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Hanson A. On being a Hydra with, and without, a nervous system: what do neurons add? Anim Cogn 2023; 26:1799-1816. [PMID: 37540280 PMCID: PMC10770230 DOI: 10.1007/s10071-023-01816-8] [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: 07/05/2023] [Revised: 07/05/2023] [Accepted: 07/27/2023] [Indexed: 08/05/2023]
Abstract
The small freshwater cnidarian Hydra has been the subject of scientific inquiry for over 300 years due to its remarkable regenerative capacities and apparent immortality. More recently, Hydra has been recognized as an excellent model system within neuroscience because of its small size, transparency, and simple nervous system, which allow high-resolution imaging of its entire nerve net while behaving. In less than a decade, studies of Hydra's nervous system have yielded insights into the activity of neural circuits in vivo unobtainable in most other animals. In addition to these unique attributes, there is yet another lesser-known feature of Hydra that makes it even more intriguing: it does not require its neural hardware to live. The extraordinary ability to survive the removal and replacement of its entire nervous system makes Hydra uniquely suited to address the question of what neurons add to an extant organism. Here, I will review what early work on nerve-free Hydra reveals about the potential role of the nervous system in these animals and point towards future directions for this work.
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Affiliation(s)
- Alison Hanson
- Department of Biological Sciences, Neurotechnology Center, Columbia University, New York, NY, USA.
- Department of Psychiatry, New York State Psychiatric Institute, Columbia University, New York, NY, USA.
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2
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Tajer B, Savage AM, Whited JL. The salamander blastema within the broader context of metazoan regeneration. Front Cell Dev Biol 2023; 11:1206157. [PMID: 37635872 PMCID: PMC10450636 DOI: 10.3389/fcell.2023.1206157] [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: 04/15/2023] [Accepted: 07/26/2023] [Indexed: 08/29/2023] Open
Abstract
Throughout the animal kingdom regenerative ability varies greatly from species to species, and even tissue to tissue within the same organism. The sheer diversity of structures and mechanisms renders a thorough comparison of molecular processes truly daunting. Are "blastemas" found in organisms as distantly related as planarians and axolotls derived from the same ancestral process, or did they arise convergently and independently? Is a mouse digit tip blastema orthologous to a salamander limb blastema? In other fields, the thorough characterization of a reference model has greatly facilitated these comparisons. For example, the amphibian Spemann-Mangold organizer has served as an amazingly useful comparative template within the field of developmental biology, allowing researchers to draw analogies between distantly related species, and developmental processes which are superficially quite different. The salamander limb blastema may serve as the best starting point for a comparative analysis of regeneration, as it has been characterized by over 200 years of research and is supported by a growing arsenal of molecular tools. The anatomical and evolutionary closeness of the salamander and human limb also add value from a translational and therapeutic standpoint. Tracing the evolutionary origins of the salamander blastema, and its relatedness to other regenerative processes throughout the animal kingdom, will both enhance our basic biological understanding of regeneration and inform our selection of regenerative model systems.
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Affiliation(s)
| | | | - Jessica L. Whited
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA, United States
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3
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Hulett RE, Gehrke AR, Gompers A, Rivera-López C, Srivastava M. A wound-induced differentiation trajectory for neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.10.540286. [PMID: 37214981 PMCID: PMC10197691 DOI: 10.1101/2023.05.10.540286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Animals capable of whole-body regeneration can replace any missing cell type and regenerate fully-functional new organs, de novo . The regeneration of a new brain requires the formation of diverse neuronal cell types and their assembly into an organized structure and correctly-wired circuits. Recent work in various regenerative animals has revealed transcriptional programs required for the differentiation of distinct neuronal subpopulations, however how these transcriptional programs are initiated upon amputation remains unknown. Here, we focused on the highly regenerative acoel worm, Hofstenia miamia , to study wound-induced transcriptional regulatory events that lead to the production of neurons. Footprinting analysis using chromatin accessibility data on an improved genome assembly revealed that binding sites for the NFY transcription factor complex were significantly bound during regeneration, showing a dynamic increase in binding within one hour upon amputation specifically in tail fragments, which will regenerate a new brain. Strikingly, NFY targets were highly enriched for genes with neuronal functional. Single-cell transcriptome analysis combined with functional studies identified sox4 + stem cells as the likely progenitor population for multiple neuronal subtypes. Further, we found that wound-induced sox4 expression is likely under direct transcriptional control by NFY, uncovering a mechanism for how early wound-induced binding of a transcriptional regulator results in the initiation of a neuronal differentiation pathway. Highlights A new chromosome-scale assembly for Hofstenia enables comprehensive analysis of transcription factor binding during regeneration NFY motifs become dynamically bound by 1hpa in regenerating tail fragments, particularly in the loci of neural genes A sox4 + neural-specialized stem cell is identified using scRNA-seq sox4 is wound-induced and required for differentiation of multiple neural cell types NFY regulates wound-induced expression of sox4 during regeneration.
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4
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Holstein TW. The Hydra stem cell system - Revisited. Cells Dev 2023; 174:203846. [PMID: 37121433 DOI: 10.1016/j.cdev.2023.203846] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 04/12/2023] [Accepted: 04/25/2023] [Indexed: 05/02/2023]
Abstract
Cnidarians are >600 million years old and are considered the sister group of Bilateria based on numerous molecular phylogenetic studies. Apart from Hydra, the genomes of all major clades of Cnidaria have been uncovered (e.g. Aurelia, Clytia, Nematostella and Acropora) and they reveal a remarkable completeness of the metazoan genomic toolbox. Of particular interest is Hydra, a model system of aging research, regenerative biology, and stem cell biology. With the knowledge gained from scRNA research, it is now possible to characterize the expression profiles of all cell types with great precision. In functional studies, our picture of the Hydra stem cell biology has changed, and we are in the process of obtaining a clear picture of the homeostasis and properties of the different stem cell populations. Even though Hydra is often compared to plant systems, the new data on germline and regeneration, but also on the dynamics and plasticity of the nervous system, show that Hydra with its simple body plan represents in a nutshell the prototype of an animal with stem cell lineages, whose properties correspond in many ways to Bilateria. This review provides an overview of the four stem cell lineages, the two epithelial lineages that constitute the ectoderm and the endoderm, as well as the multipotent somatic interstitial lineage (MPSC) and the germline stem cell lineage (GSC), also known as the interstitial cells of Hydra.
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Affiliation(s)
- Thomas W Holstein
- Heidelberg University, Centre for Organismal Studies (COS), Molecular Evolution and Genomics, Im Neuenheimer Feld 230, D-69120 Heidelberg, Germany.
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5
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Shum CW, Nong W, So WL, Li Y, Qu Z, Yip HY, Swale T, Ang PO, Chan KM, Chan TF, Chu KH, Chui AP, Lau KF, Ngai SM, Xu F, Hui JH. Genome of the sea anemone Exaiptasia pallida and transcriptome profiles during tentacle regeneration. Front Cell Dev Biol 2022; 10:900321. [PMID: 36072338 PMCID: PMC9444052 DOI: 10.3389/fcell.2022.900321] [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: 03/20/2022] [Accepted: 07/08/2022] [Indexed: 12/19/2022] Open
Abstract
Cnidarians including sea anemones, corals, hydra, and jellyfishes are a group of animals well known for their regeneration capacity. However, how non-coding RNAs such as microRNAs (also known as miRNAs) contribute to cnidarian tissue regeneration is poorly understood. Here, we sequenced and assembled the genome of the sea anemone Exaiptasia pallida collected in Hong Kong waters. The assembled genome size of E. pallida is 229.21 Mb with a scaffold N50 of 10.58 Mb and BUSCO completeness of 91.1%, representing a significantly improved genome assembly of this species. The organization of ANTP-class homeobox genes in this anthozoan further supported the previous findings in jellyfishes, where most of these genes are mainly located on three scaffolds. Tentacles of E. pallida were excised, and both mRNA and miRNA were sequenced at 9 time points (0 h, 6 h, 12 h, 18 h, 1 day, 2, 3, 6, and 8 days) from regenerating tentacles. In addition to the Wnt signaling pathway and homeobox genes that are shown to be likely involved in tissue regeneration as in other cnidarians, we have shown that GLWamide neuropeptides, and for the first time sesquiterpenoid pathway genes could potentially be involved in the late phase of cnidarian tissue regeneration. The established sea anemone model will be useful for further investigation of biology and evolution in, and the effect of climate change on this important group of animals.
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Affiliation(s)
- Cheryl W.Y. Shum
- School of Life Sciences, Simon F.S. Li Marine Science Laboratory, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Wenyan Nong
- School of Life Sciences, Simon F.S. Li Marine Science Laboratory, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Wai Lok So
- School of Life Sciences, Simon F.S. Li Marine Science Laboratory, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Yiqian Li
- School of Life Sciences, Simon F.S. Li Marine Science Laboratory, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Zhe Qu
- School of Life Sciences, Simon F.S. Li Marine Science Laboratory, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Ho Yin Yip
- School of Life Sciences, Simon F.S. Li Marine Science Laboratory, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Thomas Swale
- Dovetail Genomics, Scotts Valley, CA, United States
| | - Put O. Ang
- Institute of Space and Earth Information Science, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - King Ming Chan
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Ting Fung Chan
- School of Life Sciences, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Ka Hou Chu
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, China
| | - Apple P.Y. Chui
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Kwok Fai Lau
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Sai Ming Ngai
- School of Life Sciences, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - Fei Xu
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
| | - Jerome H.L. Hui
- School of Life Sciences, Simon F.S. Li Marine Science Laboratory, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
- *Correspondence: Jerome H.L. Hui,
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6
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Chrysostomou E, Flici H, Gornik SG, Salinas-Saavedra M, Gahan JM, McMahon ET, Thompson K, Hanley S, Kilcoyne M, Schnitzler CE, Gonzalez P, Baxevanis AD, Frank U. A cellular and molecular analysis of SoxB-driven neurogenesis in a cnidarian. eLife 2022; 11:78793. [PMID: 35608899 PMCID: PMC9173746 DOI: 10.7554/elife.78793] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 05/23/2022] [Indexed: 01/09/2023] Open
Abstract
Neurogenesis is the generation of neurons from stem cells, a process that is regulated by SoxB transcription factors (TFs) in many animals. Although the roles of these TFs are well understood in bilaterians, how their neural function evolved is unclear. Here, we use Hydractinia symbiolongicarpus, a member of the early-branching phylum Cnidaria, to provide insight into this question. Using a combination of mRNA in situ hybridization, transgenesis, gene knockdown, transcriptomics, and in vivo imaging, we provide a comprehensive molecular and cellular analysis of neurogenesis during embryogenesis, homeostasis, and regeneration in this animal. We show that SoxB genes act sequentially at least in some cases. Stem cells expressing Piwi1 and Soxb1, which have broad developmental potential, become neural progenitors that express Soxb2 before differentiating into mature neural cells. Knockdown of SoxB genes resulted in complex defects in embryonic neurogenesis. Hydractinia neural cells differentiate while migrating from the aboral to the oral end of the animal, but it is unclear whether migration per se or exposure to different microenvironments is the main driver of their fate determination. Our data constitute a rich resource for studies aiming at addressing this question, which is at the heart of understanding the origin and development of animal nervous systems.
