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Horakova L, Dalecka L, Zahradnicek O, Lochovska K, Lesot H, Peterkova R, Tucker AS, Hovorakova M. Eda controls the size of the enamel knot during incisor development. Front Physiol 2023; 13:1033130. [PMID: 36699680 PMCID: PMC9868551 DOI: 10.3389/fphys.2022.1033130] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 12/14/2022] [Indexed: 01/11/2023] Open
Abstract
Ectodysplasin (Eda) plays important roles in both shaping the developing tooth and establishing the number of teeth within the tooth row. Sonic hedgehog (Shh) has been shown to act downstream of Eda and is involved in the initiation of tooth development. Eda-/- mice possess hypoplastic and hypomineralized incisors and show changes in tooth number in the molar region. In the present study we used 3D reconstruction combined with expression analysis, cell lineage tracing experiments, and western blot analysis in order to investigate the formation of the incisor germs in Eda-/- mice. We show that a lack of functional Eda protein during early stages of incisor tooth germ development had minimal impact on development of the early expression of Shh in the incisor, a region proposed to mark formation of a rudimental incisor placode and act as an initiating signalling centre. In contrast, deficiency of Eda protein had a later impact on expression of Shh in the primary enamel knot of the functional tooth. Eda-/- mice had a smaller region where Shh was expressed, and a reduced contribution from Shh descendant cells. The reduction in the enamel knot led to the formation of an abnormal enamel organ creating a hypoplastic functional incisor. Eda therefore appears to influence the spatial formation of the successional signalling centres during odontogenesis.
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Affiliation(s)
- Lucie Horakova
- Institute of Histology and Embryology, 1st Faculty of Medicine, Charles University, Prague, Czechia,Department of Cell Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Linda Dalecka
- Institute of Histology and Embryology, 1st Faculty of Medicine, Charles University, Prague, Czechia,Department of Cell Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Oldrich Zahradnicek
- Department of Radiation Dosimetry, Nuclear Physics Institute, Czech Academy of Sciences, Prague, Czechia
| | - Katerina Lochovska
- First Department of Medicine—Department of Hematology First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czechia
| | - Herve Lesot
- Laboratory of Odontogenesis and Osteogenesis, Institute of Animal Physiology and Genetics, Academy of Sciences, Brno, Czechia
| | - Renata Peterkova
- Department of Histology and Embryology, 3rd Faculty of Medicine, Charles University, Prague, Czechia
| | - Abigail S. Tucker
- Institute of Histology and Embryology, 1st Faculty of Medicine, Charles University, Prague, Czechia,Department of Craniofacial and Regenerative Biology, King´s College London, Guys Hospital, London, United Kingdom
| | - Maria Hovorakova
- Institute of Histology and Embryology, 1st Faculty of Medicine, Charles University, Prague, Czechia,*Correspondence: Maria Hovorakova,
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2
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Qiu T, Tucker AS. Mechanisms driving vestibular lamina formation and opening in the mouse. J Anat 2022; 242:224-234. [PMID: 36181694 PMCID: PMC9877475 DOI: 10.1111/joa.13771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 09/08/2022] [Accepted: 09/13/2022] [Indexed: 02/01/2023] Open
Abstract
The vestibular lamina (VL) forms as an epithelial outgrowth parallel to the dental lamina (DL) in the oral cavity. During late development, it opens to create a furrow that divides the dental tissue from the cheeks and lips and is known as the vestibule. Defects in this process lead to failure in the separation of the teeth from the lips and cheeks, including the presence of multiple frenula. In this paper, the development of the VL is followed in the mouse, from epithelial placode in the embryo to postnatal opening and vestibule formation. During early outgrowth, differential proliferation controls the curvature of the VL as it extends under the forming incisors. Apoptosis plays a role in thinning the deepest part of the lamina, while terminal differentiation of the epithelium, highlighted by the expression of loricrin and flattening of the nuclei, predates the division of the VL into two to create the vestibule. Development in the mouse is compared to the human VL, with respect to the relationship of the VL to the DL, VL morphology and mechanisms of opening. Overall, this paper provides insight into an understudied part of the oral anatomy, shedding light on how defects could form in this region.
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Affiliation(s)
- Tengyang Qiu
- Centre for Craniofacial and Regenerative Biology, Faculty of Dentistry, Oral and Craniofacial SciencesKing's College LondonLondonUK
| | - Abigail S. Tucker
- Centre for Craniofacial and Regenerative Biology, Faculty of Dentistry, Oral and Craniofacial SciencesKing's College LondonLondonUK
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3
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Hermans F, Hemeryck L, Lambrichts I, Bronckaers A, Vankelecom H. Intertwined Signaling Pathways Governing Tooth Development: A Give-and-Take Between Canonical Wnt and Shh. Front Cell Dev Biol 2021; 9:758203. [PMID: 34778267 PMCID: PMC8586510 DOI: 10.3389/fcell.2021.758203] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 10/11/2021] [Indexed: 11/13/2022] Open
Abstract
Teeth play essential roles in life. Their development relies on reciprocal interactions between the ectoderm-derived dental epithelium and the underlying neural crest-originated mesenchyme. This odontogenic process serves as a prototype model for the development of ectodermal appendages. In the mouse, developing teeth go through distinct morphological phases that are tightly controlled by epithelial signaling centers. Crucial molecular regulators of odontogenesis include the evolutionarily conserved Wnt, BMP, FGF and sonic hedgehog (Shh) pathways. These signaling modules do not act on their own, but are closely intertwined during tooth development, thereby outlining the path to be taken by specific cell populations including the resident dental stem cells. Recently, pivotal Wnt-Shh interaction and feedback loops have been uncovered during odontogenesis, showing conservation in other developing ectodermal appendages. This review provides an integrated overview of the interplay between canonical Wnt and Shh throughout mouse tooth formation stages, extending from the initiation of dental placode to the fully formed adult tooth.
