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Asashima M, Satou-Kobayashi Y. Spemann-Mangold organizer and mesoderm induction. Cells Dev 2024; 178:203903. [PMID: 38295873 DOI: 10.1016/j.cdev.2024.203903] [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: 11/13/2023] [Revised: 01/23/2024] [Accepted: 01/24/2024] [Indexed: 02/09/2024]
Abstract
The discovery of the Spemann-Mangold organizer strongly influenced subsequent research on embryonic induction, with research aiming to elucidate the molecular characteristics of organizer activity being currently underway. Herein, we review the history of research on embryonic induction, and describe how the mechanisms of induction phenomena and developmental processes have been investigated. Classical experiments investigating the differentiation capacity and inductive activity of various embryonic regions were conducted by many researchers, and important theories of region-specific induction and the concept for chain of induction were proposed. The transition from experimental embryology to developmental biology has enabled us to understand the mechanisms of embryonic induction at the molecular level. Consequently, many inducing substances and molecules such as transcriptional factors and peptide growth factors involved in the organizer formation were identified. One of peptide growth factors, activin, acts as a mesoderm- and endoderm-inducing substance. Activin induces several tissues and organs from the undifferentiated cell mass of amphibian embryos in a concentration-dependent manner. We review the extent to which we can control in vitro organogenesis from undifferentiated cells, and discuss the application to stem cell-based regenerative medicine based on insights gained from animal experiments, such as in amphibians.
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Affiliation(s)
- Makoto Asashima
- Advanced Comprehensive Research Organization, Teikyo University, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-0003, Japan.
| | - Yumeko Satou-Kobayashi
- Advanced Comprehensive Research Organization, Teikyo University, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-0003, Japan
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2
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Tejeda-Muñoz N, Monka J, De Robertis EM. Protocol for culturing and imaging of ectodermal cells from Xenopus. STAR Protoc 2022; 3:101455. [PMID: 35839770 PMCID: PMC9293668 DOI: 10.1016/j.xpro.2022.101455] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 04/21/2022] [Accepted: 05/17/2022] [Indexed: 01/19/2023] Open
Abstract
The Xenopus embryo provides an advantageous model system where genes can be readily transplanted as DNA or mRNA or depleted with antisense techniques. Here, we present a protocol to culture and image the cell biological properties of explanted Xenopus cap cells in tissue culture. We illustrate how this protocol can be applied to visualize lysosomes, macropinocytosis, focal adhesions, Wnt signaling, and cell migration. For complete details on the use and execution of this protocol, please refer to Tejeda-Muñoz et al. (2022).
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Affiliation(s)
- Nydia Tejeda-Muñoz
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1662, USA,Corresponding author
| | - Julia Monka
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1662, USA
| | - Edward M. De Robertis
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA 90095-1662, USA
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3
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Hwang WY, Marquez J, Khokha MK. Xenopus: Driving the Discovery of Novel Genes in Patient Disease and Their Underlying Pathological Mechanisms Relevant for Organogenesis. Front Physiol 2019; 10:953. [PMID: 31417417 PMCID: PMC6682594 DOI: 10.3389/fphys.2019.00953] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 07/09/2019] [Indexed: 12/16/2022] Open
Abstract
Frog model organisms have been appreciated for their utility in exploring physiological phenomena for nearly a century. Now, a vibrant community of biologists that utilize this model organism has poised Xenopus to serve as a high throughput vertebrate organism to model patient-driven genetic diseases. This has facilitated the investigation of effects of patient mutations on specific organs and signaling pathways. This approach promises a rapid investigation into novel mechanisms that disrupt normal organ morphology and function. Considering that many disease states are still interrogated in vitro to determine relevant biological processes for further study, the prospect of interrogating genetic disease in Xenopus in vivo is an attractive alternative. This model may more closely capture important aspects of the pathology under investigation such as cellular micro environments and local forces relevant to a specific organ's development and homeostasis. This review aims to highlight recent methodological advances that allow investigation of genetic disease in organ-specific contexts in Xenopus as well as provide examples of how these methods have led to the identification of novel mechanisms and pathways important for understanding human disease.