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Affiliation(s)
- Eleni Chrysostomou
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland GalwayGalwayIreland
| | - Hakima Flici
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland GalwayGalwayIreland
| | - Sebastian G Gornik
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland GalwayGalwayIreland
| | - Miguel Salinas-Saavedra
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland GalwayGalwayIreland
| | - James M Gahan
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland GalwayGalwayIreland
| | - Emma T McMahon
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland GalwayGalwayIreland
| | - Kerry Thompson
- Centre for Microscopy and Imaging, Discipline of Anatomy, National University of Ireland, GalwayGalwayIreland
| | - Shirley Hanley
- National Centre for Biomedical Engineering Science, National University of Ireland, GalwayGalwayIreland
| | - Michelle Kilcoyne
- Carbohydrate Signalling Group, Microbiology, School of Natural Sciences, National University of Ireland GalwayGalwayIreland
| | - Christine E Schnitzler
- Whitney Laboratory for Marine Bioscience, University of FloridaSt. Augustine, FloridaUnited States,Department of Biology, University of FloridaGainesville, FloridaUnited States
| | - Paul Gonzalez
- Computational and Statistical Genomics Branch, Division of Intramural Research, National Human Genome Research Institute, National Institutes of HealthBethesda, MarylandUnited States
| | - Andreas D Baxevanis
- Computational and Statistical Genomics Branch, Division of Intramural Research, National Human Genome Research Institute, National Institutes of HealthBethesda, MarylandUnited States
| | - Uri Frank
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland GalwayGalwayIreland
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Berthézène CD, Rabiller L, Jourdan G, Cousin B, Pénicaud L, Casteilla L, Lorsignol A. Tissue Regeneration: The Dark Side of Opioids. Int J Mol Sci 2021; 22:7336. [PMID: 34298954 PMCID: PMC8307464 DOI: 10.3390/ijms22147336] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 06/25/2021] [Accepted: 06/28/2021] [Indexed: 12/13/2022] Open
Abstract
Opioids are regarded as among the most effective analgesic drugs and their use for the management of pain is considered standard of care. Despite their systematic administration in the peri-operative period, their impact on tissue repair has been studied mainly in the context of scar healing and is only beginning to be documented in the context of true tissue regeneration. Indeed, in mammals, growing evidence shows that opioids direct tissue repair towards scar healing, with a loss of tissue function, instead of the regenerative process that allows for recovery of both the morphology and function of tissue. Here, we review recent studies that highlight how opioids may prevent a regenerative process by silencing nociceptive nerve activity and a powerful anti-inflammatory effect. These data open up new perspectives for inducing tissue regeneration and argue for opioid-restricted strategies for managing pain associated with tissue injury.
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Affiliation(s)
- Cécile Dromard Berthézène
- RESTORE Research Center, INSERM, CNRS, EFS, ENVT, Université P. Sabatier, 31000 Toulouse, France; (C.D.B.); (G.J.); (B.C.); (L.P.); (L.C.)
| | - Lise Rabiller
- Alan Edwards Center for Research on Pain, Department of Physiology and Cell Information Systems, McGill University, Montreal, QC H3A 0G1, Canada;
| | - Géraldine Jourdan
- RESTORE Research Center, INSERM, CNRS, EFS, ENVT, Université P. Sabatier, 31000 Toulouse, France; (C.D.B.); (G.J.); (B.C.); (L.P.); (L.C.)
| | - Béatrice Cousin
- RESTORE Research Center, INSERM, CNRS, EFS, ENVT, Université P. Sabatier, 31000 Toulouse, France; (C.D.B.); (G.J.); (B.C.); (L.P.); (L.C.)
| | - Luc Pénicaud
- RESTORE Research Center, INSERM, CNRS, EFS, ENVT, Université P. Sabatier, 31000 Toulouse, France; (C.D.B.); (G.J.); (B.C.); (L.P.); (L.C.)
| | - Louis Casteilla
- RESTORE Research Center, INSERM, CNRS, EFS, ENVT, Université P. Sabatier, 31000 Toulouse, France; (C.D.B.); (G.J.); (B.C.); (L.P.); (L.C.)
| | - Anne Lorsignol
- RESTORE Research Center, INSERM, CNRS, EFS, ENVT, Université P. Sabatier, 31000 Toulouse, France; (C.D.B.); (G.J.); (B.C.); (L.P.); (L.C.)
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8
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Havrilak JA, Al-Shaer L, Baban N, Akinci N, Layden MJ. Characterization of the dynamics and variability of neuronal subtype responses during growth, degrowth, and regeneration of Nematostella vectensis. BMC Biol 2021; 19:104. [PMID: 34001126 PMCID: PMC8128482 DOI: 10.1186/s12915-021-01038-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 04/26/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The ability to regenerate body parts is a feature of metazoan organisms and the focus of intense research aiming to understand its basis. A number of mechanisms involved in regeneration, such as proliferation and tissue remodeling, affect whole tissues; however, little is known on how distinctively different constituent cell types respond to the dynamics of regenerating tissues. Preliminary studies suggest that a number of organisms alter neuronal numbers to scale with changes in body size. In some species with the ability of whole-body axis regeneration, it has additionally been observed that regenerates are smaller than their pre-amputated parent, but maintain the correct morphological proportionality, suggesting that scaling of tissue and neuronal numbers also occurs. However, the cell dynamics and responses of neuronal subtypes during nervous system regeneration, scaling, and whole-body axis regeneration are not well understood in any system. The cnidarian sea anemone Nematostella vectensis is capable of whole-body axis regeneration, with a number of observations suggesting the ability to alter its size in response to changes in feeding. We took advantage of Nematostella's transparent and "simple" body plan and the NvLWamide-like mCherry fluorescent reporter transgenic line to probe the response of neuron populations to variations in body size in vivo in adult animals during body scaling and regeneration. RESULTS We utilized the previously characterized NvLWamide-like::mCherry transgenic reporter line to determine the in vivo response of neuronal subtypes during growth, degrowth, and regeneration. Nematostella alters its size in response to caloric intake, and the nervous system responds by altering neuronal number to scale as the animal changes in size. Neuronal numbers in both the endodermal and ectodermal nerve nets decreased as animals shrunk, increased as they grew, and these changes were reversible. Whole-body axis regeneration resulted in regenerates that were smaller than their pre-amputated size, and the regenerated nerve nets were reduced in neuronal number. Different neuronal subtypes had distinct responses during regeneration, including consistent, not consistent, and conditional increases in number. Conditional responses were regulated, in part, by the size of the remnant fragment and the position of the amputation site. Regenerates and adults with reduced nerve nets displayed normal behaviors, indicating that the nerve net retains functionality as it scales. CONCLUSION These data suggest that the Nematostella nerve net is dynamic, capable of scaling with changes in body size, and that neuronal subtypes display differential regenerative responses, which we propose may be linked to the scale state of the regenerating animals.
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Affiliation(s)
- Jamie A Havrilak
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, 18015, USA
| | - Layla Al-Shaer
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, 18015, USA
| | - Noor Baban
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, 18015, USA
| | - Nesli Akinci
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, 18015, USA
| | - Michael J Layden
- Department of Biological Sciences, Lehigh University, Bethlehem, PA, 18015, USA.
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9
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Barve A, Galande AA, Ghaskadbi SS, Ghaskadbi S. DNA Repair Repertoire of the Enigmatic Hydra. Front Genet 2021; 12:670695. [PMID: 33995496 PMCID: PMC8117345 DOI: 10.3389/fgene.2021.670695] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 04/12/2021] [Indexed: 12/20/2022] Open
Abstract
Since its discovery by Abraham Trembley in 1744, hydra has been a popular research organism. Features like spectacular regeneration capacity, peculiar tissue dynamics, continuous pattern formation, unique evolutionary position, and an apparent lack of organismal senescence make hydra an intriguing animal to study. While a large body of work has taken place, particularly in the domain of evolutionary developmental biology of hydra, in recent years, the focus has shifted to molecular mechanisms underlying various phenomena. DNA repair is a fundamental cellular process that helps to maintain integrity of the genome through multiple repair pathways found across taxa, from archaea to higher animals. DNA repair capacity and senescence are known to be closely associated, with mutations in several repair pathways leading to premature ageing phenotypes. Analysis of DNA repair in an animal like hydra could offer clues into several aspects including hydra’s purported lack of organismal ageing, evolution of DNA repair systems in metazoa, and alternative functions of repair proteins. We review here the different DNA repair mechanisms known so far in hydra. Hydra genes from various DNA repair pathways show very high similarity with their vertebrate orthologues, indicating conservation at the level of sequence, structure, and function. Notably, most hydra repair genes are more similar to deuterostome counterparts than to common model invertebrates, hinting at ancient evolutionary origins of repair pathways and further highlighting the relevance of organisms like hydra as model systems. It appears that hydra has the full repertoire of DNA repair pathways, which are employed in stress as well as normal physiological conditions and may have a link with its observed lack of senescence. The close correspondence of hydra repair genes with higher vertebrates further demonstrates the need for deeper studies of various repair components, their interconnections, and functions in this early metazoan.
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Affiliation(s)
- Apurva Barve
- Developmental Biology Group, MACS-Agharkar Research Institute, Pune, India.,Centre of Excellence in Science and Mathematics Education, Indian Institute of Science Education and Research (IISER), Pune, India
| | - Alisha A Galande
- Developmental Biology Group, MACS-Agharkar Research Institute, Pune, India
| | - Saroj S Ghaskadbi
- Department of Zoology, Savitribai Phule Pune University, Pune, India
| | - Surendra Ghaskadbi
- Developmental Biology Group, MACS-Agharkar Research Institute, Pune, India
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10
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Zancolli G, Casewell NR. Venom Systems as Models for Studying the Origin and Regulation of Evolutionary Novelties. Mol Biol Evol 2020; 37:2777-2790. [DOI: 10.1093/molbev/msaa133] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Abstract
A central goal in biology is to determine the ways in which evolution repeats itself. One of the most remarkable examples in nature of convergent evolutionary novelty is animal venom. Across diverse animal phyla, various specialized organs and anatomical structures have evolved from disparate developmental tissues to perform the same function, that is, produce and deliver a cocktail of potent molecules to subdue prey or predators. Venomous organisms therefore offer unique opportunities to investigate the evolutionary processes of convergence of key adaptive traits, and the molecular mechanisms underlying the emergence of novel genes, cells, and tissues. Indeed, some venomous species have already proven to be highly amenable as models for developmental studies, and recent work with venom gland organoids provides manipulatable systems for directly testing important evolutionary questions. Here, we provide a synthesis of the current knowledge that could serve as a starting point for the establishment of venom systems as new models for evolutionary and molecular biology. In particular, we highlight the potential of various venomous species for the study of cell differentiation and cell identity, and the regulatory dynamics of rapidly evolving, highly expressed, tissue-specific, gene paralogs. We hope that this review will encourage researchers to look beyond traditional study organisms and consider venom systems as useful tools to explore evolutionary novelties.