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Affiliation(s)
- Florian Hermans
- Laboratory of Tissue Plasticity in Health and Disease, Cluster of Stem Cell and Developmental Biology, Department of Development and Regeneration, Leuven Stem Cell Institute, KU Leuven (University of Leuven), Leuven, Belgium.,Biomedical Research Institute (BIOMED), Department of Cardio and Organ Systems, UHasselt-Hasselt University, Diepenbeek, Belgium
| | - Lara Hemeryck
- Laboratory of Tissue Plasticity in Health and Disease, Cluster of Stem Cell and Developmental Biology, Department of Development and Regeneration, Leuven Stem Cell Institute, KU Leuven (University of Leuven), Leuven, Belgium
| | - Ivo Lambrichts
- Biomedical Research Institute (BIOMED), Department of Cardio and Organ Systems, UHasselt-Hasselt University, Diepenbeek, Belgium
| | - Annelies Bronckaers
- Biomedical Research Institute (BIOMED), Department of Cardio and Organ Systems, UHasselt-Hasselt University, Diepenbeek, Belgium
| | - Hugo Vankelecom
- Laboratory of Tissue Plasticity in Health and Disease, Cluster of Stem Cell and Developmental Biology, Department of Development and Regeneration, Leuven Stem Cell Institute, KU Leuven (University of Leuven), Leuven, Belgium
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4
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Mogollón I, Moustakas-Verho JE, Niittykoski M, Ahtiainen L. The initiation knot is a signaling center required for molar tooth development. Development 2021; 148:261701. [PMID: 33914869 PMCID: PMC8126415 DOI: 10.1242/dev.194597] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 03/28/2021] [Indexed: 12/03/2022]
Abstract
Signaling centers, or organizers, regulate many aspects of embryonic morphogenesis. In the mammalian molar tooth, reiterative signaling in specialized centers called enamel knots (EKs) determines tooth patterning. Preceding the primary EK, transient epithelial thickening appears, the significance of which remains debated. Using tissue confocal fluorescence imaging with laser ablation experiments, we show that this transient thickening is an earlier signaling center, the molar initiation knot (IK), that is required for the progression of tooth development. IK cell dynamics demonstrate the hallmarks of a signaling center: cell cycle exit, condensation and eventual silencing through apoptosis. IK initiation and maturation are defined by the juxtaposition of cells with high Wnt activity to Shh-expressing non-proliferating cells, the combination of which drives the growth of the tooth bud, leading to the formation of the primary EK as an independent cell cluster. Overall, the whole development of the tooth, from initiation to patterning, is driven by the iterative use of signaling centers. Summary: During tooth morphogenesis, transient thickening of the epithelium in the diastema anterior to the first developing molar is an early signaling center, the molar initiation knot (IK), which is required for the progression of mammalian molar tooth development.
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Affiliation(s)
- Isabel Mogollón
- Cell and Tissue Dynamics Research Program, Institute of Biotechnology, University of Helsinki, 00014, Finland
| | - Jacqueline E Moustakas-Verho
- Cell and Tissue Dynamics Research Program, Institute of Biotechnology, University of Helsinki, 00014, Finland.,Organismal & Evolutionary Biology Research Program, University of Helsinki, 00014, Finland
| | - Minna Niittykoski
- Cell and Tissue Dynamics Research Program, Institute of Biotechnology, University of Helsinki, 00014, Finland
| | - Laura Ahtiainen
- Cell and Tissue Dynamics Research Program, Institute of Biotechnology, University of Helsinki, 00014, Finland
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5
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Mogollón I, Ahtiainen L. Live Tissue Imaging Sheds Light on Cell Level Events During Ectodermal Organ Development. Front Physiol 2020; 11:818. [PMID: 32765297 PMCID: PMC7378809 DOI: 10.3389/fphys.2020.00818] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 06/18/2020] [Indexed: 12/14/2022] Open
Abstract
Embryonic development of ectodermal organs involves a very dynamic range of cellular events and, therefore, requires advanced techniques to visualize them. Ectodermal organogenesis proceeds in well-defined sequential stages mediated by tissue interactions. Different ectodermal organs feature shared morphological characteristics, which are regulated by conserved and reiterative signaling pathways. A wealth of genetic information on the expression patterns and interactions of specific signaling pathways has accumulated over the years. However, the conventional developmental biology methods have mainly relied on two-dimensional tissue histological analyses at fixed time points limiting the possibilities to follow the processes in real time on a single cell resolution. This has complicated the interpretation of cause and effect relationships and mechanisms of the successive events. Whole-mount tissue live imaging approaches are now revealing how reshaping of the epithelial sheet for the initial placodal thickening, budding morphogenesis and beyond, involve coordinated four dimensional changes in cell shapes, well-orchestrated cell movements and specific cell proliferation and apoptosis patterns. It is becoming evident that the interpretation of the reiterative morphogenic signals takes place dynamically at the cellular level. Depending on the context, location, and timing they drive different cell fate choices and cellular interactions regulating a pattern of behaviors that ultimately defines organ shapes and sizes. Here we review how new tissue models, advances in 3D and live tissue imaging techniques have brought new understanding on the cell level behaviors that contribute to the highly dynamic stages of morphogenesis in teeth, hair and related ectodermal organs during development, and in dysplasia contexts.