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Affiliation(s)
| | | | - Mustafa K. Khokha
- Department of Pediatrics and Genetics, The Pediatric Genomics Discovery Program, Yale University School of Medicine, New Haven, CT, United States
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4
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Angerilli A, Smialowski P, Rupp RA. The Xenopus animal cap transcriptome: building a mucociliary epithelium. Nucleic Acids Res 2019; 46:8772-8787. [PMID: 30165493 PMCID: PMC6158741 DOI: 10.1093/nar/gky771] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 08/24/2018] [Indexed: 01/12/2023] Open
Abstract
With the availability of deep RNA sequencing, model organisms such as Xenopus offer an outstanding opportunity to investigate the genetic basis of vertebrate organ formation from its embryonic beginnings. Here we investigate dynamics of the RNA landscape during formation of the Xenopus tropicalis larval epidermis. Differentiation of non-neural ectoderm starts at gastrulation and takes about one day to produce a functional mucociliary epithelium, highly related to the one in human airways. To obtain RNA expression data, uncontaminated by non-epidermal tissues of the embryo, we use prospective ectodermal explants called Animal Caps (ACs), which differentiate autonomously into a ciliated epidermis. Their global transcriptome is investigated at three key timepoints, with a cumulative sequencing depth of ∼108 reads per developmental stage. This database is provided as online Web Tool to the scientific community. In this paper, we report on global changes in gene expression, an unanticipated diversity of mRNA splicing isoforms, expression patterns of repetitive DNA Elements, and the complexity of circular RNAs during this process. Computationally we derive transcription factor hubs from this data set, which may help in the future to define novel genetic drivers of epidermal differentiation in vertebrates.
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Affiliation(s)
- Alessandro Angerilli
- Molecular Biology Division, Biomedical Center, Ludwig-Maximilians-University München, D-82152 Martinsried, Germany
| | - Pawel Smialowski
- Bioinformatic Core Facility, Biomedical Center, Ludwig-Maximilians-University München, D-82152 Martinsried, Germany.,Helmholtz Zentrum München, Institute of Stem Cell Research, Ingolstädter Landstraße 1, D-85764 Neuherberg-München, Germany
| | - Ralph Aw Rupp
- Molecular Biology Division, Biomedical Center, Ludwig-Maximilians-University München, D-82152 Martinsried, Germany
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5
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Afouda BA, Lynch AT, de Paiva Alves E, Hoppler S. Genome-wide transcriptomics analysis identifies sox7 and sox18 as specifically regulated by gata4 in cardiomyogenesis. Dev Biol 2017; 434:108-120. [PMID: 29229250 PMCID: PMC5814753 DOI: 10.1016/j.ydbio.2017.11.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 11/29/2017] [Accepted: 11/29/2017] [Indexed: 01/12/2023]
Abstract
The transcription factors GATA4, GATA5 and GATA6 are important regulators of heart muscle differentiation (cardiomyogenesis), which function in a partially redundant manner. We identified genes specifically regulated by individual cardiogenic GATA factors in a genome-wide transcriptomics analysis. The genes regulated by gata4 are particularly interesting because GATA4 is able to induce differentiation of beating cardiomyocytes in Xenopus and in mammalian systems. Among the specifically gata4-regulated transcripts we identified two SoxF family members, sox7 and sox18. Experimental reinstatement of gata4 restores sox7 and sox18 expression, and loss of cardiomyocyte differentiation due to gata4 knockdown is partially restored by reinstating sox7 or sox18 expression, while (as previously reported) knockdown of sox7 or sox18 interferes with heart muscle formation. In order to test for conservation in mammalian cardiomyogenesis, we confirmed in mouse embryonic stem cells (ESCs) undergoing cardiomyogenesis that knockdown of Gata4 leads to reduced Sox7 (and Sox18) expression and that Gata4 is also uniquely capable of promptly inducing Sox7 expression. Taken together, we identify an important and conserved gene regulatory axis from gata4 to the SoxF paralogs sox7 and sox18 and further to heart muscle cell differentiation. Gata 4, 5 and 6 have redundant and non-redundant functions in heart development. RNA-seq analysis of Gata4, 5 and 6 knockdown experiments was carried out. Genes specifically regulated by Gata4, 5 and 6 were identified. The SoxF genes sox7 and sox18 were identified as specifically regulated by Gata4. Epistasis demonstrates a regulatory axis from Gata4 to Sox7/18 to cardiomyogenesis.
