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Nakamura M, Kyoda T, Yoshida H, Takebayashi-Suzuki K, Koike R, Takahashi E, Moriyama Y, Wlizla M, Horb ME, Suzuki A. Injury-induced cooperation of InhibinβA and JunB is essential for cell proliferation in Xenopus tadpole tail regeneration. Sci Rep 2024; 14:3679. [PMID: 38355764 PMCID: PMC10867027 DOI: 10.1038/s41598-024-54280-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Accepted: 02/10/2024] [Indexed: 02/16/2024] Open
Abstract
In animal species that have the capability of regenerating tissues and limbs, cell proliferation is enhanced after wound healing and is essential for the reconstruction of injured tissue. Although the ability to induce cell proliferation is a common feature of such species, the molecular mechanisms that regulate the transition from wound healing to regenerative cell proliferation remain unclear. Here, we show that upon injury, InhibinβA and JunB cooperatively function for this transition during Xenopus tadpole tail regeneration. We found that the expression of inhibin subunit beta A (inhba) and junB proto-oncogene (junb) is induced by injury-activated TGF-β/Smad and MEK/ERK signaling in regenerating tails. Similarly to junb knockout (KO) tadpoles, inhba KO tadpoles show a delay in tail regeneration, and inhba/junb double KO (DKO) tadpoles exhibit severe impairment of tail regeneration compared with either inhba KO or junb KO tadpoles. Importantly, this impairment is associated with a significant reduction of cell proliferation in regenerating tissue. Moreover, JunB regulates tail regeneration via FGF signaling, while InhibinβA likely acts through different mechanisms. These results demonstrate that the cooperation of injury-induced InhibinβA and JunB is critical for regenerative cell proliferation, which is necessary for re-outgrowth of regenerating Xenopus tadpole tails.
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Affiliation(s)
- Makoto Nakamura
- Amphibian Research Center, Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan
- Cardiovascular Research Institute, University of California San Francisco, 555 Mission Bay Boulevard South, San Francisco, CA, 94158, USA
| | - Tatsuya Kyoda
- Amphibian Research Center, Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan
| | - Hitoshi Yoshida
- National Xenopus Resource and Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA, 02543, USA
| | - Kimiko Takebayashi-Suzuki
- Amphibian Research Center, Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan
| | - Ryota Koike
- Amphibian Research Center, Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan
| | - Eri Takahashi
- Amphibian Research Center, Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan
| | - Yuka Moriyama
- Amphibian Research Center, Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan
| | - Marcin Wlizla
- National Xenopus Resource and Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA, 02543, USA
- Embryology, Charles River Laboratories, Wilmington, MA, 01887, USA
| | - Marko E Horb
- National Xenopus Resource and Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA, 02543, USA
| | - Atsushi Suzuki
- Amphibian Research Center, Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan.
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2
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Chen S, Gong Y, Li S, Yang D, Zhang Y, Liu Q. Hydra gasdermin-gated pyroptosis signalling regulates tissue regeneration. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2023; 149:104904. [PMID: 37543221 DOI: 10.1016/j.dci.2023.104904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 08/02/2023] [Accepted: 08/02/2023] [Indexed: 08/07/2023]
Abstract
Pyroptosis, an inflammatory form of programmed cell death, is directly executed by gasdermin (GSDM) depending on its N-terminal pore-forming fragment-mediated membrane-disrupting, triggering intracellular contents release, which plays important roles in mammalian anti-infection and anti-tumor immune responses. However, whether pyroptosis engages in the regulation of tissue regeneration remains largely unknown. Here, utilizing Hydra vulgaris as the research model, we found that an HyCARD2-HyGSDME-mediated pyroptosis signalling is activated in both head and foot regenerated tips after amputation. Impeding pyroptosis by knocking down the expression of either HyGSDME or HyCARD2 significantly hampered both head and foot regeneration in Hydra. Mechanistically, the activation of HyCARD2-HyGSDME axis at wound sites is dependent of intracellular mitochondrial reactive oxygen species (mtROS), the removing of which hindered Hydra head regeneration. Moreover, the HyCARD2-HyGSDME axis-gated pyroptosis was found to enhance the initial secretion and upregulated expression of Wnt3. Collectively, these findings indicate that gasdermin-gated pyroptosis is critical for the evoking of Wnt signalling to facilitate Hydra tissue regeneration, which provides insights into functional diversification within the gasdermin family in the animal kingdom.
