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Ohshima H, Mishima K, Amizuka N. Oral biosciences: The annual review 2020. J Oral Biosci 2021; 63:1-7. [PMID: 33582294 DOI: 10.1016/j.job.2021.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/02/2021] [Accepted: 02/03/2021] [Indexed: 11/29/2022]
Abstract
BACKGROUND The Journal of Oral Biosciences is devoted to the advancement and dissemination of fundamental knowledge concerning every aspect of oral biosciences. HIGHLIGHT This review featured the review articles in the fields of "Microbiology," "Palate," "Stem Cells," "Mucosal Diseases," "Bone Cell Biology," "MicroRNAs," "TRPV1 Cation Channels," and "Interleukins" in addition to the review article by prize-winners of the "Rising Members Award" ("DKK3 expression and function in head and neck squamous cell carcinoma and other cancers"), presented by the Japanese Association for Oral Biology. CONCLUSION These reviews in the Journal of Oral Biosciences have inspired the readers of the journal to broaden their knowledge regarding the various aspects of oral biosciences. The current editorial review introduces these exciting review articles.
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Affiliation(s)
- Hayato Ohshima
- 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 951-8514, Japan.
| | - Kenji Mishima
- Division of Pathology, Department of Oral Diagnostic Sciences, Showa University School of Dentistry, 1-5-8, Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
| | - Norio Amizuka
- Department of Developmental Biology of Hard Tissue, Graduate School of Dental Medicine, Faculty of Dental Medicine, Hokkaido University, Kita 13 Nishi 7 Kita-ku, Sapporo 060-8586, Japan
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2
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Molecular mechanisms in palatal rugae development. J Oral Biosci 2020; 62:30-35. [DOI: 10.1016/j.job.2019.12.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 11/29/2019] [Accepted: 12/04/2019] [Indexed: 12/18/2022]
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Nakaniwa M, Kawasaki M, Kawasaki K, Yamada A, Meguro F, Takeyasu M, Ohazama A. Primary cilia in murine palatal rugae development. Gene Expr Patterns 2019; 34:119062. [PMID: 31226309 DOI: 10.1016/j.gep.2019.119062] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 06/17/2019] [Accepted: 06/17/2019] [Indexed: 10/26/2022]
Abstract
Periodic patterning of iterative structures is a fundamental process during embryonic development, since these structures are diverse across the animal kingdom. Therefore, elucidating the molecular mechanisms in the formation of these structures promotes understanding of the process of organogenesis. Periodically patterned ridges, palatal rugae (situated on the hard palate of mammals), are an excellent experimental model to clarify the molecular mechanisms involved in the formation of periodic patterning of iterative structures. Primary cilia are involved in many biological events, including the regulation of signaling pathways such as Shh and non-canonical Wnt signaling. However, the role of primary cilia in the development of palatal rugae remains unclear. We found that primary cilia were localized to the oral cavity side of the interplacode epithelium of the palatal rugae, whereas restricted localization of primary cilia could not be detected in other regions. Next, we generated mice with a placodal conditional deletion of the primary cilia protein Ift88, using ShhCre mice (Ift88 fl/fl;ShhCre). Highly disorganized palatal rugae were observed in Ift88 fl/fl;ShhCre mice. Furthermore, by comparative in situ hybridization analysis, many Shh and non-canonical Wnt signaling-related molecules showed spatiotemporal expression patterns during palatal rugae development, including restricted expression in the epithelium (placodes and interplacodes) and mesenchyme. Some of these expression were found to be altered in Ift88 fl/fl;ShhCre mice. Primary cilia is thus involved in development of palatal rugae.
