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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: 4] [Impact Index Per Article: 4.0] [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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Boughner JC, Marchiori DF, Packota GV. Unexpected variation of human molar size patterns. J Hum Evol 2021; 161:103072. [PMID: 34628299 DOI: 10.1016/j.jhevol.2021.103072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 08/15/2021] [Accepted: 08/16/2021] [Indexed: 11/17/2022]
Abstract
A tenet of mammalian, including primate dental evolution, is the Inhibitory Cascade Model, where first molar (M1) size predicts in a linear cline the size and onset time of the second (M2) and third (M3) molars: a larger M1 portends a progressively smaller and later-developing M2 and M3. In contemporary modern Homo sapiens, later-developing M3s are less likely to erupt properly. The Inhibitory Cascade Model is also used to predict molar sizes of extinct taxa, including fossil Homo. The extent to which Inhibitory Cascade Model predictions hold in contemporary H. sapiens molars is unclear, including whether this tenet informs about molar initiation, development, and eruption. We tested these questions here. In our radiographic sample of 323 oral quadrants and molar rows from contemporary humans based on mesiodistal crown lengths, we observed the distribution of molar proportions with a central tendency around parity (M1 = M2 = M3) that parsed into 13 distinct molar size ratio patterns. These patterns presented at different frequencies (e.g., M1 > M2 > M3 in about one-third of cases) that reflected whether the molar row was located in the maxilla or mandible and included both linear (e.g., M1 < M2 < M3) and nonlinear molar size ratio progressions (e.g., M1 > M2 < M3). Up to four patterns were found in the same subject's mouth. Lastly, M1 size alone does not predict M3 size, developmental timing, or eruption; rather, M2 size is integral to predicting M3 size. Our study indicates that human molar size is genetically 'softwired' and sensitive to factors local to the human upper jaw vs. lower jaw. The lack of a single stereotypical molar size ratio for contemporary H. sapiens suggests that predictions of fossil H. sapiens molar sizes using the Inhibitory Cascade Model must be made with caution.
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Affiliation(s)
- Julia C Boughner
- Department of Anatomy, Physiology & Pharmacology, College of Medicine, University of Saskatchewan, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada.
| | - Denver F Marchiori
- Department of Anatomy, Physiology & Pharmacology, College of Medicine, University of Saskatchewan, 107 Wiggins Road, Saskatoon, Saskatchewan S7N 5E5, Canada.
| | - Garnet V Packota
- College of Dentistry, University of Saskatchewan, 105 Wiggins Road, Health Sciences Building, Saskatoon, SK, S7N 5E5, Canada
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3
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Moura E, Rotenberg IS, Pimpão CT. X-Linked Hypohidrotic Ectodermal Dysplasia-General Features and Dental Abnormalities in Affected Dogs Compared With Human Dental Abnormalities. Top Companion Anim Med 2019; 35:11-17. [PMID: 31122682 DOI: 10.1053/j.tcam.2019.03.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 03/06/2019] [Accepted: 03/06/2019] [Indexed: 11/11/2022]
Abstract
X-linked hypohidrotic ectodermal dysplasia (XLHED) is a genetic disorder characterized by abnormalities in ectodermal derivatives such as sweat glands, hair, and teeth. In animals, the highest number of cases has been reported in dogs, which show characteristic congenital alopecia and develop abnormalities in the shape and number of teeth. Although the clinical phenotype of the affected individuals is typical, this disorder remains almost unknown in veterinary clinical practice. With the aim of making it better known, we gathered in this review the main clinical and genetic aspects of XLHED, placing emphasis on dental abnormalities.
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Affiliation(s)
- Enio Moura
- Service of Medical Genetics, Course of Veterinary Medicine, School of Life Sciences, Pontifícia Universidade Católica do Paraná (PUCPR), Curitiba, PR, Brazil.
| | - Isabel S Rotenberg
- Course of Veterinary Medicine, Pontifícia Universidade Católica do Paraná (PUCPR), Curitiba, PR, Brazil
| | - Cláudia T Pimpão
- Department of Animal Science, School of Life Sciences, Pontifícia Universidade Católica do Paraná (PUCPR), Curitiba, PR, Brazil
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4
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Blackburn J, Kawasaki K, Porntaveetus T, Kawasaki M, Otsuka-Tanaka Y, Miake Y, Ota MS, Watanabe M, Hishinuma M, Nomoto T, Oommen S, Ghafoor S, Harada F, Nozawa-Inoue K, Maeda T, Peterková R, Lesot H, Inoue J, Akiyama T, Schmidt-Ullrich R, Liu B, Hu Y, Page A, Ramírez Á, Sharpe PT, Ohazama A. Excess NF-κB induces ectopic odontogenesis in embryonic incisor epithelium. J Dent Res 2014; 94:121-8. [PMID: 25376721 DOI: 10.1177/0022034514556707] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Nuclear factor kappa B (NF-κB) signaling plays critical roles in many physiological and pathological processes, including regulating organogenesis. Down-regulation of NF-κB signaling during development results in hypohidrotic ectodermal dysplasia. The roles of NF-κB signaling in tooth development, however, are not fully understood. We examined mice overexpressing IKKβ, an essential component of the NF-κB pathway, under keratin 5 promoter (K5-Ikkβ). K5-Ikkβ mice showed supernumerary incisors whose formation was accompanied by up-regulation of canonical Wnt signaling. Apoptosis that is normally observed in wild-type incisor epithelium was reduced in K5-Ikkβ mice. The supernumerary incisors in K5-Ikkβ mice were found to phenocopy extra incisors in mice with mutations of Wnt inhibitor, Wise. Excess NF-κB activity thus induces an ectopic odontogenesis program that is usually suppressed under physiological conditions.