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Affiliation(s)
- Shouwen Chen
- State Key Laboratory of Bioreactor Engineering, Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, East China University of Science and Technology, Shanghai, 200237, China
| | - Yuxin Gong
- State Key Laboratory of Bioreactor Engineering, Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, East China University of Science and Technology, Shanghai, 200237, China
| | - Shuxin Li
- State Key Laboratory of Bioreactor Engineering, Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, East China University of Science and Technology, Shanghai, 200237, China
| | - Dahai Yang
- State Key Laboratory of Bioreactor Engineering, Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, East China University of Science and Technology, Shanghai, 200237, China
| | - Yuanxing Zhang
- Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000, China; Shanghai Engineering Research Center of Marine Cultured Animal Vaccines, Shanghai, 200237, China
| | - Qin Liu
- State Key Laboratory of Bioreactor Engineering, Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, East China University of Science and Technology, Shanghai, 200237, China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519000, China; Shanghai Engineering Research Center of Marine Cultured Animal Vaccines, Shanghai, 200237, China.
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3
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Patel JH, Wills AE. Gradient expectations: Revisiting Charles Manning Child's theory of metabolic regionalisation in developmental patterning and regeneration. Wound Repair Regen 2022; 30:617-622. [PMID: 35142418 PMCID: PMC9363521 DOI: 10.1111/wrr.12998] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 01/19/2022] [Accepted: 01/26/2022] [Indexed: 12/28/2022]
Abstract
Charles Manning Child introduced one of several early models to explain how an organism can both establish and re-establish positional identity during embryogenesis and regeneration. In his gradient theory model, tissues along an axis exhibit graded levels of metabolic activity demonstrated through their differential susceptibility to metabolic inhibitors. While Child's work was difficult to place in a mechanistic framework in his own time, technological advances and recent discoveries in both embryos and regenerating organisms make his early work on redox signalling as a positional cue newly pertinent.
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Affiliation(s)
- Jeet H. Patel
- Department of Biochemistry, University of Washington School of Medicine, Seattle
- Program in Molecular and Cell Biology, University of Washington, Seattle
| | - Andrea E. Wills
- Department of Biochemistry, University of Washington School of Medicine, Seattle
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle
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4
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Adamson CJ, Morrison-Welch N, Rogers CD. The amazing and anomalous axolotls as scientific models. Dev Dyn 2022; 251:922-933. [PMID: 35322911 PMCID: PMC9536427 DOI: 10.1002/dvdy.470] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 03/18/2022] [Accepted: 03/18/2022] [Indexed: 11/05/2022] Open
Abstract
Ambystoma mexicanum (axolotl) embryos and juveniles have been used as model organisms for developmental and regenerative research for many years. This neotenic aquatic species maintains the unique capability to regenerate most, if not all, of its tissues well into adulthood. With large externally developing embryos, axolotls were one of the original model species for developmental biology. However, increased access to, and use of, organisms with sequenced and annotated genomes, such as Xenopus laevis and tropicalis and Danio rerio, reduced the prevalence of axolotls as models in embryogenesis studies. Recent sequencing of the large axolotl genome opens up new possibilities for defining the recipes that drive the formation and regeneration of tissues like the limbs and spinal cord. However, to decode the large Ambystoma mexicanum genome will take a herculean effort, community resources, and the development of novel techniques. Here, we provide an updated axolotl-staging chart ranging from 1-cell stage to immature adult paired with a perspective on both historical and current axolotl research that spans from their use in early studies of development to the recent cutting-edge research, employment of transgenesis, high resolution imaging, and study of mechanisms deployed in regeneration. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Carly J Adamson
- Department of Anatomy, Physiology, and Cell Biology, UC Davis School of Veterinary Medicine, 1089 Veterinary Medicine Drive, Davis, CA
| | | | - Crystal D Rogers
- Department of Anatomy, Physiology, and Cell Biology, UC Davis School of Veterinary Medicine, 1089 Veterinary Medicine Drive, Davis, CA
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5
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Patel JH, Schattinger PA, Takayoshi EE, Wills AE. Hif1α and Wnt are required for posterior gene expression during Xenopus tropicalis tail regeneration. Dev Biol 2022; 483:157-168. [PMID: 35065905 PMCID: PMC8881967 DOI: 10.1016/j.ydbio.2022.01.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 12/16/2021] [Accepted: 01/14/2022] [Indexed: 12/13/2022]
Abstract
Regeneration of complex tissues is initiated by an injury-induced stress response, eventually leading to activation of developmental signaling pathways such as Wnt signaling. How early injury cues are interpreted and coupled to activation of these developmental signals and their targets is not well understood. Here, we show that Hif1α, a stress induced transcription factor, is required for tail regeneration in Xenopus tropicalis. We find that Hif1α is required for regeneration of differentiated axial tissues, including axons and muscle. Using RNA-sequencing, we find that Hif1α and Wnt converge on a broad set of genes required for posterior specification and differentiation, including the posterior hox genes. We further show that Hif1α is required for transcription via a Wnt-responsive element, a function that is conserved in both regeneration and early neural patterning. Our findings indicate that Hif1α has regulatory roles in Wnt target gene expression across multiple tissue contexts.