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Affiliation(s)
- Boni A Afouda
- Institute of Medical Sciences, Foresterhill Health Campus, University of Aberdeen, Scotland, UK
| | - Adam T Lynch
- Institute of Medical Sciences, Foresterhill Health Campus, University of Aberdeen, Scotland, UK
| | - Eduardo de Paiva Alves
- Centre for Genome-Enabled Biology and Medicine, King's College Campus, University of Aberdeen, Scotland, UK
| | - Stefan Hoppler
- Institute of Medical Sciences, Foresterhill Health Campus, University of Aberdeen, Scotland, UK.
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6
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Walentek P, Quigley IK. What we can learn from a tadpole about ciliopathies and airway diseases: Using systems biology in Xenopus to study cilia and mucociliary epithelia. Genesis 2017; 55:10.1002/dvg.23001. [PMID: 28095645 PMCID: PMC5276738 DOI: 10.1002/dvg.23001] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 11/14/2016] [Accepted: 11/16/2016] [Indexed: 12/11/2022]
Abstract
Over the past years, the Xenopus embryo has emerged as an incredibly useful model organism for studying the formation and function of cilia and ciliated epithelia in vivo. This has led to a variety of findings elucidating the molecular mechanisms of ciliated cell specification, basal body biogenesis, cilia assembly, and ciliary motility. These findings also revealed the deep functional conservation of signaling, transcriptional, post-transcriptional, and protein networks employed in the formation and function of vertebrate ciliated cells. Therefore, Xenopus research can contribute crucial insights not only into developmental and cell biology, but also into the molecular mechanisms underlying cilia related diseases (ciliopathies) as well as diseases affecting the ciliated epithelium of the respiratory tract in humans (e.g., chronic lung diseases). Additionally, systems biology approaches including transcriptomics, genomics, and proteomics have been rapidly adapted for use in Xenopus, and broaden the applications for current and future translational biomedical research. This review aims to present the advantages of using Xenopus for cilia research, highlight some of the evolutionarily conserved key concepts and mechanisms of ciliated cell biology that were elucidated using the Xenopus model, and describe the potential for Xenopus research to address unresolved questions regarding the molecular mechanisms of ciliopathies and airway diseases.
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Affiliation(s)
- Peter Walentek
- Department of Molecular and Cell Biology; Genetics, Genomics and Development Division; Developmental and Regenerative Biology Group; University of California, Berkeley, CA 94720, USA
| | - Ian K. Quigley
- Salk Institute for Biological Studies, La Jolla, CA 92037, USA
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7
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Turner DA, Baillie‐Johnson P, Martinez Arias A. Organoids and the genetically encoded self-assembly of embryonic stem cells. Bioessays 2016; 38:181-91. [PMID: 26666846 PMCID: PMC4737349 DOI: 10.1002/bies.201500111] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Understanding the mechanisms of early embryonic patterning and the timely allocation of specific cells to embryonic regions and fates as well as their development into tissues and organs, is a fundamental problem in Developmental Biology. The classical explanation for this process had been built around the notion of positional information. Accordingly the programmed appearance of sources of Morphogens at localized positions within a field of cells directs their differentiation. Recently, the development of organs and tissues from unpatterned and initially identical stem cells (adult and embryonic) has challenged the need for positional information and even the integrity of the embryo, for pattern formation. Here we review the emerging area of organoid biology from the perspective of Developmental Biology. We argue that the events underlying the development of these systems are not purely linked to self-organization, as often suggested, but rather to a process of genetically encoded self-assembly where genetic programs encode and control the emergence of biological structures.
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Affiliation(s)
- David A. Turner
- Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
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8
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Kirmizitas A, Gillis WQ, Zhu H, Thomsen GH. Gtpbp2 is required for BMP signaling and mesoderm patterning in Xenopus embryos. Dev Biol 2014; 392:358-67. [PMID: 24858484 DOI: 10.1016/j.ydbio.2014.05.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 04/27/2014] [Accepted: 05/07/2014] [Indexed: 12/26/2022]
Abstract
Smad proteins convey canonical intracellular signals for activated receptors in the TGFβ superfamily, but the activity of Smads and their impact on target genes are further regulated by a wide variety of cofactors and partner proteins. We have identified a new Smad1 partner, a GTPase named Gtpbp2 that is a distant relative of the translation factor eEf1a. Gtpbp2 affects canonical signaling in the BMP branch of the TGFβ superfamily, as morpholino knockdown of Gtpbp2 decreases, and overexpression of Gtpbp2 enhances, animal cap responses to BMP4. During Xenopus development, gtpbp2 transcripts are maternally expressed and localized to the egg animal pole, and partitioned into the nascent ectodermal and mesodermal cells during cleavage and early gastrulation stages. Subsequently, gtpbp2 is expressed in the neural folds, and in early tadpoles undergoing organogenesis gtpbp2 is expressed prominently in the brain, eyes, somites, ventral blood island and branchial arches. Consistent with its expression, morpholino knockdown of Gtpbp2 causes defects in ventral-posterior germ layer patterning, gastrulation and tadpole morphology. Overexpressed Gtpbp2 can induce ventral-posterior marker genes and localize to cell nuclei in Xenopus animal caps, highlighting its role in regulating BMP signaling in the early embryo. Here, we introduce this large GTPase as a novel factor in BMP signaling and ventral-posterior patterning.