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Affiliation(s)
- Isabel Mogollón
- Cell and Tissue Dynamics Research Program, Institute of Biotechnology/Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Laura Ahtiainen
- Cell and Tissue Dynamics Research Program, Institute of Biotechnology/Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
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6
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Hosoya A, Shalehin N, Takebe H, Shimo T, Irie K. Sonic Hedgehog Signaling and Tooth Development. Int J Mol Sci 2020; 21:ijms21051587. [PMID: 32111038 PMCID: PMC7084732 DOI: 10.3390/ijms21051587] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 02/18/2020] [Accepted: 02/19/2020] [Indexed: 12/11/2022] Open
Abstract
Sonic hedgehog (Shh) is a secreted protein with important roles in mammalian embryogenesis. During tooth development, Shh is primarily expressed in the dental epithelium, from initiation to the root formation stages. A number of studies have analyzed the function of Shh signaling at different stages of tooth development and have revealed that Shh signaling regulates the formation of various tooth components, including enamel, dentin, cementum, and other soft tissues. In addition, dental mesenchymal cells positive for Gli1, a downstream transcription factor of Shh signaling, have been found to have stem cell properties, including multipotency and the ability to self-renew. Indeed, Gli1-positive cells in mature teeth appear to contribute to the regeneration of dental pulp and periodontal tissues. In this review, we provide an overview of recent advances related to the role of Shh signaling in tooth development, as well as the contribution of this pathway to tooth homeostasis and regeneration.
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Affiliation(s)
- Akihiro Hosoya
- Division of Histology, Department of Oral Growth and Development, School of Dentistry, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido 061-0293, Japan; (N.S.); (H.T.); (K.I.)
- Correspondence: ; Tel.: +81-133-23-1938; Fax: +81-133-23-1236
| | - Nazmus Shalehin
- Division of Histology, Department of Oral Growth and Development, School of Dentistry, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido 061-0293, Japan; (N.S.); (H.T.); (K.I.)
| | - Hiroaki Takebe
- Division of Histology, Department of Oral Growth and Development, School of Dentistry, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido 061-0293, Japan; (N.S.); (H.T.); (K.I.)
| | - Tsuyoshi Shimo
- Division of Reconstructive Surgery for Oral and Maxillofacial Region, Department of Human Biology and Pathophysiology, School of Dentistry, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido 061-0293, Japan;
| | - Kazuharu Irie
- Division of Histology, Department of Oral Growth and Development, School of Dentistry, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido 061-0293, Japan; (N.S.); (H.T.); (K.I.)
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7
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Sharir A, Klein OD. Watching a deep dive: Live imaging provides lessons about tooth invagination. J Cell Biol 2017; 214:645-7. [PMID: 27621361 PMCID: PMC5021101 DOI: 10.1083/jcb.201608088] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 08/25/2016] [Indexed: 11/22/2022] Open
Abstract
Invagination of epithelium into the surrounding mesenchyme is a critical step that marks the developmental onset of many ectodermal organs. In this issue, Ahtiainen et al. (2016. J. Cell. Biol. http://dx.doi.org/10.1083/jcb.201512074) use the mouse incisor as a model to advance our understanding of the cellular mechanisms underlying ectodermal organ morphogenesis.
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Affiliation(s)
- Amnon Sharir
- Department of Orofacial Sciences, University of California, San Francisco, San Francisco, CA 94143 Program in Craniofacial Biology, University of California, San Francisco, San Francisco, CA 94143
| | - Ophir D Klein
- Department of Orofacial Sciences, University of California, San Francisco, San Francisco, CA 94143 Program in Craniofacial Biology, University of California, San Francisco, San Francisco, CA 94143 Department of Pediatrics and Institute for Human Genetics, University of California, San Francisco, San Francisco, CA 94143
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8
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Du W, Hu JKH, Du W, Klein OD. Lineage tracing of epithelial cells in developing teeth reveals two strategies for building signaling centers. J Biol Chem 2017; 292:15062-15069. [PMID: 28733464 DOI: 10.1074/jbc.m117.785923] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 07/21/2017] [Indexed: 02/05/2023] Open
Abstract
An important event in organogenesis is the formation of signaling centers, which are clusters of growth factor-secreting cells. In the case of tooth development, sequentially formed signaling centers known as the initiation knot (IK) and the enamel knot (EK) regulate morphogenesis. However, despite the importance of signaling centers, their origin, as well as the fate of the cells composing them, remain open questions. Here, using lineage tracing of distinct epithelial populations, we found that the EK of the mouse incisor is derived de novo from a group of SRY-box 2 (Sox2)-expressing cells in the posterior half of the tooth germ. Specifically, EK progenitors are located in the posterior ventral basal layer, as demonstrated by DiI labeling of cells. Lineage tracing the formed EK with ShhCreER , which encodes an inducible Cre recombinase under the control of the Sonic hedgehog promoter, at subsequent developmental stages showed that, once formed, some EK cells in the incisor give rise to differentiated cells, whereas in the molar, EK cells give rise to the buccal secondary EK. This work thus establishes the developmental origin as well as the fate of the EK and reveals two strategies for the emergence of serially formed signaling centers: one through de novo establishment and the other by incorporation of progeny from previously formed signaling centers.
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Affiliation(s)
- Wei Du
- From the State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, China and.,the Departments of Orofacial Sciences and Program in Craniofacial Biology and
| | | | - Wen Du
- From the State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, China and.,the Departments of Orofacial Sciences and Program in Craniofacial Biology and
| | - Ophir D Klein
- the Departments of Orofacial Sciences and Program in Craniofacial Biology and .,Pediatrics and Institute for Human Genetics, University of California, San Francisco, San Francisco, California 94143
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9
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Ahtiainen L, Uski I, Thesleff I, Mikkola ML. Early epithelial signaling center governs tooth budding morphogenesis. J Cell Biol 2017; 214:753-67. [PMID: 27621364 PMCID: PMC5021093 DOI: 10.1083/jcb.201512074] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 08/17/2016] [Indexed: 12/22/2022] Open
Abstract
During organogenesis, cell fate specification and patterning are regulated by signaling centers, specialized clusters of morphogen-expressing cells. In many organs, initiation of development is marked by bud formation, but the cellular mechanisms involved are ill defined. Here, we use the mouse incisor tooth as a model to study budding morphogenesis. We show that a group of nonproliferative epithelial cells emerges in the early tooth primordium and identify these cells as a signaling center. Confocal live imaging of tissue explants revealed that although these cells reorganize dynamically, they do not reenter the cell cycle or contribute to the growing tooth bud. Instead, budding is driven by proliferation of the neighboring cells. We demonstrate that the activity of the ectodysplasin/Edar/nuclear factor κB pathway is restricted to the signaling center, and its inactivation leads to fewer quiescent cells and a smaller bud. These data functionally link the signaling center size to organ size and imply that the early signaling center is a prerequisite for budding morphogenesis.