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Affiliation(s)
- Jeet H. Patel
- Department of Biochemistry, University of Washington, Seattle WA,Program in Molecular and Cellular Biology, University of Washington School of Medicine, Seattle WA
| | | | | | - Andrea E. Wills
- Department of Biochemistry, University of Washington, Seattle WA,Program in Molecular and Cellular Biology, University of Washington School of Medicine, Seattle WA,Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle WA,To whom correspondence should be addressed:
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6
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Farooq M, Khan AW, Kim MS, Choi S. The Role of Fibroblast Growth Factor (FGF) Signaling in Tissue Repair and Regeneration. Cells 2021; 10:cells10113242. [PMID: 34831463 PMCID: PMC8622657 DOI: 10.3390/cells10113242] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Revised: 11/10/2021] [Accepted: 11/16/2021] [Indexed: 02/06/2023] Open
Abstract
Fibroblast growth factors (FGFs) are a large family of secretory molecules that act through tyrosine kinase receptors known as FGF receptors. They play crucial roles in a wide variety of cellular functions, including cell proliferation, survival, metabolism, morphogenesis, and differentiation, as well as in tissue repair and regeneration. The signaling pathways regulated by FGFs include RAS/mitogen-activated protein kinase (MAPK), phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)–protein kinase B (AKT), phospholipase C gamma (PLCγ), and signal transducer and activator of transcription (STAT). To date, 22 FGFs have been discovered, involved in different functions in the body. Several FGFs directly or indirectly interfere with repair during tissue regeneration, in addition to their critical functions in the maintenance of pluripotency and dedifferentiation of stem cells. In this review, we summarize the roles of FGFs in diverse cellular processes and shed light on the importance of FGF signaling in mechanisms of tissue repair and regeneration.
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Affiliation(s)
- Mariya Farooq
- Department of Molecular Science and Technology, Ajou University, Suwon 16499, Korea; (M.F.); (A.W.K.); (M.S.K.)
| | - Abdul Waheed Khan
- Department of Molecular Science and Technology, Ajou University, Suwon 16499, Korea; (M.F.); (A.W.K.); (M.S.K.)
| | - Moon Suk Kim
- Department of Molecular Science and Technology, Ajou University, Suwon 16499, Korea; (M.F.); (A.W.K.); (M.S.K.)
| | - Sangdun Choi
- Department of Molecular Science and Technology, Ajou University, Suwon 16499, Korea; (M.F.); (A.W.K.); (M.S.K.)
- S&K Therapeutics, Ajou University Campus Plaza 418, 199 Worldcup-ro, Yeongtong-gu, Suwon 16502, Korea
- Correspondence:
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7
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Ta AC, Huang LC, McKeown CR, Bestman JE, Van Keuren-Jensen K, Cline HT. Temporal and Spatial Transcriptomic Dynamics across Brain Development in Xenopus laevis tadpoles. G3-GENES GENOMES GENETICS 2021; 12:6423992. [PMID: 34751375 PMCID: PMC8728038 DOI: 10.1093/g3journal/jkab387] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 10/26/2021] [Indexed: 11/13/2022]
Abstract
Amphibian metamorphosis is a transitional period that involves significant changes in the cell type populations and biological processes occurring in the brain. Analysis of gene expression dynamics during this process may provide insight into the molecular events underlying these changes. We conducted differential gene expression analyses of the developing X. laevis tadpole brain during this period in two ways: first, over stages of development in the midbrain, and second, across regions of the brain at a single developmental stage. We found that genes pertaining to positive regulation of neural progenitor cell proliferation as well as known progenitor cell markers were upregulated in the midbrain prior to metamorphic climax; concurrently, expression of cell cycle timing regulators decreased across this period, supporting the notion that cell cycle lengthening contributes to a decrease in proliferation by the end of metamorphosis. We also found that at the start of metamorphosis, neural progenitor populations appeared to be similar across the fore-, mid-, and hindbrain regions. Genes pertaining to negative regulation of differentiation were upregulated in the spinal cord compared to the rest of the brain, however, suggesting that a different program may regulate neurogenesis there. Finally, we found that regulation of biological processes like cell fate commitment and synaptic signaling follow similar trajectories in the brain across early tadpole metamorphosis and mid- to late-embryonic mouse development. By comparing expression across both temporal and spatial conditions, we have been able to illuminate cell type and biological pathway dynamics in the brain during metamorphosis.