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Affiliation(s)
- Mayuko Nakaniwa
- Division of Oral Anatomy, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Maiko Kawasaki
- Division of Oral Anatomy, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Katsushige Kawasaki
- Division of Oral Anatomy, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan; Research Center for Advanced Oral Science, Department of Oral Life Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Akane Yamada
- Division of Oral Anatomy, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Fumiya Meguro
- Division of Oral Anatomy, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Maeda Takeyasu
- Research Center for Advanced Oral Science, Department of Oral Life Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan; Faculty of Dental Medicine, University of Airlangga, Surabaya, Indonesia
| | - Atsushi Ohazama
- Division of Oral Anatomy, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
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Kawasaki M, Kawasaki K, Meguro F, Yamada A, Ishikawa R, Porntaveetus T, Blackburn J, Otsuka-Tanaka Y, Saito N, Ota MS, Sharpe PT, Kessler JA, Herz J, Cobourne MT, Maeda T, Ohazama A. Lrp4/Wise regulates palatal rugae development through Turing-type reaction-diffusion mechanisms. PLoS One 2018; 13:e0204126. [PMID: 30235284 PMCID: PMC6147471 DOI: 10.1371/journal.pone.0204126] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2018] [Accepted: 09/03/2018] [Indexed: 12/25/2022] Open
Abstract
Periodic patterning of iterative structures is diverse across the animal kingdom. Clarifying the molecular mechanisms involved in the formation of these structure helps to elucidate the process of organogenesis. Turing-type reaction-diffusion mechanisms have been shown to play a critical role in regulating periodic patterning in organogenesis. Palatal rugae are periodically patterned ridges situated on the hard palate of mammals. We have previously shown that the palatal rugae develop by a Turing-type reaction-diffusion mechanism, which is reliant upon Shh (as an inhibitor) and Fgf (as an activator) signaling for appropriate organization of these structures. The disturbance of Shh and Fgf signaling lead to disorganized palatal rugae. However, the mechanism itself is not fully understood. Here we found that Lrp4 (transmembrane protein) was expressed in a complementary pattern to Wise (a secreted BMP antagonist and Wnt modulator) expression in palatal rugae development, representing Lrp4 expression in developing rugae and Wise in the inter-rugal epithelium. Highly disorganized palatal rugae was observed in both Wise and Lrp4 mutant mice, and these mutants also showed the downregulation of Shh signaling, which was accompanied with upregulation of Fgf signaling. Wise and Lrp4 are thus likely to control palatal rugae development by regulating reaction-diffusion mechanisms through Shh and Fgf signaling. We also found that Bmp and Wnt signaling were partially involved in this mechanism.
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Affiliation(s)
- Maiko Kawasaki
- Division of Oral Anatomy, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
- Centre for Craniofacial Development and Regeneration, Dental Institute, King's College London, Guy's Hospital, London, United Kingdom
| | - Katsushige Kawasaki
- Division of Oral Anatomy, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
- Centre for Craniofacial Development and Regeneration, Dental Institute, King's College London, Guy's Hospital, London, United Kingdom
- Research Center for Advanced Oral Science, Department of Oral Life Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Fumiya Meguro
- Division of Oral Anatomy, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Akane Yamada
- Division of Oral Anatomy, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Ryuichi Ishikawa
- Division of Oral Anatomy, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Thantrira Porntaveetus
- Centre for Craniofacial Development and Regeneration, Dental Institute, King's College London, Guy's Hospital, London, United Kingdom
| | - James Blackburn
- Centre for Craniofacial Development and Regeneration, Dental Institute, King's College London, Guy's Hospital, London, United Kingdom
| | - Yoko Otsuka-Tanaka
- Centre for Craniofacial Development and Regeneration, Dental Institute, King's College London, Guy's Hospital, London, United Kingdom
| | - Naoaki Saito
- Division of Oral Anatomy, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Masato S. Ota
- Laboratory of Food Biological Science, Department of Food and Nutrition, Japan Women’s University, Bunkyo, Japan
| | - Paul T. Sharpe
- Centre for Craniofacial Development and Regeneration, Dental Institute, King's College London, Guy's Hospital, London, United Kingdom
| | - John A. Kessler
- Department of Neurology, Northwestern University, Feinberg Medical School, Chicago, IL, United States of America
| | - Joachim Herz
- Department of Molecular Genetics, UT Southwestern Medical Center, Dallas, United States of America
| | - Martyn T. Cobourne
- Centre for Craniofacial Development and Regeneration, Dental Institute, King's College London, Guy's Hospital, London, United Kingdom
| | - Takeyasu Maeda
- Division of Oral Anatomy, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
- Research Center for Advanced Oral Science, Department of Oral Life Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Atsushi Ohazama
