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Edri T, Cohen D, Shabtai Y, Fainsod A. Alcohol induces neural tube defects by reducing retinoic acid signaling and promoting neural plate expansion. Front Cell Dev Biol 2023; 11:1282273. [PMID: 38116205 PMCID: PMC10728305 DOI: 10.3389/fcell.2023.1282273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 11/22/2023] [Indexed: 12/21/2023] Open
Abstract
Introduction: Neural tube defects (NTDs) are among the most debilitating and common developmental defects in humans. The induction of NTDs has been attributed to abnormal folic acid (vitamin B9) metabolism, Wnt and BMP signaling, excess retinoic acid (RA), dietary components, environmental factors, and many others. In the present study we show that reduced RA signaling, including alcohol exposure, induces NTDs. Methods: Xenopus embryos were exposed to pharmacological RA biosynthesis inhibitors to study the induction of NTDs. Embryos were treated with DEAB, citral, or ethanol, all of which inhibit the biosynthesis of RA, or injected to overexpress Cyp26a1 to reduce RA. NTD induction was studied using neural plate and notochord markers together with morphological analysis. Expression of the neuroectodermal regulatory network and cell proliferation were analyzed to understand the morphological malformations of the neural plate. Results: Reducing RA signaling levels using retinaldehyde dehydrogenase inhibitors (ethanol, DEAB, and citral) or Cyp26a1-driven degradation efficiently induce NTDs. These NTDs can be rescued by providing precursors of RA. We mapped this RA requirement to early gastrula stages during the induction of neural plate precursors. This reduced RA signaling results in abnormal expression of neural network genes, including the neural plate stem cell maintenance genes, geminin, and foxd4l1.1. This abnormal expression of neural network genes results in increased proliferation of neural precursors giving rise to an expanded neural plate. Conclusion: We show that RA signaling is required for neural tube closure during embryogenesis. RA signaling plays a very early role in the regulation of proliferation and differentiation of the neural plate soon after the induction of neural progenitors during gastrulation. RA signaling disruption leads to the induction of NTDs through the mis regulation of the early neuroectodermal network, leading to increased proliferation resulting in the expansion of the neural plate. Ethanol exposure induces NTDs through this mechanism involving reduced RA levels.
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Affiliation(s)
| | | | | | - Abraham Fainsod
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
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2
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Kawahara G, Takayama Y, Sugiyama M, Ikadai H, Hashimoto O. Dermocystidinfection in Japanese fire-bellied newt, Cynops pyrrhogaster. J Vet Med Sci 2022; 84:1410-1416. [PMID: 36047163 PMCID: PMC9586028 DOI: 10.1292/jvms.22-0233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Here, we report details of a new infectious disease in wild-caught Japanese fire-bellied
newts (Cynops pyrrhogaster), a Near Threatened species. Skin lesions
consisting of numerous masses were found in the animals near Lake Biwa, Shiga Prefecture,
Japan. The gross appearance of the skin lesions showed blister-, cyst-, and/or tumor-like
morphology. Various sizes of skin lesions were observed on their entire body surface.
Histologically, spherical basophilic cysts, including numerous spores, were observed in
the dermis layer. Ultrastructural analysis indicated the presence of main bodies of
flagellated zoospores within the spores. While 18s rRNA gene sequencing indicated that the
skin lesions were due to dermocystid infection. To our knowledge, this is the first report
of dermocystid infection in this amphibian in Japan. Further studies are needed to prevent
epidemics and to establish diagnostic and treatment methods.