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Affiliation(s)
- J Blackburn
- Craniofacial Development and Stem Cell Biology and Biomedical Research Centre, Kings College London, London, UK
| | - K Kawasaki
- Craniofacial Development and Stem Cell Biology and Biomedical Research Centre, Kings College London, London, UK Department of Pediatric Dentistry, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - T Porntaveetus
- Craniofacial Development and Stem Cell Biology and Biomedical Research Centre, Kings College London, London, UK Department of Physiology, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
| | - M Kawasaki
- Craniofacial Development and Stem Cell Biology and Biomedical Research Centre, Kings College London, London, UK Division of Bio-Prosthodontics, Department of Oral Health Science, Course for Oral Life Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Y Otsuka-Tanaka
- Craniofacial Development and Stem Cell Biology and Biomedical Research Centre, Kings College London, London, UK Department of Special Needs Dentistry, Nihon University School of Dentistry at Matsudo, Matsudo, Japan
| | - Y Miake
- Department of Ultrastructural Science, Tokyo Dental College, Chiyoda-ku, Tokyo, Japan
| | - M S Ota
- Laboratory of Food Biological Science, Department of Food and Nutrition, Japan Women's University, Bunkyō, Japan
| | - M Watanabe
- Division of Oral Anatomy, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - M Hishinuma
- Department of Special Needs Dentistry, Nihon University School of Dentistry at Matsudo, Matsudo, Japan
| | - T Nomoto
- Department of Special Needs Dentistry, Nihon University School of Dentistry at Matsudo, Matsudo, Japan
| | - S Oommen
- Craniofacial Development and Stem Cell Biology and Biomedical Research Centre, Kings College London, London, UK
| | - S Ghafoor
- Craniofacial Development and Stem Cell Biology and Biomedical Research Centre, Kings College London, London, UK
| | - F Harada
- Craniofacial Development and Stem Cell Biology and Biomedical Research Centre, Kings College London, London, UK
| | - K Nozawa-Inoue
- Craniofacial Development and Stem Cell Biology and Biomedical Research Centre, Kings College London, London, UK
| | - T Maeda
- Division of Oral Anatomy, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - R Peterková
- Department of Teratology, Institute of Experimental Medicine, Academy of Sciences CR, Prague, Czech Republic
| | - H Lesot
- INSERM UMR_S1109, Team "Osteoarticular and Dental Regenerative NanoMedicine," FMTS, Faculté de Médecine, Faculté de Chirurgie Dentaire, Université de Strasbourg, Strasbourg, France
| | - J Inoue
- Division of Cellular and Molecular Biology, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo, Japan
| | - T Akiyama
- Division of Cellular and Molecular Biology, Institute of Medical Science, University of Tokyo, Minato-ku, Tokyo, Japan
| | - R Schmidt-Ullrich
- Department of Signal Transduction in Tumor Cells, Max-Delbrück-Center for Molecular Medicine, Berlin, Germany
| | - B Liu
- Department of Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Smithville, TX, USA
| | - Y Hu
- Laboratory of Experimental Immunology, Inflammation and Tumorigenesis Section, National. Cancer Institute-Frederick, Frederick, MD, USA
| | - A Page
- Department of Epithelial Biomedicine, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Madrid, Spain
| | - Á Ramírez
- Department of Epithelial Biomedicine, Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Madrid, Spain
| | - P T Sharpe
- Craniofacial Development and Stem Cell Biology and Biomedical Research Centre, Kings College London, London, UK
| | - A Ohazama
- Craniofacial Development and Stem Cell Biology and Biomedical Research Centre, Kings College London, London, UK Division of Oral Anatomy, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
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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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6
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Laugel-Haushalter V, Paschaki M, Marangoni P, Pilgram C, Langer A, Kuntz T, Demassue J, Morkmued S, Choquet P, Constantinesco A, Bornert F, Schmittbuhl M, Pannetier S, Viriot L, Hanauer A, Dollé P, Bloch-Zupan A. RSK2 is a modulator of craniofacial development. PLoS One 2014; 9:e84343. [PMID: 24416220 PMCID: PMC3885557 DOI: 10.1371/journal.pone.0084343] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 11/21/2013] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND The RSK2 gene is responsible for Coffin-Lowry syndrome, an X-linked dominant genetic disorder causing mental retardation, skeletal growth delays, with craniofacial and digital abnormalities typically associated with this syndrome. Craniofacial and dental anomalies encountered in this rare disease have been poorly characterized. METHODOLOGY/PRINCIPAL FINDINGS We examined, using X-Ray microtomographic analysis, the variable craniofacial dysmorphism and dental anomalies present in Rsk2 knockout mice, a model of Coffin-Lowry syndrome, as well as in triple Rsk1,2,3 knockout mutants. We report Rsk mutation produces surpernumerary teeth midline/mesial to the first molar. This highly penetrant phenotype recapitulates more ancestral tooth structures lost with evolution. Most likely this leads to a reduction of the maxillary diastema. Abnormalities of molar shape were generally restricted to the mesial part of both upper and lower first molars (M1). Expression analysis of the four Rsk genes (Rsk1, 2, 3 and 4) was performed at various stages of odontogenesis in wild-type (WT) mice. Rsk2 is expressed in the mesenchymal, neural crest-derived compartment, correlating with proliferative areas of the developing teeth. This is consistent with RSK2 functioning in cell cycle control and growth regulation, functions potentially responsible for severe dental phenotypes. To uncover molecular pathways involved in the etiology of these defects, we performed a comparative transcriptomic (DNA microarray) analysis of mandibular wild-type versus Rsk2-/Y molars. We further demonstrated a misregulation of several critical genes, using a Rsk2 shRNA knock-down strategy in molar tooth germs cultured in vitro. CONCLUSIONS This study reveals RSK2 regulates craniofacial development including tooth development and patterning via novel transcriptional targets.