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Affiliation(s)
- Laura Ahtiainen
- Developmental Biology Program, Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Isa Uski
- Developmental Biology Program, Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Irma Thesleff
- Developmental Biology Program, Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Marja L Mikkola
- Developmental Biology Program, Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
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10
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Kim R, Green JBA, Klein OD. From snapshots to movies: Understanding early tooth development in four dimensions. Dev Dyn 2017; 246:442-450. [PMID: 28324646 DOI: 10.1002/dvdy.24501] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Revised: 03/03/2017] [Accepted: 03/07/2016] [Indexed: 12/12/2022] Open
Abstract
The developing tooth offers a model for the study of ectodermal appendage organogenesis. The signaling networks that regulate tooth development have been intensively investigated, but how cell biological responses to signaling pathways regulate dental morphogenesis remains an open question. The increasing use of ex vivo imaging techniques has enabled live tracking of cell behaviors over time in high resolution. While recent studies using these techniques have improved our understanding of tooth morphogenesis, important gaps remain that require additional investigation. In addition, some discrepancies have arisen between recent studies, and resolving these will advance our knowledge of tooth development. Developmental Dynamics 246:442-450, 2016. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Rebecca Kim
- Program in Craniofacial Biology and Department of Orofacial Sciences, University of California San Francisco, San Francisco, California
| | - Jeremy B A Green
- Department of Craniofacial Development & Stem Cell Biology, King's College London, London, United Kingdom
| | - Ophir D Klein
- Program in Craniofacial Biology and Department of Orofacial Sciences, University of California San Francisco, San Francisco, California.,Institute for Human Genetics, University of California San Francisco, San Francisco, California.,Department of Pediatrics, University of California San Francisco, San Francisco, California
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11
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Hovorakova M, Lochovska K, Zahradnicek O, Domonkosova Tibenska K, Dornhoferova M, Horakova-Smrckova L, Bodorikova S. One Odontogenic Cell-Population Contributes to the Development of the Mouse Incisors and of the Oral Vestibule. PLoS One 2016; 11:e0162523. [PMID: 27611193 PMCID: PMC5017683 DOI: 10.1371/journal.pone.0162523] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 08/24/2016] [Indexed: 11/18/2022] Open
Abstract
The area of the oral vestibule is often a place where pathologies appear (e.g., peripheral odontomas). The origin of these pathologies is not fully understood. In the present study, we traced a cell population expressing Sonic hedgehog (Shh) from the beginning of tooth development using Cre-LoxP system in the lower jaw of wild-type (WT) mice. We focused on Shh expression in the area of the early appearing rudimentary incisor germs located anteriorly to the prospective incisors. The localization of the labelled cells in the incisor germs and also in the inner epithelial layer of the vestibular anlage showed that the first very early developmental events in the lower incisor area are common to the vestibulum oris and the prospective incisor primordia in mice. Scanning electron microscopic analysis of human historical tooth-like structures found in the vestibular area of jaws confirmed their relation to teeth and thus the capability of the vestibular tissue to form teeth. The location of labelled cells descendant of the early appearing Shh expression domain related to the rudimentary incisor anlage not only in the rudimentary and functional incisor germs but also in the externally located anlage of the oral vestibule documented the odontogenic potential of the vestibular epithelium. This potential can be awakened under pathological conditions and become a source of pathologies in the vestibular area.
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Affiliation(s)
- Maria Hovorakova
- Department of Teratology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, 14220, Prague 4, Czech Republic
- * E-mail:
| | - Katerina Lochovska
- Department of Teratology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, 14220, Prague 4, Czech Republic
- Department of Anthropology and Human Genetics, Faculty of Science, Charles University, Prague, Czech Republic
| | - Oldrich Zahradnicek
- Department of Teratology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, 14220, Prague 4, Czech Republic
| | - Kristina Domonkosova Tibenska
- Department of Anthropology, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovak Republic
| | - Michaela Dornhoferova
- Department of Anthropology, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovak Republic
| | - Lucie Horakova-Smrckova
- Department of Teratology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, 14220, Prague 4, Czech Republic
- Department of Cell Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Silvia Bodorikova
- Department of Anthropology, Faculty of Natural Sciences, Comenius University in Bratislava, Bratislava, Slovak Republic
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12
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Li L, Tang Q, Jung HS. The Grooved Rodent Incisor Recapitulates Rudimentary Teeth Characteristics of Ancestral Mammals. J Dent Res 2016; 95:923-30. [DOI: 10.1177/0022034516633153] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
It is known from the paleontology studies of eutherian mammals that incisor numbers were reduced during evolution. The evolutionary lost incisors may remain as vestigial structures at embryonic stages. The recapitulation of the incisor patterns among mammalian species will potentially uncover the mechanisms underlying the phenotypic transition of incisors during evolution. Here, we showed that a minute tooth formed in the presumptive groove region of the gerbil upper incisor at the early developmental stages, during which multiple epithelial swellings and Shh transcription domains spatiotemporally appeared in the dental epithelium, suggests the existence of vestigial dental primordia. Interestingly, when we trimmed the surrounding mesenchyme from incisor tooth germs at or before the bud stage prior to ex vivo culture, the explants developed different incisor phenotypes ranging from triplicated incisors, duplicated incisors, to Lagomorpha-like incisors, corresponding to the incisor patterns in the eutherian mammals. These results imply that the phenotypic transition of incisors during evolution, as well as the achievement of ultimate incisors in adults, arose from differential integrations of primordia. However, when the incisor tooth germ was trimmed at the cap stage, a grooved incisor developed similar to the normal condition. Furthermore, the incisor tooth germ developed a small but smooth incisor after the additional removal of the minute tooth and a lateral rudiment. These results suggest that multiple dental primordia integrated before the cap stage, with the labial primordia contributing to the labial face of the functional incisor. The minute tooth that occupied the boundary of the 2 labial primordia might be implicated in the groove formation. This study sheds light on how rudiments incorporate into functional organs and aids the understanding of incisor evolution.
