sequencing (RNA-seq), and quantified cuticular hydrocarbon (CHC) through gas chromatography-mass spectrometry in comparative studies of the integument (cuticle plus its underlying epidermis) of two eusocial and a solitary bee species. In addition, we used transmission electron microscopy (TEM) for studying the developing cuticle of these and other three bee species also differing in life style. We found 13,200, 55,209 and 30,161 transcript types in the integument of the eusocial Apis mellifera and Frieseomelitta varia, and the solitary Centris analis, respectively. In general, structural cuticle proteins and chitin-related genes were upregulated in pharate-adults and newly-emerged bees whereas transcripts for odorant binding proteins, cytochrome P450 and antioxidant proteins were overrepresented in foragers. Consistent with our hypothesis, a distance correlation analysis based on the differentially expressed genes suggested delayed cuticle maturation in A. mellifera in comparison to the solitary bee. However, this was not confirmed in the comparison with F. varia. The expression profiles of 27 of 119 genes displaying functional attributes related to cuticle formation/differentiation were positively correlated between A. mellifera and F. varia, and negatively or non-correlated with C. analis, suggesting roles in cuticular maturation heterochrony. However, we also found transcript profiles positively correlated between each one of the eusocial species and C. analis. Gene co-expression networks greatly differed between the bee species, but we identified common gene interactions exclusively between the eusocial species. Except for F. varia, the TEM analysis is consistent with cuticle development timing adapted to the social or solitary life style. In support to our hypothesis, the absolute quantities of n-alkanes and unsaturated CHCs were significantly higher in foragers than in the earlier developmental phases of the eusocial bees, but did not discriminate newly-emerged from foragers in C. analis. By highlighting differences in integument gene expression, cuticle ultrastructure, and CHC profiles between eusocial and solitary bees, our data provided insights into the process of heterochronic cuticle maturation associated to the way of life.
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Affiliation(s)
- Tiago Falcon
- Departamento de Genética, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
- Núcleo de Bioinformática, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Daniel G. Pinheiro
- Departamento de Tecnologia, Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista “Júlio de Mesquita Filho”, Jaboticabal, Brazil
| | - Maria Juliana Ferreira-Caliman
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Izabel C. C. Turatti
- Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Fabiano C. Pinto de Abreu
- Departamento de Genética, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Juliana S. Galaschi-Teixeira
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Juliana R. Martins
- Departamento de Genética, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Moysés Elias-Neto
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Michelle P. M. Soares
- Departamento de Genética, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Marcela B. Laure
- Departamento de Genética, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Vera L. C. Figueiredo
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Norberto Peporine Lopes
- Departamento de Física e Química, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Zilá L. P. Simões
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Carlos A. Garófalo
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Márcia M. G. Bitondi
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
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16
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Figon F, Casas J. Ommochromes in invertebrates: biochemistry and cell biology. Biol Rev Camb Philos Soc 2019; 94:156-183. [PMID: 29989284 DOI: 10.1111/brv.12441] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 06/09/2018] [Accepted: 06/12/2018] [Indexed: 01/24/2023]
Abstract
Ommochromes are widely occurring coloured molecules of invertebrates, arising from tryptophan catabolism through the so-called Tryptophan → Ommochrome pathway. They are mainly known to mediate compound eye vision, as well as reversible and irreversible colour patterning. Ommochromes might also be involved in cell homeostasis by detoxifying free tryptophan and buffering oxidative stress. These biological functions are directly linked to their unique chromophore, the phenoxazine/phenothiazine system. The most recent reviews on ommochrome biochemistry were published more than 30 years ago, since when new results on the enzymes of the ommochrome pathway, on ommochrome photochemistry as well as on their antiradical capacities have been obtained. Ommochromasomes are the organelles where ommochromes are synthesised and stored. Hence, they play an important role in mediating ommochrome functions. Ommochromasomes are part of the lysosome-related organelles (LROs) family, which includes other pigmented organelles such as vertebrate melanosomes. Ommochromasomes are unique because they are the only LRO for which a recycling process during reversible colour change has been described. Herein, we provide an update on ommochrome biochemistry, photoreactivity and antiradical capacities to explain their diversity and behaviour both in vivo and in vitro. We also highlight new biochemical techniques, such as quantum chemistry, metabolomics and crystallography, which could lead to major advances in their chemical and functional characterisation. We then focus on ommochromasome structure and formation by drawing parallels with the well-characterised melanosomes of vertebrates. The biochemical, genetic, cellular and microscopic tools that have been applied to melanosomes should provide important information on the ommochromasome life cycle. We propose LRO-based models for ommochromasome biogenesis and recycling that could be tested in the future. Using the context of insect compound eyes, we finally emphasise the importance of an integrated approach in understanding the biological functions of ommochromes.
