1
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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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2
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Keramidioti A, Schneid S, Busse C, Cramer von Laue C, Bertulat B, Salvenmoser W, Hess M, Alexandrova O, Glauber KM, Steele RE, Hobmayer B, Holstein TW, David CN. A new look at the architecture and dynamics of the Hydra nerve net. eLife 2024; 12:RP87330. [PMID: 38407174 PMCID: PMC10942621 DOI: 10.7554/elife.87330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2024] Open
Abstract
The Hydra nervous system is the paradigm of a 'simple nerve net'. Nerve cells in Hydra, as in many cnidarian polyps, are organized in a nerve net extending throughout the body column. This nerve net is required for control of spontaneous behavior: elimination of nerve cells leads to polyps that do not move and are incapable of capturing and ingesting prey (Campbell, 1976). We have re-examined the structure of the Hydra nerve net by immunostaining fixed polyps with a novel antibody that stains all nerve cells in Hydra. Confocal imaging shows that there are two distinct nerve nets, one in the ectoderm and one in the endoderm, with the unexpected absence of nerve cells in the endoderm of the tentacles. The nerve nets in the ectoderm and endoderm do not contact each other. High-resolution TEM (transmission electron microscopy) and serial block face SEM (scanning electron microscopy) show that the nerve nets consist of bundles of parallel overlapping neurites. Results from transgenic lines show that neurite bundles include different neural circuits and hence that neurites in bundles require circuit-specific recognition. Nerve cell-specific innexins indicate that gap junctions can provide this specificity. The occurrence of bundles of neurites supports a model for continuous growth and differentiation of the nerve net by lateral addition of new nerve cells to the existing net. This model was confirmed by tracking newly differentiated nerve cells.
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Affiliation(s)
- Athina Keramidioti
- Department of Biology, Ludwig-Maximilians-University MunichMartinsriedGermany
| | - Sandra Schneid
- Department of Biology, Ludwig-Maximilians-University MunichMartinsriedGermany
| | - Christina Busse
- Department of Biology, Ludwig-Maximilians-University MunichMartinsriedGermany
| | | | - Bianca Bertulat
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg UniversityHeidelbergGermany
| | - Willi Salvenmoser
- Department of Zoology and Center for Molecular Biosciences Innsbruck (CMBI), University of InnsbruckInnsbruckAustria
| | - Martin Hess
- Department of Biology, Ludwig-Maximilians-University MunichMartinsriedGermany
| | - Olga Alexandrova
- Department of Biology, Ludwig-Maximilians-University MunichMartinsriedGermany
| | - Kristine M Glauber
- Department of Biological Chemistry, University of CaliforniaIrvineUnited States
| | - Robert E Steele
- Department of Biological Chemistry, University of CaliforniaIrvineUnited States
| | - Bert Hobmayer
- Department of Zoology and Center for Molecular Biosciences Innsbruck (CMBI), University of InnsbruckInnsbruckAustria
| | - Thomas W Holstein
- Centre for Organismal Studies (COS) Heidelberg, Heidelberg UniversityHeidelbergGermany
| | - Charles N David
- Department of Biology, Ludwig-Maximilians-University MunichMartinsriedGermany
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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 whole-body neural activity in behaving Hydra. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.22.559063. [PMID: 37790332 PMCID: PMC10542483 DOI: 10.1101/2023.09.22.559063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
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
- Neurotechnology Center, Department of Biological Sciences, Columbia University, New York, NY, USA
- Department of Psychiatry, New York State Psychiatric Institute, Columbia University, New York, NY, USA
| | - Raphael Reme
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, BioImage Analysis Unit, Paris, France
| | - Noah Telerman
- Neurotechnology Center, Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Wataru Yamamoto
- Neurotechnology Center, Department of Biological Sciences, Columbia University, New York, NY, USA
| | | | - Thibault Lagache
- Institut Pasteur, Université Paris Cité, CNRS UMR3691, BioImage Analysis Unit, Paris, France
| | - Rafael Yuste
- Neurotechnology Center, Department of Biological Sciences, Columbia University, New York, NY, USA
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4
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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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5
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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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6
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Adams JK, Yan D, Wu J, Boominathan V, Gao S, Rodriguez AV, Kim S, Carns J, Richards-Kortum R, Kemere C, Veeraraghavan A, Robinson JT. In vivo lensless microscopy via a phase mask generating diffraction patterns with high-contrast contours. Nat Biomed Eng 2022; 6:617-628. [PMID: 35256759 PMCID: PMC9142365 DOI: 10.1038/s41551-022-00851-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 01/21/2022] [Indexed: 12/25/2022]
Abstract
The simple and compact optics of lensless microscopes and the associated computational algorithms allow for large fields of view and the refocusing of the captured images. However, existing lensless techniques cannot accurately reconstruct the typical low-contrast images of optically dense biological tissue. Here we show that lensless imaging of tissue in vivo can be achieved via an optical phase mask designed to create a point spread function consisting of high-contrast contours with a broad spectrum of spatial frequencies. We built a prototype lensless microscope incorporating the 'contour' phase mask and used it to image calcium dynamics in the cortex of live mice (over a field of view of about 16 mm2) and in freely moving Hydra vulgaris, as well as microvasculature in the oral mucosa of volunteers. The low cost, small form factor and computational refocusing capability of in vivo lensless microscopy may open it up to clinical uses, especially for imaging difficult-to-reach areas of the body.