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Affiliation(s)
- Virginie Laugel-Haushalter
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), Centre National de la Recherche Scientifique (UMR 7104), Institut National de la Santé et de la Recherche Médicale (U 964), University of Strasbourg, Illkirch, France
| | - Marie Paschaki
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), Centre National de la Recherche Scientifique (UMR 7104), Institut National de la Santé et de la Recherche Médicale (U 964), University of Strasbourg, Illkirch, France
| | - Pauline Marangoni
- Team «Evo-Devo of Vertebrate Dentition», Institut de Génomique Fonctionnelle de Lyon, Unité Mixte de Recherche 5242 Centre National de la Recherche Scientifique, Ecole Normale Supérieure de Lyon, Claude Bernard Lyon 1 University, Lyon, France
| | - Coralie Pilgram
- Faculty of Dentistry, University of Strasbourg, Strasbourg France
| | - Arnaud Langer
- Faculty of Dentistry, University of Strasbourg, Strasbourg France
| | - Thibaut Kuntz
- Faculty of Dentistry, University of Strasbourg, Strasbourg France
| | - Julie Demassue
- Faculty of Dentistry, University of Strasbourg, Strasbourg France
| | - Supawich Morkmued
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), Centre National de la Recherche Scientifique (UMR 7104), Institut National de la Santé et de la Recherche Médicale (U 964), University of Strasbourg, Illkirch, France
- Faculty of Dentistry, University of Strasbourg, Strasbourg France
- Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand
| | - Philippe Choquet
- UF6237 Preclinical Imaging Lab, Biophysics and Nuclear Medicine, Hôpitaux Universitaires de Strasbourg (HUS), Strasbourg, France; ICube, CNRS, University of Strasbourg, Strasbourg, France
| | - André Constantinesco
- UF6237 Preclinical Imaging Lab, Biophysics and Nuclear Medicine, Hôpitaux Universitaires de Strasbourg (HUS), Strasbourg, France; ICube, CNRS, University of Strasbourg, Strasbourg, France
| | - Fabien Bornert
- Faculty of Dentistry, University of Strasbourg, Strasbourg France
- INSERM U1121, "Biomaterials and Bioengineering", University of Strasbourg, Strasbourg, France
| | - Matthieu Schmittbuhl
- Faculty of Dentistry, University of Strasbourg, Strasbourg France
- Reference Centre for Orodental Manifestations of Rare Diseases, Pôle de Médecine et Chirurgie Bucco-dentaires, Hôpitaux Universitaires de Strasbourg (HUS), Strasbourg, France
- INSERM U1121, "Biomaterials and Bioengineering", University of Strasbourg, Strasbourg, France
| | - Solange Pannetier
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), Centre National de la Recherche Scientifique (UMR 7104), Institut National de la Santé et de la Recherche Médicale (U 964), University of Strasbourg, Illkirch, France
| | - Laurent Viriot
- Team «Evo-Devo of Vertebrate Dentition», Institut de Génomique Fonctionnelle de Lyon, Unité Mixte de Recherche 5242 Centre National de la Recherche Scientifique, Ecole Normale Supérieure de Lyon, Claude Bernard Lyon 1 University, Lyon, France
| | - André Hanauer
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), Centre National de la Recherche Scientifique (UMR 7104), Institut National de la Santé et de la Recherche Médicale (U 964), University of Strasbourg, Illkirch, France
| | - Pascal Dollé
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), Centre National de la Recherche Scientifique (UMR 7104), Institut National de la Santé et de la Recherche Médicale (U 964), University of Strasbourg, Illkirch, France
| | - Agnès Bloch-Zupan
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), Centre National de la Recherche Scientifique (UMR 7104), Institut National de la Santé et de la Recherche Médicale (U 964), University of Strasbourg, Illkirch, France
- Faculty of Dentistry, University of Strasbourg, Strasbourg France
- Reference Centre for Orodental Manifestations of Rare Diseases, Pôle de Médecine et Chirurgie Bucco-dentaires, Hôpitaux Universitaires de Strasbourg (HUS), Strasbourg, France
- * E-mail:
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Molecular patterning of the mammalian dentition. Semin Cell Dev Biol 2013; 25-26:61-70. [PMID: 24355560 DOI: 10.1016/j.semcdb.2013.12.003] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 11/20/2013] [Accepted: 12/09/2013] [Indexed: 01/15/2023]
Abstract
Four conserved signaling pathways, including the bone morphogenetic proteins (Bmp), fibroblast growth factors (Fgf), sonic hedgehog (Shh), and wingless-related (Wnt) pathways, are each repeatedly used throughout tooth development. Inactivation of any of these resulted in early tooth developmental arrest in mice. The mutations identified thus far in human patients with tooth agenesis also affect these pathways. Recent studies show that these signaling pathways interact through positive and negative feedback loops to regulate not only morphogenesis of individual teeth but also tooth number, shape, and spatial pattern. Increased activity of each of the Fgf, Shh, and canonical Wnt signaling pathways revitalizes development of the physiologically arrested mouse diastemal tooth germs whereas constitutive activation of canonical Wnt signaling in the dental epithelium is able to induce supernumerary tooth formation even in the absence of Msx1 and