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Affiliation(s)
- Aaron C Ta
- The Scripps Research Institute, La Jolla, CA, 92037, USA.,Department of Neuroscience, University of California, San Diego, La Jolla, CA, 92037, USA
| | | | | | | | | | - Hollis T Cline
- The Scripps Research Institute, La Jolla, CA, 92037, USA
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8
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Ivanova AS, Tereshina MB, Araslanova KR, Martynova NY, Zaraisky AG. The Secreted Protein Disulfide Isomerase Ag1 Lost by Ancestors of Poorly Regenerating Vertebrates Is Required for Xenopus laevis Tail Regeneration. Front Cell Dev Biol 2021; 9:738940. [PMID: 34676214 PMCID: PMC8523854 DOI: 10.3389/fcell.2021.738940] [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: 07/09/2021] [Accepted: 09/09/2021] [Indexed: 11/18/2022] Open
Abstract
Warm-blooded vertebrates regenerate lost limbs and their parts in general much worse than fishes and amphibians. We previously hypothesized that this reduction in regenerative capability could be explained in part by the loss of some genes important for the regeneration in ancestors of warm-blooded vertebrates. One of such genes could be ag1, which encodes secreted protein disulfide isomerase of the Agr family. Ag1 is activated during limb and tail regeneration in the frog Xenopus laevis tadpoles and is absent in warm-blooded animals. The essential role of another agr family gene, agr2, in limb regeneration was demonstrated previously in newts. However, agr2, as well as the third member of agr family, agr3, are present in all vertebrates. Therefore, it is important to verify if the activity of ag1 lost by warm-blooded vertebrates is also essential for regeneration in amphibians, which could be a further argument in favor of our hypothesis. Here, we show that in the Xenopus laevis tadpoles in which the expression of ag1 or agr2 was artificially suppressed, regeneration of amputated tail tips was also significantly reduced. Importantly, overexpression of any of these agrs or treatment of tadpoles with any of their recombinant proteins resulted in the restoration of tail regeneration in the refractory period when these processes are severely inhibited in normal development. These findings demonstrate the critical roles of ag1 and agr2 in regeneration in frogs and present indirect evidence that the loss of ag1 in evolution could be one of the prerequisites for the reduction of regenerative ability in warm-blooded vertebrates.
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Affiliation(s)
- Anastasiya S Ivanova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.,Pirogov Russian National Research Medical University, Moscow, Russia
| | - Maria B Tereshina
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.,Pirogov Russian National Research Medical University, Moscow, Russia
| | - Karina R Araslanova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Natalia Y Martynova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.,Pirogov Russian National Research Medical University, Moscow, Russia
| | - Andrey G Zaraisky
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.,Pirogov Russian National Research Medical University, Moscow, Russia
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9
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Morphogenic fields: A coming of age. Explore (NY) 2021; 18:187-194. [PMID: 33903061 DOI: 10.1016/j.explore.2021.04.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 04/02/2021] [Accepted: 04/05/2021] [Indexed: 11/22/2022]
Abstract
Morphogenesis, the coming-into-being of living organisms, was first described in the 4th century BC by Aristotle, progenitor of biology and embryology. Over the centuries it has been the subject of innumerable commentaries by philosophers, theologians and scientists but no consensus has ever been reached as to its causes. In the late 19th century, along with the emergence of cellular and molecular biology, embryology underwent a renaissance and became a topic of great interest and research. Early on the discipline divided into two opposing factions, those who attempted to explain fetal development on the basis of cellular and molecular mechanisms, and those who invoked the presence of organizing fields. The morphogenic field was first articulated in the early decades of the 20th century by multiple researchers independently of each other. The field became an extremely useful conceptual tool by which to explain a wide range of developmental phenomena. While embryology and genetics originally formed a unified discipline, during the 1930s 40 s geneticists became progressively skeptical of the field notion. The discovery of the DNA structure by Watson and Crick in the early 1950s decisively settled matters and thereafter the two disciplines pursued different lines of inquiry. After World War II embryology and the field concept went into a decades-long decline. By the 1980s an increasing number of scientists began to critically reexamine the morphogenic field concept and it underwent a second renaissance. In this paper I examine the development and evolution of the field concept, both experimentally and conceptually, and highlight the failure of genetic mechanisms to explain morphogenesis. I provide three instances from the medical literature of developmental phenomena which are only explainable on the basis of morphogenic field dynamics and argue that the field concept must be readmitted into mainstream scientific discourse.