- Division of Oral Anatomy, Department of Oral Biological Science, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
- Centre for Craniofacial Development and Regeneration, Dental Institute, King's College London, Guy's Hospital, London, United Kingdom
- * E-mail:
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The importance of basonuclin 2 in adult mice and its relation to basonuclin 1. Mech Dev 2016; 140:53-73. [PMID: 26923665 DOI: 10.1016/j.mod.2016.02.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 02/17/2016] [Accepted: 02/18/2016] [Indexed: 11/20/2022]
Abstract
BNC2 is an extremely conserved zinc finger protein with important functions in the development of craniofacial bones and male germ cells. Because disruption of the Bnc2 gene in mice causes neonatal lethality, the function of the protein in adult animals has not been studied. Until now BNC2 was considered to have a wider tissue distribution than its paralog, BNC1, but the precise cell types expressing Bnc2 are largely unknown. We identify here the cell types containing BNC2 in the mouse and we show the unexpected presence of BNC1 in many BNC2-containing cells. BNC1 and BNC2 are colocalized in male and female germ cells, ovarian epithelial cells, sensory neurons, hair follicle keratinocytes and connective cells of organ capsules. In many cell lineages, the two basonuclins appear and disappear synchronously. Within the male germ cell lineage, BNC1 and BNC2 are found in prospermatogonia and undifferentiated spermatogonia, and disappear abruptly from differentiating spermatogonia. During oogenesis, the two basonuclins accumulate specifically in maturing oocytes. During the development of hair follicles, BNC1 and BNC2 concentrate in the primary hair germs. As follicle morphogenesis proceeds, cells possessing BNC1 and BNC2 invade the dermis and surround the papilla. During anagen, BNC1 and BNC2 are largely restricted to the basal layer of the outer root sheath and the matrix. During catagen, the compartment of cells possessing BNC1 and BNC2 regresses, and in telogen, the two basonuclins are confined to the secondary hair germ. During the next anagen, the BNC1/BNC2-containing cell population regenerates the hair follicle. By examining Bnc2(-/-) mice that have escaped the neonatal lethality usually associated with lack of BNC2, we demonstrate that BNC2 possesses important functions in many of the cell types where it resides. Hair follicles of postnatal Bnc2(-/-) mice do not fully develop during the first cycle and thereafter remain blocked in telogen. It is concluded that the presence of BNC2 in the secondary hair germ is required to regenerate the transient segment of the follicle. Postnatal Bnc2(-/-) mice also show severe dwarfism, defects in oogenesis and alterations of palatal rugae. Although the two basonuclins possess very similar zinc fingers and are largely coexpressed, BNC1 cannot substitute for BNC2. This is shown incontrovertibly in knockin mice expressing Bnc1 instead of Bnc2 as these mice invariably die at birth with craniofacial abnormalities undistinguishable from those of Bnc2(-/-) mice. The function of the basonuclins in the secondary hair germ is of particular interest.
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Yamazaki T, Yokoyama M, Fujiseki M, Moriguchi M, Miake Y, Sawada T, Sohn WJ, Kim JY, Yamamoto H. Histological Observation of the Palate in Alligator Mississippiensis. J HARD TISSUE BIOL 2013. [DOI: 10.2485/jhtb.22.455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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7
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Shh signaling is essential for rugae morphogenesis in mice. Histochem Cell Biol 2011; 136:663-75. [DOI: 10.1007/s00418-011-0870-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/03/2011] [Indexed: 12/31/2022]
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8
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Sohn WJ, Yamamoto H, Shin HI, Ryoo ZY, Lee S, Bae YC, Jung HS, Kim JY. Importance of region-specific epithelial rearrangements in mouse rugae development. Cell Tissue Res 2011; 344:271-7. [PMID: 21400215 DOI: 10.1007/s00441-011-1148-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2010] [Accepted: 02/06/2011] [Indexed: 12/11/2022]
Abstract
Epithelial appendages on palatal rugae develop during mouse palatogenesis through epithelial thickening and pattern formation. Recently, the patterned formation of nine rugae was observed together with the specific expression patterns of Shh in rodents. However, no crucial evidence was found for a direct association between Shh expression and the distinct structural formation of rugae. In order to reveal possible relationships, we investigated the morphological changes of rugae and expression patterns of Shh directly by in vitro organ culture at embryonic day 13 (E13) for 2 days. To compare and examine the diverse growing aspects of the palate and rugae, we carefully observed the detailed morphogenesis, with cell proliferation of the rugae occurring between E13 and E14.5. After 2 days of cultivation at E13, DiI micro-injections revealed that the middle part of the palate, adjacent to the upper molar-forming region, contributed to the formation of the subsequent structure of rugae by extensive cell rearrangement and proliferation within the epithelium in the preferred anteroposterior direction. The results also defined the intimate relationship between Shh expression and rugae formation.