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Affiliation(s)
- Florent Figon
- Institut de Recherche sur la Biologie de l'Insecte, UMR CNRS 7261, Université de Tours, 37200 Tours, France
| | - Jérôme Casas
- Institut de Recherche sur la Biologie de l'Insecte, UMR CNRS 7261, Université de Tours, 37200 Tours, France
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17
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Lindsay-Mosher N, Pearson BJ. The true colours of the flatworm: Mechanisms of pigment biosynthesis and pigment cell lineage development in planarians. Semin Cell Dev Biol 2018; 87:37-44. [PMID: 29758350 DOI: 10.1016/j.semcdb.2018.05.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 05/07/2018] [Accepted: 05/10/2018] [Indexed: 11/28/2022]
Abstract
Pigment cells serve a variety of important uses across the animal kingdom, and in many species can change and regenerate throughout the lifetime of the organism. The functions of these cells, as well as their origins in both embryonic development and adult regeneration, are not fully understood. Here, we review advances in the study of pigment cells in the freshwater planarian, a model system for stem cell biology and regeneration. Freshwater planarians produce at least three pigment types to generate brown eye and body colouration: melanin, porphyrin, and ommochrome. The body pigments of planarians are produced and contained by a specialized, highly dendritic cell type located in the subepidermal parenchymal space. This cell type is specifically ablated following intense light exposure, a characteristic which has been exploited to discover the gene expression and regeneration of planarian pigment cells. Regenerating pigment cells progress through an immature state marked by upregulation of pigment synthesis genes before differentiating into mature pigment cells; these two states are dynamically regulated in homeostasis to maintain constant body pigmentation. The transcription factors Albino, FoxF-1, and Ets-1, as well as an FGFR-like molecule, are required for proper maintenance of the pigment lineage in both regeneration and homeostasis. These discoveries set the stage for research into external signals that regulate the pigment lineage, as well as possible functions for pigment cells in planarians, including the extra-ocular light response. These insights will address outstanding questions about the evolutionarily-conserved biology of pigment cells.
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Affiliation(s)
- Nicole Lindsay-Mosher
- Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON, M5G 0A4, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON, M5G 0A4, Canada
| | - Bret J Pearson
- Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, ON, M5G 0A4, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON, M5G 0A4, Canada; Ontario Institute for Cancer Research, Toronto, ON, M5G 0A4, Canada.
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18
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Fincher CT, Wurtzel O, de Hoog T, Kravarik KM, Reddien PW. Cell type transcriptome atlas for the planarian Schmidtea mediterranea. Science 2018; 360:science.aaq1736. [PMID: 29674431 DOI: 10.1126/science.aaq1736] [Citation(s) in RCA: 255] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 04/05/2018] [Indexed: 12/31/2022]
Abstract
The transcriptome of a cell dictates its unique cell type biology. We used single-cell RNA sequencing to determine the transcriptomes for essentially every cell type of a complete animal: the regenerative planarian Schmidtea mediterranea. Planarians contain a diverse array of cell types, possess lineage progenitors for differentiated cells (including pluripotent stem cells), and constitutively express positional information, making them ideal for this undertaking. We generated data for 66,783 cells, defining transcriptomes for known and many previously unknown planarian cell types and for putative transition states between stem and differentiated cells. We also uncovered regionally expressed genes in muscle, which harbors positional information. Identifying the transcriptomes for potentially all cell types for many organisms should be readily attainable and represents a powerful approach to metazoan biology.