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Affiliation(s)
- Giulia Zancolli
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Nicholas R Casewell
- Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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11
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van der Burg CA, Pavasovic A, Gilding EK, Pelzer ES, Surm JM, Smith HL, Walsh TP, Prentis PJ. The Rapid Regenerative Response of a Model Sea Anemone Species Exaiptasia pallida Is Characterised by Tissue Plasticity and Highly Coordinated Cell Communication. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2020; 22:285-307. [PMID: 32016679 DOI: 10.1007/s10126-020-09951-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Accepted: 01/20/2020] [Indexed: 06/10/2023]
Abstract
Regeneration of a limb or tissue can be achieved through multiple different pathways and mechanisms. The sea anemone Exaiptasia pallida has been observed to have excellent regenerative proficiency, but this has not yet been described transcriptionally. In this study, we examined the genetic expression changes during a regenerative timecourse and reported key genes involved in regeneration and wound healing. We found that the major response was an early (within the first 8 h) upregulation of genes involved in cellular movement and cell communication, which likely contribute to a high level of tissue plasticity resulting in the rapid regeneration response observed in this species. We find the immune system was only transcriptionally active in the first 8 h post-amputation and conclude, in accordance with previous literature, that the immune system and regeneration have an inverse relationship. Fifty-nine genes (3.8% of total) differentially expressed during regeneration were identified as having no orthologues in other species, indicating that regeneration in E. pallida may rely on the activation of species-specific novel genes. Additionally, taxonomically restricted novel genes, including species-specific novels, and highly conserved genes were identified throughout the regenerative timecourse, showing that both may work in concert to achieve complete regeneration.
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Affiliation(s)
- Chloé A van der Burg
- School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, QLD, 4000, Australia.
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, 4059, Australia.
| | - Ana Pavasovic
- School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, QLD, 4000, Australia
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, 4059, Australia
| | - Edward K Gilding
- Institute for Molecular Bioscience, University of Queensland, Brisbane, QLD, 4067, Australia
| | - Elise S Pelzer
- School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, QLD, 4000, Australia
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, 4059, Australia
| | - Joachim M Surm
- Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, 9190401, Jerusalem, Israel
| | - Hayden L Smith
- Earth, Environment and Biological Sciences, Science and Engineering Faculty, Queensland University of Technology, Brisbane, QLD, 4000, Australia
- Institute for Future Environments, Science and Engineering Faculty, Queensland University of Technology, Brisbane, QLD, 4000, Australia
| | - Terence P Walsh
- School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, Brisbane, QLD, 4000, Australia
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, QLD, 4059, Australia
| | - Peter J Prentis
- Earth, Environment and Biological Sciences, Science and Engineering Faculty, Queensland University of Technology, Brisbane, QLD, 4000, Australia
- Institute for Future Environments, Science and Engineering Faculty, Queensland University of Technology, Brisbane, QLD, 4000, Australia
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12
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Gonzales DL, Badhiwala KN, Avants BW, Robinson JT. Bioelectronics for Millimeter-Sized Model Organisms. iScience 2020; 23:100917. [PMID: 32114383 PMCID: PMC7049667 DOI: 10.1016/j.isci.2020.100917] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 01/29/2020] [Accepted: 02/10/2020] [Indexed: 01/27/2023] Open
Abstract
Advances in microfabrication technologies and biomaterials have enabled a growing class of electronic devices that can stimulate and record bioelectronic signals. Many of these devices have been developed for humans or vertebrate animals, where miniaturization allows for implantation within the body. There are, however, another class of bioelectronic interfaces that exploit microfabrication and nanoelectronics to record signals from tiny, millimeter-sized organisms. In these cases, rather than implanting a device inside an animal, animals themselves are loaded in large numbers into bioelectronic devices for neural circuit and behavioral interrogation. These scalable interfaces provide platforms to develop new therapeutics as well as better understand basic principles of bioelectronic communication, neuroscience, and behavior. Here we review recent progress in these bioelectronic technologies and describe how they can complement on-chip optical, mechanical, and chemical interrogation methods to achieve high-throughput, multimodal studies of millimeter-sized small animals.
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Affiliation(s)
- Daniel L Gonzales
- Weldon School of Biomedical Engineering, Purdue University, 206 S. Martin Jischke Dr., West Lafayette, IN 47907, USA
| | - Krishna N Badhiwala
- Department of Bioengineering, Rice University, 6100 Main St., Houston, TX 77005, USA
| | - Benjamin W Avants
- Department of Electrical and Computer Engineering, Rice University, 6100 Main St., Houston, TX 77005, USA
| | - Jacob T Robinson
- Department of Bioengineering, Rice University, 6100 Main St., Houston, TX 77005, USA; Department of Electrical and Computer Engineering, Rice University, 6100 Main St., Houston, TX 77005, USA; Applied Physics Program, Rice University, 6100 Main St., Houston, TX 77005, USA; Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
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13
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Buzgariu W, Curchod ML, Perruchoud C, Galliot B. Combining BrdU-Labeling to Detection of Neuronal Markers to Monitor Adult Neurogenesis in Hydra. Methods Mol Biol 2020; 2047:3-24. [PMID: 31552646 DOI: 10.1007/978-1-4939-9732-9_1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The nervous system is produced and maintained in adult Hydra through the continuous production of nerve cells and mechanosensory cells (nematocytes or cnidocytes). De novo neurogenesis occurs slowly in intact animals that replace their dying nerve cells, at a faster rate in animals regenerating their head as a complete apical nervous system is built in few days. To dissect the molecular mechanisms that underlie these properties, a precise monitoring of the markers of neurogenesis and nematogenesis is required. Here we describe the conditions for an efficient BrdU-labeling coupled to an immunodetection of neuronal markers, either regulators of neurogenesis, here the homeoprotein prdl-a, or neuropeptides such as RFamide or Hym-355. This method can be performed on whole-mount animals as well as on macerated tissues when cells retain their morphology. Moreover, when antibodies are not available, BrdU-labeling can be combined with the analysis of gene expression by whole-mount in situ hybridization. This co-immunodetection procedure is well adapted to visualize and quantify the dynamics of de novo neurogenesis. Upon continuous BrdU labeling, the repeated measurements of BrdU-labeling indexes in specific cellular populations provide a precise monitoring of nematogenesis as well as neurogenesis, in homeostatic or developmental conditions.
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Affiliation(s)
- Wanda Buzgariu
- Department of Genetics and Evolution, iGE3, Faculty of Sciences, University of Geneva, Geneva, Switzerland
| | - Marie-Laure Curchod
- Department of Genetics and Evolution, iGE3, Faculty of Sciences, University of Geneva, Geneva, Switzerland
| | - Chrystelle Perruchoud
- Department of Genetics and Evolution, iGE3, Faculty of Sciences, University of Geneva, Geneva, Switzerland
| | - Brigitte Galliot
- Department of Genetics and Evolution, iGE3, Faculty of Sciences, University of Geneva, Geneva, Switzerland.
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14
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Macias-Muñoz A, Murad R, Mortazavi A. Molecular evolution and expression of opsin genes in Hydra vulgaris. BMC Genomics 2019; 20:992. [PMID: 31847811 PMCID: PMC6918707 DOI: 10.1186/s12864-019-6349-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 11/28/2019] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND The evolution of opsin genes is of great interest because it can provide insight into the evolution of light detection and vision. An interesting group in which to study opsins is Cnidaria because it is a basal phylum sister to Bilateria with much visual diversity within the phylum. Hydra vulgaris (H. vulgaris) is a cnidarian with a plethora of genomic resources to characterize the opsin gene family. This eyeless cnidarian has a behavioral reaction to light, but it remains unknown which of its many opsins functions in light detection. Here, we used phylogenetics and RNA-seq to investigate the molecular evolution of opsin genes and their expression in H. vulgaris. We explored where opsin genes are located relative to each other in an improved genome assembly and where they belong in a cnidarian opsin phylogenetic tree. In addition, we used RNA-seq data from different tissues of the H. vulgaris adult body and different time points during regeneration and budding stages to gain insight into their potential functions. RESULTS We identified 45 opsin genes in H. vulgaris, many of which were located near each other suggesting evolution by tandem duplications. Our phylogenetic tree of cnidarian opsin genes supported previous claims that they are evolving by lineage-specific duplications. We identified two H. vulgaris genes (HvOpA1 and HvOpB1) that fall outside of the two commonly determined Hydra groups; these genes possibly have a function in nematocytes and mucous gland cells respectively. We also found opsin genes that have similar expression patterns to phototransduction genes in H. vulgaris. We propose a H. vulgaris phototransduction cascade that has components of both ciliary and rhabdomeric cascades. CONCLUSIONS This extensive study provides an in-depth look at the molecular evolution and expression of H. vulgaris opsin genes. The expression data that we have quantified can be used as a springboard for additional studies looking into the specific function of opsin genes in this species. Our phylogeny and expression data are valuable to investigations of opsin gene evolution and cnidarian biology.
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Affiliation(s)
- Aide Macias-Muñoz
- Department of Developmental and Cell Biology, University of California, Irvine, CA, 92697, USA.
| | - Rabi Murad
- Department of Developmental and Cell Biology, University of California, Irvine, CA, 92697, USA
| | - Ali Mortazavi
- Department of Developmental and Cell Biology, University of California, Irvine, CA, 92697, USA.
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15
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Abstract
The freshwater polyp Hydra provides a potent model system for investigating the conditions that promote wound healing, reactivation of a developmental process and, ultimately, regeneration of an amputated body part. Hydra polyps can also be dissociated to the single cell level and can regenerate a complete body axis from aggregates, behaving as natural organoids. In recent years, the ability to exploit Hydra has been expanded with the advent of new live-imaging approaches, genetic manipulations that include stable transgenesis, gene silencing and genome editing, and the accumulation of high-throughput omics data. In this Primer, we provide an overview of Hydra as a model system for studying regeneration, highlighting recent results that question the classical self-enhancement and long-range inhibition model supposed to drive Hydra regeneration. We underscore the need for integrative explanations incorporating biochemical as well as mechanical signalling.