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Affiliation(s)
- Wern-Joo Sohn
- School of Life Science and Biotechnology, Kyungpook National University, Daegu, Korea
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9
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Yamamoto H, Muramatsu T, Shibukawa Y, Sohn WJ, Kim JY, Tazaki M. Alteration of the Cytokeratin Expression During Palatine Rugae Development in Mice. J HARD TISSUE BIOL 2011. [DOI: 10.2485/jhtb.20.17] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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10
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Expression of Fgf signalling pathway related genes during palatal rugae development in the mouse. Gene Expr Patterns 2010; 10:193-8. [DOI: 10.1016/j.gep.2010.03.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2010] [Revised: 03/16/2010] [Accepted: 03/21/2010] [Indexed: 01/21/2023]
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11
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Imura H, Yamada T, Mishima K, Fujiwara K, Kawaki H, Hirata A, Sogawa N, Ueno T, Sugahara T. Effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin suggests abnormal palate development after palatal fusion. Congenit Anom (Kyoto) 2010; 50:77-84. [PMID: 20156238 DOI: 10.1111/j.1741-4520.2010.00271.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Mouse embryos exposed to 2,3,7,8-tetrachloridedibenzo-p-dioxin (TCDD) develop cleft palates and hydronephrosis. Cleft palates occur after TCDD exposure due to contact and/or fusion failure. We investigated whether cleft palate can be induced by dissociation of the palatine process after fusion. Pregnant mice on gestational day (GD) 12 were randomly divided into two groups: one group was administered through gastric tubes one dose of olive oil (control group) and the other group was administered one dose of TCDD diluted with olive oil, both at a dose of 40 microg/kg body weight. Embryos were removed by cesarean section from pregnant mice during the palatal formation stage (GD 13-18) and the palatal form was observed using a stereoscopic microscope. In TCDD-exposed embryos, palatal fusion was observed on GD 14, 15 and 16 and the incidence of cleft palate was 100% on GD 18. Fusion rates were 17.5 +/- 15.2% and 12.4 +/- 11.8% on GD 15 and 16, respectively. Some palates from the TCDD-exposed mouse embryos showed clearly developed cleft palate after fusion of the lateral palatine processes during palatal formation. A mass of cells, which were chiefly epithelial in the fused palates was observed in the TCDD-exposed mouse embryos. A decrease in E-cadherin expression was observed in this mass of cells, indicating its involvement in the development of cleft palate.
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Affiliation(s)
- Hideto Imura
- Division of Research and Treatment for Oral and Maxillofacial Congenital Anomalies, School of Dentistry, Aichi-Gakuin University, Nagoya, Japan.
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Pantalacci S, Prochazka J, Martin A, Rothova M, Lambert A, Bernard L, Charles C, Viriot L, Peterkova R, Laudet V. Patterning of palatal rugae through sequential addition reveals an anterior/posterior boundary in palatal development. BMC DEVELOPMENTAL BIOLOGY 2008; 8:116. [PMID: 19087265 PMCID: PMC2637861 DOI: 10.1186/1471-213x-8-116] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2008] [Accepted: 12/16/2008] [Indexed: 01/12/2023]
Abstract
Background The development of the secondary palate has been a main topic in craniofacial research, as its failure results in cleft palate, one of the most common birth defects in human. Nevertheless, palatal rugae (or rugae palatinae), which are transversal ridges developing on the secondary palate, received little attention. However, rugae could be useful as landmarks to monitor anterior/posterior (A/P) palatal growth, and they provide a simple model of mesenchymal-epithelial structures arranged in a serial pattern. Results We first determined in which order the nine mouse rugae appear during development. Our results revealed a reiterative process, which is coupled with A/P growth of palatal shelves, and by which rugae 3 to 7b are sequentially interposed, in the increasing distance between the second most anterior ruga, ruga 2, and the two most posterior rugae, rugae 8 and 9. We characterized the steps of ruga interposition in detail, showing that a new ruga forms from an active zone of high proliferation rate, next to the last formed ruga. Then, by analyzing the polymorphism of wild type and EdaTa mutant mice, we suggest that activation-inhibition mechanisms may be involved in positioning new rugae, like for other skin appendages. Finally, we show that the ruga in front of which new rugae form, i.e. ruga 8 in mouse, coincides with an A/P gene expression boundary in the palatal shelves (Shox2/Meox2-Tbx22). This coincidence is significant, since we also found it in hamster, despite differences in the adult ruga pattern of these two species. Conclusion We showed that palatal rugae are sequentially added to the growing palate, in an interposition process that appears to be dependent on activation-inhibition mechanisms and reveals a new developmental boundary in the growing palate. Further studies on rugae may help to shed light on both the development and evolution of structures arranged in regular patterns. Moreover, rugae will undoubtedly be powerful tools to further study the anteroposterior regionalization of the growing palate.