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Affiliation(s)
- L. Li
- Division in Anatomy and Developmental Biology, Department of Oral Biology, Oral Science Research Center, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, Korea
| | - Q. Tang
- Division in Anatomy and Developmental Biology, Department of Oral Biology, Oral Science Research Center, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, Korea
| | - H.-S. Jung
- Division in Anatomy and Developmental Biology, Department of Oral Biology, Oral Science Research Center, BK21 PLUS Project, Yonsei University College of Dentistry, Seoul, Korea
- Oral Biosciences, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR
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13
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Rasch LJ, Martin KJ, Cooper RL, Metscher BD, Underwood CJ, Fraser GJ. An ancient dental gene set governs development and continuous regeneration of teeth in sharks. Dev Biol 2016; 415:347-370. [PMID: 26845577 DOI: 10.1016/j.ydbio.2016.01.038] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 01/11/2016] [Accepted: 01/29/2016] [Indexed: 12/20/2022]
Abstract
The evolution of oral teeth is considered a major contributor to the overall success of jawed vertebrates. This is especially apparent in cartilaginous fishes including sharks and rays, which develop elaborate arrays of highly specialized teeth, organized in rows and retain the capacity for life-long regeneration. Perpetual regeneration of oral teeth has been either lost or highly reduced in many other lineages including important developmental model species, so cartilaginous fishes are uniquely suited for deep comparative analyses of tooth development and regeneration. Additionally, sharks and rays can offer crucial insights into the characters of the dentition in the ancestor of all jawed vertebrates. Despite this, tooth development and regeneration in chondrichthyans is poorly understood and remains virtually uncharacterized from a developmental genetic standpoint. Using the emerging chondrichthyan model, the catshark (Scyliorhinus spp.), we characterized the expression of genes homologous to those known to be expressed during stages of early dental competence, tooth initiation, morphogenesis, and regeneration in bony vertebrates. We have found that expression patterns of several genes from Hh, Wnt/β-catenin, Bmp and Fgf signalling pathways indicate deep conservation over ~450 million years of tooth development and regeneration. We describe how these genes participate in the initial emergence of the shark dentition and how they are redeployed during regeneration of successive tooth generations. We suggest that at the dawn of the vertebrate lineage, teeth (i) were most likely continuously regenerative structures, and (ii) utilised a core set of genes from members of key developmental signalling pathways that were instrumental in creating a dental legacy redeployed throughout vertebrate evolution. These data lay the foundation for further experimental investigations utilizing the unique regenerative capacity of chondrichthyan models to answer evolutionary, developmental, and regenerative biological questions that are impossible to explore in classical models.
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Affiliation(s)
- Liam J Rasch
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Kyle J Martin
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Rory L Cooper
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Brian D Metscher
- Department of Theoretical Biology, University of Vienna, Vienna A-1090, Austria
| | - Charlie J Underwood
- Department of Earth and Planetary Sciences, Birkbeck, University of London, London WC1E 7HX, United Kingdom
| | - Gareth J Fraser
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom.
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14
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15
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Kiso H, Takahashi K, Saito K, Togo Y, Tsukamoto H, Huang B, Sugai M, Shimizu A, Tabata Y, Economides AN, Slavkin HC, Bessho K. Interactions between BMP-7 and USAG-1 (uterine sensitization-associated gene-1) regulate supernumerary organ formations. PLoS One 2014; 9:e96938. [PMID: 24816837 PMCID: PMC4016158 DOI: 10.1371/journal.pone.0096938] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 04/13/2014] [Indexed: 11/26/2022] Open
Abstract
Bone morphogenetic proteins (BMPs) are highly conserved signaling molecules that are part of the transforming growth factor (TGF)-beta superfamily, and function in the patterning and morphogenesis of many organs including development of the dentition. The functions of the BMPs are controlled by certain classes of molecules that are recognized as BMP antagonists that inhibit BMP binding to their cognate receptors. In this study we tested the hypothesis that USAG-1 (uterine sensitization-associated gene-1) suppresses deciduous incisors by inhibition of BMP-7 function. We learned that USAG-1 and BMP-7 were expressed within odontogenic epithelium as well as mesenchyme during the late bud and early cap stages of tooth development. USAG-1 is a BMP antagonist, and also modulates Wnt signaling. USAG-1 abrogation rescued apoptotic elimination of odontogenic mesenchymal cells. BMP signaling in the rudimentary maxillary incisor, assessed by expressions of Msx1 and Dlx2 and the phosphorylation of Smad protein, was significantly enhanced. Using explant culture and subsequent subrenal capsule transplantation of E15 USAG-1 mutant maxillary incisor tooth primordia supplemented with BMP-7 demonstrated in USAG-1+/- as well as USAG-1-/- rescue and supernumerary tooth development. Based upon these results, we conclude that USAG-1 functions as an antagonist of BMP-7 in this model system. These results further suggest that the phenotypes of USAG-1 and BMP-7 mutant mice reported provide opportunities for regenerative medicine and dentistry.