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Affiliation(s)
- Go Kawahara
- Nagahama Institute of Bio-Science and Technology
| | - Yuta Takayama
- Laboratory of Veterinary Parasitology, School of Veterinary Medicine, Kitasato University
| | - Makoto Sugiyama
- Laboratory of Veterinary Anatomy, School of Veterinary Medicine, Kitasato University
| | - Hiromi Ikadai
- Laboratory of Veterinary Parasitology, School of Veterinary Medicine, Kitasato University
| | - Osamu Hashimoto
- Nagahama Institute of Bio-Science and Technology.,Laboratory of Veterinary Toxicology, Department of Veterinary Medicine, College of Bioresource Sciences, Nihon University
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3
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Gur M, Edri T, Moody SA, Fainsod A. Retinoic Acid is Required for Normal Morphogenetic Movements During Gastrulation. Front Cell Dev Biol 2022; 10:857230. [PMID: 35531100 PMCID: PMC9068879 DOI: 10.3389/fcell.2022.857230] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 03/21/2022] [Indexed: 11/23/2022] Open
Abstract
Retinoic acid (RA) is a central regulatory signal that controls numerous developmental processes in vertebrate embryos. Although activation of Hox expression is considered one of the earliest functions of RA signaling in the embryo, there is evidence that embryos are poised to initiate RA signaling just before gastrulation begins, and manipulations of the RA pathway have been reported to show gastrulation defects. However, which aspects of gastrulation are affected have not been explored in detail. We previously showed that partial inhibition of RA biosynthesis causes a delay in the rostral migration of some of the earliest involuting cells, the leading edge mesendoderm (LEM) and the prechordal mesoderm (PCM). Here we identify several detrimental gastrulation defects resulting from inhibiting RA biosynthesis by three different treatments. RA reduction causes a delay in the progression through gastrulation as well as the rostral migration of the goosecoid-positive PCM cells. RA inhibition also hampered the elongation of explanted dorsal marginal zones, the compaction of the blastocoel, and the length of Brachet’s cleft, all of which indicate an effect on LEM/PCM migration. The cellular mechanisms underlying this deficit were shown to include a reduced deposition of fibronectin along Brachet’s cleft, the substrate for their migration, as well as impaired separation of the blastocoel roof and involuting mesoderm, which is important for the formation of Brachet’s cleft and successful LEM/PCM migration. We further show reduced non-canonical Wnt signaling activity and altered expression of genes in the Ephrin and PDGF signaling pathways, both of which are required for the rostral migration of the LEM/PCM, following RA reduction. Together, these experiments demonstrate that RA signaling performs a very early function critical for the progression of gastrulation morphogenetic movements.
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Affiliation(s)
- Michal Gur
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Tamir Edri
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Sally A. Moody
- Department of Anatomy and Cell Biology, School of Medicine and Health Sciences, George Washington University, Washington, DC, United States
- *Correspondence: Sally A. Moody, ; Abraham Fainsod,
| | - Abraham Fainsod
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
- *Correspondence: Sally A. Moody, ; Abraham Fainsod,
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4
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Gur M, Bendelac-Kapon L, Shabtai Y, Pillemer G, Fainsod A. Reduced Retinoic Acid Signaling During Gastrulation Induces Developmental Microcephaly. Front Cell Dev Biol 2022; 10:844619. [PMID: 35372345 PMCID: PMC8967241 DOI: 10.3389/fcell.2022.844619] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 02/24/2022] [Indexed: 12/21/2022] Open
Abstract
Retinoic acid (RA) is a central signaling molecule regulating multiple developmental decisions during embryogenesis. Excess RA induces head malformations, primarily by expansion of posterior brain structures at the expense of anterior head regions, i.e., hindbrain expansion. Despite this extensively studied RA teratogenic effect, a number of syndromes exhibiting microcephaly, such as DiGeorge, Vitamin A Deficiency, Fetal Alcohol Syndrome, and others, have been attributed to reduced RA signaling. This causative link suggests a requirement for RA signaling during normal head development in all these syndromes. To characterize this novel RA function, we studied the involvement of RA in the early events leading to head formation in Xenopus embryos. This effect was mapped to the earliest RA biosynthesis in the embryo within the gastrula Spemann-Mangold organizer. Head malformations were observed when reduced RA signaling was induced in the endogenous Spemann-Mangold organizer and in the ectopic organizer of twinned embryos. Two embryonic retinaldehyde dehydrogenases, ALDH1A2 (RALDH2) and ALDH1A3 (RALDH3) are initially expressed in the organizer and subsequently mark the trunk and the migrating leading edge mesendoderm, respectively. Gene-specific knockdowns and CRISPR/Cas9 targeting show that RALDH3 is a key enzyme involved in RA production required for head formation. These observations indicate that in addition to the teratogenic effect of excess RA on head development, RA signaling also has a positive and required regulatory role in the early formation of the head during gastrula stages. These results identify a novel RA activity that concurs with its proposed reduction in syndromes exhibiting microcephaly.
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5
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Sheng G, Martinez Arias A, Sutherland A. The primitive streak and cellular principles of building an amniote body through gastrulation. Science 2021; 374:abg1727. [PMID: 34855481 DOI: 10.1126/science.abg1727] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
[Figure: see text].
