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Giez C, Noack C, Sakib E, Hofacker LM, Repnik U, Bramkamp M, Bosch TCG. Satiety controls behavior in Hydra through an interplay of pre-enteric and central nervous system-like neuron populations. Cell Rep 2024; 43:114210. [PMID: 38787723 DOI: 10.1016/j.celrep.2024.114210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 03/11/2024] [Accepted: 04/23/2024] [Indexed: 05/26/2024] Open
Abstract
Hunger and satiety can have an influence on decision-making, sensory processing, and motor behavior by altering the internal state of the brain. This process necessitates the integration of peripheral sensory stimuli into the central nervous system. Here, we show how animals without a central nervous system such as the cnidarian Hydra measure and integrate satiety into neuronal circuits and which specific neuronal populations are involved. We demonstrate that this simple nervous system, previously referred to as diffuse, has an endodermal subpopulation (N4) similar to the enteric nervous system (feeding-associated behavior) and an ectodermal population (N3) that performs central nervous system-like functions (physiology/motor). This view of a supposedly simple nervous system could open an important window into the origin of more complex nervous systems.
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Affiliation(s)
- Christoph Giez
- Zoological Institute, University of Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany; Neural Circuits and Evolution Laboratory, Francis Crick Institute, London NW1 1AT, UK.
| | - Christopher Noack
- Zoological Institute, University of Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany
| | - Ehsan Sakib
- Zoological Institute, University of Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany
| | - Lisa-Marie Hofacker
- Zoological Institute, University of Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany
| | - Urska Repnik
- Centrale Microscopy, University of Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany
| | - Marc Bramkamp
- Centrale Microscopy, University of Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany; Institute for General Microbiology, University of Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany
| | - Thomas C G Bosch
- Zoological Institute, University of Kiel, Am Botanischen Garten 1-9, 24118 Kiel, Germany.
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2
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Klimovich A, Bosch TCG. Novel technologies uncover novel 'anti'-microbial peptides in Hydra shaping the species-specific microbiome. Philos Trans R Soc Lond B Biol Sci 2024; 379:20230058. [PMID: 38497265 PMCID: PMC10945409 DOI: 10.1098/rstb.2023.0058] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 11/16/2023] [Indexed: 03/19/2024] Open
Abstract
The freshwater polyp Hydra uses an elaborate innate immune machinery to maintain its specific microbiome. Major components of this toolkit are conserved Toll-like receptor (TLR)-mediated immune pathways and species-specific antimicrobial peptides (AMPs). Our study harnesses advanced technologies, such as high-throughput sequencing and machine learning, to uncover a high complexity of the Hydra's AMPs repertoire. Functional analysis reveals that these AMPs are specific against diverse members of the Hydra microbiome and expressed in a spatially controlled pattern. Notably, in the outer epithelial layer, AMPs are produced mainly in the neurons. The neuron-derived AMPs are secreted directly into the glycocalyx, the habitat for symbiotic bacteria, and display high selectivity and spatial restriction of expression. In the endodermal layer, in contrast, endodermal epithelial cells produce an abundance of different AMPs including members of the arminin and hydramacin families, while gland cells secrete kazal-type protease inhibitors. Since the endodermal layer lines the gastric cavity devoid of symbiotic bacteria, we assume that endodermally secreted AMPs protect the gastric cavity from intruding pathogens. In conclusion, Hydra employs a complex set of AMPs expressed in distinct tissue layers and cell types to combat pathogens and to maintain a stable spatially organized microbiome. This article is part of the theme issue 'Sculpting the microbiome: how host factors determine and respond to microbial colonization'.
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Affiliation(s)
- Alexander Klimovich
- Zoological Institute, Christian-Albrechts University of Kiel, Am Botanischen Garten 1-9, Kiel 24118, Germany
| | - Thomas C. G. Bosch
- Zoological Institute, Christian-Albrechts University of Kiel, Am Botanischen Garten 1-9, Kiel 24118, Germany
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3
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Hanson A, Reme R, Telerman N, Yamamoto W, Olivo-Marin JC, Lagache T, Yuste R. Automatic monitoring of neural activity with single-cell resolution in behaving Hydra. Sci Rep 2024; 14:5083. [PMID: 38429381 PMCID: PMC10907378 DOI: 10.1038/s41598-024-55608-2] [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: 09/25/2023] [Accepted: 02/26/2024] [Indexed: 03/03/2024] Open
Abstract
The ability to record every spike from every neuron in a behaving animal is one of the holy grails of neuroscience. Here, we report coming one step closer towards this goal with the development of an end-to-end pipeline that automatically tracks and extracts calcium signals from individual neurons in the cnidarian Hydra vulgaris. We imaged dually labeled (nuclear tdTomato and cytoplasmic GCaMP7s) transgenic Hydra and developed an open-source Python platform (TraSE-IN) for the Tracking and Spike Estimation of Individual Neurons in the animal during behavior. The TraSE-IN platform comprises a series of modules that segments and tracks each nucleus over time and extracts the corresponding calcium activity in the GCaMP channel. Another series of signal processing modules allows robust prediction of individual spikes from each neuron's calcium signal. This complete pipeline will facilitate the automatic generation and analysis of large-scale datasets of single-cell resolution neural activity in Hydra, and potentially other model organisms, paving the way towards deciphering the neural code of an entire animal.
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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.
| | - Raphael Reme
- UMR3691, BioImage Analysis Unit, Institut Pasteur, Université Paris Cité, CNRS, Paris, France
| | - Noah Telerman
- Department of Biological Sciences, Neurotechnology Center, Columbia University, New York, NY, USA
| | - Wataru Yamamoto
- Department of Biological Sciences, Neurotechnology Center, Columbia University, New York, NY, USA
| | | | - Thibault Lagache
- UMR3691, BioImage Analysis Unit, Institut Pasteur, Université Paris Cité, CNRS, Paris, France
| | - Rafael Yuste
- Department of Biological Sciences, Neurotechnology Center, Columbia University, New York, NY, USA
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4
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Giez C, Pinkle D, Giencke Y, Wittlieb J, Herbst E, Spratte T, Lachnit T, Klimovich A, Selhuber-Unkel C, Bosch TCG. Multiple neuronal populations control the eating behavior in Hydra and are responsive to microbial signals. Curr Biol 2023; 33:5288-5303.e6. [PMID: 37995697 DOI: 10.1016/j.cub.2023.10.038] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 09/05/2023] [Accepted: 10/20/2023] [Indexed: 11/25/2023]
Abstract
Although recent studies indicate the impact of microbes on the central nervous systems and behavior, it remains unclear how the relationship between the functionality of the nervous system, behavior, and the microbiota evolved. In this work, we analyzed the eating behavior of Hydra, a host that has a simple nervous system and a low-complexity microbiota. To identify the neuronal subpopulations involved, we used a subpopulation-specific cell ablation system and calcium imaging. The role of the microbiota was uncovered by manipulating the diversity of the natural microbiota. We show that different neuronal subpopulations are functioning together to control eating behavior. Animals with a drastically reduced microbiome had severe difficulties in mouth opening due to a significantly increased level of glutamate. This could be reversed by adding a full complement of the microbiota. In summary, we provide a mechanistic explanation of how Hydra's nervous system controls eating behavior and what role microbes play in this.