Pax9, two transcription factors required for normal tooth development beyond the early bud stage. Bmp4 and Msx1 act in a positive feedback loop to drive sequential tooth formation whereas the Osr2 transcription factor restricts Msx1-mediated expansion of the mesenchymal odontogenic field along both the buccolingual and anteroposterior axes to pattern mouse molar teeth in a single row. Moreover, the ectodermal-specific ectodysplasin (EDA) signaling pathway controls tooth number and tooth shape through regulation of Fgf20 expression in the dental epithelium, whereas Shh suppresses Wnt signaling through a negative feedback loop to regulate spatial patterning of teeth. In this article, we attempt to integrate these exciting findings in the understanding of the molecular networks regulating tooth development and patterning.
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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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Bornert F, Choquet P, Gros CI, Aubertin G, Perrin-Schmitt F, Clauss F, Lesot H, Constantinesco A, Schmittbuhl M. Subtle Morphological Changes in the Mandible of Tabby Mice Revealed by Micro-CT Imaging and Elliptical Fourier Quantification. Front Physiol 2011; 2:15. [PMID: 21541253 PMCID: PMC3082932 DOI: 10.3389/fphys.2011.00015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2011] [Accepted: 03/26/2011] [Indexed: 11/13/2022] Open
Abstract
X-linked hypohidrotic ectodermal dysplasia (XLHED) is a genetic disorder due to a mutation of the EDA gene and is mainly characterized by an impaired formation of hair, teeth and sweat glands, and craniofacial dysmorphologies. Although tooth abnormalities in Tabby (Ta) mutant mice - the murine model of XLHED - have been extensively studied, characterization of the craniofacial complex, and more specifically the mandibular morphology has received less attention. From 3D micro-CT reconstructions of the left mandible, the mandibular outline observed in lateral view, was quantified using 2D elliptical Fourier analysis. Comparisons between Ta specimens and their wild-type controls were carried out showing significant shape differences between mouse strains enabling a clear distinction between hemizygous Ta specimens and the other mouse groups (WT and heterozygous Eda(Ta/+) specimens). Morphological differences associated with HED correspond not only to global mandibular features (restrained development of that bone along dorsoventral axis), but also to subtle aspects such as the marked backward projection of the coronoid process or the narrowing of the mandibular condylar neck. These modifications provide for the first time, evidence of a predominant effect of the Ta mutation on the mandibular morphology. These findings parallel the well described abnormalities of jugal tooth row and skeletal defects in Ta mice, and underline the role played by EDA-A in the reciprocal epithelial-mesenchymal interactions that are of critical importance in normal dental and craniofacial development.
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Affiliation(s)
- Fabien Bornert
- Institut National de la Santé et de la Recherche Médicale, INSERM UMR 977, University of Strasbourg Strasbourg, France
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10
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Lewis JR, Reiter AM, Mauldin EA, Casal ML. Dental abnormalities associated with X-linked hypohidrotic ectodermal dysplasia in dogs. Orthod Craniofac Res 2010; 13:40-7. [PMID: 20078794 DOI: 10.1111/j.1601-6343.2009.01473.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
OBJECTIVES X-linked hypohidrotic ectodermal dysplasia (XLHED) occurs in several species, including humans, mice, cattle and dogs. The orofacial manifestations of ectodermal dysplasia in humans and mice have been extensively studied, but documentation of dental abnormalities in dogs is lacking. The current study describes the results of clinical and radiographic examinations of XLHED-affected dogs and demonstrates profound similarities to findings of XLHED-affected humans. SETTING AND SAMPLE POPULATION Section of Medical Genetics at the University of Pennsylvania, School of Veterinary Medicine. Clinical and radiographic oral examinations were performed on 17 dogs with XLHED, three normal dogs, and two dogs heterozygous for XLHED. MATERIALS AND METHODS The prevalence and severity of orofacial and dental abnormalities were evaluated by means of a sedated examination, photographs, and full-mouth intraoral radiographs. RESULTS Crown and root abnormalities were common in dogs affected by XLHED, including hypodontia, oligodontia, conical crown shape, decreased number of cusps, decreased number of roots, and dilacerated roots. Persistent deciduous teeth were frequently encountered. Malocclusion was common, with Angle Class I mesioversion of the maxillary and/or mandibular canine teeth noted in 15 of 17 dogs. Angle Class III malocclusion (maxillary brachygnathism) was seen in one affected dog. CONCLUSION Dental abnormalities are common and severe in dogs with XLHED. Dental manifestations of canine XLHED share characteristics of brachyodont tooth type and diphyodont dentition, confirming this species to be an orthologous animal model for study of human disease.