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Affiliation(s)
- Matthias C Vogg
- Department of Genetics and Evolution, Institute of Genetics and Genomics in Geneva (iGE3), Faculty of Sciences, University of Geneva, 30 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
| | - Brigitte Galliot
- Department of Genetics and Evolution, Institute of Genetics and Genomics in Geneva (iGE3), Faculty of Sciences, University of Geneva, 30 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
| | - Charisios D Tsiairis
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058 Basel, Switzerland
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16
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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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17
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Wang R, Goel T, Khazoyan K, Sabry Z, Quan HJ, Diamond PH, Collins EMS. Mouth Function Determines the Shape Oscillation Pattern in Regenerating Hydra Tissue Spheres. Biophys J 2019; 117:1145-1155. [PMID: 31443907 DOI: 10.1016/j.bpj.2019.07.051] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 06/25/2019] [Accepted: 07/30/2019] [Indexed: 12/12/2022] Open
Abstract
Hydra is a small freshwater polyp capable of regeneration from small tissue pieces and from aggregates of cells. During regeneration, a hollow bilayered sphere is formed that undergoes osmotically driven shape oscillations of inflation and rupture. These oscillations are necessary for successful regeneration. Eventually, the oscillating sphere breaks rotational symmetry along the future head-foot axis of the animal. Notably, the shape oscillations show an abrupt shift from large-amplitude, long-period oscillations to small-amplitude, short-period oscillations. It has been widely accepted that this shift in oscillation pattern is linked to symmetry breaking and axis formation, and current theoretical models of Hydra symmetry breaking use this assumption as a model constraint. However, a mechanistic explanation for the shift in oscillation pattern is lacking. Using in vivo manipulation and imaging, we quantified the shape oscillation dynamics and dissected the timing and triggers of the pattern shift. Our experiments demonstrate that the shift in the shape oscillation pattern in regenerating Hydra tissue pieces is caused by the formation of a functional mouth and not by shape symmetry breaking as previously assumed. Thus, model assumptions must be revised in light of these new experimental data, which can be used to constrain and validate improved theoretical models of pattern formation in Hydra.
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Affiliation(s)
- Rui Wang
- Department of Bioengineering, University of California San Diego, La Jolla, California; Biology Department, Swarthmore College, Swarthmore, Pennsylvania
| | - Tapan Goel
- Department of Physics, University of California San Diego, La Jolla, California; Biology Department, Swarthmore College, Swarthmore, Pennsylvania
| | - Kate Khazoyan
- Department of Bioengineering, University of California San Diego, La Jolla, California
| | - Ziad Sabry
- Biology Department, Swarthmore College, Swarthmore, Pennsylvania
| | - Heng J Quan
- Department of Physics, University of California San Diego, La Jolla, California; Department of Mathematics, University of California San Diego, La Jolla, California
| | - Patrick H Diamond
- Department of Physics, University of California San Diego, La Jolla, California
| | - Eva-Maria S Collins
- Department of Physics, University of California San Diego, La Jolla, California; Biology Department, Swarthmore College, Swarthmore, Pennsylvania.
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18
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Siebert S, Farrell JA, Cazet JF, Abeykoon Y, Primack AS, Schnitzler CE, Juliano CE. Stem cell differentiation trajectories in Hydra resolved at single-cell resolution. Science 2019; 365:eaav9314. [PMID: 31346039 PMCID: PMC7104783 DOI: 10.1126/science.aav9314] [Citation(s) in RCA: 177] [Impact Index Per Article: 35.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 06/11/2019] [Indexed: 12/31/2022]
Abstract
The adult Hydra polyp continually renews all of its cells using three separate stem cell populations, but the genetic pathways enabling this homeostatic tissue maintenance are not well understood. We sequenced 24,985 Hydra single-cell transcriptomes and identified the molecular signatures of a broad spectrum of cell states, from stem cells to terminally differentiated cells. We constructed differentiation trajectories for each cell lineage and identified gene modules and putative regulators expressed along these trajectories, thus creating a comprehensive molecular map of all developmental lineages in the adult animal. In addition, we built a gene expression map of the Hydra nervous system. Our work constitutes a resource for addressing questions regarding the evolution of metazoan developmental processes and nervous system function.
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Affiliation(s)
- Stefan Siebert
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA.
| | - Jeffrey A Farrell
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
| | - Jack F Cazet
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA
| | - Yashodara Abeykoon
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA
| | - Abby S Primack
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA
| | - Christine E Schnitzler
- Whitney Laboratory for Marine Bioscience and Department of Biology, University of Florida, St. Augustine, FL, USA
| | - Celina E Juliano
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA.
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19
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Tomczyk S, Buzgariu W, Perruchoud C, Fisher K, Austad S, Galliot B. Loss of Neurogenesis in Aging Hydra. Dev Neurobiol 2019; 79:479-496. [PMID: 30912256 PMCID: PMC6586502 DOI: 10.1002/dneu.22676] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 02/27/2019] [Accepted: 03/14/2019] [Indexed: 01/07/2023]
Abstract
In Hydra the nervous system is composed of neurons and mechanosensory cells that differentiate from interstitial stem cells (ISCs), which also provide gland cells and germ cells. The adult nervous system is actively maintained through continuous de novo neurogenesis that occurs at two distinct paces, slow in intact animals and fast in regenerating ones. Surprisingly Hydra vulgaris survive the elimination of cycling interstitial cells and the subsequent loss of neurogenesis if force-fed. By contrast, H. oligactis animals exposed to cold temperature undergo gametogenesis and a concomitant progressive loss of neurogenesis. In the cold-sensitive strain Ho_CS, this loss irreversibly leads to aging and animal death. Within four weeks, Ho_CS animals lose their contractility, feeding response, and reaction to light. Meanwhile, two positive regulators of neurogenesis, the homeoprotein prdl-a and the neuropeptide Hym-355, are no longer expressed, while the "old" RFamide-expressing neurons persist. A comparative transcriptomic analysis performed in cold-sensitive and cold-resistant strains confirms the downregulation of classical neuronal markers during aging but also shows the upregulation of putative regulators of neurotransmission and neurogenesis such as AHR, FGFR, FoxJ3, Fral2, Jagged, Meis1, Notch, Otx1, and TCF15. The switch of Fral2 expression from neurons to germ cells suggests that in aging animals, the neurogenic program active in ISCs is re-routed to germ cells, preventing de novo neurogenesis and impacting animal survival.
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Affiliation(s)
- Szymon Tomczyk
- Faculty of Sciences, Department of Genetics and EvolutionUniversity of GenevaGenevaSwitzerland
- iGE3 ‐ Institute for Genomics and Genetics in GenevaGenevaSwitzerland
| | - Wanda Buzgariu
- Faculty of Sciences, Department of Genetics and EvolutionUniversity of GenevaGenevaSwitzerland
- iGE3 ‐ Institute for Genomics and Genetics in GenevaGenevaSwitzerland
| | - Chrystelle Perruchoud
- Faculty of Sciences, Department of Genetics and EvolutionUniversity of GenevaGenevaSwitzerland
- iGE3 ‐ Institute for Genomics and Genetics in GenevaGenevaSwitzerland
| | - Kathleen Fisher
- Department of BiologyUniversity of Alabama at BirminghamBirminghamAlabama
| | - Steven Austad
- Department of BiologyUniversity of Alabama at BirminghamBirminghamAlabama
| | - Brigitte Galliot
- Faculty of Sciences, Department of Genetics and EvolutionUniversity of GenevaGenevaSwitzerland
- iGE3 ‐ Institute for Genomics and Genetics in GenevaGenevaSwitzerland
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20
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Rentzsch F, Juliano C, Galliot B. Modern genomic tools reveal the structural and cellular diversity of cnidarian nervous systems. Curr Opin Neurobiol 2019; 56:87-96. [PMID: 30654234 DOI: 10.1016/j.conb.2018.12.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 12/10/2018] [Accepted: 12/11/2018] [Indexed: 12/11/2022]
Abstract
Cnidarians shared a common ancestor with bilaterians more than 600 million years ago. This sister group relationship gives them an informative phylogenetic position for understanding the fascinating morphological and molecular cell type diversity of bilaterian nervous systems. Moreover, cnidarians display novel features such as endodermal neurogenesis and independently evolved centralizations, which provide a platform for understanding the evolution of nervous system innovations. In recent years, the application of modern genomic tools has significantly advanced our understanding of cnidarian nervous system structure and function. For example, transgenic reporter lines and gene knockdown experiments in several cnidarian species reveal a significant degree of conservation in the neurogenesis gene regulatory program, while single cell RNA sequencing projects are providing a much deeper understanding of cnidarian neural cell type diversity. At the level of neural function, the physiological properties of ion channels have been described and calcium imaging of the nervous system in whole animals has allowed for the identification of neural circuits underlying specific behaviours. Cnidarians have arrived in the modern era of molecular neurobiology and are primed to provide exciting new insights into the early evolution of nervous systems.
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Affiliation(s)
- Fabian Rentzsch
- Sars Centre for Marine Molecular Biology, Norway; Department for Biological Sciences, University of Bergen, Norway.
| | - Celina Juliano
- Department of Molecular and Cellular Biology, University of California Davis, CA 95616, United States.
| | - Brigitte Galliot
- Department of Genetics and Evolution, Institute of Genetics and Genomics in Geneva (iGE3), University of Geneva, Switzerland.
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21
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Impact of cycling cells and cell cycle regulation on Hydra regeneration. Dev Biol 2018; 433:240-253. [DOI: 10.1016/j.ydbio.2017.11.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 10/31/2017] [Accepted: 11/08/2017] [Indexed: 01/12/2023]
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22
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Tran CM, Fu S, Rowe T, Collins EMS. Generation and Long-term Maintenance of Nerve-free Hydra. J Vis Exp 2017. [PMID: 28715393 DOI: 10.3791/56115] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The interstitial cell lineage of Hydra includes multipotent stem cells, and their derivatives: gland cells, nematocytes, germ cells, and nerve cells. The interstitial cells can be eliminated through two consecutive treatments with colchicine, a plant-derived toxin that kills dividing cells, thus erasing the potential for renewal of the differentiated cells that are derived from the interstitial stem cells. This allows for the generation of Hydra that lack nerve cells. A nerve-free polyp cannot open its mouth to feed, egest, or regulate osmotic pressure. Such animals, however, can survive and be cultured indefinitely in the laboratory if regularly force-fed and burped. The lack of nerve cells allows for studies of the role of the nervous system in regulating animal behavior and regeneration. Previously published protocols for nerve-free Hydra maintenance involve outdated techniques such as mouth-pipetting with hand-pulled micropipette tips to feed and clean the Hydra. Here, an improved protocol for maintenance of nerve-free Hydra is introduced. Fine-tipped forceps are used to force open the mouth and insert freshly killed Artemia. Following force-feeding, the body cavity of the animal is flushed with fresh medium using a syringe and hypodermic needle to remove undigested material, referred to here as "burping". This new method of force-feeding and burping nerve-free Hydra through the use of forceps and syringes eliminates the need for mouth-pipetting using hand-pulled micropipette tips. It thus makes the process safer and significantly more time efficient. To ensure that the nerve cells in the hypostome have been eliminated, immunohistochemistry using anti-tyrosine-tubulin is conducted.