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Guerin DJ, Kha CX, Tseng KAS. From Cell Death to Regeneration: Rebuilding After Injury. Front Cell Dev Biol 2021; 9:655048. [PMID: 33816506 PMCID: PMC8012889 DOI: 10.3389/fcell.2021.655048] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 02/22/2021] [Indexed: 12/22/2022] Open
Abstract
The ability to regrow lost or damaged tissues is widespread, but highly variable among animals. Understanding this variation remains a challenge in regeneration biology. Numerous studies from Hydra to mouse have shown that apoptosis acts as a potent and necessary mechanism in regeneration. Much is known about the involvement of apoptosis during normal development in regulating the number and type of cells in the body. In the context of regeneration, apoptosis also regulates cell number and proliferation in tissue remodeling. Apoptosis acts both early in the process to stimulate regeneration and later to regulate regenerative patterning. Multiple studies indicate that apoptosis acts as a signal to stimulate proliferation within the regenerative tissues, producing the cells needed for full regeneration. The conservation of apoptosis as a regenerative mechanism demonstrated across species highlights its importance and motivates the continued investigation of this important facet of programmed cell death. This review summarizes what is known about the roles of apoptosis during regeneration, and compares regenerative apoptosis with the mechanisms and function of apoptosis in development. Defining the complexity of regenerative apoptosis will contribute to new knowledge and perspectives for understanding mechanisms of apoptosis induction and regulation.
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Affiliation(s)
- Dylan J Guerin
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV, United States
| | - Cindy X Kha
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV, United States
| | - Kelly Ai-Sun Tseng
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV, United States
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11
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Edwards-Faret G, González-Pinto K, Cebrián-Silla A, Peñailillo J, García-Verdugo JM, Larraín J. Cellular response to spinal cord injury in regenerative and non-regenerative stages in Xenopus laevis. Neural Dev 2021; 16:2. [PMID: 33526076 PMCID: PMC7852093 DOI: 10.1186/s13064-021-00152-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 01/14/2021] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND The efficient regenerative abilities at larvae stages followed by a non-regenerative response after metamorphosis in froglets makes Xenopus an ideal model organism to understand the cellular responses leading to spinal cord regeneration. METHODS We compared the cellular response to spinal cord injury between the regenerative and non-regenerative stages of Xenopus laevis. For this analysis, we used electron microscopy, immunofluorescence and histological staining of the extracellular matrix. We generated two transgenic lines: i) the reporter line with the zebrafish GFAP regulatory regions driving the expression of EGFP, and ii) a cell specific inducible ablation line with the same GFAP regulatory regions. In addition, we used FACS to isolate EGFP+ cells for RNAseq analysis. RESULTS In regenerative stage animals, spinal cord regeneration triggers a rapid sealing of the injured stumps, followed by proliferation of cells lining the central canal, and formation of rosette-like structures in the ablation gap. In addition, the central canal is filled by cells with similar morphology to the cells lining the central canal, neurons, axons, and even synaptic structures. Regeneration is almost completed after 20 days post injury. In non-regenerative stage animals, mostly damaged tissue was observed, without clear closure of the stumps. The ablation gap was filled with fibroblast-like cells, and deposition of extracellular matrix components. No reconstruction of the spinal cord was observed even after 40 days post injury. Cellular markers analysis confirmed these histological differences, a transient increase of vimentin, fibronectin and collagen was detected in regenerative stages, contrary to a sustained accumulation of most of these markers, including chondroitin sulfate proteoglycans in the NR-stage. The zebrafish GFAP transgenic line was validated, and we have demonstrated that is a very reliable and new tool to study the role of neural stem progenitor cells (NSPCs). RNASeq of GFAP::EGFP cells has allowed us to clearly demonstrate that indeed these cells are NSPCs. On the contrary, the GFAP::EGFP transgene is mainly expressed in astrocytes in non-regenerative stages. During regenerative stages, spinal cord injury activates proliferation of NSPCs, and we found that are mainly differentiated into neurons and glial cells. Specific ablation of these cells abolished proper regeneration, confirming that NSPCs cells are necessary for functional regeneration of the spinal cord. CONCLUSIONS The cellular response to spinal cord injury in regenerative and non-regenerative stages is profoundly different between both stages. A key hallmark of the regenerative response is the activation of NSPCs, which massively proliferate, and are differentiated into neurons to reconstruct the spinal cord. Also very notably, no glial scar formation is observed in regenerative stages, but a transient, glial scar-like structure is formed in non-regenerative stage animals.