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Affiliation(s)
- Christoph Giez
- Zoological Institute, University of Kiel, Christian-Albrechts-Platz 4, 24118 Kiel, Germany.
| | - Denis Pinkle
- Zoological Institute, University of Kiel, Christian-Albrechts-Platz 4, 24118 Kiel, Germany
| | - Yan Giencke
- Zoological Institute, University of Kiel, Christian-Albrechts-Platz 4, 24118 Kiel, Germany
| | - Jörg Wittlieb
- Zoological Institute, University of Kiel, Christian-Albrechts-Platz 4, 24118 Kiel, Germany
| | - Eva Herbst
- Zoological Institute, University of Kiel, Christian-Albrechts-Platz 4, 24118 Kiel, Germany
| | - Tobias Spratte
- Institute for Molecular Systems Engineering and Advanced Materials (INSEAM), University Heidelberg, Im Neuenheimer Feld 225, 69120 Heidelberg, Germany
| | - Tim Lachnit
- Zoological Institute, University of Kiel, Christian-Albrechts-Platz 4, 24118 Kiel, Germany
| | - Alexander Klimovich
- Zoological Institute, University of Kiel, Christian-Albrechts-Platz 4, 24118 Kiel, Germany
| | - Christine Selhuber-Unkel
- Institute for Molecular Systems Engineering and Advanced Materials (INSEAM), University Heidelberg, Im Neuenheimer Feld 225, 69120 Heidelberg, Germany
| | - Thomas C G Bosch
- Zoological Institute, University of Kiel, Christian-Albrechts-Platz 4, 24118 Kiel, Germany.
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5
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Cao M. CRISPR-Cas9 genome editing in Steinernema entomopathogenic nematodes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.24.568619. [PMID: 38045388 PMCID: PMC10690278 DOI: 10.1101/2023.11.24.568619] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Molecular tool development in traditionally non-tractable animals opens new avenues to study gene functions in the relevant ecological context. Entomopathogenic nematodes (EPN) Steinernema and their symbiotic bacteria of Xenorhabdus spp are a valuable experimental system in the laboratory and are applicable in the field to promote agricultural productivity. The infective juvenile (IJ) stage of the nematode packages mutualistic symbiotic bacteria in the intestinal pocket and invades insects that are agricultural pests. The lack of consistent and heritable genetics tools in EPN targeted mutagenesis severely restricted the study of molecular mechanisms underlying both parasitic and mutualistic interactions. Here, I report a protocol for CRISPR-Cas9 based genome-editing that is successful in two EPN species, S. carpocapsae and S. hermaphroditum . I adapted a gonadal microinjection technique in S. carpocapsae , which created on-target modifications of a homologue Sc-dpy-10 (cuticular collagen) by homology-directed repair. A similar delivery approach was used to introduce various alleles in S. hermaphroditum including Sh-dpy-10 and Sh-unc-22 (a muscle gene), resulting in visible and heritable phenotypes of dumpy and twitching, respectively. Using conditionally dominant alleles of Sh-unc-22 as a co-CRISPR marker, I successfully modified a second locus encoding Sh-Daf-22 (a homologue of human sterol carrier protein SCPx), predicted to function as a core enzyme in the biosynthesis of nematode pheromone that is required for IJ development. As a proof of concept, Sh-daf-22 null mutant showed IJ developmental defects in vivo ( in insecta) . This research demonstrates that Steinernema spp are highly tractable for targeted mutagenesis and has great potential in the study of gene functions under controlled laboratory conditions within the relevant context of its ecological niche.
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6
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Agam O, Braun E. Universal calcium fluctuations in Hydramorphogenesis. Phys Biol 2023; 20:066002. [PMID: 37696269 DOI: 10.1088/1478-3975/acf8a4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 09/11/2023] [Indexed: 09/13/2023]
Abstract
Understanding the collective physical processes that drive robust morphological transitions in animal development necessitates the characterization of the relevant fields involved in morphogenesis. Calcium (Ca2+) is recognized as one such field. In this study, we demonstrate that the spatial fluctuations of Ca2+duringHydraregeneration exhibit universal characteristics. To investigate this phenomenon, we employ two distinct controls, an external electric field andheptanol, a gap junction-blocking drug. Both lead to the modulation of the Ca2+activity and a reversible halting of the regeneration process. The application of an electric field enhances Ca2+activity in theHydra's tissue and increases its spatial correlations, while the administration ofheptanolinhibits its activity and diminishes the spatial correlations. Remarkably, the statistical characteristics of Ca2+spatial fluctuations, including the coefficient of variation and skewness, manifest universal shape distributions across tissue samples and conditions. We introduce a field-theoretic model, describing fluctuations in a tilted double-well potential, which successfully captures these universal properties. Moreover, our analysis reveals that the Ca2+activity is spatially localized, and theHydra's tissue operates near the onset of bistability, where the local Ca2+activity fluctuates between low and high excited states in distinct regions. These findings highlight the prominent role of the Ca2+field inHydramorphogenesis and provide insights into the underlying mechanisms governing robust morphological transitions.