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Affiliation(s)
| | - Sharon Fu
- Division of Biological Sciences, UC San Diego
| | | | - Eva-Maria S Collins
- Division of Biological Sciences, UC San Diego; Physics Department, UC San Diego;
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23
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Gahan JM, Schnitzler CE, DuBuc TQ, Doonan LB, Kanska J, Gornik SG, Barreira S, Thompson K, Schiffer P, Baxevanis AD, Frank U. Functional studies on the role of Notch signaling in Hydractinia development. Dev Biol 2017; 428:224-231. [PMID: 28601529 DOI: 10.1016/j.ydbio.2017.06.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 06/06/2017] [Accepted: 06/06/2017] [Indexed: 11/19/2022]
Abstract
The function of Notch signaling was previously studied in two cnidarians, Hydra and Nematostella, representing the lineages Hydrozoa and Anthozoa, respectively. Using pharmacological inhibition in Hydra and a combination of pharmacological and genetic approaches in Nematostella, it was shown in both animals that Notch is required for tentacle morphogenesis and for late stages of stinging cell maturation. Surprisingly, a role for Notch in neural development, which is well documented in bilaterians, was evident in embryonic Nematostella but not in adult Hydra. Adult neurogenesis in the latter seemed to be unaffected by DAPT, a drug that inhibits Notch signaling. To address this apparent discrepancy, we studied the role of Notch in Hydractinia echinata, an additional hydrozoan, in all life stages. Using CRISPR-Cas9 mediated mutagenesis, transgenesis, and pharmacological interference we show that Notch is dispensable for Hydractinia normal neurogenesis in all life stages but is required for the maturation of stinging cells and for tentacle morphogenesis. Our results are consistent with a conserved role for Notch in morphogenesis and nematogenesis across Cnidaria, and a lineage-specific loss of Notch dependence in neurogenesis in hydrozoans.
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Affiliation(s)
- James M Gahan
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Christine E Schnitzler
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 320803, USA; Department of Biology, University of Florida, Gainesville, FL 32611, USA; Division of Intramural Research, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Timothy Q DuBuc
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Liam B Doonan
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Justyna Kanska
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Sebastian G Gornik
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Sofia Barreira
- Division of Intramural Research, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Kerry Thompson
- Centre for Microscopy and Imaging, Discipline of Anatomy, School of Medicine, National University of Ireland, Galway, Galway, Ireland
| | - Philipp Schiffer
- Department for Genetics Environment and Evolution, University College London, London, UK
| | - Andreas D Baxevanis
- Division of Intramural Research, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Uri Frank
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland.
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24
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Flici H, Schnitzler CE, Millane RC, Govinden G, Houlihan A, Boomkamp SD, Shen S, Baxevanis AD, Frank U. An Evolutionarily Conserved SoxB-Hdac2 Crosstalk Regulates Neurogenesis in a Cnidarian. Cell Rep 2017; 18:1395-1409. [PMID: 28178518 PMCID: PMC5312794 DOI: 10.1016/j.celrep.2017.01.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 12/09/2016] [Accepted: 01/10/2017] [Indexed: 10/20/2022] Open
Abstract
SoxB transcription factors and histone deacetylases (HDACs) are each major players in the regulation of neurogenesis, but a functional link between them has not been previously demonstrated. Here, we show that SoxB2 and Hdac2 act together to regulate neurogenesis in the cnidarian Hydractinia echinata during tissue homeostasis and head regeneration. We find that misexpression of SoxB genes modifies the number of neural cells in all life stages and interferes with head regeneration. Hdac2 was co-expressed with SoxB2, and its downregulation phenocopied SoxB2 knockdown. We also show that SoxB2 and Hdac2 promote each other's transcript levels, but Hdac2 counteracts this amplification cycle by deacetylating and destabilizing SoxB2 protein. Finally, we present evidence for conservation of these interactions in human neural progenitors. We hypothesize that crosstalk between SoxB transcription factors and Hdac2 is an ancient feature of metazoan neurogenesis and functions to stabilize the correct levels of these multifunctional proteins.
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Affiliation(s)
- Hakima Flici
- Centre for Chromosome Biology (CCB), School of Natural Sciences, National University of Ireland, Galway H91 CF50, Ireland
| | - Christine E Schnitzler
- Whitney Laboratory for Marine Bioscience, University of Florida, St. Augustine, FL 32080, USA; Department of Biology, University of Florida, Gainesville, FL 32611, USA; Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892-8002, USA
| | - R Cathriona Millane
- Centre for Chromosome Biology (CCB), School of Natural Sciences, National University of Ireland, Galway H91 CF50, Ireland
| | - Graham Govinden
- Centre for Chromosome Biology (CCB), School of Natural Sciences, National University of Ireland, Galway H91 CF50, Ireland
| | - Amy Houlihan
- Centre for Chromosome Biology (CCB), School of Natural Sciences, National University of Ireland, Galway H91 CF50, Ireland
| | - Stephanie D Boomkamp
- Regenerative Medicine Institute (REMEDI), National University of Ireland, Galway, Galway H91 CF50, Ireland
| | - Sanbing Shen
- Regenerative Medicine Institute (REMEDI), National University of Ireland, Galway, Galway H91 CF50, Ireland
| | - Andreas D Baxevanis
- Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892-8002, USA
| | - Uri Frank
- Centre for Chromosome Biology (CCB), School of Natural Sciences, National University of Ireland, Galway H91 CF50, Ireland.
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Rentzsch F, Layden M, Manuel M. The cellular and molecular basis of cnidarian neurogenesis. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2016; 6. [PMID: 27882698 PMCID: PMC6680159 DOI: 10.1002/wdev.257] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 08/30/2016] [Accepted: 09/21/2016] [Indexed: 12/22/2022]
Abstract
Neurogenesis initiates during early development and it continues through later developmental stages and in adult animals to enable expansion, remodeling, and homeostasis of the nervous system. The generation of nerve cells has been analyzed in detail in few bilaterian model organisms, leaving open many questions about the evolution of this process. As the sister group to bilaterians, cnidarians occupy an informative phylogenetic position to address the early evolution of cellular and molecular aspects of neurogenesis and to understand common principles of neural development. Here we review studies in several cnidarian model systems that have revealed significant similarities and interesting differences compared to neurogenesis in bilaterian species, and between different cnidarian taxa. Cnidarian neurogenesis is currently best understood in the sea anemone Nematostella vectensis, where it includes epithelial neural progenitor cells that express transcription factors of the soxB and atonal families. Notch signaling regulates the number of these neural progenitor cells, achaete‐scute and dmrt genes are required for their further development and Wnt and BMP signaling appear to be involved in the patterning of the nervous system. In contrast to many vertebrates and Drosophila, cnidarians have a high capacity to generate neurons throughout their lifetime and during regeneration. Utilizing this feature of cnidarian biology will likely allow gaining new insights into the similarities and differences of embryonic and regenerative neurogenesis. The use of different cnidarian model systems and their expanding experimental toolkits will thus continue to provide a better understanding of evolutionary and developmental aspects of nervous system formation. WIREs Dev Biol 2017, 6:e257. doi: 10.1002/wdev.257 This article is categorized under:
Gene Expression and Transcriptional Hierarchies > Cellular Differentiation Signaling Pathways > Cell Fate Signaling Comparative Development and Evolution > Organ System Comparisons Between Species
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Affiliation(s)
- Fabian Rentzsch
- Sars Centre for Marine Molecular Biology, University of Bergen, Bergen, Norway
| | | | - Michaël Manuel
- Sorbonne Universités, UMPC Univ Paris 06, CNRS, Evolution Paris-Seine, Institut de Biologie Paris-Seine (IBPS), Paris, France
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Gahan JM, Bradshaw B, Flici H, Frank U. The interstitial stem cells in Hydractinia and their role in regeneration. Curr Opin Genet Dev 2016; 40:65-73. [DOI: 10.1016/j.gde.2016.06.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 05/26/2016] [Accepted: 06/16/2016] [Indexed: 10/21/2022]
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Rubin BP, Brockes J, Galliot B, Grossniklaus U, Lobo D, Mainardi M, Mirouze M, Prochiantz A, Steger A. A dynamic architecture of life. F1000Res 2015; 4:1288. [PMID: 26949518 PMCID: PMC4760269 DOI: 10.12688/f1000research.7315.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/06/2015] [Indexed: 12/15/2022] Open
Abstract
In recent decades, a profound conceptual transformation has occurred comprising different areas of biological research, leading to a novel understanding of life processes as much more dynamic and changeable. Discoveries in plants and animals, as well as novel experimental approaches, have prompted the research community to reconsider established concepts and paradigms. This development was taken as an incentive to organise a workshop in May 2014 at the Academia Nazionale dei Lincei in Rome. There, experts on epigenetics, regeneration, neuroplasticity, and computational biology, using different animal and plant models, presented their insights on important aspects of a dynamic architecture of life, which comprises all organisational levels of the organism. Their work demonstrates that a dynamic nature of life persists during the entire existence of the organism and permits animals and plants not only to fine-tune their response to particular environmental demands during development, but underlies their continuous capacity to do so. Here, a synthesis of the different findings and their relevance for biological thinking is presented.
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Affiliation(s)
- Beatrix P Rubin
- Collegium Helveticum, University of Zurich and ETH Zurich, Zurich, 8092, Switzerland
| | - Jeremy Brockes
- Department of Structural and Molecular Biology, University College London, London, WC1E 6BT, UK
| | - Brigitte Galliot
- Department of Genetics and Evolution, University of Geneva, Geneva, 1211, Switzerland
| | - Ueli Grossniklaus
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, Zurich, 8008, Switzerland
| | - Daniel Lobo
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD, 21250, USA
| | - Marco Mainardi
- CNR Neuroscience Institute, 56124 Pisa, Italy; Institute of Human Physiology, Catholic University, 00168 Rome, Italy
| | - Marie Mirouze
- Institut de Recherche pour le Développement, UMR DIADE, Laboratoire Génome et Développement des Plantes, 66860 Perpignan, France
| | - Alain Prochiantz
- Chaire des Processus Morphogénétiques, Centre Interdisciplinaire de Recherche en Biologie, Paris, 75231, France
| | - Angelika Steger
- Institute of Theoretical Computer Science, ETH Zurich, Zurich, 8092, Switzerland
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Pirotte N, Leynen N, Artois T, Smeets K. Do you have the nerves to regenerate? The importance of neural signalling in the regeneration process. Dev Biol 2015; 409:4-15. [PMID: 26586202 DOI: 10.1016/j.ydbio.2015.09.025] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 08/26/2015] [Accepted: 09/07/2015] [Indexed: 02/06/2023]
Abstract
The importance of nerve-derived signalling for correct regeneration has been the topic of research for more than a hundred years, but we are just beginning to identify the underlying molecular pathways of this process. Within the current review, we attempt to provide an extensive overview of the neural influences during early and late phases of both vertebrate and invertebrate regeneration. In general, denervation impairs limb regeneration, but the presence of nerves is not essential for the regeneration of aneurogenic extremities. This observation led to the "neurotrophic factor(s) hypothesis", which states that certain trophic factors produced by the nerves are necessary for proper regeneration. Possible neuron-derived factors which regulate regeneration as well as the denervation-affected processes are discussed.