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Affiliation(s)
- Honoka Kiso
- Department of Oral and Maxillofacial Surgery, Graduate School of Medicine, Kyoto University, Shogoin-Kawahara-cho, Sakyo-ku, Kyoto, Japan
| | - Katsu Takahashi
- Department of Oral and Maxillofacial Surgery, Graduate School of Medicine, Kyoto University, Shogoin-Kawahara-cho, Sakyo-ku, Kyoto, Japan
| | - Kazuyuki Saito
- Department of Oral and Maxillofacial Surgery, Graduate School of Medicine, Kyoto University, Shogoin-Kawahara-cho, Sakyo-ku, Kyoto, Japan
| | - Yumiko Togo
- Department of Oral and Maxillofacial Surgery, Graduate School of Medicine, Kyoto University, Shogoin-Kawahara-cho, Sakyo-ku, Kyoto, Japan
| | - Hiroko Tsukamoto
- Department of Oral and Maxillofacial Surgery, Graduate School of Medicine, Kyoto University, Shogoin-Kawahara-cho, Sakyo-ku, Kyoto, Japan
| | - Boyen Huang
- Department of Paediatric Dentistry, School of Medicine and Dentistry, James Cook University, Cairns, Australia
| | - Manabu Sugai
- Translational Research Center, Kyoto University Hospital, Shogoin-Kawahara-cho, Sakyo-ku, Kyoto, Japan
| | - Akira Shimizu
- Laboratory of Host Defense, World Premier International Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan
| | - Yasuhiko Tabata
- Department of Biomaterials, Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan
| | - Aris N. Economides
- Regeneron Pharmaceuticals, Tarrytown, New York, United States of America
| | - Harold C. Slavkin
- Center for Craniofacial Molecular Biology, Division of Biomedical Sciences, Ostrow School of Dentistry, University of Southern California, Los Angeles, California, United States of America
| | - Kazuhisa Bessho
- Department of Oral and Maxillofacial Surgery, Graduate School of Medicine, Kyoto University, Shogoin-Kawahara-cho, Sakyo-ku, Kyoto, Japan
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16
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Lesot H, Hovorakova M, Peterka M, Peterkova R. Three-dimensional analysis of molar development in the mouse from the cap to bell stage. Aust Dent J 2014; 59 Suppl 1:81-100. [DOI: 10.1111/adj.12132] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- H Lesot
- Institut National de la Santé et de la Recherche Médicale; UMR 1109, Team ‘Osteoarticular and Dental Regenerative NanoMedicine’; Strasbourg France
- Université de Strasbourg; Faculté de Chirurgie Dentaire; Strasbourg France
| | - M Hovorakova
- Department of Teratology; Institute of Experimental Medicine, Academy of Sciences of the Czech Republic; Prague Czech Republic
| | - M Peterka
- Department of Teratology; Institute of Experimental Medicine, Academy of Sciences of the Czech Republic; Prague Czech Republic
| | - R Peterkova
- Department of Teratology; Institute of Experimental Medicine, Academy of Sciences of the Czech Republic; Prague Czech Republic
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17
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Peterkova R, Hovorakova M, Peterka M, Lesot H. Three-dimensional analysis of the early development of the dentition. Aust Dent J 2014; 59 Suppl 1:55-80. [PMID: 24495023 PMCID: PMC4199315 DOI: 10.1111/adj.12130] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Tooth development has attracted the attention of researchers since the 19th century. It became obvious even then that morphogenesis could not fully be appreciated from two-dimensional histological sections. Therefore, methods of three-dimensional (3D) reconstructions were employed to visualize the surface morphology of developing structures and to help appreciate the complexity of early tooth morphogenesis. The present review surveys the data provided by computer-aided 3D analyses to update classical knowledge of early odontogenesis in the laboratory mouse and in humans. 3D reconstructions have demonstrated that odontogenesis in the early stages is a complex process which also includes the development of rudimentary odontogenic structures with different fates. Their developmental, evolutionary, and pathological aspects are discussed. The combination of in situ hybridization and 3D reconstruction have demonstrated the temporo-spatial dynamics of the signalling centres that reflect transient existence of rudimentary tooth primordia at loci where teeth were present in ancestors. The rudiments can rescue their suppressed development and revitalize, and then their subsequent autonomous development can give rise to oral pathologies. This shows that tooth-forming potential in mammals can be greater than that observed from their functional dentitions. From this perspective, the mouse rudimentary tooth primordia represent a natural model to test possibilities of tooth regeneration.
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Affiliation(s)
- R Peterkova
- Department of Teratology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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18
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Linhares ND, Svartman M, Salgado MI, Rodrigues TC, da Costa SS, Rosenberg C, Valadares ER. Dental developmental abnormalities in a patient with subtelomeric 7q36 deletion syndrome may confirm a novel role for the SHH gene. Meta Gene 2013; 2:16-24. [PMID: 25606385 PMCID: PMC4287791 DOI: 10.1016/j.mgene.2013.10.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 10/03/2013] [Accepted: 10/09/2013] [Indexed: 11/18/2022] Open
Abstract
Studies in mice demonstrated that the Shh gene is crucial for normal development of both incisors and molars, causing a severe retardation in tooth growth, which leads to abnormal placement of the tooth in the jaw and disrupted tooth morphogenesis. In humans the SHH gene is located on chromosome 7q36. Defects in its protein or signaling pathway may cause holoprosencephaly spectrum, a disorder in which the developing forebrain fails to correctly separate into right and left hemispheres and that can be manifested in microforms such as single maxillary central incisor. A novel role for this gene in the developing human primary dentition was recently demonstrated. We report a 12-year old boy with a de novo 7q36.1-qter deletion characterized by high-resolution karyotyping, oligonucleotide aCGH and FISH. His phenotype includes intellectual disability, non-verbal communication, hypospadia, partial sacral agenesis and absence of coccyx, which are distinctive features of the syndrome and mainly correlated with the MNX1, HTR5A and EN2 genes. No microforms of holoprosencephaly spectrum were observed; but the patient had diastema and dental developmental abnormalities, such as conical, asymmetric and tapered inferior central incisors. The dental anomalies are reported herein for the first time in subtelomeric 7q36 deletion syndrome and may confirm clinically a novel role for the SHH gene in dental development. We report a boy with 7q-, dental developmental abnormalities and sacral agenesis. We propose novel roles for SHH gene related to dental developmental abnormalities. The MNX1 gene may be associated with caudal deficiency sequence in 7q- patients. HTR5A and EN2 may be related to abnormal brain development in 7q- patients.