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Affiliation(s)
- Oded Agam
- The Racah Institute of Physics, Edmond J. Safra Campus, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Erez Braun
- Department of Physics and Network Biology Research Laboratories, Technion-Israel Institute of Technology, Haifa 32000, Israel
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7
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Yamamoto W, Yuste R. Two-photon manipulation of neuronal activity and behavior in Hydra vulgaris. STAR Protoc 2023; 4:102453. [PMID: 37515760 PMCID: PMC10400962 DOI: 10.1016/j.xpro.2023.102453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 05/07/2023] [Accepted: 06/21/2023] [Indexed: 07/31/2023] Open
Abstract
The introduction of calcium imaging has rendered cnidarians, such as Hydra vulgaris, valuable model organisms for investigating neuronal activity and behavior. Here, we present a comprehensive protocol to image and manipulate neuronal activity and behavior of Hydra. We describe steps for wide-field imaging and two-photon simulation and ablation of neurons. We then detail imaging behavior and post-ablation analysis. We address challenges that may arise during the preparation and execution of the experiments.
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Affiliation(s)
- Wataru Yamamoto
- Neurotechnology Center, Department Biological Sciences, Columbia University, New York, NY 10027, USA.
| | - Rafael Yuste
- Neurotechnology Center, Department Biological Sciences, Columbia University, New York, NY 10027, USA
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8
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Lechable M, Tang X, Siebert S, Feldbacher A, Fernández-Quintero ML, Breuker K, Juliano CE, Liedl KR, Hobmayer B, Hartl M. High Intrinsic Oncogenic Potential in the Myc-Box-Deficient Hydra Myc3 Protein. Cells 2023; 12:cells12091265. [PMID: 37174665 PMCID: PMC10177328 DOI: 10.3390/cells12091265] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 04/17/2023] [Accepted: 04/25/2023] [Indexed: 05/15/2023] Open
Abstract
The proto-oncogene myc has been intensively studied primarily in vertebrate cell culture systems. Myc transcription factors control fundamental cellular processes such as cell proliferation, cell cycle control and stem cell maintenance. Myc interacts with the Max protein and Myc/Max heterodimers regulate thousands of target genes. The genome of the freshwater polyp Hydra encodes four myc genes (myc1-4). Previous structural and biochemical characterization showed that the Hydra Myc1 and Myc2 proteins share high similarities with vertebrate c-Myc, and their expression patterns suggested a function in adult stem cell maintenance. In contrast, an additional Hydra Myc protein termed Myc3 is highly divergent, lacking the common N-terminal domain and all conserved Myc-boxes. Single cell transcriptome analysis revealed that the myc3 gene is expressed in a distinct population of interstitial precursor cells committed to nerve- and gland-cell differentiation, where the Myc3 protein may counteract the stemness actions of Myc1 and Myc2 and thereby allow the implementation of a differentiation program. In vitro DNA binding studies showed that Myc3 dimerizes with Hydra Max, and this dimer efficiently binds to DNA containing the canonical Myc consensus motif (E-box). In vivo cell transformation assays in avian fibroblast cultures further revealed an unexpected high potential for oncogenic transformation in the conserved Myc3 C-terminus, as compared to Hydra Myc2 or Myc1. Structure modeling of the Myc3 protein predicted conserved amino acid residues in its bHLH-LZ domain engaged in Myc3/Max dimerization. Mutating these amino acid residues in the human c-Myc (MYC) sequence resulted in a significant decrease in its cell transformation potential. We discuss our findings in the context of oncogenic transformation and cell differentiation, both relevant for human cancer, where Myc represents a major driver.
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Affiliation(s)
- Marion Lechable
- Institute of Zoology, University of Innsbruck, 6020 Innsbruck, Austria
- Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020 Innsbruck, Austria
| | - Xuechen Tang
- Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020 Innsbruck, Austria
- Institute of Inorganic and Theoretical Chemistry, University of Innsbruck, 6020 Innsbruck, Austria
| | - Stefan Siebert
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
| | - Angelika Feldbacher
- Institute of Zoology, University of Innsbruck, 6020 Innsbruck, Austria
- Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020 Innsbruck, Austria
| | - Monica L Fernández-Quintero
- Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020 Innsbruck, Austria
- Institute of Inorganic and Theoretical Chemistry, University of Innsbruck, 6020 Innsbruck, Austria
| | - Kathrin Breuker
- Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020 Innsbruck, Austria
- Institute of Organic Chemistry, University of Innsbruck, 6020 Innsbruck, Austria
| | - Celina E Juliano
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
| | - Klaus R Liedl
- Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020 Innsbruck, Austria
- Institute of Inorganic and Theoretical Chemistry, University of Innsbruck, 6020 Innsbruck, Austria
| | - Bert Hobmayer
- Institute of Zoology, University of Innsbruck, 6020 Innsbruck, Austria
- Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020 Innsbruck, Austria
| | - Markus Hartl
- Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020 Innsbruck, Austria
- Institute of Biochemistry, University of Innsbruck, 6020 Innsbruck, Austria
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9
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Primack AS, Cazet JF, Little HM, Mühlbauer S, Cox BD, David CN, Farrell JA, Juliano CE. Differentiation trajectories of the Hydra nervous system reveal transcriptional regulators of neuronal fate. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.15.531610. [PMID: 36993575 PMCID: PMC10055148 DOI: 10.1101/2023.03.15.531610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
The small freshwater cnidarian polyp Hydra vulgaris uses adult stem cells (interstitial stem cells) to continually replace neurons throughout its life. This feature, combined with the ability to image the entire nervous system (Badhiwala et al., 2021; Dupre & Yuste, 2017) and availability of gene knockdown techniques (Juliano, Reich, et al., 2014; Lohmann et al., 1999; Vogg et al., 2022), makes Hydra a tractable model for studying nervous system development and regeneration at the whole-organism level. In this study, we use single-cell RNA sequencing and trajectory inference to provide a comprehensive molecular description of the adult nervous system. This includes the most detailed transcriptional characterization of the adult Hydra nervous system to date. We identified eleven unique neuron subtypes together with the transcriptional changes that occur as the interstitial stem cells differentiate into each subtype. Towards the goal of building gene regulatory networks to describe Hydra neuron differentiation, we identified 48 transcription factors expressed specifically in the Hydra nervous system, including many that are conserved regulators of neurogenesis in bilaterians. We also performed ATAC-seq on sorted neurons to uncover previously unidentified putative regulatory regions near neuron-specific genes. Finally, we provide evidence to support the existence of transdifferentiation between mature neuron subtypes and we identify previously unknown transition states in these pathways. All together, we provide a comprehensive transcriptional description of an entire adult nervous system, including differentiation and transdifferentiation pathways, which provides a significant advance towards understanding mechanisms that underlie nervous system regeneration.