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Affiliation(s)
- Nicky Pirotte
- Zoology: Biodiversity and Toxicology, Centre for Environmental Sciences, Hasselt University, Agoralaan, Building D, BE 3590 Diepenbeek, Belgium
| | - Nathalie Leynen
- Zoology: Biodiversity and Toxicology, Centre for Environmental Sciences, Hasselt University, Agoralaan, Building D, BE 3590 Diepenbeek, Belgium
| | - Tom Artois
- Zoology: Biodiversity and Toxicology, Centre for Environmental Sciences, Hasselt University, Agoralaan, Building D, BE 3590 Diepenbeek, Belgium
| | - Karen Smeets
- Zoology: Biodiversity and Toxicology, Centre for Environmental Sciences, Hasselt University, Agoralaan, Building D, BE 3590 Diepenbeek, Belgium.
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Reddy PC, Unni MK, Gungi A, Agarwal P, Galande S. Evolution of Hox-like genes in Cnidaria: Study of Hydra Hox repertoire reveals tailor-made Hox-code for Cnidarians. Mech Dev 2015; 138 Pt 2:87-96. [DOI: 10.1016/j.mod.2015.08.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 08/05/2015] [Accepted: 08/07/2015] [Indexed: 11/26/2022]
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Merabet S, Galliot B. The TALE face of Hox proteins in animal evolution. Front Genet 2015; 6:267. [PMID: 26347770 PMCID: PMC4539518 DOI: 10.3389/fgene.2015.00267] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Accepted: 07/31/2015] [Indexed: 01/22/2023] Open
Abstract
Hox genes are major regulators of embryonic development. One of their most conserved functions is to coordinate the formation of specific body structures along the anterior-posterior (AP) axis in Bilateria. This architectural role was at the basis of several morphological innovations across bilaterian evolution. In this review, we traced the origin of the Hox patterning system by considering the partnership with PBC and Meis proteins. PBC and Meis belong to the TALE-class of homeodomain-containing transcription factors and act as generic cofactors of Hox proteins for AP axis patterning in Bilateria. Recent data indicate that Hox proteins acquired the ability to interact with their TALE partners in the last common ancestor of Bilateria and Cnidaria. These interactions relied initially on a short peptide motif called hexapeptide (HX), which is present in Hox and non-Hox protein families. Remarkably, Hox proteins can also recruit the TALE cofactors by using specific PBC Interaction Motifs (SPIMs). We describe how a functional Hox/TALE patterning system emerged in eumetazoans through the acquisition of SPIMs. We anticipate that interaction flexibility could be found in other patterning systems, being at the heart of the astonishing morphological diversity observed in the animal kingdom.
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Affiliation(s)
- Samir Merabet
- Centre National de Recherche Scientifique, Institut de Génomique Fonctionnelle de Lyon Lyon, France ; Institut de Génomique Fonctionnelle de Lyon, Ecole Normale Supérieure de Lyon Lyon, France
| | - Brigitte Galliot
- Department of Genetics and Evolution, Faculty of Science, Institute of Genetics and Genomics in Geneva, University of Geneva Geneva, Switzerland
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Petersen HO, Höger SK, Looso M, Lengfeld T, Kuhn A, Warnken U, Nishimiya-Fujisawa C, Schnölzer M, Krüger M, Özbek S, Simakov O, Holstein TW. A Comprehensive Transcriptomic and Proteomic Analysis of Hydra Head Regeneration. Mol Biol Evol 2015; 32:1928-47. [PMID: 25841488 PMCID: PMC4833066 DOI: 10.1093/molbev/msv079] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The cnidarian freshwater polyp Hydra sp. exhibits an unparalleled regeneration capacity in the animal kingdom. Using an integrative transcriptomic and stable isotope labeling by amino acids in cell culture proteomic/phosphoproteomic approach, we studied stem cell-based regeneration in Hydra polyps. As major contributors to head regeneration, we identified diverse signaling pathways adopted for the regeneration response as well as enriched novel genes. Our global analysis reveals two distinct molecular cascades: an early injury response and a subsequent, signaling driven patterning of the regenerating tissue. A key factor of the initial injury response is a general stabilization of proteins and a net upregulation of transcripts, which is followed by a subsequent activation cascade of signaling molecules including Wnts and transforming growth factor (TGF) beta-related factors. We observed moderate overlap between the factors contributing to proteomic and transcriptomic responses suggesting a decoupled regulation between the transcriptional and translational levels. Our data also indicate that interstitial stem cells and their derivatives (e.g., neurons) have no major role in Hydra head regeneration. Remarkably, we found an enrichment of evolutionarily more recent genes in the early regeneration response, whereas conserved genes are more enriched in the late phase. In addition, genes specific to the early injury response were enriched in transposon insertions. Genetic dynamicity and taxon-specific factors might therefore play a hitherto underestimated role in Hydra regeneration.
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Affiliation(s)
- Hendrik O Petersen
- Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany
| | - Stefanie K Höger
- Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany
| | - Mario Looso
- Max Planck Institute (MPI) for Heart and Lung Research, Bad Nauheim, Germany
| | - Tobias Lengfeld
- Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany
| | - Anne Kuhn
- Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany
| | - Uwe Warnken
- Functional Proteome Analysis Unit, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Chiemi Nishimiya-Fujisawa
- Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology, Myodaiji, Okazaki, Japan
| | - Martina Schnölzer
- Functional Proteome Analysis Unit, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Marcus Krüger
- Max Planck Institute (MPI) for Heart and Lung Research, Bad Nauheim, Germany CECAD, University of Cologne, Germany
| | - Suat Özbek
- Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany
| | - Oleg Simakov
- Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany Molecular Genetics Unit, Okinawa Institute of Science and Technology, Okinawa, Japan
| | - Thomas W Holstein
- Centre for Organismal Studies (COS), Heidelberg University, Heidelberg, Germany
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Bradshaw B, Thompson K, Frank U. Distinct mechanisms underlie oral vs aboral regeneration in the cnidarian Hydractinia echinata. eLife 2015; 4:e05506. [PMID: 25884246 PMCID: PMC4421858 DOI: 10.7554/elife.05506] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 04/16/2015] [Indexed: 12/12/2022] Open
Abstract
Cnidarians possess remarkable powers of regeneration, but the cellular and molecular mechanisms underlying this capability are unclear. Studying the hydrozoan Hydractinia echinata we show that a burst of stem cell proliferation occurs following decapitation, forming a blastema at the oral pole within 24 hr. This process is necessary for head regeneration. Knocking down Piwi1, Vasa, Pl10 or Ncol1 expressed by blastema cells inhibited regeneration but not blastema formation. EdU pulse-chase experiments and in vivo tracking of individual transgenic Piwi1+ stem cells showed that the cellular source for blastema formation is migration of stem cells from a remote area. Surprisingly, no blastema developed at the aboral pole after stolon removal. Instead, polyps transformed into stolons and then budded polyps. Hence, distinct mechanisms act to regenerate different body parts in Hydractinia. This model, where stem cell behavior can be monitored in vivo at single cell resolution, offers new insights for regenerative biology. DOI:http://dx.doi.org/10.7554/eLife.05506.001 Although all animals are capable of regenerating damaged tissue to some extent, a few—including jellyfish, coral, and their relatives—are able to regenerate entire lost body parts. Closely related species may have very different regeneration capabilities. This has led some researchers to propose that higher animals, such as mammals, still possess the ancient genes that allow entire body parts to regenerate, but that somehow the genes have been disabled during their evolution. Studying animals that can regenerate large parts of their bodies may therefore help scientists understand what prevents others, including humans, from doing so. An animal that is particularly useful for studies into regeneration is called Hydractinia echinata. These tiny marine animals make their homes on the shells of hermit crabs. They are small, transparent and stay fixed to one spot, making it easy for scientists to grow them in the laboratory and closely observe what is going on when they regenerate. Bradshaw et al. genetically engineered Hydractinia individuals to produce a fluorescent protein in their stem cells; these cells have the ability to become one of several kinds of mature cell, and often help to repair and grow tissues. This allowed the stem cells to be tracked using a microscope. When the head of Hydractinia was cut off, stem cells in the animals' mid body section migrated to the end where the head used to be and multiplied. These stem cells then created a bud (known as a blastema) that developed into a new, fully functional head within two days, allowing the animals to capture prey. Reducing the activity of certain stem cell genes prevented the new head from growing, but the bud still formed. Next, Bradshaw et al. removed a structure from the opposite end of the animal, called the stolon, which normally helps Hydractinia attach to hermit crabs shells. Stolons regenerated in a completely different way to heads. No bud formed. Instead, the remainder of the animal's body, which included the head and the body column, gradually transformed into a stolon rather than regenerating this structure, and only then grew a new body column and head. Therefore, different tissues in the same animal can regenerate in different ways. Understanding the ‘tricks’ used by animals like Hydractinia to regenerate may help translate these abilities to regenerative medicine. DOI:http://dx.doi.org/10.7554/eLife.05506.002
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Affiliation(s)
- Brian Bradshaw
- School of Natural Sciences and Regenerative Medicine Institute, National University of Ireland, Galway, Ireland
| | - Kerry Thompson
- Centre for Microscopy and Imaging, Discipline of Anatomy, School of Medicine, National University of Ireland, Galway, Ireland
| | - Uri Frank
- School of Natural Sciences and Regenerative Medicine Institute, National University of Ireland, Galway, Ireland
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Abstract
Recent studies in Drosophila, Hydra, planarians, zebrafish, mice, indicate that cell death can open paths to regeneration in adult animals. Indeed injury can induce cell death, itself triggering regeneration following an immediate instructive mechanism, whereby the dying cells release signals that induce cellular responses over short and/or long-range distances. Cell death can also provoke a sustained derepressing response through the elimination of cells that suppress regeneration in homeostatic conditions. Whether common properties support what we name "regenerative cell death," is currently unclear. As key parameters, we review here the injury proapoptotic signals, the signals released by the dying cells, the cellular responses, and their respective timing. ROS appears as a common signal triggering cell death through MAPK and/or JNK pathway activation. But the modes of ROS production vary, from a brief pulse upon wounding, to repeated waves as observed in the zebrafish fin where ROS supports two peaks of cell death. Indeed regenerative cell death can be restricted to the injury phase, as in Hydra, Drosophila, or biphasic, immediate, and delayed, as in planarians and zebrafish. The dying cells release in a caspase-dependent manner a variety of signaling molecules, cytokines, growth factors, but also prostaglandins or ATP as recorded in Drosophila, Hydra, mice, and zebrafish, respectively. Interestingly, the ROS-producing cells often resist to cell death, implying a complex paracrine mode of signaling to launch regeneration, involving ROS-producing cells, ROS-sensing cells that release signaling molecules upon caspase activation, and effector cells that respond to these signals by proliferating, migrating, and/or differentiating.
