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1.
Ann Anat ; 253: 152227, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38336176

RESUMO

BACKGROUND: Vascularization is an essential event for both embryonic organ development and tissue repair in adults. During mouse tooth development, endothelial cells migrate into dental papilla during the cap stage, and form blood vessels through angiogenesis. Megakaryocytes and/or platelets, as other hematopoietic cells, express angiogenic molecules and can promote angiogenesis in adult tissues. However, it remains unknown which cells are responsible for attracting and leading blood vessels through the dental papilla during tooth development. METHODS: Here we analyzed the spatiotemporal expression of c-Mpl mRNA in developing molar teeth of fetal mice. Expression patterns were then compared with those of several markers of hematopoietic cells as well as of angiogenic elements including CD41, erythropoietin receptor, CD34, angiopoietin-1 (Ang-1), Tie-2, and vascular endothelial growth factor receptor2 (VEGFR2) through in situ hybridization or immunohistochemistry. RESULTS: Cells expressing c-Mpl mRNA was found in several parts of the developing tooth germ, including the peridental mesenchyme, dental papilla, enamel organ, and dental lamina. This expression occurred in a spatiotemporally controlled fashion. CD41-expressing cells were not detected during tooth development. The spatiotemporal expression pattern of c-Mpl mRNA in the dental papilla was similar to that of Ang-1, which preceded invasion of endothelial cells. Eventually, at the early bell stage, the c-Mpl mRNA signal was detected in morphologically differentiating odontoblasts that accumulated in the periphery of the dental papilla along the inner enamel epithelium layer of the future cusp region. CONCLUSION: During tooth development, several kinds of cells express c-Mpl mRNA in a spatiotemporally controlled fashion, including differentiating odontoblasts. We hypothesize that c-Mpl-expressing cells appearing in the forming dental papilla at the cap stage are odontoblast progenitor cells that migrate to the site of odontoblast differentiation. There they attract vascular endothelial cells into the forming dental papilla and lead cells toward the inner enamel epithelium layer through production of angiogenic molecules (e.g., Ang-1) during migration to the site of differentiation. C-Mpl may regulate apoptosis and/or proliferation of expressing cells in order to execute normal development of the tooth.


Assuntos
Dente , Fator A de Crescimento do Endotélio Vascular , Animais , Camundongos , Células Endoteliais , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Germe de Dente/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo
2.
J Dent Res ; 103(4): 345-358, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38407002

RESUMO

Tooth development and regeneration are regulated through a complex signaling network. Previous studies have focused on the exploration of intracellular signaling regulatory networks, but the regulatory roles of extracellular networks have only been revealed recently. Proteoglycans, which are essential components of the extracellular matrix (ECM) and pivotal signaling molecules, are extensively involved in the process of odontogenesis. Proteoglycans are composed of core proteins and covalently attached glycosaminoglycan chains (GAGs). The core proteins exhibit spatiotemporal expression patterns during odontogenesis and are pivotal for dental tissue formation and periodontium development. Knockout of core protein genes Biglycan, Decorin, Perlecan, and Fibromodulin has been shown to result in structural defects in enamel and dentin mineralization. They are also closely involved in the development and homeostasis of periodontium by regulating signaling transduction. As the functional component of proteoglycans, GAGs are negatively charged unbranched polysaccharides that consist of repeating disaccharides with various sulfation groups; they provide binding sites for cytokines and growth factors in regulating various cellular processes. In mice, GAG deficiency in dental epithelium leads to the reinitiation of tooth germ development and the formation of supernumerary incisors. Furthermore, GAGs are critical for the differentiation of dental stem cells. Inhibition of GAGs assembly hinders the differentiation of ameloblasts and odontoblasts. In summary, core proteins and GAGs are expressed distinctly and exert different functions at various stages of odontogenesis. Given their unique contributions in odontogenesis, this review summarizes the roles of proteoglycans and GAGs throughout the process of odontogenesis to provide a comprehensive understanding of tooth development.


Assuntos
Glicosaminoglicanos , Odontogênese , Camundongos , Animais , Glicosaminoglicanos/metabolismo , Camundongos Knockout , Odontogênese/genética , Proteínas da Matriz Extracelular/metabolismo , Germe de Dente/metabolismo
3.
Int J Oral Sci ; 16(1): 15, 2024 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-38369512

RESUMO

Mammalian teeth, developing inseparable from epithelial-mesenchymal interaction, come in many shapes and the key factors governing tooth morphology deserve to be answered. By merging single-cell RNA sequencing analysis with lineage tracing models, we have unearthed a captivating correlation between the contrasting morphology of mouse molars and the specific presence of PRX1+ cells within M1. These PRX1+ cells assume a profound responsibility in shaping tooth morphology through a remarkable divergence in dental mesenchymal cell proliferation. Deeper into the mechanisms, we have discovered that Wnt5a, bestowed by mesenchymal PRX1+ cells, stimulates mesenchymal cell proliferation while orchestrating molar morphogenesis through WNT signaling pathway. The loss of Wnt5a exhibits a defect phenotype similar to that of siPrx1. Exogenous addition of WNT5A can successfully reverse the inhibited cell proliferation and consequent deviant appearance exhibited in Prx1-deficient tooth germs. These findings bestow compelling evidence of PRX1-positive mesenchymal cells to be potential target in regulating tooth morphology.