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Affiliation(s)
- Christopher T Fincher
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA.,Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Omri Wurtzel
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA.,Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Thom de Hoog
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA.,Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Kellie M Kravarik
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA.,Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Peter W Reddien
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA. .,Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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19
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Plass M, Solana J, Wolf FA, Ayoub S, Misios A, Glažar P, Obermayer B, Theis FJ, Kocks C, Rajewsky N. Cell type atlas and lineage tree of a whole complex animal by single-cell transcriptomics. Science 2018; 360:science.aaq1723. [PMID: 29674432 DOI: 10.1126/science.aaq1723] [Citation(s) in RCA: 276] [Impact Index Per Article: 46.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 02/14/2018] [Accepted: 04/12/2018] [Indexed: 12/16/2022]
Abstract
Flatworms of the species Schmidtea mediterranea are immortal-adult animals contain a large pool of pluripotent stem cells that continuously differentiate into all adult cell types. Therefore, single-cell transcriptome profiling of adult animals should reveal mature and progenitor cells. By combining perturbation experiments, gene expression analysis, a computational method that predicts future cell states from transcriptional changes, and a lineage reconstruction method, we placed all major cell types onto a single lineage tree that connects all cells to a single stem cell compartment. We characterized gene expression changes during differentiation and discovered cell types important for regeneration. Our results demonstrate the importance of single-cell transcriptome analysis for mapping and reconstructing fundamental processes of developmental and regenerative biology at high resolution.
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Affiliation(s)
- Mireya Plass
- Laboratory for Systems Biology of Gene Regulatory Elements, Berlin Institute for Medical Systems Biology, Max-Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Jordi Solana
- Laboratory for Systems Biology of Gene Regulatory Elements, Berlin Institute for Medical Systems Biology, Max-Delbrück Center for Molecular Medicine, Berlin, Germany
| | - F Alexander Wolf
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Computational Biology, Neuherberg, Germany
| | - Salah Ayoub
- Laboratory for Systems Biology of Gene Regulatory Elements, Berlin Institute for Medical Systems Biology, Max-Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Aristotelis Misios
- Laboratory for Systems Biology of Gene Regulatory Elements, Berlin Institute for Medical Systems Biology, Max-Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Petar Glažar
- Laboratory for Systems Biology of Gene Regulatory Elements, Berlin Institute for Medical Systems Biology, Max-Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Benedikt Obermayer
- Laboratory for Systems Biology of Gene Regulatory Elements, Berlin Institute for Medical Systems Biology, Max-Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Fabian J Theis
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Computational Biology, Neuherberg, Germany.,Department of Mathematics, Technische Universität München, München, Germany
| | - Christine Kocks
- Laboratory for Systems Biology of Gene Regulatory Elements, Berlin Institute for Medical Systems Biology, Max-Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Nikolaus Rajewsky
- Laboratory for Systems Biology of Gene Regulatory Elements, Berlin Institute for Medical Systems Biology, Max-Delbrück Center for Molecular Medicine, Berlin, Germany.
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20
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Grohme MA, Schloissnig S, Rozanski A, Pippel M, Young GR, Winkler S, Brandl H, Henry I, Dahl A, Powell S, Hiller M, Myers E, Rink JC. The genome of Schmidtea mediterranea and the evolution of core cellular mechanisms. Nature 2018; 554:56-61. [PMID: 29364871 PMCID: PMC5797480 DOI: 10.1038/nature25473] [Citation(s) in RCA: 138] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 12/21/2017] [Indexed: 12/18/2022]
Abstract
The planarian Schmidtea mediterranea is an important model for stem cell research and regeneration, but adequate genome resources for this species have been lacking. Here we report a highly contiguous genome assembly of S. mediterranea, using long-read sequencing and a de novo assembler (MARVEL) enhanced for low-complexity reads. The S. mediterranea genome is highly polymorphic and repetitive, and harbours a novel class of giant retroelements. Furthermore, the genome assembly lacks a number of highly conserved genes, including critical components of the mitotic spindle assembly checkpoint, but planarians maintain checkpoint function. Our genome assembly provides a key model system resource that will be useful for studying regeneration and the evolutionary plasticity of core cell biological mechanisms.