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Affiliation(s)
- Guojun Sheng
- International Research Center for Medical Sciences, Kumamoto University, Kumamoto, Japan
| | - Alfonso Martinez Arias
- Systems Bioengineering, DCEXS, Universidad Pompeu Fabra, Doctor Aiguader, 88 ICREA, Pag Lluis Companys 23, Barcelona, Spain
| | - Ann Sutherland
- Department of Cell Biology, University of Virginia Health System, Charlottesville, VA, USA
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6
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Castro Colabianchi AM, Tavella MB, Boyadjián López LE, Rubinstein M, Franchini LF, López SL. Segregation of brain and organizer precursors is differentially regulated by Nodal signaling at blastula stage. Biol Open 2021; 10:bio.051797. [PMID: 33563608 PMCID: PMC7928228 DOI: 10.1242/bio.051797] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The blastula Chordin- and Noggin-expressing (BCNE) center comprises animal-dorsal and marginal-dorsal cells of the amphibian blastula and contains the precursors of the brain and the gastrula organizer. Previous findings suggested that the BCNE behaves as a homogeneous cell population that only depends on nuclear β-catenin activity but does not require Nodal and later segregates into its descendants during gastrulation. In contrast to previous findings, in this work, we show that the BCNE does not behave as a homogeneous cell population in response to Nodal antagonists. In fact, we found that chordin.1 expression in a marginal subpopulation of notochordal precursors indeed requires Nodal input. We also establish that an animal BCNE subpopulation of cells that express both, chordin.1 and sox2 (a marker of pluripotent neuroectodermal cells), and gives rise to most of the brain, persisted at blastula stage after blocking Nodal. Therefore, Nodal signaling is required to define a population of chordin.1+ cells and to restrict the recruitment of brain precursors within the BCNE as early as at blastula stage. We discuss our findings in Xenopus in comparison to other vertebrate models, uncovering similitudes in early brain induction and delimitation through Nodal signaling. This article has an associated First Person interview with the first author of the paper. Summary: Nodal signaling is involved in the delimitation of the blastula cell populations that give rise to the brain and axial mesoderm in Xenopus.
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Affiliation(s)
- Aitana M Castro Colabianchi
- Universidad de Buenos Aires. Facultad de Medicina, Departamento de Biología Celular e Histología / 1° U.A. Departamento de Histología, Embriología, Biología Celular y Genética, Laboratorio de Embriología Molecular "Prof. Dr. Andrés E. Carrasco", Buenos Aires 1121, Argentina.,CONICET - Universidad de Buenos Aires. Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis" (IBCN), Universidad de Buenos Aires, Buenos Aires 1121, Argentina
| | - María B Tavella
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI) "Dr. Héctor N. Torres", Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires C1428, Argentina
| | - Laura E Boyadjián López
- Universidad de Buenos Aires. Facultad de Medicina, Departamento de Biología Celular e Histología / 1° U.A. Departamento de Histología, Embriología, Biología Celular y Genética, Laboratorio de Embriología Molecular "Prof. Dr. Andrés E. Carrasco", Buenos Aires 1121, Argentina.,CONICET - Universidad de Buenos Aires. Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis" (IBCN), Universidad de Buenos Aires, Buenos Aires 1121, Argentina
| | - Marcelo Rubinstein
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI) "Dr. Héctor N. Torres", Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires C1428, Argentina.,Departamento de Fisiología, Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires 1428, Argentina
| | - Lucía F Franchini
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular (INGEBI) "Dr. Héctor N. Torres", Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires C1428, Argentina
| | - Silvia L López
- Universidad de Buenos Aires. Facultad de Medicina, Departamento de Biología Celular e Histología / 1° U.A. Departamento de Histología, Embriología, Biología Celular y Genética, Laboratorio de Embriología Molecular "Prof. Dr. Andrés E. Carrasco", Buenos Aires 1121, Argentina .,CONICET - Universidad de Buenos Aires. Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis" (IBCN), Universidad de Buenos Aires, Buenos Aires 1121, Argentina
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7
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Desnitskiy AG. Surface contraction waves or cell proliferation waves in the presumptive neurectoderm during amphibian gastrulation: Mexican axolotl versus African clawed frog. Biosystems 2020; 198:104286. [PMID: 33181236 DOI: 10.1016/j.biosystems.2020.104286] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 09/21/2020] [Accepted: 11/03/2020] [Indexed: 11/19/2022]
Abstract
This essay represents a critical analysis of the literary data on various types of waves occurring in the amphibian embryos during gastrulation. A surface contraction wave travels through the presumptive neurectoderm during Mexican axolotl gastrulation. This wave coincides temporally and spatially with involution of the inducing chordomesoderm and with the prospective neural plate. By contrast, there is no similar surface contraction wave during African clawed frog gastrulation. However, the clawed frog displays the waves of DNA synthesis and mitosis in the presumptive neurectoderm during gastrulation, whereas no such waves were discovered in axolotl gastrulae. These sets of experimental data are in accordance with the contemporary concept of considerable ontogenetic diversity of the class Amphibia.