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Affiliation(s)
- Sophie Pantalacci
- Molecular Zoology, Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, Université Lyon 1, CNRS, INRA, Ecole Normale Supérieure de Lyon, Lyon, France.
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Gu S, Wei N, Yu X, Jiang Y, Fei J, Chen Y. Mice with an anterior cleft of the palate survive neonatal lethality. Dev Dyn 2008; 237:1509-16. [PMID: 18393307 DOI: 10.1002/dvdy.21534] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Many genes are known to function in a region-specific manner in the developing secondary palate. We have previously shown that Shox2-deficient embryos die at mid-gestation stage and develop an anterior clefting phenotype. Here, we show that mice carrying a conditional inactivation of Shox2 in the palatal mesenchyme survive the embryonic and neonatal lethality, but develop a wasting syndrome. Phenotypic analyses indicate a delayed closure of the secondary palate at the anterior end, leading to a failed fusion of the primary and secondary palates. Consistent with a role proposed for Shox2 in skeletogenesis, Shox2 inactivation causes a significantly reduced bone formation in the hard palate, probably due to a down-regulation of Runx2 and Osterix. We conclude that the secondary palatal shelves are capable of fusion with each other, but fail to fuse with the primary palate in a developmentally delayed manner. Mice carrying an anterior cleft can survive neonatal lethality.
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Affiliation(s)
- Shuping Gu
- Section of Oral Biology, The Ohio State University College of Dentistry, Columbus, Ohio 43210, USA
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Welsh IC, Hagge-Greenberg A, O'Brien TP. A dosage-dependent role for Spry2 in growth and patterning during palate development. Mech Dev 2007; 124:746-61. [PMID: 17693063 PMCID: PMC2043129 DOI: 10.1016/j.mod.2007.06.007] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2007] [Revised: 06/12/2007] [Accepted: 06/30/2007] [Indexed: 11/28/2022]
Abstract
The formation of the palate involves the coordinated outgrowth, elevation and midline fusion of bilateral shelves leading to the separation of the oral and nasal cavities. Reciprocal signaling between adjacent fields of epithelial and mesenchymal cells directs palatal shelf growth and morphogenesis. Loss of function mutations in genes encoding FGF ligands and receptors have demonstrated a critical role for FGF signaling in mediating these epithelial-mesenchymal interactions. The Sprouty family of genes encode modulators of FGF signaling. We have established that mice carrying a deletion that removes the FGF signaling antagonist Spry2 have cleft palate. We show that excessive cell proliferation in the Spry2-deficient palate is accompanied by the abnormal progression of shape changes and movements required for medially directed shelf outgrowth and midline contact. Expression of the FGF responsive transcription factors Etv5, Msx1, and Barx1, as well as the morphogen Shh, is restricted to specific regions of the developing palate. We detected elevated and ectopic expression of these transcription factors and disorganized Shh expression in the Spry2-deficient palate. Mice carrying a targeted disruption of Spry2 fail to complement the craniofacial phenotype characterized in Spry2 deletion mice. Furthermore, a Spry2-BAC transgene rescues the palate defect. However, the BAC transgenic mouse lines express reduced levels of Spry2. The resulting hypomorphic phenotype demonstrates that palate development is Spry2 dosage sensitive. Our results demonstrate the importance of proper FGF signaling thresholds in regulation of epithelial-mesenchymal interactions and cellular responses necessary for coordinated morphogenesis of the face and palate.
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Affiliation(s)
- Ian C Welsh
- Department of Biomedical Sciences, Cornell University, Ithaca, NY 14853, USA
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15
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Ishizaki K, Sakurai K, Tazaki M, Inoue T. Response of Merkel cells in the palatal rugae to the continuous mechanical stimulation by palatal plate. Somatosens Mot Res 2006; 23:63-72. [PMID: 16846961 DOI: 10.1080/08990220600741069] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The aim of the present study was to investigate the responses of Merkel cells that are numerous in the palatine rugae, due to the continuous mechanical stimulation exerted by the palatal plate. Forty golden hamsters were used in this experiment. The palatal plate was made of adhesive resin and it was set on the palate of the animal. To exert a continuous pressure, a 0.8 mm elevation on the internal surface of the palatal plate was created at the middle portion of the fourth palatine ruga. Thereafter, the number of Merkel cells in the mucosa was calculated by immunohistochemical observation. Morphological changes of Merkel cells were examined by electron microscopy. There was significant difference among the control and any of the treated groups on the number of CK20 positive Merkel cells (p < 0.05) and that numbers were decreased at the sites where continuous mechanical stimulation was exerted. Degeneration of the cytoplasm mitochondria and nerve endings, and a decrease in both the number of neurosecretory granules and cytoplasmic processes were observed. Furthermore, the presence of nuclear chromatin aggregation and fragmentation was recognized. The continuous mechanical stimulation by the palatal plate affected the responses of Merkel cells and nerve endings, thus inducing a decrease in the number of Merkel cells. A portion of these changes was also associated with the expression of apoptosis.