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Affiliation(s)
- Markus Alexander Grohme
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Siegfried Schloissnig
- Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, 69118 Heidelberg, Germany
| | - Andrei Rozanski
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Martin Pippel
- Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, 69118 Heidelberg, Germany
| | | | - Sylke Winkler
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Holger Brandl
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Ian Henry
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Andreas Dahl
- Deep Sequencing Group, BIOTEC / Center for Regenerative Therapies Dresden, Cluster of Excellence at TU Dresden, Fetscherstraße 105, 01307 Dresden, Germany
| | - Sean Powell
- Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, 69118 Heidelberg, Germany
| | - Michael Hiller
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Str. 38 01187 Dresden, Germany
| | - Eugene Myers
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Jochen Christian Rink
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
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21
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He X, Lindsay-Mosher N, Li Y, Molinaro AM, Pellettieri J, Pearson BJ. FOX and ETS family transcription factors regulate the pigment cell lineage in planarians. Development 2017; 144:4540-4551. [PMID: 29158443 DOI: 10.1242/dev.156349] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 11/03/2017] [Indexed: 12/16/2022]
Abstract
Many pigment cells acquire unique structural properties and gene expression profiles during animal development. The underlying differentiation pathways have been well characterized in cells formed during embryogenesis, such as the neural crest-derived melanocyte. However, much less is known about the developmental origins of pigment cells produced in adult organisms during tissue homeostasis and repair. Here we report a lineage analysis of ommochrome- and porphyrin-producing cells in the brown, freshwater planarian Schmidtea mediterranea Using an RNA-sequencing approach, we identified two classes of markers expressed in sequential fashion when new pigment cells are generated during regeneration or in response to pigment cell ablation. We also report roles for FOXF-1 and ETS-1 transcription factors, as well as for an FGFR-like molecule, in the specification and maintenance of this cell type. Together, our results provide insights into mechanisms of adult pigment cell development in the strikingly colorful Platyhelminthes phylum.
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Affiliation(s)
- Xinwen He
- Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, Ontario M5G0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5G0A4, Canada
| | - Nicole Lindsay-Mosher
- Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, Ontario M5G0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5G0A4, Canada
| | - Yan Li
- Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, Ontario M5G0A4, Canada.,Ontario Institute for Cancer Research, Toronto, Ontario M5G0A4, Canada
| | - Alyssa M Molinaro
- Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, Ontario M5G0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5G0A4, Canada
| | | | - Bret J Pearson
- Hospital for Sick Children, Program in Developmental and Stem Cell Biology, Toronto, Ontario M5G0A4, Canada .,Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5G0A4, Canada.,Ontario Institute for Cancer Research, Toronto, Ontario M5G0A4, Canada
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22
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Birkholz TR, Beane WS. The planarian TRPA1 homolog mediates extraocular behavioral responses to near-ultraviolet light. J Exp Biol 2017; 220:2616-2625. [PMID: 28495872 PMCID: PMC5536891 DOI: 10.1242/jeb.152298] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 05/04/2017] [Indexed: 12/17/2022]
Abstract
Although light is most commonly thought of as a visual cue, many animals possess mechanisms to detect light outside of the eye for various functions, including predator avoidance, circadian rhythms, phototaxis and migration. Here we confirm that planarians (like Caenorhabditis elegans, leeches and Drosophila larvae) are capable of detecting and responding to light using extraocular photoreception. We found that, when either eyeless or decapitated worms were exposed to near-ultraviolet (near-UV) light, intense wild-type photophobic behaviors were still observed. Our data also revealed that behavioral responses to green wavelengths were mediated by ocular mechanisms, whereas near-UV responses were driven by extraocular mechanisms. As part of a candidate screen to uncover the genetic basis of extraocular photoreception in the planarian species Schmidtea mediterranea, we identified a potential role for a homolog of the transient receptor potential channel A1 (TRPA1) in mediating behavioral responses to extraocular light cues. RNA interference (RNAi) to Smed-TrpA resulted in worms that lacked extraocular photophobic responses to near-UV light, a mechanism previously only identified in Drosophila These data show that the planarian TRPA1 homolog is required for planarian extraocular-light avoidance and may represent a potential ancestral function of this gene. TRPA1 is an evolutionarily conserved detector of temperature and chemical irritants, including reactive oxygen species that are byproducts of UV-light exposure. Our results suggest that planarians possess extraocular photoreception and display an unconventional TRPA1-mediated photophobic response to near-UV light.