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Affiliation(s)
- J R Lewis
- Department of Clinical Studies, Matthew J. Ryan Veterinary Hospital, University of Pennsylvania, Philadelphia, PA 19104-6010, USA.
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Peterkova R, Churava S, Lesot H, Rothova M, Prochazka J, Peterka M, Klein OD. Revitalization of a diastemal tooth primordium in Spry2 null mice results from increased proliferation and decreased apoptosis. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART B, MOLECULAR AND DEVELOPMENTAL EVOLUTION 2009; 312B:292-308. [PMID: 19127536 PMCID: PMC2880865 DOI: 10.1002/jez.b.21266] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
An understanding of the factors that promote or inhibit tooth development is essential for designing biological tooth replacements. The embryonic mouse dentition provides an ideal system for studying such factors because it consists of two types of tooth primordia. One type of primordium will go on to form a functional tooth, whereas the other initiates development but arrests at or before the bud stage. This developmental arrest contributes to the formation of the toothless mouse diastema. It is accompanied by the apoptosis of the rudimentary diastemal buds, which presumably results from the insufficient activity of anti-apoptotic signals such as fibroblast growth factors (FGFs). We have previously shown that the arrest of a rudimentary tooth bud can be rescued by inactivating Spry2, an antagonist of FGF signaling. Here, we studied the role of the epithelial cell death and proliferation in this process by comparing the development of a rudimentary diastemal tooth bud (R(2)) and the first molar in the mandibles of Spry2(-/-) and wild-type (WT) embryos using histological sections, image analysis and 3D reconstructions. In the WT R(2) at embryonic day 13.5, significantly increased apoptosis and decreased proliferation were found compared with the first molar. In contrast, increased levels of FGF signaling in Spry2(-/-) embryos led to significantly decreased apoptosis and increased proliferation in the R(2) bud. Consequently, the R(2) was involved in the formation of a supernumerary tooth primordium. Studies of the revitalization of rudimentary tooth primordia in mutant mice can help to lay the foundation for tooth regeneration by enhancing our knowledge of mechanisms that regulate tooth formation.
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Affiliation(s)
- Renata Peterkova
- Department of Teratology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Svatava Churava
- Department of Teratology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czech Republic
- Department of Anthropology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Herve Lesot
- INSERM U595, Faculté de Médecine, Université Louis Pasteur, Strasbourg, France
- Faculté de Chirurgie Dentaire, Université Louis Pasteur, Strasbourg, France
- International Collaborating Centre in Oro-Facial Genetics and Development, University of Liverpool, Liverpool, United Kingdom
| | - Michaela Rothova
- Department of Teratology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czech Republic
- Department of Developmental Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Jan Prochazka
- Department of Teratology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czech Republic
- Department of Developmental Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Miroslav Peterka
- Department of Teratology, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, Prague, Czech Republic
- Department of Anthropology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Ophir D. Klein
- Department of Orofacial Sciences, University of California, San Francisco, California
- Department of Pediatrics, University of California, San Francisco, California
- Institutes of Human Genetics and Regeneration Medicine, University of California, San Francisco, California
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Charles C, Pantalacci S, Peterkova R, Tafforeau P, Laudet V, Viriot L. Effect of eda loss of function on upper jugal tooth morphology. Anat Rec (Hoboken) 2009; 292:299-308. [PMID: 19051250 DOI: 10.1002/ar.20804] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The Tabby/eda mice, which bear a loss of function mutation for the eda (ectodysplasinA) gene, are known to display developmental anomalies in organs with an ectodermal origin. Although the lower jugal (cheek) teeth of Tabby/eda mice have been extensively studied, upper teeth have never been investigated in detail. However, this may help us to further understand the function of the eda gene in tooth development. In this work, the shape and size of both the crown and the radicular system were studied in the Tabby/eda mice upper jugal teeth. To deal with the high morphological variability, we defined several morphotypes based on cusp numbers and position. Statistical tests were then performed within and between the different morphotypes to test the correlation between tooth size and morphology. Our analysis reveals that, as in lower teeth, eda is necessary to segment the dental lamina into three teeth with the characteristic size and proportions of the mouse. Nevertheless, since strong effects are observed in heterozygous upper teeth while lower are only mildly affected, it seems that the upper jaw is more sensitive than the lower jaw to the loss of eda function. Modifications in cusp number and the abnormal crown size of the teeth are clearly linked, and our results indicate a role of eda in cusp patterning. Moreover, we found that the Tabby mutation induces variations in the dental root pattern, sometimes associated with hypercementosis, suggesting a newly uncovered role played by eda in root patterning and formation.
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Affiliation(s)
- Cyril Charles
- iPHEP, CNRS UMR 6046, Faculté SFA, Université de Poitiers, 40 avenue du recteur Pineau, Poitiers Cedex, France.