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Affiliation(s)
- Alexey G Desnitskiy
- Department of Embryology, Saint-Petersburg State University, Universitetskaya nab 7/9, 199034, St. Petersburg, Russia.
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8
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Fagotto F. Tissue segregation in the early vertebrate embryo. Semin Cell Dev Biol 2020; 107:130-146. [DOI: 10.1016/j.semcdb.2020.05.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 05/22/2020] [Accepted: 05/26/2020] [Indexed: 11/30/2022]
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9
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Bruce AEE, Winklbauer R. Brachyury in the gastrula of basal vertebrates. Mech Dev 2020; 163:103625. [PMID: 32526279 DOI: 10.1016/j.mod.2020.103625] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 05/11/2020] [Accepted: 06/03/2020] [Indexed: 12/20/2022]
Abstract
The Brachyury gene encodes a transcription factor that is conserved across all animals. In non-chordate metazoans, brachyury is primarily expressed in ectoderm regions that are added to the endodermal gut during development, and often form a ring around the site of endoderm internalization in the gastrula, the blastopore. In chordates, this brachyury ring is conserved, but the gene has taken on a new role in the formation of the mesoderm. In this phylum, a novel type of mesoderm that develops into notochord and somites has been added to the ancestral lateral plate mesoderm. Brachyury contributes to a shift in cell fate from neural ectoderm to posterior notochord and somites during a major lineage segregation event that in Xenopus and in the zebrafish takes place in the early gastrula. In the absence of this brachyury function, impaired formation of posterior mesoderm indirectly affects the gastrulation movements of peak involution and convergent extension. These movements are confined to specific regions and stages, leaving open the question why brachyury expression in an extensive, coherent ring, before, during and after gastrulation, is conserved in the two species whose gastrulation modes differ considerably, and also in many other metazoan gastrulae of diverse structure.
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Affiliation(s)
- Ashley E E Bruce
- Department of Cell and Systems Biology, University of Toronto, Canada
| | - Rudolf Winklbauer
- Department of Cell and Systems Biology, University of Toronto, Canada.
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10
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Petrelli B, Bendelac L, Hicks GG, Fainsod A. Insights into retinoic acid deficiency and the induction of craniofacial malformations and microcephaly in fetal alcohol spectrum disorder. Genesis 2019; 57:e23278. [DOI: 10.1002/dvg.23278] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 12/03/2018] [Accepted: 12/04/2018] [Indexed: 12/14/2022]
Affiliation(s)
- Berardino Petrelli
- Regenerative Medicine Program and the Department of Biochemistry & Medical Genetics, Max Rady College of Medicine, Rady Faculty of Health SciencesUniversity of Manitoba Winnipeg Manitoba Canada
| | - Liat Bendelac
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel‐CanadaFaculty of Medicine, Hebrew University Jerusalem Israel
| | - Geoffrey G. Hicks
- Regenerative Medicine Program and the Department of Biochemistry & Medical Genetics, Max Rady College of Medicine, Rady Faculty of Health SciencesUniversity of Manitoba Winnipeg Manitoba Canada
| | - Abraham Fainsod
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel‐CanadaFaculty of Medicine, Hebrew University Jerusalem Israel
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11
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Shabtai Y, Fainsod A. Competition between ethanol clearance and retinoic acid biosynthesis in the induction of fetal alcohol syndrome. Biochem Cell Biol 2018; 96:148-160. [DOI: 10.1139/bcb-2017-0132] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Several models have been proposed to explain the neurodevelopmental syndrome induced by exposure of human embryos to alcohol, which is known as fetal alcohol spectrum disorder (FASD). One of the proposed models suggests a competition for the enzymes required for the biosynthesis of retinoic acid. The outcome of such competition is development under conditions of reduced retinoic acid signaling. Retinoic acid is one of the biologically active metabolites of vitamin A (retinol), and regulates numerous embryonic and differentiation processes. The developmental malformations characteristic of FASD resemble those observed in vitamin A deficiency syndrome as well as from inhibition of retinoic acid biosynthesis or signaling in experimental models. There is extensive biochemical and enzymatic overlap between ethanol clearance and retinoic acid biosynthesis. Several lines of evidence suggest that in the embryo, the competition takes place between acetaldehyde and retinaldehyde for the aldehyde dehydrogenase activity available. In adults, this competition also extends to the alcohol dehydrogenase activity. Ethanol-induced developmental defects can be ameliorated by increasing the levels of retinol, retinaldehyde, or retinaldehyde dehydrogenase. Acetaldehyde inhibits the production of retinoic acid by retinaldehyde dehydrogenase, further supporting the competition model. All of the evidence supports the reduction of retinoic acid signaling as the etiological trigger in the induction of FASD.