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Affiliation(s)
- Natália D. Linhares
- Setor de Citogenética/Laboratório Central do Hospital das Clínicas da Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
- Corresponding author at: Universidade Federal de Minas Gerais, Faculdade de Medicina, Av. Alfredo Balena, 145-1º Andar, Bairro Santa Efigênia, 30130-100 Belo Horizonte, MG, Brazil. Tel.: + 55 31 34099906.
| | - Marta Svartman
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Brazil
| | - Mauro Ivan Salgado
- Departamento de Cirurgia, Faculdade de Medicina, Universidade Federal de Minas Gerais, Brazil
| | - Tatiane C. Rodrigues
- Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Silvia S. da Costa
- Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Carla Rosenberg
- Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Eugênia R. Valadares
- Departamento de Propedêutica Complementar, Faculdade de Medicina, Universidade Federal de Minas Gerais, Brazil
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19
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Klein OD, Oberoi S, Huysseune A, Hovorakova M, Peterka M, Peterkova R. Developmental disorders of the dentition: an update. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2013; 163C:318-32. [PMID: 24124058 DOI: 10.1002/ajmg.c.31382] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Dental anomalies are common congenital malformations that can occur either as isolated findings or as part of a syndrome. This review focuses on genetic causes of abnormal tooth development and the implications of these abnormalities for clinical care. As an introduction, we describe general insights into the genetics of tooth development obtained from mouse and zebrafish models. This is followed by a discussion of isolated as well as syndromic tooth agenesis, including Van der Woude syndrome (VWS), ectodermal dysplasias (EDs), oral-facial-digital (OFD) syndrome type I, Rieger syndrome, holoprosencephaly, and tooth anomalies associated with cleft lip and palate. Next, we review delayed formation and eruption of teeth, as well as abnormalities in tooth size, shape, and form. Finally, isolated and syndromic causes of supernumerary teeth are considered, including cleidocranial dysplasia and Gardner syndrome.
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20
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Hovorakova M, Smrckova L, Lesot H, Lochovska K, Peterka M, Peterkova R. Sequential Shh expression in the development of the mouse upper functional incisor. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2013; 320:455-64. [PMID: 23913503 DOI: 10.1002/jez.b.22522] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 05/21/2013] [Accepted: 06/03/2013] [Indexed: 11/06/2022]
Abstract
The mouse incisor is a frequently used model in studies of the molecular control of organ development. The appropriate interpretation of data on normogenesis is essential for understanding the data obtained in mutant mice. For this reason, we performed a very detailed investigation of the development of the upper incisor in wild-type mice from embryonic day (ED) 11.5 till 14.5. A combination of histology, whole mount in situ hybridization, computer-aided three-dimensional reconstructions, and fluorescent microscopy, has been used. Several sonic hedgehog (Shh) expression domains have been detected in the upper incisor region during early prenatal development. At ED11.5-13.5, there was a single Shh positive domain present in the anterior part of left or right upper jaw arches, corresponding to the epithelial thickening. More posteriorly, a new Shh expression domain appeared in the incisor bud in the developmentally more advanced ED13.5 embryos. At ED14.5, only this posterior Shh expression in the incisor germ remained detectable. This study brings new insights into the early development of the upper incisor in mice and completes the data on normal mouse incisor development. The temporal-spatial pattern of Shh expression reflects the development of two tooth generations, being detectable in two successive, antero-posteriorly located areas in the prospective incisor region in the upper jaw. The first, anterior and superficial Shh expression domain reflects the rudimentary tooth development suppressed during evolution. Only the subsequent, posterior and deeper Shh expression region, appearing at ED13.5, correlates with the prospective upper functional incisor in wild-type mice.
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Affiliation(s)
- Maria Hovorakova
- Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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21
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Lagronova-Churava S, Spoutil F, Vojtechova S, Lesot H, Peterka M, Klein OD, Peterkova R. The dynamics of supernumerary tooth development are differentially regulated by Sprouty genes. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2013; 320:307-20. [PMID: 23606267 DOI: 10.1002/jez.b.22502] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Revised: 02/28/2013] [Accepted: 03/01/2013] [Indexed: 11/10/2022]
Abstract
In mice, a toothless diastema separates the single incisor from the three molars in each dental quadrant. In the prospective diastema of the embryo, small rudimentary buds are found that are presumed to be rudiments of suppressed teeth. A supernumerary tooth occurs in the diastema of adult mice carrying mutations in either Spry2 or Spry4. In the case of Spry2 mutants, the origin of the supernumerary tooth involves the revitalization of a rudimentary tooth bud (called R2), whereas its origin in the Spry4 mutants is not known. In addition to R2, another rudimentary primordium (called MS) arises more anteriorly in the prospective diastema. We investigated the participation of both rudiments (MS and R2) in supernumerary tooth development in Spry2 and Spry4 mutants by comparing morphogenesis, proliferation, apoptosis, size and Shh expression in the dental epithelium of MS and R2 rudiments. Increased proliferation and decreased apoptosis were found in MS and R2 at embryonic day (ED) 12.5 and 13.5 in Spry2(-/-) embryos. Apoptosis was also decreased in both rudiments in Spry4(-/-) embryos, but the proliferation was lower (similar to WT mice), and supernumerary tooth development was accelerated, exhibiting a cap stage by ED13.5. Compared to Spry2(-/-) mice, a high number of Spry4(-/-) supernumerary tooth primordia degenerated after ED13.5, resulting in a low percentage of supernumerary teeth in adults. We propose that Sprouty genes were implicated during evolution in reduction of the cheek teeth in Muridae, and their deletion can reveal ancestral stages of murine dental evolution.