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Townsend G, Harris EF, Lesot H, Clauss F, Brook A. Morphogenetic fields within the human dentition: a new, clinically relevant synthesis of an old concept. Arch Oral Biol 2008; 54 Suppl 1:S34-44. [PMID: 18760768 PMCID: PMC2981872 DOI: 10.1016/j.archoralbio.2008.06.011] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2008] [Revised: 06/24/2008] [Accepted: 06/25/2008] [Indexed: 12/23/2022]
Abstract
This paper reviews the concept of morphogenetic fields within the dentition that was first proposed by Butler (Butler PM. Studies of the mammalian dentition. Differentiation of the post-canine dentition. Proc Zool Soc Lond B 1939;109:1–36), then adapted for the human dentition by Dahlberg (Dahlberg AA. The changing dentition of man. J Am Dent Assoc 1945;32:676–90; Dahlberg AA. The dentition of the American Indian. In: Laughlin WS, editor. The Physical Anthropology of the American Indian. New York: Viking Fund Inc.; 1951. p. 138–76). The clone theory of dental development, proposed by Osborn (Osborn JW. Morphogenetic gradients: fields versus clones. In: Butler PM, Joysey KA, editors Development, function and evolution of teeth. London: Academic Press, 1978. p. 171–201), is then considered before these two important concepts are interpreted in the light of recent findings from molecular, cellular, genetic and theoretical and anthropological investigation. Sharpe (Sharpe PT. Homeobox genes and orofacial development. Connect Tissue Res 1995;32:17–25) put forward the concept of an odontogenic homeobox code to explain how different tooth classes are initiated in different parts of the oral cavity in response to molecular cues and the expression of specific groups of homeobox genes. Recently, Mitsiadis and Smith (Mitsiadis TA, Smith MM. How do genes make teeth to order through development? J Exp Zool (Mol Dev Evol) 2006; 306B:177–82.) proposed that the field, clone and homeobox code models could all be incorporated into a single model to explain dental patterning. We agree that these three models should be viewed as complementary rather than contradictory and propose that this unifying view can be extended into the clinical setting using findings on dental patterning in individuals with missing and extra teeth. The proposals are compatible with the unifying aetiological model developed by Brook (Brook AH. A unifying aetiological explanation for anomalies of tooth number and size. Archs Oral Biol 1984;29:373–78) based on human epidemiological and clinical findings. Indeed, this new synthesis can provide a sound foundation for clinical diagnosis, counselling and management of patients with various anomalies of dental development as well as suggesting hypotheses for future studies.
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Affiliation(s)
- Grant Townsend
- School of Dentistry, The University of Adelaide, Adelaide, South Australia 5005, Australia.
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14
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Epithelial histogenesis during tooth development. Arch Oral Biol 2008; 54 Suppl 1:S25-33. [PMID: 18656852 DOI: 10.1016/j.archoralbio.2008.05.019] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2008] [Revised: 05/07/2008] [Accepted: 05/07/2008] [Indexed: 12/31/2022]
Abstract
This paper reviews the current understanding of the progressive changes mediating dental epithelial histogenesis as a basis for future collaborative studies. Tooth development involves morphogenesis, epithelial histogenesis and cell differentiation. The consecutive morphological stages of lamina, bud, cap and bell are also characterized by changes in epithelial histogenesis. Differential cell proliferation rates, apoptosis, and alterations in adhesion and shape lead to the positioning of groups of cells with different functions. During tooth histo-morphogenesis changes occur in basement membrane composition, expression of signalling molecules and the localization of cell surface components. Cell positional identity may be related to cell history. Another important parameter is cell plasticity. Independently of signalling molecules, which play a major role in inducing or modulating specific steps, cell-cell and cell-matrix interactions regulate the plasticity/rigidity of particular domains of the enamel organ. This involves specifying in space the differential growth and influences the progressive tooth morphogenesis by shaping the epithelial-mesenchymal junction. Deposition of a mineralized matrix determines the final shape of the crown. All data reviewed in this paper were investigated in the mouse.
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Fraser GJ, Bloomquist RF, Streelman JT. A periodic pattern generator for dental diversity. BMC Biol 2008; 6:32. [PMID: 18625062 PMCID: PMC2496899 DOI: 10.1186/1741-7007-6-32] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2008] [Accepted: 07/14/2008] [Indexed: 11/18/2022] Open
Abstract
Background Periodic patterning of iterative structures is a fundamental process during embryonic organization and development. Studies have shown how gene networks are employed to pattern butterfly eyespots, fly bristles and vertebrate epithelial appendages such as teeth, feathers, hair and mammary glands. Despite knowledge of how these features are organized, little is known about how diversity in periodic patterning is generated in nature. We address this problem through the molecular analysis of oral jaw dental diversity in Lake Malawi cichlids, where closely related species exhibit from 1 to 20 rows of teeth, with total teeth counts ranging from around 10 to 700. Results We investigate the expression of conserved gene networks (involving bmp2, bmp4, eda, edar, fgf8, pax9, pitx2, runx2, shh and wnt7b) known to pattern iterative structures and teeth in other vertebrates. We show that spatiotemporal variation in expression pattern reflects adult morphological diversity among three closely related Malawi cichlid species. Combinatorial epithelial expression of pitx2 and shh appears to govern the competence both of initial tooth sites and future tooth rows. Epithelial wnt7b and mesenchymal eda are expressed in the inter-germ and inter-row regions, and likely regulate the spacing of these shh-positive units. Finally, we used chemical knockdown to demonstrate the fundamental role of hedgehog signalling and initial placode formation in the organization of the periodically patterned cichlid dental programme. Conclusion Coordinated patterns of gene expression differ among Malawi species and prefigure the future-ordered distribution of functional teeth of specific size and spacing. This variation in gene expression among species occurs early in the developmental programme for dental patterning. These data show how a complex multi-rowed vertebrate dentition is organized and how developmental tinkering of conserved gene networks during iterative pattern formation can impact upon the evolution of trophic novelty.