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Affiliation(s)
- Taylor R Birkholz
- 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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23
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Gutiérrez-Gutiérrez Ó, Felix DA, González-Estévez C. Planarian finds time(less) to fight infection. Virulence 2017; 8:1043-1048. [PMID: 28277898 DOI: 10.1080/21505594.2017.1300735] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
| | - Daniel A Felix
- a Leibniz Institute on Aging - Fritz Lipmann Institute (FLI) , Jena , Germany
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24
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Wang C, Han XS, Li FF, Huang S, Qin YW, Zhao XX, Jing Q. Forkhead containing transcription factor Albino controls tetrapyrrole-based body pigmentation in planarian. Cell Discov 2016; 2:16029. [PMID: 27551436 PMCID: PMC4969599 DOI: 10.1038/celldisc.2016.29] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 07/12/2016] [Indexed: 01/22/2023] Open
Abstract
Pigmentation processes occur from invertebrates to mammals. Owing to the complexity of the pigmentary system, in vivo animal models for pigmentation study are limited. Planarians are capable of regenerating any missing part including the dark-brown pigments, providing a promising model for pigmentation study. However, the molecular mechanism of planarian body pigmentation is poorly understood. We found in an RNA interference screen that a forkhead containing transcription factor, Albino, was required for pigmentation without affecting survival or other regeneration processes. In addition, the body color recovered after termination of Albino double stranded RNA feeding owing to the robust stem cell system. Further expression analysis revealed a spatial and temporal correlation between Albino and pigmentation process. Gene expression arrays revealed that the expression of three tetrapyrrole biosynthesis enzymes, ALAD, ALAS and PBGD, was impaired upon Albino RNA interference. RNA interference of PBGD led to a similar albinism phenotype caused by Albino RNA interference. Moreover, PBGD was specifically expressed in pigment cells and can serve as a pigment cell molecular marker. Our results revealed that Albino controls planarian body color pigmentation dominantly via regulating tetrapyrrole biogenesis. These results identified Albino as the key regulator of the tetrapyrrole-based planarian body pigmentation, suggesting a role of Albino during stem cell-pigment cell fate decision and provided new insights into porphyria pathogenesis.
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Affiliation(s)
- Chen Wang
- Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Jiao Tong University School of Medicine & Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai, China
| | - Xiao-Shuai Han
- Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Jiao Tong University School of Medicine & Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai, China
| | - Fang-Fang Li
- Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Jiao Tong University School of Medicine & Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences , Shanghai, China
| | - Shuang Huang
- Department of Cardiology, Changhai Hospital , Shanghai, China
| | - Yong-Wen Qin
- Department of Cardiology, Changhai Hospital , Shanghai, China
| | - Xian-Xian Zhao
- Department of Cardiology, Changhai Hospital , Shanghai, China
| | - Qing Jing
- Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Jiao Tong University School of Medicine & Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China; Department of Cardiology, Changhai Hospital, Shanghai, China
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