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Affiliation(s)
- Jesse K Adams
- Applied Physics Program, Rice University, Houston, TX, USA
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, USA
| | - Dong Yan
- Applied Physics Program, Rice University, Houston, TX, USA
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, USA
| | - Jimin Wu
- Department of Bioengineering, Rice University, Houston, TX, USA
| | - Vivek Boominathan
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, USA
| | - Sibo Gao
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Alex V Rodriguez
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, USA
| | - Soonyoung Kim
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, USA
| | - Jennifer Carns
- Department of Bioengineering, Rice University, Houston, TX, USA
| | - Rebecca Richards-Kortum
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, USA
- Department of Bioengineering, Rice University, Houston, TX, USA
| | - Caleb Kemere
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, USA
- Department of Bioengineering, Rice University, Houston, TX, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Ashok Veeraraghavan
- Applied Physics Program, Rice University, Houston, TX, USA.
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, USA.
- Department of Computer Science, Rice University, Houston, TX, USA.
| | - Jacob T Robinson
- Applied Physics Program, Rice University, Houston, TX, USA.
- Department of Electrical and Computer Engineering, Rice University, Houston, TX, USA.
- Department of Bioengineering, Rice University, Houston, TX, USA.
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA.
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7
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Tzouanas CN, Kim S, Badhiwala KN, Avants BW, Robinson JT. Hydra vulgaris shows stable responses to thermal stimulation despite large changes in the number of neurons. iScience 2021; 24:102490. [PMID: 34095784 PMCID: PMC8164038 DOI: 10.1016/j.isci.2021.102490] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 02/03/2021] [Accepted: 04/27/2021] [Indexed: 11/27/2022] Open
Abstract
Many animals that lose neural tissue to injury or disease can maintain behavioral repertoires by regenerating new neurons or reorganizing existing neural circuits. However, most neuroscience small model organisms lack this high degree of neural plasticity. We show that Hydra vulgaris can maintain stable sensory-motor behaviors despite 2-fold changes in neuron count, due to naturally occurring size variation or surgical resection. Specifically, we find that both behavioral and neural responses to rapid temperature changes are maintained following these perturbations. We further describe possible mechanisms for the observed neural activity and argue that Hydra's radial symmetry may allow it to maintain stable behaviors when changes in the numbers of neurons do not selectively eliminate any specific neuronal cell type. These results suggest that Hydra provides a powerful model for studying how animals maintain stable sensory-motor responses within dynamic neural circuits and may lead to the development of general principles for injury-tolerant neural architectures. Thermal stimulation drives temperature-dependent firing rate in specific Hydra neurons Hydra show stable neural responses to temperature despite 2× decrease in neuron count Injury tolerance of Hydra offers model for stable neural architecture
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Affiliation(s)
| | - Soonyoung Kim
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA
| | - Krishna N Badhiwala
- Department of Bioengineering, Rice University, 6100 Main Street, Houston, TX 77005, USA
| | - Benjamin W Avants
- Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA
| | - Jacob T Robinson
- Department of Bioengineering, Rice University, 6100 Main Street, Houston, TX 77005, USA.,Department of Electrical and Computer Engineering, Rice University, 6100 Main Street, Houston, TX 77005, USA.,Department of Neuroscience, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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8
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Skokan TD, Vale RD, McKinley KL. Cell Sorting in Hydra vulgaris Arises from Differing Capacities for Epithelialization between Cell Types. Curr Biol 2020; 30:3713-3723.e3. [PMID: 32795440 PMCID: PMC7541579 DOI: 10.1016/j.cub.2020.07.035] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 07/05/2020] [Accepted: 07/09/2020] [Indexed: 12/22/2022]
Abstract