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Affiliation(s)
- Gareth J Fraser
- School of Biology, Petit Institute of Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332-0230, USA.
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16
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Asymmetrical growth, differential cell proliferation, and dynamic cell rearrangement underlie epithelial morphogenesis in mouse molar development. Cell Tissue Res 2007; 330:461-73. [DOI: 10.1007/s00441-007-0502-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Accepted: 08/29/2007] [Indexed: 10/22/2022]
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Mitchell J, Hicklin D, Doughty P, Hicklin J, Dickert J, Tolbert S, Peterkova R, Kern M. The Prx1 homeobox gene is critical for molar tooth morphogenesis. J Dent Res 2006; 85:888-93. [PMID: 16998126 PMCID: PMC2231809 DOI: 10.1177/154405910608501003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The paired-related homeobox genes, Prx1 and Prx2, encode transcription factors critical for orofacial development. Prx1(-/-)/Prx2(-/-) neonates have mandibular hypoplasia and malformed mandibular incisors. Although the mandibular incisor phenotype has been briefly described (ten Berge et al., 1998, 2001; Lu et al., 1999), very little is known about the role of Prx proteins during tooth morphogenesis. Since the posterior mandibular region was relatively normal, we examined molar tooth development in Prx1(-/-)/Prx2(-/-) embryos to determine whether the tooth malformation is primary to the loss of Prx protein or secondary to defects in surrounding tissues. Three-dimensional (3D) morphological reconstructions demonstrated that Prx1(-/-)/Prx2(-/-) embryos had molar malformations, including cuspal changes and ectopic epithelial projections. Although we demonstrate that Prx1 protein is expressed only mesenchymally, 3D reconstructions showed important morphological defects in epithelial tissues at the cap and bell stages. Analysis of these data suggests that the Prx homeoproteins are critical for mesenchymal-epithelial signaling during tooth morphogenesis.
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Affiliation(s)
- J.M. Mitchell
- Department of Cell Biology and Anatomy, Suite 601, Medical University of South Carolina, 171 Ashley Avenue, Charleston, SC 29435
- College of Dental Medicine, Medical University of South Carolina, 171 Ashley Avenue, Charleston, SC 29435
| | - D.M. Hicklin
- College of Dental Medicine, Medical University of South Carolina, 171 Ashley Avenue, Charleston, SC 29435
| | - P.M. Doughty
- College of Dental Medicine, Medical University of South Carolina, 171 Ashley Avenue, Charleston, SC 29435
| | - J.H. Hicklin
- College of Dental Medicine, Medical University of South Carolina, 171 Ashley Avenue, Charleston, SC 29435
- Furman University, Greenville, SC
| | - J.W. Dickert
- College of Dental Medicine, Medical University of South Carolina, 171 Ashley Avenue, Charleston, SC 29435
| | - S.M. Tolbert
- College of Dental Medicine, Medical University of South Carolina, 171 Ashley Avenue, Charleston, SC 29435
| | - R. Peterkova
- Department of Teratology, Institute of Experimental Medicine, Academy of Sciences of the CR, Prague, Czech Republic
| | - M.J. Kern
- Department of Cell Biology and Anatomy, Suite 601, Medical University of South Carolina, 171 Ashley Avenue, Charleston, SC 29435
- corresponding author,
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Peterkova R, Lesot H, Peterka M. Phylogenetic memory of developing mammalian dentition. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2006; 306:234-50. [PMID: 16463376 DOI: 10.1002/jez.b.21093] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Structures suppressed during evolution can be retraced due to atavisms and vestiges. Atavism is an exceptional emergence of an ancestral form in a living individual. In contrast, ancestral vestige regularly occurs in all members of an actual species. We surveyed data about the vestigial and atavistic teeth in mammals, updated them by recent findings in mouse and human embryos, and discussed their ontogenetic and evolutionary implications. In the mouse incisor and diastema regions, dental placodes are transiently distinct being morphologically similar to the early tooth primordia in reptiles. Two large vestigial buds emerge in front of the prospective first molar and presumably correspond to the premolars eliminated during mouse evolution. The incorporation of the posterior premolar vestige into the lower first molar illustrates the putative mechanism of evolutionary disappearance of the last premolar in the mice. In mutant mice, devious development of the ancestral tooth primordia might lead to their revivification and origin of atavistic supernumerary teeth. Similarity in the developmental schedule between three molars in mice and the respective third and fourth deciduous premolar and the first molar in humans raises a question about putative homology of these teeth. The complex patterning of the vestibular and dental epithelium in human embryos is reminiscent of the pattern of "Zahnreihen" in lower vertebrates. A hypothesis was presented about the developmental relationship between the structures at the external aspect of the dentition in mammals (oral vestibule, pre-lacteal teeth, paramolar cusps/teeth), the tooth glands in reptiles, and the earliest teeth in lower vertebrates.