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22
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Nakatomi M, Hovorakova M, Gritli-Linde A, Blair H, MacArthur K, Peterka M, Lesot H, Peterkova R, Ruiz-Perez V, Goodship J, Peters H. Evc Regulates a Symmetrical Response to Shh Signaling in Molar Development. J Dent Res 2013; 92:222-8. [DOI: 10.1177/0022034512471826] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Tooth morphogenesis involves patterning through the activity of epithelial signaling centers that, among other molecules, secrete Sonic hedgehog (Shh). While it is known that Shh responding cells need intact primary cilia for signal transduction, the roles of individual cilia components for tooth morphogenesis are poorly understood. The clinical features of individuals with Ellis-van Creveld syndrome include various dental anomalies, and we show here that absence of the cilial protein Evc in mice causes various hypo- and hyperplasia defects during molar development. During first molar development, the response to Shh signaling is progressively lost in Evc-deficient embryos and, unexpectedly, the response consistently disappears in a buccal to lingual direction. The important role of Evc for establishing the buccal-lingual axis of the developing first molar is also supported by a displaced activity of the Wnt pathway in Evc mutants. The observed growth abnormalities eventually manifest in first molar microdontia, disruption of molar segmentation and symmetry, root fusions, and delayed differentiation. Analysis of our data indicates that both spatially and temporally disrupted activities of the Shh pathway are the primary cause for the variable dental anomalies seen in patients with Ellis-van Creveld syndrome or Weyers acrodental dysostosis.
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Affiliation(s)
- M. Nakatomi
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
- present address, Division of Anatomy and Cell Biology of the Hard Tissue, Department of Tissue Regeneration and Reconstruction, Niigata University Graduate School of Medical and Dental Sciences, 2-5274, Gakkocho-dori, Chuo-ku, Niigata, Japan
| | - M. Hovorakova
- Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Czech Republic
| | - A. Gritli-Linde
- Department of Oral Biochemistry, Sahlgrenska Academy at the University of Gothenburg, Sweden
| | - H.J. Blair
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - K. MacArthur
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - M. Peterka
- Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Czech Republic
| | - H. Lesot
- INSERM UMR 1109, Team “Osteoarticular and Dental Regenerative NanoMedicine,” and Dental School, University of Strasbourg, Strasbourg, 67085 France
| | - R. Peterkova
- Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Czech Republic
| | - V.L. Ruiz-Perez
- Instituto de Investigaciones Biomédicas de Madrid (CSIC-UAM), Spain
- CIBERER, Instituto de Salud Carlos III, Spain
| | - J.A. Goodship
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - H. Peters
- Institute of Genetic Medicine, Newcastle University, International Centre for Life, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
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Jheon AH, Seidel K, Biehs B, Klein OD. From molecules to mastication: the development and evolution of teeth. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2012; 2:165-82. [PMID: 24009032 DOI: 10.1002/wdev.63] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Teeth are unique to vertebrates and have played a central role in their evolution. The molecular pathways and morphogenetic processes involved in tooth development have been the focus of intense investigation over the past few decades, and the tooth is an important model system for many areas of research. Developmental biologists have exploited the clear distinction between the epithelium and the underlying mesenchyme during tooth development to elucidate reciprocal epithelial/mesenchymal interactions during organogenesis. The preservation of teeth in the fossil record makes these organs invaluable for the work of paleontologists, anthropologists, and evolutionary biologists. In addition, with the recent identification and characterization of dental stem cells, teeth have become of interest to the field of regenerative medicine. Here, we review the major research areas and studies in the development and evolution of teeth, including morphogenesis, genetics and signaling, evolution of tooth development, and dental stem cells.
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Affiliation(s)
- Andrew H Jheon
- Department of Orofacial Sciences and Program in Craniofacial and Mesenchymal Biology, University of California San Francisco, San Francisco, CA, USA
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24
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Charles C, Hovorakova M, Ahn Y, Lyons DB, Marangoni P, Churava S, Biehs B, Jheon A, Lesot H, Balooch G, Krumlauf R, Viriot L, Peterkova R, Klein OD. Regulation of tooth number by fine-tuning levels of receptor-tyrosine kinase signaling. Development 2011; 138:4063-73. [PMID: 21862563 DOI: 10.1242/dev.069195] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Much of our knowledge about mammalian evolution comes from examination of dental fossils, because the highly calcified enamel that covers teeth causes them to be among the best-preserved organs. As mammals entered new ecological niches, many changes in tooth number occurred, presumably as adaptations to new diets. For example, in contrast to humans, who have two incisors in each dental quadrant, rodents only have one incisor per quadrant. The rodent incisor, because of its unusual morphogenesis and remarkable stem cell-based continuous growth, presents a quandary for evolutionary biologists, as its origin in the fossil record is difficult to trace, and the genetic regulation of incisor number remains a largely open question. Here, we studied a series of mice carrying mutations in sprouty genes, the protein products of which are antagonists of receptor-tyrosine kinase signaling. In sprouty loss-of-function mutants, splitting of gene expression domains and reduced apoptosis was associated with subdivision of the incisor primordium and a multiplication of its stem cell-containing regions. Interestingly, changes in sprouty gene dosage led to a graded change in incisor number, with progressive decreases in sprouty dosage leading to increasing numbers of teeth. Moreover, the independent development of two incisors in mutants with large decreases in sprouty dosage mimicked the likely condition of rodent ancestors. Together, our findings indicate that altering genetic dosage of an antagonist can recapitulate ancestral dental characters, and that tooth number can be progressively regulated by changing levels of activity of a single signal transduction pathway.
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Affiliation(s)
- Cyril Charles
- Department of Orofacial Sciences and Program in Craniofacial and Mesenchymal Biology, University of California San Francisco, San Francisco, CA 94143, USA
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