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Affiliation(s)
- Abby S Primack
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616
| | - Jack F Cazet
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616
| | - Hannah Morris Little
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616
| | - Susanne Mühlbauer
- Department of Plant Biochemistry, Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany
| | - Ben D Cox
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616
| | - Charles N David
- Department of Biology, Ludwig-Maximilians-University Munich, 82152 Martinsried, Germany
| | - Jeffrey A Farrell
- Division of Developmental Biology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, Bethesda, MD 20814, USA
| | - Celina E Juliano
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616
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10
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A chromosome-scale epigenetic map of the Hydra genome reveals conserved regulators of cell state. Genome Res 2023; 33:283-298. [PMID: 36639202 PMCID: PMC10069465 DOI: 10.1101/gr.277040.122] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 01/10/2023] [Indexed: 01/15/2023]
Abstract
The epithelial and interstitial stem cells of the freshwater polyp Hydra are the best-characterized stem cell systems in any cnidarian, providing valuable insight into cell type evolution and the origin of stemness in animals. However, little is known about the transcriptional regulatory mechanisms that determine how these stem cells are maintained and how they give rise to their diverse differentiated progeny. To address such questions, a thorough understanding of transcriptional regulation in Hydra is needed. To this end, we generated extensive new resources for characterizing transcriptional regulation in Hydra, including new genome assemblies for Hydra oligactis and the AEP strain of Hydra vulgaris, an updated whole-animal single-cell RNA-seq atlas, and genome-wide maps of chromatin interactions, chromatin accessibility, sequence conservation, and histone modifications. These data revealed the existence of large kilobase-scale chromatin interaction domains in the Hydra genome that contain transcriptionally coregulated genes. We also uncovered the transcriptomic profiles of two previously molecularly uncharacterized cell types: isorhiza-type nematocytes and somatic gonad ectoderm. Finally, we identified novel candidate regulators of cell type-specific transcription, several of which have likely been conserved at least since the divergence of Hydra and the jellyfish Clytia hemisphaerica more than 400 million years ago.
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11
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Puntin G, Sweet M, Fraune S, Medina M, Sharp K, Weis VM, Ziegler M. Harnessing the Power of Model Organisms To Unravel Microbial Functions in the Coral Holobiont. Microbiol Mol Biol Rev 2022; 86:e0005322. [PMID: 36287022 PMCID: PMC9769930 DOI: 10.1128/mmbr.00053-22] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Stony corals build the framework of coral reefs, ecosystems of immense ecological and economic importance. The existence of these ecosystems is threatened by climate change and other anthropogenic stressors that manifest in microbial dysbiosis such as coral bleaching and disease, often leading to coral mortality. Despite a significant amount of research, the mechanisms ultimately underlying these destructive phenomena, and what could prevent or mitigate them, remain to be resolved. This is mostly due to practical challenges in experimentation on corals and the highly complex nature of the coral holobiont that also includes bacteria, archaea, protists, and viruses. While the overall importance of these partners is well recognized, their specific contributions to holobiont functioning and their interspecific dynamics remain largely unexplored. Here, we review the potential of adopting model organisms as more tractable systems to address these knowledge gaps. We draw on parallels from the broader biological and biomedical fields to guide the establishment, implementation, and integration of new and emerging model organisms with the aim of addressing the specific needs of coral research. We evaluate the cnidarian models Hydra, Aiptasia, Cassiopea, and Astrangia poculata; review the fast-evolving field of coral tissue and cell cultures; and propose a framework for the establishment of "true" tropical reef-building coral models. Based on this assessment, we also suggest future research to address key aspects limiting our ability to understand and hence improve the response of reef-building corals to future ocean conditions.
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Affiliation(s)
- Giulia Puntin
- Department of Animal Ecology and Systematics, Marine Holobiomics Lab, Justus Liebig University Giessen, Giessen, Germany
| | - Michael Sweet
- Aquatic Research Facility, Environmental Sustainability Research Centre, University of Derby, Derby, United Kingdom
| | - Sebastian Fraune
- Institute for Zoology and Organismic Interactions, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
| | - Mónica Medina
- Department of Biology, Pennsylvania State University, State College, Pennsylvania, USA
| | - Koty Sharp
- Department of Biology, Marine Biology, and Environmental Science, Roger Williams University, Bristol, Rhode Island, USA
| | - Virginia M. Weis
- Department of Integrative Biology, Oregon State University, Corvallis, Oregon, USA
| | - Maren Ziegler
- Department of Animal Ecology and Systematics, Marine Holobiomics Lab, Justus Liebig University Giessen, Giessen, Germany
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12
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Wright BA, Kvansakul M, Schierwater B, Humbert PO. Cell polarity signalling at the birth of multicellularity: What can we learn from the first animals. Front Cell Dev Biol 2022; 10:1024489. [PMID: 36506100 PMCID: PMC9729800 DOI: 10.3389/fcell.2022.1024489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Accepted: 10/31/2022] [Indexed: 11/25/2022] Open
Abstract
The innovation of multicellularity has driven the unparalleled evolution of animals (Metazoa). But how is a multicellular organism formed and how is its architecture maintained faithfully? The defining properties and rules required for the establishment of the architecture of multicellular organisms include the development of adhesive cell interactions, orientation of division axis, and the ability to reposition daughter cells over long distances. Central to all these properties is the ability to generate asymmetry (polarity), coordinated by a highly conserved set of proteins known as cell polarity regulators. The cell polarity complexes, Scribble, Par and Crumbs, are considered to be a metazoan innovation with apicobasal polarity and adherens junctions both believed to be present in all animals. A better understanding of the fundamental mechanisms regulating cell polarity and tissue architecture should provide key insights into the development and regeneration of all animals including humans. Here we review what is currently known about cell polarity and its control in the most basal metazoans, and how these first examples of multicellular life can inform us about the core mechanisms of tissue organisation and repair, and ultimately diseases of tissue organisation, such as cancer.