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Affiliation(s)
- Arif Kirmizitas
- Department of Biochemistry and Cell Biology, Graduate Program in Molecular and Cellular Biology, Center for Developmental Genetics, Stony Brook University, Stony Brook, NY 11794-5215, USA
| | - William Q Gillis
- Department of Biochemistry and Cell Biology, Graduate Program in Molecular and Cellular Biology, Center for Developmental Genetics, Stony Brook University, Stony Brook, NY 11794-5215, USA
| | - Haitao Zhu
- Department of Biochemistry and Cell Biology, Graduate Program in Molecular and Cellular Biology, Center for Developmental Genetics, Stony Brook University, Stony Brook, NY 11794-5215, USA
| | - Gerald H Thomsen
- Department of Biochemistry and Cell Biology, Graduate Program in Molecular and Cellular Biology, Center for Developmental Genetics, Stony Brook University, Stony Brook, NY 11794-5215, USA.
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9
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Kriegmair MCM, Frenz S, Dusl M, Franz WM, David R, Rupp RAW. Cardiac differentiation in Xenopus is initiated by mespa. Cardiovasc Res 2012; 97:454-63. [PMID: 23241315 DOI: 10.1093/cvr/cvs354] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
AIMS Future cardiac repair strategies will require a profound understanding of the principles underlying cardiovascular differentiation. Owing to its extracorporal and rapid development, Xenopus laevis provides an ideal experimental system to address these issues in vivo. Whereas mammalian MesP1 is currently regarded as the earliest marker for the cardiovascular system, several MesP1-related factors from Xenopus-mespa, mespb, and mespo-have been assigned only to somitogenesis so far. We, therefore, analysed these genes comparatively for potential contributions to cardiogenesis. METHODS AND RESULTS RNA in situ hybridizations revealed a novel anterior expression domain exclusively occupied by mespa during gastrulation, which precedes the prospective heart field. Correspondingly, when overexpressed mespa most strongly induced cardiac markers in vivo as well as ex vivo. Transference to murine embryonic stem (ES) cells and subsequent FACS analyses for Flk-1 and Troponin I confirmed the high potential of mespa as a cardiac inducer. In vivo, Morpholino-based knockdown of mespa protein led to a dramatic loss of pro-cardiac and sarcomeric markers, which could be rescued either by mespa itself or human MesP1, but neither by mespb nor mespo. Epistatic analysis positioned mespa upstream of mespo and mespb, and revealed positive autoregulation for mespa at the time of its induction. CONCLUSIONS Our findings contribute to the understanding of conserved events initiating vertebrate cardiogenesis. We identify mespa as functional amphibian homologue of mammalian MesP1. These results will enable the dissection of cardiac specification from the very beginning in the highly versatile Xenopus system.