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Affiliation(s)
- Yehuda Shabtai
- Department of Cellular Biochemistry and Cancer Research, Institute for Medical Research Israel–Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
- Department of Cellular Biochemistry and Cancer Research, Institute for Medical Research Israel–Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Abraham Fainsod
- Department of Cellular Biochemistry and Cancer Research, Institute for Medical Research Israel–Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
- Department of Cellular Biochemistry and Cancer Research, Institute for Medical Research Israel–Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
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12
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Fainsod A, Kot-Leibovich H. Xenopus embryos to study fetal alcohol syndrome, a model for environmental teratogenesis. Biochem Cell Biol 2018; 96:77-87. [DOI: 10.1139/bcb-2017-0219] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Vertebrate model systems are central to characterize the outcomes of ethanol exposure and the etiology of fetal alcohol spectrum disorder (FASD), taking advantage of their genetic and morphological closeness and similarity to humans. We discuss the contribution of amphibian embryos to FASD research, focusing on Xenopus embryos. The Xenopus experimental system is characterized by external development and accessibility throughout embryogenesis, large clutch sizes, gene and protein activity manipulation, transgenesis and genome editing, convenient chemical treatment, explants and conjugates, and many other experimental approaches. Taking advantage of these methods, many insights regarding FASD have been obtained. These studies characterized the malformations induced by ethanol including quantitative analysis of craniofacial malformations, induction of fetal growth restriction, delay in gut maturation, and defects in the differentiation of the neural crest. Mechanistic, biochemical, and molecular studies in Xenopus embryos identified early gastrula as the high alcohol sensitivity window, targeting the embryonic organizer and inducing a delay in gastrulation movements. Frog embryos have also served to demonstrate the involvement of reduced retinoic acid production and an increase in reactive oxygen species in FASD. Amphibian embryos have helped pave the way for our mechanistic, molecular, and biochemical understanding of the etiology and pathophysiology of FASD.