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Affiliation(s)
- Gabriela Edwards-Faret
- Center for Aging and Regeneration, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile
| | - Karina González-Pinto
- Center for Aging and Regeneration, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile
| | - Arantxa Cebrián-Silla
- Laboratorio de Neurobiología Comparada, Instituto Cavanilles, Universidad de Valencia, CIBERNED, 46980, Valencia, Spain
| | - Johany Peñailillo
- Center for Aging and Regeneration, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile
| | - José Manuel García-Verdugo
- Laboratorio de Neurobiología Comparada, Instituto Cavanilles, Universidad de Valencia, CIBERNED, 46980, Valencia, Spain
| | - Juan Larraín
- Center for Aging and Regeneration, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Alameda 340, Santiago, Chile.
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12
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Exner CRT, Willsey HR. Xenopus leads the way: Frogs as a pioneering model to understand the human brain. Genesis 2021; 59:e23405. [PMID: 33369095 PMCID: PMC8130472 DOI: 10.1002/dvg.23405] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 12/12/2020] [Accepted: 12/14/2020] [Indexed: 12/20/2022]
Abstract
From its long history in the field of embryology to its recent advances in genetics, Xenopus has been an indispensable model for understanding the human brain. Foundational studies that gave us our first insights into major embryonic patterning events serve as a crucial backdrop for newer avenues of investigation into organogenesis and organ function. The vast array of tools available in Xenopus laevis and Xenopus tropicalis allows interrogation of developmental phenomena at all levels, from the molecular to the behavioral, and the application of CRISPR technology has enabled the investigation of human disorder risk genes in a higher-throughput manner. As the only major tetrapod model in which all developmental stages are easily manipulated and observed, frogs provide the unique opportunity to study organ development from the earliest stages. All of these features make Xenopus a premier model for studying the development of the brain, a notoriously complex process that demands an understanding of all stages from fertilization to organogenesis and beyond. Importantly, core processes of brain development are conserved between Xenopus and human, underlining the advantages of this model. This review begins by summarizing discoveries made in amphibians that form the cornerstones of vertebrate neurodevelopmental biology and goes on to discuss recent advances that have catapulted our understanding of brain development in Xenopus and in relation to human development and disease. As we engage in a new era of patient-driven gene discovery, Xenopus offers exceptional potential to uncover conserved biology underlying human brain disorders and move towards rational drug design.
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Affiliation(s)
- Cameron R T Exner
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California, 94143, USA
| | - Helen Rankin Willsey
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California, 94143, USA
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Williams MC, Patel JH, Kakebeen AD, Wills AE. Nutrient availability contributes to a graded refractory period for regeneration in Xenopus tropicalis. Dev Biol 2021; 473:59-70. [PMID: 33484704 DOI: 10.1016/j.ydbio.2021.01.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 11/17/2020] [Accepted: 01/12/2021] [Indexed: 11/28/2022]
Abstract
Xenopus tadpoles are a unique model for regeneration in that they exhibit two distinct phases of age-specific regenerative competence. In Xenopus laevis, young tadpoles fully regenerate following major injuries such as tail transection, then transiently lose regenerative competence during the "refractory period" from stages 45-47. Regenerative competence is then regained in older tadpoles before being permanently lost during metamorphosis. Here we show that a similar refractory period exists in X. tropicalis. Notably, tadpoles lose regenerative competence gradually in X. tropicalis, with full regenerative competence lost at stage 47. We find that the refractory period coincides closely with depletion of maternal yolk stores and the onset of independent feeding, and so we hypothesized that it might be caused in part by nutrient stress. In support of this hypothesis, we find that cell proliferation declines throughout the tail as the refractory period approaches. When we block nutrient mobilization by inhibiting mTOR signaling, we find that tadpole growth and regeneration are reduced, while yolk stores persist. Finally, we are able to restore regenerative competence and cell proliferation during the refractory period by abundantly feeding tadpoles. Our study argues that nutrient stress contributes to lack of regenerative competence and introduces the X. tropicalis refractory period as a valuable new model for interrogating how metabolic constraints inform regeneration.