Hydra vulgaris exhibits a remarkable capacity to reassemble its body plan from a disordered aggregate of cells. Reassembly begins by sorting two epithelial cell types, endoderm and ectoderm, into inner and outer layers, respectively. The cellular features and behaviors that distinguish ectodermal and endodermal lineages to drive sorting have not been fully elucidated. To dissect this process, we use micromanipulation to position single cells of diverse lineages on the surface of defined multicellular aggregates and monitor sorting outcomes by live imaging. Although sorting has previously been attributed to intrinsic differences between the epithelial lineages, we find that single cells of all lineages sort to the interior of ectodermal aggregates, including single ectodermal cells. This reveals that cells of the same lineage can adopt opposing positions when sorting as individuals or a collective. Ectodermal cell collectives adopt their position at the aggregate exterior by rapidly reforming an epithelium that engulfs cells adhered to its surface through a collective spreading behavior. In contrast, aggregated endodermal cells persistently lose epithelial features. These non-epithelialized aggregates, like isolated cells of all lineages, are adherent passengers for engulfment by the ectodermal epithelium. We find that collective spreading of the ectoderm and persistent de-epithelialization in the endoderm also arise during local wounding in Hydra, suggesting that Hydra's wound-healing and self-organization capabilities may employ similar mechanisms. Together, our data suggest that differing propensities for epithelialization can sort cell types into distinct compartments to build and restore complex tissue architecture.
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Affiliation(s)
- Taylor D Skokan
- Howard Hughes Medical Institute and Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Ronald D Vale
- Howard Hughes Medical Institute and Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA 20147, USA.
| | - Kara L McKinley
- Howard Hughes Medical Institute and Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA.
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9
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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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10
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Mehta AS, Singh A. Insights into regeneration tool box: An animal model approach. Dev Biol 2019; 453:111-129. [PMID: 30986388 PMCID: PMC6684456 DOI: 10.1016/j.ydbio.2019.04.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 04/04/2019] [Accepted: 04/09/2019] [Indexed: 12/20/2022]
Abstract
For ages, regeneration has intrigued countless biologists, clinicians, and biomedical engineers. In recent years, significant progress made in identification and characterization of a regeneration tool kit has helped the scientific community to understand the mechanism(s) involved in regeneration across animal kingdom. These mechanistic insights revealed that evolutionarily conserved pathways like Wnt, Notch, Hedgehog, BMP, and JAK/STAT are involved in regeneration. Furthermore, advancement in high throughput screening approaches like transcriptomic analysis followed by proteomic validations have discovered many novel genes, and regeneration specific enhancers that are specific to highly regenerative species like Hydra, Planaria, Newts, and Zebrafish. Since genetic machinery is highly conserved across the animal kingdom, it is possible to engineer these genes and regeneration specific enhancers in species with limited regeneration properties like Drosophila, and mammals. Since these models are highly versatile and genetically tractable, cross-species comparative studies can generate mechanistic insights in regeneration for animals with long gestation periods e.g. Newts. In addition, it will allow extrapolation of regenerative capabilities from highly regenerative species to animals with low regeneration potential, e.g. mammals. In future, these studies, along with advancement in tissue engineering applications, can have strong implications in the field of regenerative medicine and stem cell biology.
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Affiliation(s)
- Abijeet S Mehta
- Department of Biology, University of Dayton, Dayton, OH, 45469, USA
| | - Amit Singh
- Department of Biology, University of Dayton, Dayton, OH, 45469, USA; Premedical Program, University of Dayton, Dayton, OH, 45469, USA; Center for Tissue Regeneration and Engineering at Dayton (TREND), University of Dayton, Dayton, OH, 45469, USA; The Integrative Science and Engineering Center, University of Dayton, Dayton, OH, 45469, USA; Center for Genomic Advocacy (TCGA), Indiana State University, Terre Haute, IN, USA.