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Affiliation(s)
- Maximilian C M Kriegmair
- Department of Molecular Biology, Adolf-Butenandt-Institute, University of Munich LMU, Schillerstraβe 44, 80336 München, Germany
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10
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Kuwabara T, Asashima M. Regenerative medicine using adult neural stem cells: the potential for diabetes therapy and other pharmaceutical applications. J Mol Cell Biol 2012; 4:133-9. [PMID: 22577214 DOI: 10.1093/jmcb/mjs016] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Neural stem cells (NSCs), which are responsible for continuous neurogenesis during the adult stage, are present in human adults. The typical neurogenic regions are the hippocampus and the subventricular zone; recent studies have revealed that NSCs also exist in the olfactory bulb. Olfactory bulb-derived neural stem cells (OB NSCs) have the potential to be used in therapeutic applications and can be easily harvested without harm to the patient. Through the combined influence of extrinsic cues and innate programming, adult neurogenesis is a finely regulated process occurring in a specialized cellular environment, a niche. Understanding the regulatory mechanisms of adult NSCs and their cellular niche is not only important to understand the physiological roles of neurogenesis in adulthood, but also to provide the knowledge necessary for developing new therapeutic applications using adult NSCs in other organs with similar regulatory environments. Diabetes is a devastating disease affecting more than 200 million people worldwide. Numerous diabetic patients suffer increased symptom severity after the onset, involving complications such as retinopathy and nephropathy. Therefore, the development of treatments for fundamental diabetes is important. The utilization of autologous cells from patients with diabetes may address challenges regarding the compatibility of donor tissues as well as provide the means to naturally and safely restore function, reducing future risks while also providing a long-term cure. Here, we review recent findings regarding the use of adult OB NSCs as a potential diabetes cure, and discuss the potential of OB NSC-based pharmaceutical applications for neuronal diseases and mental disorders.
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Affiliation(s)
- Tomoko Kuwabara
- Research Center for Stem Cell Engineering, National Institute of Advanced Industrial Science and Technology, Central 4, 1-1-4 Higashi, Tsukuba Science City 305-8562, Japan
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11
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Khokha MK. Xenopuswhite papers and resources: Folding functional genomics and genetics into the frog. Genesis 2012; 50:133-42. [DOI: 10.1002/dvg.22015] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 01/13/2012] [Accepted: 01/15/2012] [Indexed: 02/04/2023]
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12
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Mereau A, Hardy S. Investigating alternative RNA splicing in Xenopus. Methods Mol Biol 2012; 917:347-368. [PMID: 22956098 DOI: 10.1007/978-1-61779-992-1_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Alternative splicing, the process by which distinct mature mRNAs can be produced from a single primary transcript, is a key mechanism to increase the organism complexity. The generation of alternative splicing pattern is a means to expand the proteome diversity and also to control gene expression through the regulation of mRNA abundance. Alternative splicing is therefore particularly prevalent during development and accordingly numerous splicing events are regulated in a tissue or temporal manner. To study the roles of alternative splicing during developmental processes and decipher the molecular mechanisms that underlie temporal and spatial regulation, it is important to develop in vivo whole animal studies. In this chapter, we present the advantages of using the amphibian Xenopus as a fully in vivo model to study alternative splicing and we describe the experimental procedures that can be used with Xenopus laevis embryos and oocytes to define the cis-regulatory elements and identify the associated trans-acting factors.
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Affiliation(s)
- Agnès Mereau
- UMR 6061 CNRS-Université de Rennes 1, Rennes, France
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13
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Abstract
Cells from the animal pole of Xenopus blastula embryo possess pluripotency that can be used to generate various tissues and even functional organs ex vivo. This finding has sparkled development of a variety of experimental protocols to study mechanisms that underlie formation of various organs and explore strategies for organ engineering for clinical applications. In this chapter, key methods are described for using Xenopus stem-cell-like embryonic explants as an assay system for studying organ development, with a focus on cardiogenesis. This assay allows investigation of cardiogenesis in isolation from neighboring tissues, minimizes interference with other developmental processes, and presents the further advantage of a heterologous system to study cardiogenesis in isolation of endogenous development of the heart. The cardiogenic assays can be exploited to investigate molecular mechanisms and cellular processes that underlie function of different molecules involved in cardiogenesis.
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Affiliation(s)
- Boni A Afouda
- Institute of Medical Sciences, University of Aberdeen, Scotland, UK.