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Affiliation(s)
- Abraham Fainsod
- Department of Cellular Biochemistry and Cancer Research, Institute for Medical Research Israel–Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
- Department of Cellular Biochemistry and Cancer Research, Institute for Medical Research Israel–Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Hadas Kot-Leibovich
- Department of Cellular Biochemistry and Cancer Research, Institute for Medical Research Israel–Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
- Department of Cellular Biochemistry and Cancer Research, Institute for Medical Research Israel–Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
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13
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Taniguchi Y, Kurth T, Weiche S, Reichelt S, Tazaki A, Perike S, Kappert V, Epperlein HH. The posterior neural plate in axolotl gives rise to neural tube or turns anteriorly to form somites of the tail and posterior trunk. Dev Biol 2017; 422:155-170. [DOI: 10.1016/j.ydbio.2016.12.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 12/21/2016] [Accepted: 12/21/2016] [Indexed: 11/28/2022]
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14
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Yanagi T, Ito K, Nishihara A, Minamino R, Mori S, Sumida M, Hashimoto C. The Spemann organizer meets the anterior-most neuroectoderm at the equator of early gastrulae in amphibian species. Dev Growth Differ 2015; 57:218-31. [PMID: 25754292 PMCID: PMC4402005 DOI: 10.1111/dgd.12200] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 01/08/2015] [Accepted: 01/20/2015] [Indexed: 11/17/2022]
Abstract
The dorsal blastopore lip (known as the Spemann organizer) is important for making the body plan in amphibian gastrulation. The organizer is believed to involute inward and migrate animally to make physical contact with the prospective head neuroectoderm at the blastocoel roof of mid- to late-gastrula. However, we found that this physical contact was already established at the equatorial region of very early gastrula in a wide variety of amphibian species. Here we propose a unified model of amphibian gastrulation movement. In the model, the organizer is present at the blastocoel roof of blastulae, moves vegetally to locate at the region that lies from the blastocoel floor to the dorsal lip at the onset of gastrulation. The organizer located at the blastocoel floor contributes to the anterior axial mesoderm including the prechordal plate, and the organizer at the dorsal lip ends up as the posterior axial mesoderm. During the early step of gastrulation, the anterior organizer moves to establish the physical contact with the prospective neuroectoderm through the “subduction and zippering” movements. Subduction makes a trench between the anterior organizer and the prospective neuroectoderm, and the tissues face each other via the trench. Zippering movement, with forming Brachet's cleft, gradually closes the gap to establish the contact between them. The contact is completed at the equator of early gastrulae and it continues throughout the gastrulation. After the contact is established, the dorsal axis is formed posteriorly, but not anteriorly. The model also implies the possibility of constructing a common model of gastrulation among chordate species.
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Affiliation(s)
- Takanori Yanagi
- JT Biohistory Research Hall, 1-1 Murasaki-cho, Takatsuki, Osaka, 569-1125, Japan; Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, 560-0043, Japan
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15
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Brown LE, King JR, Loose M. Two different network topologies yield bistability in models of mesoderm and anterior mesendoderm specification in amphibians. J Theor Biol 2014; 353:67-77. [PMID: 24650939 PMCID: PMC4029075 DOI: 10.1016/j.jtbi.2014.03.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 03/06/2014] [Accepted: 03/09/2014] [Indexed: 01/03/2023]
Abstract
Understanding the Gene Regulatory Networks (GRNs) that underlie development is a major question for systems biology. The establishment of the germ layers is amongst the earliest events of development and has been characterised in numerous model systems. The establishment of the mesoderm is best characterised in the frog Xenopus laevis and has been well studied both experimentally and mathematically. However, the Xenopus network has significant differences from that in mouse and humans, including the presence of multiple copies of two key genes in the network, Mix and Nodal. The axolotl, a urodele amphibian, provides a model with all the benefits of amphibian embryology but crucially only a single Mix and Nodal gene required for the specification of the mesoderm. Remarkably, the number of genes within the network is not the only difference. The interaction between Mix and Brachyury, two transcription factors involved in the establishment of the endoderm and mesoderm respectively, is not conserved. While Mix represses Brachyury in Xenopus, it activates Brachyury in axolotl. Thus, whilst the topology of the networks in the two species differs, both are able to form mesoderm and endoderm in vivo. Based on current knowledge of the structure of the mesendoderm GRN we develop deterministic models that describe the time evolution of transcription factors in a single axolotl cell and compare numerical simulations with previous results from Xenopus. The models are shown to have stable steady states corresponding to mesoderm and anterior mesendoderm, with the in vitro model showing how the concentration of Activin can determine cell fate, while the in vivo model shows that β-catenin concentration can determine cell fate. Moreover, our analysis suggests that additional components must be important in the axolotl network in the specification of the full range of tissues. We present models of mesendoderm specification in the urodele amphibian, the axolotl. in vitro and in vivo models are simulated and compared with experimental data. The model topology differs from that of the anuran amphibian, Xenopus laevis. Steady states representing mesoderm and anterior mesendoderm are found in both models. Both the axolotl and Xenopus topologies can account for similar qualitative data.
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Affiliation(s)
- L E Brown
- MyCIB, School of Biosciences, University of Nottingham, Sutton Bonington LE12 5RD, UK.
| | - J R King
- School of Mathematical Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
| | - M Loose
- Centre for Genetics and Genomics, University of Nottingham, Queen׳s Medical Centre, Nottingham NG7 2UH, UK.
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