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Affiliation(s)
- Bree A. Wright
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia
| | - Marc Kvansakul
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia,Research Centre for Molecular Cancer Prevention, La Trobe University, Melbourne, VIC, Australia
| | - Bernd Schierwater
- Institute of Animal Ecology and Evolution, University of Veterinary Medicine Hannover, Foundation, Bünteweg, Hannover, Germany
| | - Patrick O. Humbert
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC, Australia,Research Centre for Molecular Cancer Prevention, La Trobe University, Melbourne, VIC, Australia,Department of Biochemistry and Pharmacology, University of Melbourne, Melbourne, VIC, Australia,Department of Clinical Pathology, University of Melbourne, Melbourne, VIC, Australia,*Correspondence: Patrick O. Humbert,
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13
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Bosch TCG. Beyond Lynn Margulis’ green hydra. Symbiosis 2022. [DOI: 10.1007/s13199-022-00849-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
AbstractLynn Margulis has made it clear that in nature partnerships are the predominant form of life; that life processes can only be understood in terms of the interactions of such partnerships; and that their inherent complexity can only be understood by taking a holistic approach. Here I attempt to relate Lynn Margulis´ observations on the freshwater polyp hydra to the perceptions and problems of today’s Hydra research. To accomplish this, I will synthesize our current understanding of how symbionts influence the phenotype and fitness of hydra. Based on this new findings, a fundamental paradigm shift and a new era is emerging in the way that we consider organisms such as hydra as multi-organismic metaorganisms, just as Lynn Margulis may have thought about it.
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14
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Traffic light Hydra allows for simultaneous in vivo imaging of all three cell lineages. Dev Biol 2022; 488:74-80. [DOI: 10.1016/j.ydbio.2022.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Revised: 05/06/2022] [Accepted: 05/10/2022] [Indexed: 11/19/2022]
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15
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Chrysostomou E, Febrimarsa, DuBuc T, Frank U. Gene Manipulation in Hydractinia. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2022; 2450:419-436. [PMID: 35359321 DOI: 10.1007/978-1-0716-2172-1_22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The ability to regenerate lost body parts is irregularly distributed among animals, with substantial differences in regenerative potential between and within metazoan phyla. It is widely believed that regenerative animal clades inherited some aspects of their capacity to regenerate from their common ancestors but have also evolved new mechanisms that are not shared with other regenerative animals. Therefore, to gain a broad understanding of animal regenerative mechanisms and evolution, a broad sampling approach is necessary. Unfortunately, only few regenerative animals have been established as laboratory models with protocols for functional gene studies. Here, we describe the methods to establish transgenic individuals of the marine cnidarian Hydractinia. We also provide methods for transient gene expression manipulation without modifying the genome of the animals.
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Affiliation(s)
- Eleni Chrysostomou
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Febrimarsa
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Timothy DuBuc
- Biology Department, Swarthmore College, Swarthmore, PA, USA
| | - Uri Frank
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland.
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16
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Martinez P, Ballarin L, Ereskovsky AV, Gazave E, Hobmayer B, Manni L, Rottinger E, Sprecher SG, Tiozzo S, Varela-Coelho A, Rinkevich B. Articulating the "stem cell niche" paradigm through the lens of non-model aquatic invertebrates. BMC Biol 2022; 20:23. [PMID: 35057814 PMCID: PMC8781081 DOI: 10.1186/s12915-022-01230-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 01/12/2022] [Indexed: 12/13/2022] Open
Abstract
Stem cells (SCs) in vertebrates typically reside in "stem cell niches" (SCNs), morphologically restricted tissue microenvironments that are important for SC survival and proliferation. SCNs are broadly defined by properties including physical location, but in contrast to vertebrates and other "model" organisms, aquatic invertebrate SCs do not have clearly documented niche outlines or properties. Life strategies such as regeneration or asexual reproduction may have conditioned the niche architectural variability in aquatic or marine animal groups. By both establishing the invertebrates SCNs as independent types, yet allowing inclusiveness among them, the comparative analysis will allow the future functional characterization of SCNs.
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Affiliation(s)
- P Martinez
- Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Av. Diagonal 643, 08028, Barcelona, Spain.
- Institut Català de Recerca i Estudis Avançats (ICREA), Barcelona, Spain.
| | - L Ballarin
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35100, Padova, Italy
| | - A V Ereskovsky
- Aix Marseille University, Avignon Université, CNRS, IRD, IMBE, Marseille, France
- St. Petersburg State University, Biological Faculty, Universitetskaya emb. 7/9, St. Petersburg, 199034, Russia
- N. K. Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Vavilova Street 26, Moscow, 119334, Russia
| | - E Gazave
- Université de Paris, CNRS, Institut Jacques Monod, F-75006, Paris, France
| | - B Hobmayer
- Department of Zoology and Center of Molecular Biosciences, University of Innsbruck, Technikerstr. 25, 6020, Innsbruck, Austria
| | - L Manni
- Department of Biology, University of Padova, Via U. Bassi 58/B, 35100, Padova, Italy
| | - E Rottinger
- Université Côte d'Azur, CNRS, INSERM, Institute for Research on Cancer and Aging, Nice (IRCAN), Nice, France
- Université Côte d'Azur, Federative Research Institute - Marine Resources (IFR MARRES), Nice, France
| | - S G Sprecher
- Department of Biology, University of Fribourg, Chemin du Musee 10, 1700, Fribourg, Switzerland
| | - S Tiozzo
- Sorbonne Université, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Paris, France
| | - A Varela-Coelho
- ITQB NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Av. da República, 2780-157, Oeiras, Portugal
| | - B Rinkevich
- Israel Oceanography and Limnological Research, National Institute of Oceanography, Tel Shikmona, P.O. Box 8030, 31080, Haifa, Israel.