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11
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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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12
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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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de Boer WDAM, Hirtz JJ, Capretti A, Gregorkiewicz T, Izquierdo-Serra M, Han S, Dupre C, Shymkiv Y, Yuste R. Neuronal photoactivation through second-harmonic near-infrared absorption by gold nanoparticles. LIGHT, SCIENCE & APPLICATIONS 2018; 7:100. [PMID: 30534369 PMCID: PMC6279767 DOI: 10.1038/s41377-018-0103-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 11/13/2018] [Accepted: 11/13/2018] [Indexed: 05/05/2023]
Abstract
Optical activation of neurons requires genetic manipulation or the use of chemical photoactivators with undesirable side effects. As a solution to these disadvantages, here, we demonstrate optically evoked neuronal activity in mouse cortical neurons in acute slices and in vivo by nonlinear excitation of gold nanoparticles. In addition, we use this approach to stimulate individual epitheliomuscular cells and evoke body contractions in Hydra vulgaris. To achieve this, we use a low-power pulsed near-infrared excitation at the double-wavelength of the plasmon resonance of gold nanoparticles, which enables optical sectioning and allows for high spatial precision and large penetration depth. The effect is explained by second-harmonic Mie scattering, demonstrating light absorption by a second-order nonlinear process, which enables photothermal stimulation of the cells. Our approach also minimizes photodamage, demonstrating a major advancement towards precise and harmless photoactivation for neuroscience and human therapeutics.
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Affiliation(s)
- Wieteke D. A. M. de Boer
- NeuroTechnology Center, Department of Biological Sciences, Columbia University, New York, NY 10027 USA
| | - Jan J. Hirtz
- NeuroTechnology Center, Department of Biological Sciences, Columbia University, New York, NY 10027 USA
| | - Antonio Capretti
- Van der Waals–Zeeman Institute, University of Amsterdam, 1098 XH Amsterdam, Netherlands
| | - Tom Gregorkiewicz
- Van der Waals–Zeeman Institute, University of Amsterdam, 1098 XH Amsterdam, Netherlands
| | - Mercè Izquierdo-Serra
- NeuroTechnology Center, Department of Biological Sciences, Columbia University, New York, NY 10027 USA
- Present Address: Laboratori de Fisiologia Molecular, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, Barcelona, Spain
| | - Shuting Han
- NeuroTechnology Center, Department of Biological Sciences, Columbia University, New York, NY 10027 USA
| | - Christophe Dupre
- NeuroTechnology Center, Department of Biological Sciences, Columbia University, New York, NY 10027 USA
| | - Yuriy Shymkiv
- NeuroTechnology Center, Department of Biological Sciences, Columbia University, New York, NY 10027 USA
| | - Rafael Yuste
- NeuroTechnology Center, Department of Biological Sciences, Columbia University, New York, NY 10027 USA
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Abstract
Medusae (aka jellyfish) have multiphasic life cycles and a propensity to adapt to, and proliferate in, a plethora of aquatic habitats, connecting them to a number of ecological and societal issues. Now, in the midst of the genomics era, affordable next-generation sequencing (NGS) platforms coupled with publically available bioinformatics tools present the much-anticipated opportunity to explore medusa taxa as potential model systems. Genome-wide studies of medusae would provide a remarkable opportunity to address long-standing questions related to the biology, physiology, and nervous system of some of the earliest pelagic animals. Furthermore, medusae have become key targets in the exploration of marine natural products, in the development of marine biomarkers, and for their application to the biomedical and robotics fields. Presented here is a synopsis of the current state of medusa research, highlighting insights provided by multi-omics studies, as well as existing knowledge gaps, calling upon the scientific community to adopt a number of medusa taxa as model systems in forthcoming research endeavors.
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Affiliation(s)
- Cheryl Lewis Ames
- Department of Invertebrate Zoology, National Museum of Natural History, Smithsonian Institution, NW, Washington, DC, USA.