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Affiliation(s)
- Ken Ishizaki
- Department of Complete Denture Prosthodontics, Tokyo Dental College, Chiba, Japan
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Sasaki Y, O'Kane S, Dixon J, Dixon MJ, Ferguson MWJ. Temporal and spatial expression of Pax9 and Sonic hedgehog during development of normal mouse palates and cleft palates in TGF-beta3 null embryos. Arch Oral Biol 2006; 52:260-7. [PMID: 17097601 DOI: 10.1016/j.archoralbio.2006.09.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2006] [Accepted: 09/18/2006] [Indexed: 11/27/2022]
Abstract
Transforming growth factor-beta (TGF-beta3) gene disruption causes cleft secondary palate. Pax9 and Sonic hedgehog (Shh) genes are involved in the patterning of vertebrate embryonic tissues, including the facial skeleton. We investigated the expression of Pax9 and Shh genes during normal mouse palate development and in the developing cleft palates of TGF-beta3 null embryos. Whole mount in situ hybridization was conducted with use of Pax9 and Shh riboprobes for TGF-beta3 null, heterozygous and wild type mice at E12.5-E16.5. Histological analysis was processed by section in situ hybridization. In the wild type, Pax9 and Shh were expressed in the palate between E12.5-E15.5. Shh expression in the secondary palate was restricted to the rugae and the soft palate. Pax9 expression was predominantly in the palatal medial edge between E14.5 and E15.5. These patterns suggest that Shh and Pax9 may have different functions during palate development. In TGF-beta3 null mice, both genes expression patterns in the palate were different to those in wild type mice. In TGF-beta3 null mice, Pax9 expression was much reduced in the palatal medial edge at the critical time of palatal fusion (E14.5-E15.5). Shh expression in the palates of TGF-beta3 null mice was reduced throughout E12.5-E15.5, whilst Shh expression in heterozygous did not appear down regulated compared with the wild type. These results indicate that Pax9 and Shh expression are altered when the TGF-beta3 gene is deleted and suggest that Pax9 and Shh may be involved in the TGF-beta3 regulation of normal palatal fusion.
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Affiliation(s)
- Yasunori Sasaki
- Faculty of Life Sciences, University of Manchester, Manchester, UK.
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Okano J, Suzuki S, Shiota K. Regional heterogeneity in the developing palate: morphological and molecular evidence for normal and abnormal palatogenesis. Congenit Anom (Kyoto) 2006; 46:49-54. [PMID: 16732762 DOI: 10.1111/j.1741-4520.2006.00103.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Development of the mammalian secondary palate involves the growth, elevation, medial elongation and midline fusion of palatal shelves. Recent morphological and molecular studies on palatogenesis suggest that the developing palate is not a homogeneous organ but each part may behave differently during organogenesis. Especially, some key molecules involved in palate development have been shown to exhibit heterogeneous patterns of expression in the palatal tissue. Therefore it seems necessary to recognize the regional heterogeneity of the developing palate along the dorsoventral and anteroposterior axes when analyzing the mechanisms of normal and abnormal morphogenesis. Based on recent studies, we discuss the issue of the regional heterogeneity in the fetal palate and propose a principle that divides the fetal palate into several regions from the morphological and molecular standpoint.
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Affiliation(s)
- Junko Okano
- Department of Anatomy and Developmental Biology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
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18
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Abstract
The success of vertebrates was due in part to the acquisition and modification of jaws. Jaws are principally derived from the branchial arches, embryonic structures that exhibit proximodistal polarity. To investigate the mechanisms that specify the identity of skeletal elements within the arches, we examined mice lacking expression of Dlx5 and Dlx6, linked homeobox genes expressed distally but not proximally within the arches. Dlx5/6-/- mutants exhibit a homeotic transformation of lower jaws to upper jaws. We suggest that nested Dlx expression in the arches patterns their proximodistal axes. Evolutionary acquisition and subsequent refinement of jaws may have been dependent on modification of Dlx expression.