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14
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Hulme SE, Whitesides GM. Die Chemie und der Wurm: Caenorhabditis elegans als Plattform für das Zusammenführen von chemischer und biologischer Forschung. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201005461] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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15
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Hulme SE, Whitesides GM. Chemistry and the Worm: Caenorhabditis elegans as a Platform for Integrating Chemical and Biological Research. Angew Chem Int Ed Engl 2011; 50:4774-807. [DOI: 10.1002/anie.201005461] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Indexed: 12/15/2022]
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Drews C, Senkel S, Ryffel GU. The nephrogenic potential of the transcription factors osr1, osr2, hnf1b, lhx1 and pax8 assessed in Xenopus animal caps. BMC DEVELOPMENTAL BIOLOGY 2011; 11:5. [PMID: 21281489 PMCID: PMC3042965 DOI: 10.1186/1471-213x-11-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Accepted: 01/31/2011] [Indexed: 11/10/2022]
Abstract
BACKGROUND The three distinct types of kidneys, pronephros, mesonephros and metanephros, develop consecutively in vertebrates. The earliest form of embryonic kidney, the pronephros, is derived from intermediate mesoderm and the first expressed genes localized in the pronephros anlage are the transcription factors osr1, osr2, hnf1b, lhx1 and pax8, here referred to as the early nephrogenic transcription factors. However, the pathway inducing nephrogenesis and the network of theses factors are poorly understood. Treatment of the undifferentiated animal pole explant (animal cap) of Xenopus with activin A and retinoic acid induces pronephros formation providing a powerful tool to analyze key molecular events in nephrogenesis. RESULTS We have investigated the expression kinetics of the early nephrogenic transcription factors in activin A and retinoic acid treated animal caps and their potential to induce pronephric differentiation. In treated animal caps, expression of osr1, osr2, hnf1b and lhx1 are induced early, whereas pax8 expression occurs later implying an indirect activation. Activin A alone is able to induce osr2 and lhx1 after three hours treatment in animal caps while retinoic acid fails to induce any of these nephrogenic transcription factors. The early expression of the five transcription factors and their interference with pronephros development when overexpressed in embryos suggest that these factors potentially induce nephrogenesis upon expression in animal caps. But no pronephros development is achieved by either overexpression of OSR1, by HNF1B injection with activin A treatment, or the combined application of LHX1 and PAX8, although they influenced the expression of several early nephrogenic transcription factors in some cases. In an additional approach we could show that HNF1B induces several genes important in nephrogenesis and regulates lhx1 expression by an HNF1 binding site in the lhx1 promoter. CONCLUSIONS The early nephrogenic transcription factors play an important role in nephrogenesis, but have no pronephros induction potential upon overexpression in animal caps. They activate transcriptional cascades that partially reflect the gene activation initiated by activin A and retinoic acid. Significantly, HNF1B activates the lhx1 promoter directly, thus extending the known activin A regulation of the lhx1 gene via an activin A responsive element.
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Affiliation(s)
- Christiane Drews
- Institut für Zellbiologie (Tumorforschung) Universitätsklinikum Essen, Universität Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany
| | - Sabine Senkel
- Institut für Zellbiologie (Tumorforschung) Universitätsklinikum Essen, Universität Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany
| | - Gerhart U Ryffel
- Institut für Zellbiologie (Tumorforschung) Universitätsklinikum Essen, Universität Duisburg-Essen, Hufelandstrasse 55, 45122 Essen, Germany
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17
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Cho GS, Choi SC, Park EC, Han JK. Role of Tbx2 in defining the territory of the pronephric nephron. Development 2011; 138:465-74. [PMID: 21205791 DOI: 10.1242/dev.061234] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Despite extensive study of the development of the nephron, which is the functional unit of the kidney, the molecular mechanisms underlying the determination of nephron size remain largely unknown. Using the Xenopus pronephros, we demonstrate here that Tbx2, a T-box transcriptional repressor, functions to demarcate the territory of the pronephric nephron. Tbx2 is specifically expressed around three distinct components of the pronephric nephron: the tubule, duct and glomus. Gain of function of Tbx2 inhibits nephric mesoderm formation. Conversely, Tbx2 loss of function expands the boundary of each component of the pronephric nephron, resulting in an enlarged pronephros. BMP signals induce Tbx2 in the non-nephric mesoderm, which inhibits the expression of the nephric markers Hey1 and Gremlin. Importantly, these pronephric molecules repress Tbx2 expression by antagonizing BMP signals in the nephric mesoderm. These results suggest that the negative regulatory loops between BMP/Tbx2 and Gremlin or Hey1 are responsible for defining the territory of the pronephric nephron.