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Affiliation(s)
- Sophie Vriz
- Collège de France, Center for Interdisciplinary Research in Biology (CIRB), Paris, France; University Paris-Diderot, Paris, France
| | - Silke Reiter
- Department of Genetics and Evolution, University of Geneva, Switzerland
| | - Brigitte Galliot
- Department of Genetics and Evolution, University of Geneva, Switzerland.
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Fraguas S, Barberán S, Iglesias M, Rodríguez-Esteban G, Cebrià F. egr-4, a target of EGFR signaling, is required for the formation of the brain primordia and head regeneration in planarians. Development 2014; 141:1835-47. [PMID: 24700819 DOI: 10.1242/dev.101345] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
During the regeneration of freshwater planarians, polarity and patterning programs play essential roles in determining whether a head or a tail regenerates at anterior or posterior-facing wounds. This decision is made very soon after amputation. The pivotal role of the Wnt/β-catenin and Hh signaling pathways in re-establishing anterior-posterior (AP) polarity has been well documented. However, the mechanisms that control the growth and differentiation of the blastema in accordance with its AP identity are less well understood. Previous studies have described a role of Smed-egfr-3, a planarian epidermal growth factor receptor, in blastema growth and differentiation. Here, we identify Smed-egr-4, a zinc-finger transcription factor belonging to the early growth response gene family, as a putative downstream target of Smed-egfr-3. Smed-egr-4 is mainly expressed in the central nervous system and its silencing inhibits anterior regeneration without affecting the regeneration of posterior regions. Single and combinatorial RNA interference to target different elements of the Wnt/β-catenin pathway, together with expression analysis of brain- and anterior-specific markers, revealed that Smed-egr-4: (1) is expressed in two phases - an early Smed-egfr-3-independent phase and a late Smed-egfr-3-dependent phase; (2) is necessary for the differentiation of the brain primordia in the early stages of regeneration; and (3) that it appears to antagonize the activity of the Wnt/β-catenin pathway to allow head regeneration. These results suggest that a conserved EGFR/egr pathway plays an important role in cell differentiation during planarian regeneration and indicate an association between early brain differentiation and the proper progression of head regeneration.
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Affiliation(s)
- Susanna Fraguas
- Departament de Genètica de la Universitat de Barcelona and Institut de Biomedicina de la Universitat de Barcelona (IBUB), Avenida Diagonal 643, Edifici Prevosti planta 1, Barcelona 08028, Spain
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Buzgariu W, Crescenzi M, Galliot B. Robust G2 pausing of adult stem cells in Hydra. Differentiation 2014; 87:83-99. [PMID: 24703763 DOI: 10.1016/j.diff.2014.03.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 03/10/2014] [Accepted: 03/13/2014] [Indexed: 12/18/2022]
Abstract
Hydra is a freshwater hydrozoan polyp that constantly renews its two tissue layers thanks to three distinct stem cell populations that cannot replace each other, epithelial ectodermal, epithelial endodermal, and multipotent interstitial. These adult stem cells, located in the central body column, exhibit different cycling paces, slow for the epithelial, fast for the interstitial. To monitor the changes in cell cycling in Hydra, we established a fast and efficient flow cytometry procedure, which we validated by confirming previous findings, as the Nocodazole-induced reversible arrest of cell cycling in G2/M, and the mitogenic signal provided by feeding. Then to dissect the cycling and differentiation behaviors of the interstitial stem cells, we used the AEP_cnnos1 and AEP_Icy1 transgenic lines that constitutively express GFP in this lineage. For the epithelial lineages we used the sf-1 strain that rapidly eliminates the fast cycling cells upon heat-shock and progressively becomes epithelial. This study evidences similar cycling patterns for the interstitial and epithelial stem cells, which all alternate between the G2 and S-phases traversing a minimal G1-phase. We also found interstitial progenitors with a shorter G2 that pause in G1/G0. At the animal extremities, most cells no longer cycle, the epithelial cells terminally differentiate in G2 and the interstitial progenitors in G1/G0. At the apical pole ~80% cells are post-mitotic differentiated cells, reflecting the higher density of neurons and nematocytes in this region. We discuss how the robust G2 pausing of stem cells, maintained over weeks of starvation, may contribute to regeneration.
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Affiliation(s)
- Wanda Buzgariu
- Department of Genetics and Evolution, University of Geneva, Sciences III, 30 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
| | | | - Brigitte Galliot
- Department of Genetics and Evolution, University of Geneva, Sciences III, 30 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland.
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Kanska J, Frank U. New roles for Nanos in neural cell fate determination revealed by studies in a cnidarian. J Cell Sci 2013; 126:3192-203. [PMID: 23659997 DOI: 10.1242/jcs.127233] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nanos is a pan-metazoan germline marker, important for germ cell development and maintenance. In flies, Nanos also acts in posterior and neural development, but these functions have not been demonstrated experimentally in other animals. Using the cnidarian Hydractinia we have uncovered novel roles for Nanos in neural cell fate determination. Ectopic expression of Nanos2 increased the numbers of embryonic stinging cell progenitors, but decreased the numbers of neurons. Downregulation of Nanos2 had the opposite effect. Furthermore, Nanos2 blocked maturation of committed, post-mitotic nematoblasts. Hence, Nanos2 acts as a switch between two differentiation pathways, increasing the numbers of nematoblasts at the expense of neuroblasts, but preventing nematocyte maturation. Nanos2 ectopic expression also caused patterning defects, but these were not associated with deregulation of Wnt signaling, showing that the basic anterior-posterior polarity remained intact, and suggesting that numerical imbalance between nematocytes and neurons might have caused these defects, affecting axial patterning only indirectly. We propose that the functions of Nanos in germ cells and in neural development are evolutionarily conserved, but its role in posterior patterning is an insect or arthropod innovation.
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Affiliation(s)
- Justyna Kanska
- School of Natural Sciences and Regenerative Medicine Institute (REMEDI), National University of Ireland, Galway, Ireland
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37
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Passamaneck YJ, Martindale MQ. Cell proliferation is necessary for the regeneration of oral structures in the anthozoan cnidarian Nematostella vectensis. BMC DEVELOPMENTAL BIOLOGY 2012. [PMID: 23206430 PMCID: PMC3553063 DOI: 10.1186/1471-213x-12-34] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Background The contribution of cell proliferation to regeneration varies greatly between different metazoan models. Planarians rely on pluripotent neoblasts and amphibian limb regeneration depends upon formation of a proliferative blastema, while regeneration in Hydra can occur in the absence of cell proliferation. Recently, the cnidarian Nematostella vectensis has shown potential as a model for studies of regeneration because of the ability to conduct comparative studies of patterning during embryonic development, asexual reproduction, and regeneration. The present study investigates the pattern of cell proliferation during the regeneration of oral structures and the role of cell proliferation in this process. Results In intact polyps, cell proliferation is observed in both ectodermal and endodermal tissues throughout the entire oral-aboral axis, including in the tentacles and physa. Following bisection, there is initially little change in proliferation at the wound site of the aboral fragment, however, beginning 18 to 24 hours after amputation there is a dramatic increase in cell proliferation at the wound site in the aboral fragment. This elevated level of proliferation is maintained throughout the course or regeneration of oral structures, including the tentacles, the mouth, and the pharynx. Treatments with the cell proliferation inhibitors hydroxyurea and nocodazole demonstrate that cell proliferation is indispensable for the regeneration of oral structures. Although inhibition of regeneration by nocodazole was generally irreversible, secondary amputation reinitiates cell proliferation and regeneration. Conclusions The study has found that high levels of cell proliferation characterize the regeneration of oral structures in Nematostella, and that this cell proliferation is necessary for the proper progression of regeneration. Thus, while cell proliferation contributes to regeneration of oral structures in both Nematostella and Hydra, Nematostella lacks the ability to undergo the compensatory morphallactic mode of regeneration that characterizes Hydra. Our results are consistent with amputation activating a quiescent population of mitotically competent stem cells in spatial proximity to the wound site, which form the regenerated structures.
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Affiliation(s)
- Yale J Passamaneck
- Kewalo Marine Laboratory, Pacific Biosciences Research Center, University of Hawaii, 41 Ahui Street, Honolulu, HI 96813, USA.
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38
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Kumar A, Brockes JP. Nerve dependence in tissue, organ, and appendage regeneration. Trends Neurosci 2012; 35:691-9. [PMID: 22989534 DOI: 10.1016/j.tins.2012.08.003] [Citation(s) in RCA: 204] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 08/06/2012] [Accepted: 08/13/2012] [Indexed: 12/20/2022]
Abstract
Many regeneration contexts require the presence of regenerating nerves as a transient component of the progenitor cell niche. Here we review nerve involvement in regeneration of various structures in vertebrates and invertebrates. Nerves are also implicated as persistent determinants in the niche of certain stem cells in mammals, as well as in Drosophila. We consider our present understanding of the cellular and molecular mechanisms underlying nerve dependence, including evidence of critical interactions with glia and non-neural cell types. The example of the salamander aneurogenic limb illustrates that developmental interactions between the limb bud and its innervation can be determinative for adult regeneration. These phenomena provide a different perspective on nerve cells to that based on chemical and electrical excitability.
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Affiliation(s)
- Anoop Kumar
- Institute of Structural and Molecular Biology, Division of Life Sciences, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
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39
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Galliot B. Injury-induced asymmetric cell death as a driving force for head regeneration in Hydra. Dev Genes Evol 2012; 223:39-52. [DOI: 10.1007/s00427-012-0411-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 06/04/2012] [Indexed: 12/25/2022]
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40
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Abstract
Cnidarians belong to the first phylum differentiating a nervous system, thus providing suitable model systems to trace the origins of neurogenesis. Indeed corals, sea anemones, jellyfish and hydra contract, swim and catch their food thanks to sophisticated nervous systems that share with bilaterians common neurophysiological mechanisms. However, cnidarian neuroanatomies are quite diverse, and reconstructing the urcnidarian nervous system is ambiguous. At least a series of characters recognized in all classes appear plesiomorphic: (1) the three cell types that build cnidarian nervous systems (sensory-motor cells, ganglionic neurons and mechanosensory cells called nematocytes or cnidocytes); (2) an organization of nerve nets and nerve rings [those working as annular central nervous system (CNS)]; (3) a neuronal conduction via neurotransmitters; (4) a larval anterior sensory organ required for metamorphosis; (5) a persisting neurogenesis in adulthood. By contrast, the origin of the larval and adult neural stem cells differs between hydrozoans and other cnidarians; the sensory organs (ocelli, lens-eyes, statocysts) are present in medusae but absent in anthozoans; the electrical neuroid conduction is restricted to hydrozoans. Evo-devo approaches might help reconstruct the neurogenic status of the last common cnidarian ancestor. In fact, recent genomic analyses show that if most components of the postsynaptic density predate metazoan origin, the bilaterian neurogenic gene families originated later, in basal metazoans or as eumetazoan novelties. Striking examples are the ParaHox Gsx, Pax, Six, COUP-TF and Twist-type regulators, which seemingly exert neurogenic functions in cnidarians, including eye differentiation, and support the view of a two-step process in the emergence of neurogenesis.