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17
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Courtney A, Liegey J, Burke N, Hassett AR, Lowery M, Pickering M. Characterisation of geometric variance in the epithelial nerve net of the ctenophore Pleurobrachia pileus. J Comp Neurol 2021; 530:1438-1458. [PMID: 34933399 DOI: 10.1002/cne.25290] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 11/23/2021] [Accepted: 12/15/2021] [Indexed: 11/10/2022]
Abstract
Neuroscience lacks a diverse repertoire of model organisms, resulting in an incomplete understanding into the general principles of neural function. Ctenophores display many neurobiological and experimental features which make them a promising candidate to fill this gap. They possess a nerve net distributed across their body surface, in the epithelial layer. There is a long-held assumption that nerve nets are 'simple' and lack distinct organisational principles. We want to challenge this assumption and determine how stereotyped the structure of this network is. We estimated body surface area in Pleurobrachia pileus using custom Optical Projection Tomography and Light Sheet Morphometry imaging systems. Using an antibody against tyrosinated α-tubulin we visualised the nerve net in situ and quantified the geometric properties using an automated segmentation approach. We characterised organisational rules of the epithelial nerve net in animals of different sizes and at different regions of the body. We found that specific morphological features within the nerve net are largely unchanged during growth. These properties must be essential to the functionality of the nervous system and therefore are maintained during a change in body size. We have also established the principles of organisation of the network and showed that some of the geometric properties are variable across different parts of the body. This suggests that there may be different functions occurring in regions with different structural characteristics. This is the most comprehensive structural description of a ctenophore nerve net to date and demonstrates the amenability of P. pileus for whole organism network analysis. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Amy Courtney
- School of Medicine, University College Dublin, Ireland.,UCD Centre for Biomedical Engineering, University College Dublin, Ireland
| | - Jérémy Liegey
- UCD Centre for Biomedical Engineering, University College Dublin, Ireland.,School of Electrical & Electronic Engineering, University College Dublin, Ireland
| | - Niamh Burke
- School of Medicine, University College Dublin, Ireland.,UCD Centre for Biomedical Engineering, University College Dublin, Ireland
| | - Amy R Hassett
- School of Medicine, University College Dublin, Ireland.,UCD Centre for Biomedical Engineering, University College Dublin, Ireland
| | - Madeleine Lowery
- UCD Centre for Biomedical Engineering, University College Dublin, Ireland.,School of Electrical & Electronic Engineering, University College Dublin, Ireland
| | - Mark Pickering
- School of Medicine, University College Dublin, Ireland.,UCD Centre for Biomedical Engineering, University College Dublin, Ireland
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18
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Vogg MC, Buzgariu W, Suknovic NS, Galliot B. Cellular, Metabolic, and Developmental Dimensions of Whole-Body Regeneration in Hydra. Cold Spring Harb Perspect Biol 2021; 13:a040725. [PMID: 34230037 PMCID: PMC8635000 DOI: 10.1101/cshperspect.a040725] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Here we discuss the developmental and homeostatic conditions necessary for Hydra regeneration. Hydra is characterized by populations of adult stem cells paused in the G2 phase of the cell cycle, ready to respond to injury signals. The body column can be compared to a blastema-like structure, populated with multifunctional epithelial stem cells that show low sensitivity to proapoptotic signals, and high inducibility of autophagy that promotes resistance to stress and starvation. Intact Hydra polyps also exhibit a dynamic patterning along the oral-aboral axis under the control of homeostatic organizers whose activity results from regulatory loops between activators and inhibitors. As in bilaterians, injury triggers the immediate production of reactive oxygen species (ROS) signals that promote wound healing and contribute to the reactivation of developmental programs via cell death and the de novo formation of new organizing centers from somatic tissues. In aging Hydra, regeneration is rapidly lost as homeostatic conditions are no longer pro-regenerative.
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Affiliation(s)
- Matthias Christian Vogg
- Department of Genetics and Evolution, Institute of Genetics and Genomics in Geneva (iGE3), Faculty of Sciences, University of Geneva, Geneva 4, Switzerland
| | - Wanda Buzgariu
- Department of Genetics and Evolution, Institute of Genetics and Genomics in Geneva (iGE3), Faculty of Sciences, University of Geneva, Geneva 4, Switzerland
| | - Nenad Slavko Suknovic
- Department of Genetics and Evolution, Institute of Genetics and Genomics in Geneva (iGE3), Faculty of Sciences, University of Geneva, Geneva 4, Switzerland
| | - Brigitte Galliot
- Department of Genetics and Evolution, Institute of Genetics and Genomics in Geneva (iGE3), Faculty of Sciences, University of Geneva, Geneva 4, Switzerland
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19
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Weissbourd B, Momose T, Nair A, Kennedy A, Hunt B, Anderson DJ. A genetically tractable jellyfish model for systems and evolutionary neuroscience. Cell 2021; 184:5854-5868.e20. [PMID: 34822783 PMCID: PMC8629132 DOI: 10.1016/j.cell.2021.10.021] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 08/30/2021] [Accepted: 10/19/2021] [Indexed: 11/22/2022]
Abstract
Jellyfish are radially symmetric organisms without a brain that arose more than 500 million years ago. They achieve organismal behaviors through coordinated interactions between autonomously functioning body parts. Jellyfish neurons have been studied electrophysiologically, but not at the systems level. We introduce Clytia hemisphaerica as a transparent, genetically tractable jellyfish model for systems and evolutionary neuroscience. We generate stable F1 transgenic lines for cell-type-specific conditional ablation and whole-organism GCaMP imaging. Using these tools and computational analyses, we find that an apparently diffuse network of RFamide-expressing umbrellar neurons is functionally subdivided into a series of spatially localized subassemblies whose synchronous activation controls directional food transfer from the tentacles to the mouth. These data reveal an unanticipated degree of structured neural organization in this species. Clytia affords a platform for systems-level studies of neural function, behavior, and evolution within a clade of marine organisms with growing ecological and economic importance.
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Affiliation(s)
- Brandon Weissbourd
- Division of Biology and Biological Engineering 140-18, California Institute of Technology, Pasadena, CA 91125, USA; Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA; Tianqiao and Chrissy Chen Institute for Neuroscience, California Institute of Technology, Pasadena, CA 91125, USA.
| | - Tsuyoshi Momose
- Sorbonne Université, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-Mer (LBDV), 06230 Villefranche-sur-Mer, France
| | - Aditya Nair
- Division of Biology and Biological Engineering 140-18, California Institute of Technology, Pasadena, CA 91125, USA; Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA; Tianqiao and Chrissy Chen Institute for Neuroscience, California Institute of Technology, Pasadena, CA 91125, USA
| | - Ann Kennedy
- Division of Biology and Biological Engineering 140-18, California Institute of Technology, Pasadena, CA 91125, USA; Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA; Tianqiao and Chrissy Chen Institute for Neuroscience, California Institute of Technology, Pasadena, CA 91125, USA
| | - Bridgett Hunt
- Division of Biology and Biological Engineering 140-18, California Institute of Technology, Pasadena, CA 91125, USA; Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA; Tianqiao and Chrissy Chen Institute for Neuroscience, California Institute of Technology, Pasadena, CA 91125, USA
| | - David J Anderson
- Division of Biology and Biological Engineering 140-18, California Institute of Technology, Pasadena, CA 91125, USA; Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA; Tianqiao and Chrissy Chen Institute for Neuroscience, California Institute of Technology, Pasadena, CA 91125, USA.