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Affiliation(s)
- Michael J Depew
- Nina Ireland Laboratory of Developmental Neurobiology, 401 Parnassus Avenue, University of California, San Francisco, San Francisco, CA 94143-0984, USA
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Takanosu M, Amasaki H, Iwama Y, Ogawa M, Hibi S, Suzuki K. Epithelial cell proliferation and apoptosis in the developing murine palatal rugae. Anat Histol Embryol 2002; 31:9-14. [PMID: 11841352 DOI: 10.1046/j.1439-0264.2002.00351.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Epithelial cell proliferation and apoptosis during morphogenesis of the murine palatal rugae (PR) were examined histochemically by using anti-bromodeoxyuridine (BrdU) and the terminal deoxynucleotidyl transferase-mediated UTP nick-end-labelling (TUNEL) technique. Formation of the PR rudiment was observed as an epithelial placode in fetuses at 12.5 days post-coitus (dpc). During the PR formation, BrdU-positive cells were detected mainly in the epithelium of the interplacode and interprotruding areas in fetuses administered BrdU maternally at 2 h before killing. TUNEL-positive cells were detected only at the epithelial placode area in 12.5-14.5 dpc. At 16.5-18.5 dpc, the BrdU-positive cells were decreased in number in the epithelial cells at the interprotruding area of the PR. Only a few TUNEL-positive cells were observed in the protruding area of the PR at 16.5 dpc. These results suggest that cell proliferation and apoptosis in the palatal epithelium are involved spatiotemporally in the murine PR morphogenesis.
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Affiliation(s)
- M Takanosu
- Department of Veterinary Physiology, Nippon Veterinary and Animal Science University, Tokyo 180-8602, Japan
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Ikemi N, Otani Y, Ikegami T, Yasuda M. Palatal ruga anomaly induced by all-trans-retinoic acid in the Crj:SD rat: possible warning sign of teratogenicity. Reprod Toxicol 2001; 15:87-93. [PMID: 11137383 DOI: 10.1016/s0890-6238(00)00114-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have reported that the critical period for cleft palate formation by all-trans-retinoic acid (RA) is on gestation day 14 in rats, and classified abnormal patterns of palatal rugae into minor variations and anomalous patterns. In this study, we examined the dose-response relationship for cleft palate and an anomalous pattern of palatal rugae formation and discussed the toxicologic significance of the palatal ruga anomaly as an indicator of teratogenicity. The ED(50) values for cleft palate and anomalous pattern were calculated to be 43.6 and 4.95 mg/kg, respectively. The results clearly show that anomalous rugal patterns occur in the fetuses from litters receiving RA at a lower dose than cleft palate induction; the anomalous ruga pattern is thus more sensitive than cleft palate induction. The anomalies of palatal rugae could be taken as a warning sign or an indicator of teratogenicity of a drug.
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Affiliation(s)
- N Ikemi
- Agrochemical Development Department, Otsuka Chemical Co., Ltd., 3-2-27, Ote-dori, Chuo-ku, 540-0021, Osaka, Japan.
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21
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Takagi TN, Matsui KA, Yamashita K, Ohmori H, Yasuda M. Pathogenesis of cleft palate in mouse embryos exposed to 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD). TERATOGENESIS, CARCINOGENESIS, AND MUTAGENESIS 2000; 20:73-86. [PMID: 10679751 DOI: 10.1002/(sici)1520-6866(2000)20:2<73::aid-tcm3>3.0.co;2-m] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induces cleft palate in mouse embryos. It has been believed that TCDD inhibits palatal fusion by suppression of disappearance of medial edge epithelial (MEE) cells on palatal shelves. However, we found that exencephalic mouse embryos were resistant to the cleft palate-inducing action of TCDD. In the present study, we examined cell kinetics in MEE and palatal mesenchyme in embryos exposed to TCDD with or without exencephaly for elucidation of pathogenesis of cleft palate by TCDD. Pregnant Jcl:ICR mice were given TCDD orally at 40 microg/kg at gestation day (GD) 12.5. Embryos were harvested between GD 13.5 and GD 14.5 and examined for cell kinetics by bromodeoxyuridine (BrdU) and TUNEL methods. Exencephaly was induced by intraperitoneal injection of CdCl(2) at 6 mg/kg at GD 7.5. BrdU-positive cells were decreased in TCDD-treated embryos in MEE and mesenchymal cells. TUNEL-positive cells were detected in MEE both in TCDD-treated and untreated control embryos, as well as in embryos with or without exencephaly. We also measured the gap between shelves between GD 14. 0 and GD 14.5. There were no differences at GD 14.0 between control and TCDD-exposed embryos, but at GD 14.25 and GD 14.5, TCDD-exposed embryos had wider gaps than controls. These findings indicate that cleft palate by TCDD results from poor development of palatal shelves. Teratogenesis Carcinog. Mutagen. 20:73-86, 2000.