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Affiliation(s)
| | - Jeet H Patel
- Department of Biochemistry, University of Washington, Seattle, WA, USA; Program in Molecular and Cellular Biology, University of Washington School of Medicine, Seattle, WA, USA
| | - Anneke D Kakebeen
- Department of Biochemistry, University of Washington, Seattle, WA, USA
| | - Andrea E Wills
- Department of Biochemistry, University of Washington, Seattle, WA, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA.
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Kakebeen AD, Chitsazan AD, Wills AE. Tissue disaggregation and isolation of specific cell types from transgenic Xenopus appendages for transcriptional analysis by FACS. Dev Dyn 2020; 250:1381-1392. [PMID: 33137227 DOI: 10.1002/dvdy.268] [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: 07/30/2020] [Revised: 10/10/2020] [Accepted: 10/26/2020] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Xenopus embryos and tadpoles are versatile models for embryological, cell biological, and regenerative studies. Genomic and transcriptomic approaches have been increasingly employed in these frogs. Most of these genome-wide analyses have profiled tissues in bulk, but there are many scenarios where isolation of single cells may be advantageous, including isolation of a preferred cell type, or generation of a single-cell suspension for applications such as scRNA-Seq. RESULTS Here we present a protocol for the disaggregation of complex tail and limb bud tissue, and use cell type-specific fluorescence in transgenic X. tropicalis appendages to isolate specific cell populations using fluorescence activated cell sorting (FACS). Our protocol addresses a specific challenge in Xenopus embryos and tadpoles: the storage of maternal yolk platelets in each cell, which can introduce light scatter and thereby false positives into FACS analysis. CONCLUSIONS Here we gate against both nontransgenic and ubiquitously transgenic animals to reduce both false positives and false negatives. We use the Xtr.Tg(pax6:GFP;cryga:RFP;actc1:RFP)Papal transgenic line as a test case to demonstrate that nucleic acid preparations made from sorted cells are high quality and specific. We anticipate this method will be adaptable to study various cell types that have transgenic reporter lines to better profile cell types of interest.
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Affiliation(s)
- Anneke Dixie Kakebeen
- Department of Biochemistry, University of Washington Seattle, Seattle, Washington, USA
| | - Alexander Daniel Chitsazan
- Oregon Health Sciences Center For Early Detection Advanced Research Center (CEDAR), Portland, Oregon, USA
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Kakebeen AD, Chitsazan AD, Williams MC, Saunders LM, Wills AE. Chromatin accessibility dynamics and single cell RNA-Seq reveal new regulators of regeneration in neural progenitors. eLife 2020; 9:e52648. [PMID: 32338593 PMCID: PMC7250574 DOI: 10.7554/elife.52648] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 04/25/2020] [Indexed: 12/24/2022] Open
Abstract
Vertebrate appendage regeneration requires precisely coordinated remodeling of the transcriptional landscape to enable the growth and differentiation of new tissue, a process executed over multiple days and across dozens of cell types. The heterogeneity of tissues and temporally-sensitive fate decisions involved has made it difficult to articulate the gene regulatory programs enabling regeneration of individual cell types. To better understand how a regenerative program is fulfilled by neural progenitor cells (NPCs) of the spinal cord, we analyzed pax6-expressing NPCs isolated from regenerating Xenopus tropicalis tails. By intersecting chromatin accessibility data with single-cell transcriptomics, we find that NPCs place an early priority on neuronal differentiation. Late in regeneration, the priority returns to proliferation. Our analyses identify Pbx3 and Meis1 as critical regulators of tail regeneration and axon organization. Overall, we use transcriptional regulatory dynamics to present a new model for cell fate decisions and their regulators in NPCs during regeneration.
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Affiliation(s)
| | | | | | - Lauren M Saunders
- Department of Genome Sciences, University of WashingtonSeattleUnited States
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