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15
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Non-overlapping Neural Networks in Hydra vulgaris. Curr Biol 2017; 27:1085-1097. [PMID: 28366745 DOI: 10.1016/j.cub.2017.02.049] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Revised: 11/08/2016] [Accepted: 02/20/2017] [Indexed: 11/23/2022]
Abstract
To understand the emergent properties of neural circuits, it would be ideal to record the activity of every neuron in a behaving animal and decode how it relates to behavior. We have achieved this with the cnidarian Hydra vulgaris, using calcium imaging of genetically engineered animals to measure the activity of essentially all of its neurons. Although the nervous system of Hydra is traditionally described as a simple nerve net, we surprisingly find instead a series of functional networks that are anatomically non-overlapping and are associated with specific behaviors. Three major functional networks extend through the entire animal and are activated selectively during longitudinal contractions, elongations in response to light, and radial contractions, whereas an additional network is located near the hypostome and is active during nodding. These results demonstrate the functional sophistication of apparently simple nerve nets, and the potential of Hydra and other basal metazoans as a model system for neural circuit studies.
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Qin J, Xu H, Zhang P, Zhang C, Zhu Z, Qu R, Qin Y, Zeng W. An efficient strategy for generation of transgenic mice by lentiviral transduction of male germline stem cells in vivo. J Anim Sci Biotechnol 2015; 6:59. [PMID: 26705472 PMCID: PMC4690335 DOI: 10.1186/s40104-015-0058-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 12/09/2015] [Indexed: 12/27/2022] Open
Abstract
Background Male germline stem cells (MGSCs) are a subpopulation of germ cells in the testis tissue. MGSCs are capable of differentiation into spermatozoa and thus are perfect targets for genomic manipulation to generate transgenic animals. Method The present study was to optimize a protocol of production of transgenic mice through transduction of MGSCs in vivo using lentiviral-based vectors. The recombinant lentiviral vectors with either EF-1 or CMV promoter to drive the expression of enhanced green fluorescent protein (eGFP) transgene were injected into seminiferous tubules or inter-tubular space of 7-day-old and 28-day-old mouse testes. At 5 or 6 wk post-surgery, these pre-founders were mated with wild-type C57BL/6J female mice (1.5 to 2.0-month-old). Results Sixty-seven percent of F1 generation and 55.56 % of F2 offspring were positive for eGFP transgene under the control of EF-1 promoter via PCR analysis. The transgenic pups were generated in an injection site-and age-independent manner. The expression of transgene was displayed in the progeny derived from lentiviral vector containing CMV promoter to drive transgene, but it was silenced or undetectable in the offspring derived from lentiviral vector with transgene under EF-1 promoter. The methylation level of gDNA in the promoter region of transgene was much higher in the samples derived lentiviral vectors with EF-1 promoter than that with CMV promoter, suggesting eGFP transgene was suppressed by DNA methylation in vivo. Conclusion This research reported here an effective strategy for generation of transgenic mice through transduction of MGSCs in vivo using lentivirus vectors with specific promoters, and the transgenic offspring were obtained in an injection site-and age-independent manner. This protocol could be applied to other animal species, leading to advancement of animal transgenesis in agricultural and biomedical fields. Electronic supplementary material The online version of this article (doi:10.1186/s40104-015-0058-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jinzhou Qin
- College of Animal Science and Technology, Northwest A&F University, No. 22 Xinong Road, Yangling, Shaanxi 712100 China
| | - Haixia Xu
- College of Animal Science and Technology, Northwest A&F University, No. 22 Xinong Road, Yangling, Shaanxi 712100 China
| | - Pengfei Zhang
- College of Animal Science and Technology, Northwest A&F University, No. 22 Xinong Road, Yangling, Shaanxi 712100 China
| | - Conghui Zhang
- College of Animal Science and Technology, Northwest A&F University, No. 22 Xinong Road, Yangling, Shaanxi 712100 China
| | - Zhendong Zhu
- College of Animal Science and Technology, Northwest A&F University, No. 22 Xinong Road, Yangling, Shaanxi 712100 China
| | - Rongfeng Qu
- College of Animal Science and Technology, Northwest A&F University, No. 22 Xinong Road, Yangling, Shaanxi 712100 China
| | - Yuwei Qin
- College of Animal Science and Technology, Northwest A&F University, No. 22 Xinong Road, Yangling, Shaanxi 712100 China
| | - Wenxian Zeng
- College of Animal Science and Technology, Northwest A&F University, No. 22 Xinong Road, Yangling, Shaanxi 712100 China
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17
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Affiliation(s)
- Bor L Tang
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore Singapore, Singapore
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