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Affiliation(s)
- Gun-Sik Cho
- Division of Molecular and Life Sciences, Pohang University of Science and Technology, San 31, Hyoja-dong, Nam-gu, Pohang, Kyungbuk, Republic of Korea
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18
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Borchers A, Pieler T. Programming pluripotent precursor cells derived from Xenopus embryos to generate specific tissues and organs. Genes (Basel) 2010; 1:413-26. [PMID: 24710095 PMCID: PMC3966229 DOI: 10.3390/genes1030413] [Citation(s) in RCA: 124] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 10/21/2010] [Accepted: 11/05/2010] [Indexed: 11/16/2022] Open
Abstract
Xenopus embryos provide a rich source of pluripotent cells that can be differentiated into functional organs. Since the molecular principles of vertebrate organogenesis appear to be conserved between Xenopus and mammals, this system can provide useful guidelines for the directional manipulation of human embryonic stem cells. Pluripotent Xenopus cells can be easily isolated from the animal pole of blastula stage Xenopus embryos. These so called "animal cap" cells represent prospective ectodermal cells, but give rise to endodermal, mesodermal and neuro-ectodermal derivatives if treated with the appropriate factors. These factors include evolutionary conserved modulators of the key developmental signal transduction pathways that can be supplied either by mRNA microinjection or direct application of recombinant proteins. This relatively simple system has added to our understanding of pancreas, liver, kidney, eye and heart development. In particular, recent studies have used animal cap cells to generate ectopic eyes and hearts, setting the stage for future work aimed at programming pluripotent cells for regenerative medicine.
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Affiliation(s)
- Annette Borchers
- Department of Developmental Biochemistry, Center of Molecular Physiology of the Brain (CMPB), GZMB, University of Goettingen, Justus-von-Liebig-Weg 11, 37077 Goettingen, Germany.
| | - Tomas Pieler
- Department of Developmental Biochemistry, Center of Molecular Physiology of the Brain (CMPB), GZMB, University of Goettingen, Justus-von-Liebig-Weg 11, 37077 Goettingen, Germany.
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Abstract
Many developmental processes are highly conserved in all vertebrate organisms. This conservation has allowed developmental biologists to use numerous animal models to further our understanding of the molecular mechanisms that govern heart development and congenital heart disease. Amphibian embryos represent a useful model for such studies because their relatively large embryos are available in large numbers and survive simple microsurgery. In addition, until swimming tadpole stages, an amphibian embryo develops using nutrients stored in each of its many cells. This feature has the advantage that explants isolated from embryonic tissue will continue to survive in isolation and differentiate in culture. Furthermore, cells from the ectodermal layer of the blastula or gastrula embryos are stem cell like in that they are pluripotent and can be induced to form various tissues in vitro. Here, we will review work from recent studies in which explants from the amphibian embryos were used to further our understanding of vertebrate heart development. We will bring together the key facts needed for using Xenopus explants as experimental approaches for studying molecular pathways and gene regulatory networks in vertebrate cardiogenesis. The knowledge generated with these approaches supports the usefulness of amphibian explants, and the relevance of the findings strongly validates the conservation of molecular pathways that underlie heart development in all vertebrates.
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White JT, Zhang B, Cerqueira DM, Tran U, Wessely O. Notch signaling, wt1 and foxc2 are key regulators of the podocyte gene regulatory network in Xenopus. Development 2010; 137:1863-73. [PMID: 20431116 PMCID: PMC2867321 DOI: 10.1242/dev.042887] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/24/2010] [Indexed: 11/20/2022]
Abstract
Podocytes are highly specialized cells in the vertebrate kidney. They participate in the formation of the size-exclusion barrier of the glomerulus/glomus and recruit mesangial and endothelial cells to form a mature glomerulus. At least six transcription factors (wt1, foxc2, hey1, tcf21, lmx1b and mafb) are known to be involved in podocyte specification, but how they interact to drive the differentiation program is unknown. The Xenopus pronephros was used as a paradigm to address this question. All six podocyte transcription factors were systematically eliminated by antisense morpholino oligomers. Changes in the expression of the podocyte transcription factors and of four selected markers of terminal differentiation (nphs1, kirrel, ptpru and nphs2) were analyzed by in situ hybridization. The data were assembled into a transcriptional regulatory network for podocyte development. Although eliminating the six transcription factors individually interfered with aspects of podocyte development, no single gene regulated the entire differentiation program. Only the combined knockdown of wt1 and foxc2 resulted in a loss of all podocyte marker gene expression. Gain-of-function studies showed that wt1 and foxc2 were sufficient to increase podocyte gene expression within the glomus proper. However, the combination of wt1, foxc2 and Notch signaling was required for ectopic expression in ventral marginal zone explants. Together, this approach demonstrates how complex interactions are required for the correct spatiotemporal execution of the podocyte gene expression program.