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Affiliation(s)
- Renata Peterkova
- Department of Teratology, Institute of Experimental Medicine, Academy of Sciences CR, 142 20 Prague, Czech Republic.
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Boran T, Lesot H, Peterka M, Peterkova R. Increased apoptosis during morphogenesis of the lower cheek teeth in tabby/EDA mice. J Dent Res 2005; 84:228-33. [PMID: 15723861 DOI: 10.1177/154405910508400304] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
In wild-type (WT) mice, epithelial apoptosis is involved in reducing the embryonic tooth number and the mesial delimitation of the first molar. We investigated whether apoptosis could also be involved in the reduction of tooth number and the determination of anomalous tooth boundaries in tabby (Ta)/EDA mice. Using serial histological sections and computer-aided 3D reconstructions, we investigated epithelial apoptosis in the lower cheek dentition at embryonic days 14.5-17.5. In comparison with WT mice, apoptosis was increased mainly mesially in Ta dental epithelium from day 15.5. This apoptosis showed a similar mesio-distal extent in all 5 morphotypes (Ia,b,c and IIa,b) of Ta dentition and eliminated the first cheek tooth in morphotypes IIa,b. Apoptosis did not appear to play any causal role in positioning inter-dental gaps. Analysis of the present data suggests that the increased apoptosis in Ta mice is a consequence of impaired tooth development caused by a defect in segmentation of dental epithelium.
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Affiliation(s)
- T Boran
- Department of Teratology, Institute of Experimental Medicine, Academy of Sciences of the CR, Prague, Czech Republic
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Peterková R, Lesot H, Viriot L, Peterka M. The supernumerary cheek tooth in tabby/EDA mice-a reminiscence of the premolar in mouse ancestors. Arch Oral Biol 2005; 50:219-25. [PMID: 15721153 DOI: 10.1016/j.archoralbio.2004.10.020] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2004] [Accepted: 10/12/2004] [Indexed: 12/29/2022]
Abstract
OBJECTIVE A supernumerary cheek tooth occurs mesially to the first molar in tabby/EDA (Ta) mice affected by hypohidrotic ectodermal dysplasia. The supernumerary tooth (S) has been hypothetically homologized to the premolar, which has disappeared during mouse evolution. DESIGN This hypothesis was tested using available morphological data on the lower cheek teeth in wild type (WT) and Ta mice. RESULTS The presence of S is accompanied by a reduction in the mesial portion of the M(1) in mutant mice. 3D reconstructions suggest that the S in Ta homo/hemizygous embryos originates from a split off the mesial portion of the first molar (M(1)) cap. In WT embryos, two vestigial tooth primordia are transiently distinct in front of the M(1). The distal vestige has the form of a wide bud and participates during the development of the mesial portion of the M(1). This bud has been homologized with the vestigial primordium of the fourth premolar of mouse ancestors. The premolar disappearance coincided with a mesial lengthening of the M(1) during mouse evolution. The incorporation of the distal premolar vestige into the mesial part of the M(1) in WT embryos can be regarded as a repetition of the premolar disappearance during evolution. CONCLUSION : Ontogenetic and phylogenetic data support that the S in Ta mice arises due to the segregation of the distal premolar vestige from the molar dentition and thus represents an evolutionary throwback (atavism).
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Affiliation(s)
- R Peterková
- Department of Teratology, Institute of Experimental Medicine, Academy of Sciences CR, Videnska 1083, 14220 Prague, Czech Republic.
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Witter K, Lesot H, Peterka M, Vonesch JL, Mísek I, Peterková R. Origin and developmental fate of vestigial tooth primordia in the upper diastema of the field vole (Microtus agrestis, Rodentia). Arch Oral Biol 2004; 50:401-9. [PMID: 15748693 DOI: 10.1016/j.archoralbio.2004.10.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2004] [Accepted: 10/10/2004] [Indexed: 11/20/2022]
Abstract
OBJECTIVE Odontogenesis in voles is a convenient model to test hypotheses on tooth development generated from investigations in the mouse. Similar to other rodents, the functional dentition of the vole includes a toothless diastema. At its mesial end, a vestigial tooth bud has been found in the upper jaw of vole embryos. The aim of this study was to analyse the developmental dynamics of vestigial tooth structures in the upper diastema of the field vole and to compare it with the situation in the mouse. DESIGN The development of odontogenic structures in the upper diastema of the field vole was investigated using serial histological sections and three-dimensional (3D) computer-aided reconstruction. RESULTS A transient continuous dental lamina in the upper diastema of the field vole extended mesially to the first molar primordium, but was not continuous with the dental lamina in the incisor region. At its mesial limit, a large vestigial tooth primordium was regularly present. A further distinct vestigial bud was located mesially to the first molar primordium. The segmentation of the dental lamina suggested a potential to give rise to further vestiges in the upper diastema of the vole. CONCLUSIONS In the prospective diastema of the vole exists as in the mouse a continuous dental lamina. Beside the prominent vestigial tooth bud in the mesial diastema, a further large bud was transiently located in front of the molars. The incorporation of dental epithelium into the first upper molar (M(1)) primordium in the vole differs from that in the mouse.
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Affiliation(s)
- Kirsti Witter
- Institute of Histology and Embryology, Department of Pathobiology, University of Veterinary Medicine Vienna, Veterinärplatz 1, A-1210 Wien, Austria.
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