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Affiliation(s)
- Brigitte Galliot
- Department of Genetics and Evolution, Faculty of Science, University of Geneva, Sciences III, 30 quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland.
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Fraguas S, Barberán S, Cebrià F. EGFR signaling regulates cell proliferation, differentiation and morphogenesis during planarian regeneration and homeostasis. Dev Biol 2011; 354:87-101. [PMID: 21458439 DOI: 10.1016/j.ydbio.2011.03.023] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2010] [Revised: 02/14/2011] [Accepted: 03/23/2011] [Indexed: 02/08/2023]
Abstract
Similarly to development, the process of regeneration requires that cells accurately sense and respond to their external environment. Thus, intrinsic cues must be integrated with signals from the surrounding environment to ensure appropriate temporal and spatial regulation of tissue regeneration. Identifying the signaling pathways that control these events will not only provide insights into a fascinating biological phenomenon but may also yield new molecular targets for use in regenerative medicine. Among classical models to study regeneration, freshwater planarians represent an attractive system in which to investigate the signals that regulate cell proliferation and differentiation, as well as the proper patterning of the structures being regenerated. Recent studies in planarians have begun to define the role of conserved signaling pathways during regeneration. Here, we extend these analyses to the epidermal growth factor (EGF) receptor pathway. We report the characterization of three epidermal growth factor (EGF) receptors in the planarian Schmidtea mediterranea. Silencing of these genes by RNA interference (RNAi) yielded multiple defects in intact and regenerating planarians. Smed-egfr-1(RNAi) resulted in decreased differentiation of eye pigment cells, abnormal pharynx regeneration and maintenance, and the development of dorsal outgrowths. In contrast, Smed-egfr-3(RNAi) animals produced smaller blastemas associated with abnormal differentiation of certain cell types. Our results suggest important roles for the EGFR signaling in controlling cell proliferation, differentiation and morphogenesis during planarian regeneration and homeostasis.
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Affiliation(s)
- Susanna Fraguas
- Department of Genetics, Faculty of Biology, University of Barcelona and Institute of Biomedicine of the University of Barcelona (IBUB), Av. Diagonal 645, Barcelona, Catalunya, Spain
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Abstract
There is growing interest in the use of cnidarians (corals, sea anemones, jellyfish and hydroids) to investigate the evolution of key aspects of animal development, such as the formation of the third germ layer (mesoderm), the nervous system and the generation of bilaterality. The recent sequencing of the Nematostella and Hydra genomes, and the establishment of methods for manipulating gene expression, have inspired new research efforts using cnidarians. Here, we present the main features of cnidarian models and their advantages for research, and summarize key recent findings using these models that have informed our understanding of the evolution of the developmental processes underlying metazoan body plan formation.
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Affiliation(s)
- Ulrich Technau
- Department for Molecular Evolution and Development, Centre for Organismal Systems Biology, Faculty of Life Sciences, University of Vienna, Althanstrasse 14, Vienna, Austria.
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Abstract
Over the past decades, genetic analyses performed in vertebrate and invertebrate organisms deciphered numerous cellular and molecular mechanisms deployed during sexual development and identified genetic circuitries largely shared among bilaterians. In contrast, the functional analysis of the mechanisms that support regenerative processes in species randomly scattered among the animal kingdom, were limited by the lack of genetic tools. Consequently, unifying principles explaining how stress and injury can lead to the reactivation of a complete developmental program with restoration of original shape and function remained beyond reach of understanding. Recent data on cell plasticity suggest that beside the classical developmental approach, the analysis of homeostasis and asexual reproduction in adult organisms provides novel entry points to dissect the regenerative potential of a given species, a given organ or a given tissue. As a clue, both tissue homeostasis and regeneration dynamics rely on the availability of stem cells and/or on the plasticity of differentiated cells to replenish the missing structure. The freshwater Hydra polyp provides us with a unique model system to study the intricate relationships between the mechanisms that regulate the maintenance of homeostasis, even in extreme conditions (starvation and overfeeding) and the reactivation of developmental programs after bisection or during budding. Interestingly head regeneration in Hydra can follow several routes according to the level of amputation, suggesting that indeed the homeostatic background dramatically influences the route taken to bridge injury and regeneration.
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Affiliation(s)
- Brigitte Galliot
- Faculty of Sciences, Department of Zoology and Animal Biology, University of Geneva, Geneva, Switzerland.
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Steele RE, David CN, Technau U. A genomic view of 500 million years of cnidarian evolution. Trends Genet 2010; 27:7-13. [PMID: 21047698 DOI: 10.1016/j.tig.2010.10.002] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Revised: 09/23/2010] [Accepted: 10/08/2010] [Indexed: 01/29/2023]
Abstract
Cnidarians (corals, anemones, jellyfish and hydras) are a diverse group of animals of interest to evolutionary biologists, ecologists and developmental biologists. With the publication of the genome sequences of Hydra and Nematostella, whose last common ancestor was the stem cnidarian, researchers are beginning to see the genomic underpinnings of cnidarian biology. Cnidarians are known for the remarkable plasticity of their morphology and life cycles. This plasticity is reflected in the Hydra and Nematostella genomes, which differ to an exceptional degree in size, base composition, transposable element content and gene conservation. It is now known what cnidarian genomes, given 500 million years, are capable of; as we discuss here, the next challenge is to understand how this genomic history has led to the striking diversity seen in this group.
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Affiliation(s)
- Robert E Steele
- Department of Biological Chemistry and the Developmental Biology Center, University of California, Irvine, CA 92697, USA.
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Houliston E, Momose T, Manuel M. Clytia hemisphaerica: a jellyfish cousin joins the laboratory. Trends Genet 2010; 26:159-67. [DOI: 10.1016/j.tig.2010.01.008] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2009] [Revised: 01/24/2010] [Accepted: 01/25/2010] [Indexed: 11/29/2022]
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Abstract
Analysis of the origin and evolution of neurons is crucial for revealing principles of organization of neural circuits with unexpected implications for genomic sciences, biomedical applications and regenerative medicine. This article presents an overview of some controversial ideas about the origin and evolution of neurons and nervous systems, focusing on the independent origin of complex brains and possible independent origins of neurons. First, earlier hypotheses related to the origin of neurons are summarized. Second, the diversity of nervous systems and convergent evolution of complex brains in relation to current views about animal phylogeny is discussed. Third, the lineages of molluscs and basal metazoans are used as illustrated examples of multiple origins of complex brains and neurons. Finally, a hypothesis about the independent origin of complex brains, centralized nervous systems and neurons is outlined. Injury-associated mechanisms leading to secretion of signal peptides (and related molecules) can be considered as evolutionary predecessors of inter-neuronal signaling and the major factors in the appearance of neurons in the first place.
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Affiliation(s)
- Leonid L Moroz
- Department of Neuroscience and McKnight Brain Institute, Gainesville, Fla., USA.
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Chera S, Ghila L, Dobretz K, Wenger Y, Bauer C, Buzgariu W, Martinou JC, Galliot B. Apoptotic cells provide an unexpected source of Wnt3 signaling to drive hydra head regeneration. Dev Cell 2009; 17:279-89. [PMID: 19686688 DOI: 10.1016/j.devcel.2009.07.014] [Citation(s) in RCA: 287] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2008] [Revised: 04/06/2009] [Accepted: 07/20/2009] [Indexed: 11/28/2022]
Abstract
Decapitated Hydra regenerate their heads via morphallaxis, i.e., without significant contributions made by cell proliferation or interstitial stem cells. Indeed, Hydra depleted of interstitial stem cells regenerate robustly, and Wnt3 from epithelial cells triggers head regeneration. However, we find a different mechanism controlling regeneration after midgastric bisection in animals equipped with both epithelial and interstitial cell lineages. In this context, we see rapid induction of apoptosis and Wnt3 secretion among interstitial cells at the head- (but not foot-) regenerating site. Apoptosis is both necessary and sufficient to induce Wnt3 production and head regeneration, even at ectopic sites. Further, we identify a zone of proliferation beneath the apoptotic zone, reminiscent of proliferative blastemas in regenerating limbs and of compensatory proliferation induced by dying cells in Drosophila imaginal discs. We propose that different types of injuries induce distinct cellular modes of Hydra head regeneration, which nonetheless converge on a central effector, Wnt3.
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Affiliation(s)
- Simona Chera
- Department of Zoology and Animal Biology, University of Geneva, 30 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
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Origins of neurogenesis, a cnidarian view. Dev Biol 2009; 332:2-24. [PMID: 19465018 DOI: 10.1016/j.ydbio.2009.05.563] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Revised: 05/14/2009] [Accepted: 05/16/2009] [Indexed: 11/22/2022]
Abstract
New perspectives on the origin of neurogenesis emerged with the identification of genes encoding post-synaptic proteins as well as many "neurogenic" regulators as the NK, Six, Pax, bHLH proteins in the Demosponge genome, a species that might differentiate sensory cells but no neurons. However, poriferans seem to miss some key regulators of the neurogenic circuitry as the Hox/paraHox and Otx-like gene families. Moreover as a general feature, many gene families encoding evolutionarily-conserved signaling proteins and transcription factors were submitted to a wave of gene duplication in the last common eumetazoan ancestor, after Porifera divergence. In contrast gene duplications in the last common bilaterian ancestor, Urbilateria, are limited, except for the bHLH Atonal-class. Hence Cnidaria share with Bilateria a large number of genetic tools. The expression and functional analyses currently available suggest a neurogenic function for numerous orthologs in developing or adult cnidarians where neurogenesis takes place continuously. As an example, in the Hydra polyp, the Clytia medusa and the Acropora coral, the Gsx/cnox2/Anthox-2 ParaHox gene likely supports neurogenesis. Also neurons and nematocytes (mechanosensory cells) share in hydrozoans a common stem cell and several regulatory genes indicating that they can be considered as sister cells. Performed in anthozoan and medusozoan species, these studies should tell us more about the way(s) evolution hazards achieved the transition from epithelial to neuronal cell fate, and about the robustness of the genetic circuitry that allowed neuromuscular transmission to arise and be maintained across evolution.
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Quiquand M, Yanze N, Schmich J, Schmid V, Galliot B, Piraino S. More constraint on ParaHox than Hox gene families in early metazoan evolution. Dev Biol 2009; 328:173-87. [DOI: 10.1016/j.ydbio.2009.01.022] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2008] [Revised: 01/14/2009] [Accepted: 01/14/2009] [Indexed: 12/28/2022]
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