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Affiliation(s)
- Jeffrey T. White
- Department of Cell Biology and Anatomy, LSU Health Sciences Center, MEB 6A12, 1901 Perdido Street, New Orleans, LA 70112, USA
| | - Bo Zhang
- Department of Cell Biology and Anatomy, LSU Health Sciences Center, MEB 6A12, 1901 Perdido Street, New Orleans, LA 70112, USA
| | - Débora M. Cerqueira
- Department of Cell Biology and Anatomy, LSU Health Sciences Center, MEB 6A12, 1901 Perdido Street, New Orleans, LA 70112, USA
| | - Uyen Tran
- Department of Cell Biology and Anatomy, LSU Health Sciences Center, MEB 6A12, 1901 Perdido Street, New Orleans, LA 70112, USA
| | - Oliver Wessely
- Department of Cell Biology and Anatomy, LSU Health Sciences Center, MEB 6A12, 1901 Perdido Street, New Orleans, LA 70112, USA
- Department of Genetics, LSU Health Sciences Center, MEB 6A12, 1901 Perdido Street, New Orleans, LA 70112, USA
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Osafune K. In vitro regeneration of kidney from pluripotent stem cells. Exp Cell Res 2010; 316:2571-7. [PMID: 20451514 DOI: 10.1016/j.yexcr.2010.04.034] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Accepted: 04/30/2010] [Indexed: 12/16/2022]
Abstract
Although renal transplantation has proved a successful treatment for the patients with end-stage renal failure, the therapy is hampered by the problem of serious shortage of donor organs. Regenerative medicine using stem cells, including cell transplantation therapy, needs to be developed to solve the problem. We previously identified the multipotent progenitor cells in the embryonic mouse kidney that can give rise to several kinds of epithelial cells found in adult kidney, such as glomerular podocytes and renal tubular epithelia. Establishing the method to generate the progenitors from human pluripotent stem cells that have the capacity to indefinitely proliferate in vitro is required for the development of kidney regeneration strategy. We review the current status of the research on the differentiation of pluripotent stem cells into renal lineages and describe cues to promote this research field.
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Affiliation(s)
- Kenji Osafune
- Center for iPS Cell Research and Application (CiRA), Kyoto University, 53 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto 606-8507, Japan.
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Samuel LJ, Latinkić BV. Early activation of FGF and nodal pathways mediates cardiac specification independently of Wnt/beta-catenin signaling. PLoS One 2009; 4:e7650. [PMID: 19862329 PMCID: PMC2763344 DOI: 10.1371/journal.pone.0007650] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2009] [Accepted: 10/07/2009] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Cardiac induction, the first step in heart development in vertebrate embryos, is thought to be initiated by anterior endoderm during gastrulation, but what the signals are and how they act is unknown. Several signaling pathways, including FGF, Nodal, BMP and Wnt have been implicated in cardiac specification, in both gain- and loss-of-function experiments. However, as these pathways regulate germ layer formation and patterning, their specific roles in cardiac induction have been difficult to define. METHODOLOGY/PRINCIPAL FINDINGS To investigate the mechanisms of cardiac induction directly we devised an assay based on conjugates of anterior endoderm from early gastrula stage Xenopus embryos as the inducing tissue and pluripotent ectodermal explants as the responding tissue. We show that the anterior endoderm produces a specific signal, as skeletal muscle is not induced. Cardiac inducing signal needs up to two hours of interaction with the responding tissue to produce an effect. While we found that the BMP pathway was not necessary, our results demonstrate that the FGF and Nodal pathways are essential for cardiogenesis. They were required only during the first hour of cardiogenesis, while sustained activation of ERK was required for at least four hours. Our results also show that transient early activation of the Wnt/beta-catenin pathway has no effect on cardiogenesis, while later activation of the pathway antagonizes cardiac differentiation. CONCLUSIONS/SIGNIFICANCE We have described an assay for investigating the mechanisms of cardiac induction by anterior endoderm. The assay was used to provide evidence for a direct, early and transient requirement of FGF and Nodal pathways. In addition, we demonstrate that Wnt/beta-catenin pathway plays no direct role in vertebrate cardiac specification, but needs to be suppressed just prior to differentiation.
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Affiliation(s)
- Lee J. Samuel
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Branko V. Latinkić
- School of Biosciences, Cardiff University, Cardiff, United Kingdom
- * E-mail:
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Okabayashi K, Ohnuma K, Asashima M. Development of in vitro differentiation systems using vertebrate stem cells. Inflamm Regen 2009. [DOI: 10.2492/inflammregen.29.302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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