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20
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Schierwater B, Osigus HJ, Bergmann T, Blackstone NW, Hadrys H, Hauslage J, Humbert PO, Kamm K, Kvansakul M, Wysocki K, DeSalle R. The enigmatic Placozoa part 2: Exploring evolutionary controversies and promising questions on earth and in space. Bioessays 2021; 43:e2100083. [PMID: 34490659 DOI: 10.1002/bies.202100083] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 07/21/2021] [Accepted: 08/16/2021] [Indexed: 12/28/2022]
Abstract
The placozoan Trichoplax adhaerens has been bridging gaps between research disciplines like no other animal. As outlined in part 1, placozoans have been subject of hot evolutionary debates and placozoans have challenged some fundamental evolutionary concepts. Here in part 2 we discuss the exceptional genetics of the phylum Placozoa and point out some challenging model system applications for the best known species, Trichoplax adhaerens.
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Affiliation(s)
- Bernd Schierwater
- Institute of Animal Ecology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Hans-Jürgen Osigus
- Institute of Animal Ecology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Tjard Bergmann
- Institute of Animal Ecology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Neil W Blackstone
- Department of Biological Sciences, Northern Illinois University, DeKalb, Illinois, USA
| | - Heike Hadrys
- Institute of Animal Ecology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Jens Hauslage
- Gravitational Biology, Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany
| | - Patrick O Humbert
- Department of Biochemistry & Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia.,Research Centre for Molecular Cancer Prevention, La Trobe University, Melbourne, Victoria, Australia
| | - Kai Kamm
- Institute of Animal Ecology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Marc Kvansakul
- Department of Biochemistry & Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia.,Research Centre for Molecular Cancer Prevention, La Trobe University, Melbourne, Victoria, Australia
| | - Kathrin Wysocki
- Institute of Animal Ecology, University of Veterinary Medicine Hannover, Foundation, Hannover, Germany
| | - Rob DeSalle
- American Museum of Natural History, New York, New York, USA
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21
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Muhr J, Hagey DW. The cell cycle and differentiation as integrated processes: Cyclins and CDKs reciprocally regulate Sox and Notch to balance stem cell maintenance. Bioessays 2021; 43:e2000285. [PMID: 34008221 DOI: 10.1002/bies.202000285] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 04/15/2021] [Accepted: 04/21/2021] [Indexed: 12/18/2022]
Abstract
Development and maintenance of diverse organ systems require context-specific regulation of stem cell behaviour. We hypothesize that this is achieved via reciprocal regulation between the cell cycle machinery and differentiation factors. This idea is supported by the parallel evolutionary emergence of differentiation pathways, cell cycle components and complex multicellularity. In addition, the activities of different cell cycle phases have been found to bias cells towards stem cell maintenance or differentiation. Finally, several direct mechanistic links between these two processes have been established. Here, we focus on interactions between cyclin-CDK complexes and differentiation regulators of the Notch pathway and Sox family of transcription factors within the context of pluripotent and neural stem cells. Thus, this hypothesis formalizes the links between these two processes as an integrated network. Since such factors are common to all stem cells, better understanding their interconnections will help to explain their behaviour in health and disease.
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Affiliation(s)
- Jonas Muhr
- Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, Sweden
| | - Daniel W Hagey
- Department of Laboratory Medicine, Karolinska Institute, Stockholm, Sweden
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22
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Pillai A, Gungi A, Reddy PC, Galande S. Epigenetic Regulation in Hydra: Conserved and Divergent Roles. Front Cell Dev Biol 2021; 9:663208. [PMID: 34041242 PMCID: PMC8141815 DOI: 10.3389/fcell.2021.663208] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Accepted: 04/13/2021] [Indexed: 12/12/2022] Open
Abstract
Transitions in gene regulatory processes responsible for the emergence of specialized cell types and spatiotemporal regulation of developmental signaling prior to the divergence of Cnidaria and Bilateria are poorly understood. As a sister group of Bilateria, the phylum Cnidaria can provide significant insights into these processes. Among the cnidarians, hydrae have been studied for >250 years to comprehend the mechanisms underlying their unique immortality and robust regenerative capacity. Studies on Hydra spp. and other pre-bilaterians alike have advanced our understanding of the evolutionary underpinnings governing eumetazoan tissue development, homeostasis, and regeneration. In addition to its regenerative potential, Hydra exhibits continuously active axial patterning due to its peculiar tissue dynamics. These distinctive physiological processes necessitate large scale gene expression changes that are governed by the multitude of epigenetic mechanisms operating in cells. This review highlights the contemporary knowledge of epigenetic regulation in Hydra with contemporary studies from other members of Cnidaria, as well as the interplay between regulatory mechanisms wherever demonstrated. The studies covered in the scope of this review reveal both ancestral and divergent roles played by conserved epigenetic mechanisms with emphasis on transcriptional regulation. Additionally, single-cell transcriptomics data was mined to predict the physiological relevance of putative gene regulatory components, which is in agreement with published findings and yielded insights into the possible functions of the gene regulatory mechanisms that are yet to be deciphered in Hydra, such as DNA methylation. Finally, we delineate potentially rewarding epigenetics research avenues that can further leverage the unique biology of Hydra.
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Affiliation(s)
| | | | - Puli Chandramouli Reddy
- Centre of Excellence in Epigenetics, Department of Biology, Indian Institute of Science Education and Research, Pune, India
| | - Sanjeev Galande
- Centre of Excellence in Epigenetics, Department of Biology, Indian Institute of Science Education and Research, Pune, India
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23
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Klimovich A, Giacomello S, Björklund Å, Faure L, Kaucka M, Giez C, Murillo-Rincon AP, Matt AS, Willoweit-Ohl D, Crupi G, de Anda J, Wong GCL, D'Amato M, Adameyko I, Bosch TCG. Prototypical pacemaker neurons interact with the resident microbiota. Proc Natl Acad Sci U S A 2020; 117:17854-17863. [PMID: 32647059 PMCID: PMC7395494 DOI: 10.1073/pnas.1920469117] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Pacemaker neurons exert control over neuronal circuit function by their intrinsic ability to generate rhythmic bursts of action potential. Recent work has identified rhythmic gut contractions in human, mice, and hydra to be dependent on both neurons and the resident microbiota. However, little is known about the evolutionary origin of these neurons and their interaction with microbes. In this study, we identified and functionally characterized prototypical ANO/SCN/TRPM ion channel-expressing pacemaker cells in the basal metazoan Hydra by using a combination of single-cell transcriptomics, immunochemistry, and functional experiments. Unexpectedly, these prototypical pacemaker neurons express a rich set of immune-related genes mediating their interaction with the microbial environment. Furthermore, functional experiments gave a strong support to a model of the evolutionary emergence of pacemaker cells as neurons using components of innate immunity to interact with the microbial environment and ion channels to generate rhythmic contractions.