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Affiliation(s)
- T N Takagi
- Department of Otolaryngology, Hiroshima University School of Medicine, Hiroshima, Japan
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22
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Ikemi N, Kawata M, Yasuda M. All-trans-retinoic acid-induced variant patterns of palatal rugae in Crj:SD rat fetuses and their potential as indicators for teratogenicity. Reprod Toxicol 1995; 9:369-77. [PMID: 7496093 DOI: 10.1016/0890-6238(95)00024-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
We determined the critical period for cleft palate formation in the presence of all-trans-retinoic acid (RA) and defined anomalous patterns within the variants of palatal rugae. The total incidence of variant patterns of palatal rugae in rat fetuses treated with RA at 40 mg/kg on gestation days 13 and 14 dramatically increased with concurrent induction of cleft palate. Correspondence analysis connected the variant patterns of palatal rugae, such as median discontinuity, extra peaks, supernumerary ruga (extra type), shortness, fusion, and bifurcation, with cleft palate. Therefore, these variants were concluded to be anomalous. The incidence of the anomalous patterns of palatal rugae was about 10 times that of cleft palate, and consequently, these anomalies might be sensitive indicators of the teratogenicity of a chemical.
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Affiliation(s)
- N Ikemi
- Naruto Research Center, Otsuka Chemical Co., Ltd., Tokushima, Japan
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Zucker RM, Elstein KH, Shuey DL, Ebron-McCoy M, Rogers JM. Utility of fluorescence microscopy in embryonic/fetal topographical analysis. TERATOLOGY 1995; 51:430-4. [PMID: 7502242 DOI: 10.1002/tera.1420510608] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
For topographical analysis of developing embryos, investigators typically rely on scanning electron microscopy (SEM) to provide the surface detail not attainable with light microscopy. SEM is an expensive and time-consuming technique, however, and the preparation procedure may alter morphology and leave the specimen friable. We report that by using a high-resolution compound epifluorescence microscope with inexpensive low-power objectives and the fluorochrome acridine orange, we were able to obtain surface images of fixed or fresh whole rat embryos and fetal palates of considerably greater topographical detail than those obtained using routine light microscopy. Indeed the resulting high-resolution images afford not only superior qualitative documentation of morphological observations, but the capability for detailed morphometry via digitization and computer-assisted image analysis.
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Affiliation(s)
- R M Zucker
- Developmental Toxicology Division, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA
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Sakamoto MK, Nakamura K, Handa J, Kihara T, Tanimura T. Studies of variant palatal rugae in normal and corticosteroid-treated mouse embryos. Anat Rec (Hoboken) 1991; 230:121-30. [PMID: 2064023 DOI: 10.1002/ar.1092300112] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Fourteen- and 15-day mouse embryos treated with triamcinolone on day 11 of gestation were examined for the presence of variant rugae. Nontreated mouse embryos served as controls. Variant rugae found were classified into five types. All five types of variations (bifurcation, division, supernumerary, shortness and cross) were observed in triamcinolone-treated embryos, and shortness was most frequently seen. Supernumerary, bifurcation and division were ranked next, following by cross. Variant, rugae, except the cross, were also observed in non-treated embryos in low frequencies, but more than one-half of them were the bifurcation of the second ruga. Divided rugae ranked next, and supernumerary and shortness were found occasionally. Except for the bifurcated and supernumerary rugae, the greater part of the variant rugae were found in the fifth and fourth ruga in the triamcinolone-treated groups and in the fifth ruga in the nontreated groups. As the incidence of variant rugae in the triamcinolone-treated embryos was significantly higher than that in the nontreated, it was regarded as one of the changes induced by the corticoid. Based on the characteristic features of the rugal region, it is speculated that the formation of variant rugae is associated with the disturbance of normal epithelial-mesenchymal interaction which may be controlled by the nerve fibers appearing at the time of rugal formation. The relationship between the increased appearance of variant rugae and the failure of palatal shelf elevation was examined, but no direct evidence was obtained.
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Affiliation(s)
- M K Sakamoto
- Department of Anatomy, Kinki University School of Medicine, Osaka, Japan
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