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Affiliation(s)
- Alexander Klimovich
- Department of Cell and Developmental Biology, Zoological Institute, University of Kiel, D-24118 Kiel, Germany;
| | - Stefania Giacomello
- Department of Biochemistry and Biophysics, National Infrastructure of Sweden, Science for Life Laboratory, Stockholm University, 17121 Solna, Sweden
- Department of Gene Technology, Science for Life Laboratory, Kungligia Tekniska Högskolan Royal Institute of Technology, 17121 Solna, Sweden
| | - Åsa Björklund
- Department of Cell and Molecular Biology, National Infrastructure of Sweden, Science for Life Laboratory, Uppsala University, 75237 Uppsala, Sweden
| | - Louis Faure
- Department of Molecular Neurosciences, Center for Brain Research, Medical University Vienna, 1090 Vienna, Austria
| | - Marketa Kaucka
- Department of Molecular Neurosciences, Center for Brain Research, Medical University Vienna, 1090 Vienna, Austria
- Department of Physiology and Pharmacology, Karolinska Institutet, 17177 Stockholm, Sweden
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Biology, SH 24306 Plön, Germany
| | - Christoph Giez
- Department of Cell and Developmental Biology, Zoological Institute, University of Kiel, D-24118 Kiel, Germany
| | - Andrea P Murillo-Rincon
- Department of Cell and Developmental Biology, Zoological Institute, University of Kiel, D-24118 Kiel, Germany
| | - Ann-Sophie Matt
- Department of Cell and Developmental Biology, Zoological Institute, University of Kiel, D-24118 Kiel, Germany
| | - Doris Willoweit-Ohl
- Department of Cell and Developmental Biology, Zoological Institute, University of Kiel, D-24118 Kiel, Germany
| | - Gabriele Crupi
- Department of Cell and Developmental Biology, Zoological Institute, University of Kiel, D-24118 Kiel, Germany
| | - Jaime de Anda
- Department of Bioengineering, California NanoSystems Institute, University of California, Los Angeles, CA 90095-1600
- Department of Chemistry and Biochemistry, California NanoSystems Institute, University of California, Los Angeles, CA 90095-1600
| | - Gerard C L Wong
- Department of Bioengineering, California NanoSystems Institute, University of California, Los Angeles, CA 90095-1600
- Department of Chemistry and Biochemistry, California NanoSystems Institute, University of California, Los Angeles, CA 90095-1600
| | - Mauro D'Amato
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
| | - Igor Adameyko
- Department of Molecular Neurosciences, Center for Brain Research, Medical University Vienna, 1090 Vienna, Austria
- Department of Physiology and Pharmacology, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Thomas C G Bosch
- Department of Cell and Developmental Biology, Zoological Institute, University of Kiel, D-24118 Kiel, Germany;
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24
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Alternative pathways control actomyosin contractility in epitheliomuscle cells during morphogenesis and body contraction. Dev Biol 2020; 463:88-98. [PMID: 32361004 DOI: 10.1016/j.ydbio.2020.04.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 03/10/2020] [Accepted: 04/14/2020] [Indexed: 11/23/2022]
Abstract
In adult Hydra, epitheliomuscle cells form the monolayered ecto- and endodermal epithelia. Their basal myonemes function as a longitudinal and circular muscle, respectively. Based on the observation that a Rho/Rock pathway, controlling the cell shape changes during detachment of Hydra buds, is not involved in body movement, at least two actomyosin compartments must exist in these cells: a basal one for body movement and a cortical one for cell shape changes. We therefore analyzed the regional and subcellular localization of the Ser19-phosphorylated myosin regulatory light chain (pMLC20). Along the body column, pMLC20 was detected strongly in the basal myonemes and weakly in the apical cell compartments of ectodermal epitheliomuscle cells. In cells of the bud base undergoing morphogenesis, pMLC20 was localized to intracellular stress fibers as well as to the apical and additionally to the lateral cortical compartment. Pharmacological inhibition revealed that pMLC20 is induced in these compartments by at least two independent pathways. In myonemes, MLC is phosphorylated mainly by myosin light chain kinase (MLCK). In contrast, the cortical apical and lateral MLC phosphorylation in constricting ectodermal cells of the bud base is stimulated via the Rho/ROCK pathway.
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25
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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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26
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Electric-Induced Reversal of Morphogenesis in Hydra. Biophys J 2019; 117:1514-1523. [PMID: 31570230 PMCID: PMC6817546 DOI: 10.1016/j.bpj.2019.09.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 09/09/2019] [Indexed: 02/06/2023] Open
Abstract
Morphogenesis involves the dynamic interplay of biochemical, mechanical, and electrical processes. Here, we ask to what extent can the course of morphogenesis be modulated and controlled by an external electric field? We show that at a critical amplitude, an external electric field can halt morphogenesis in Hydra regeneration. Moreover, above this critical amplitude, the electric field can lead to reversal dynamics: a fully developed Hydra folds back into its incipient spheroid morphology. The potential to renew morphogenesis is reexposed when the field is reduced back to amplitudes below criticality. These dynamics are accompanied by modulations of the Wnt3 activity, a central component of the head organizer in Hydra. The controlled backward-forward cycle of morphogenesis can be repeated several times, showing that the reversal trajectory maintains the integrity of the tissue and its regeneration capability. Each cycle of morphogenesis leads to a newly emerged body plan in the redeveloped folded tissue, which is not necessarily similar to the one before the reversal process. Reversal of morphogenesis is shown to be triggered by enhanced electrical excitations in the Hydra tissue, leading to intensified calcium activity. Folding back of the body-plan morphology together with the decay of a central biosignaling system, indicate that electrical processes are tightly integrated with biochemical and mechanical-structural processes in morphogenesis and play an instructive role to a level that can direct developmental trajectories. Reversal of morphogenesis by external fields calls for extending its framework beyond program-like, forward-driven, hierarchical processes based on reaction diffusion and positional information.
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