Assuntos
Células-Tronco Mesenquimais , Dente Molar , Animais , Camundongos , Dente Molar/crescimento & desenvolvimento , Morfogênese , Germe de Dente/crescimento & desenvolvimento
4.
Cell Prolif ; 57(6): e13598, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38196265

RESUMO

Ecto-mesenchymal cells of mammalian tooth germ develops from cranial neural crest cells. These cells are recognised as a promising source for tooth development and regeneration. Despite the high heterogeneity of the neural crest, the cellular landscape of in vitro cultured cranial neural crest cells (CNCCs) for odontogenesis remains unclear. In this study, we used large-scale single-cell RNA sequencing to analyse the cellular landscape of in vitro cultured mouse CNCCs for odontogenesis. We revealed distinct cell trajectories from primary cells to passage 5 and identified a rare Alx3+/Barx1+ sub-population in primary CNCCs that differentiated into two odontogenic clusters characterised by the up-regulation of Pax9/Bmp3 and Lhx6/Dmp1. We successfully induced whole tooth-like structures containing enamel, dentin, and pulp under the mouse renal capsule using in vitro cultured cells from both cranial and trunk neural crests with induction rates of 26.7% and 22.1%, respectively. Importantly, we confirmed only cells sorted from odontogenic path can induce tooth-like structures. Cell cycle and DNA replication genes were concomitantly upregulated in the cultured NCCs of the tooth induction groups. Our data provide valuable insights into the cell heterogeneity of in vitro cultured CNCCs and their potential as a source for tooth regeneration.


Assuntos
Diferenciação Celular , Crista Neural , Odontogênese , RNA-Seq , Análise de Célula Única , Animais , Crista Neural/citologia , Crista Neural/metabolismo , Camundongos , Odontogênese/genética , Análise de Célula Única/métodos , Células Cultivadas , Germe de Dente/metabolismo , Germe de Dente/citologia , Análise da Expressão Gênica de Célula Única
5.
J Morphol ; 285(1): e21657, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38100745

RESUMO

Studies of teleost teeth are important for understanding the evolution and mechanisms of tooth development, replacement, and regeneration. Here, we used gross specimens, microcomputed tomography, and histological analysis to characterize tooth structure, development, and resorption patterns in adult Pelteobagrus fulvidraco. The oral and pharyngeal teeth are villiform and conical. Multiple rows of dentition are densely distributed and the tooth germ is derived from the epithelium. P. fulvidraco exhibits a discontinuous and non-permanent dental lamina. Epithelial cells surround the teeth and are separated into distinct tooth units by mesenchymal tissue. Tooth development is completed in the form of independent tooth units. P. fulvidraco does not undergo simultaneous tooth replacement. Based on tooth development and resorption status, five forms of teeth are present in adult P. fulvidraco: developing tooth germs, accompanied by relatively immature tooth germs; mature and well-mineralized tooth accompanied by one tooth germ; teeth that have begun resorption, but not completely fractured; fractured teeth with only residual attachment to the underlying bone; and teeth that are completely resorbed and detached. Seven biological stages of a tooth in P. fulvidraco were also described.


Assuntos
Peixes-Gato , Dente , Animais , Dente/diagnóstico por imagem , Microtomografia por Raio-X , Odontogênese , Germe de Dente/diagnóstico por imagem
6.
J Mol Histol ; 54(6): 665-673, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37787911

RESUMO

Histone lactylation on its lysine (K) residues has been reported to have indispensable roles in lung fibrosis, embryogenesis, neural development, inflammation, and tumors. However, little is known about the lactylation activity towards histone lysine residue during tooth development. We investigated the dynamic patterns of lactate-derived histone lysine lactylation (Kla) using a pan-Kla antibody during murine tooth development, including lower first molar and lower incisor. The results showed that pan-Kla exhibited temporo-spatial patterns in both dental epithelium and mesenchyme cells during development. Notably, pan-Kla was identified in primary enamel knot (PEK), stratum intermedium (SI), stellate reticulum (SR), dental follicle cells, odontoblasts, ameloblasts, proliferating cells in dental mesenchyme, as well as osteoblasts around the tooth germ. More importantly, pan-Kla was also identified to be co-localized with neurofilament during tooth development, suggesting histone lysine lactylation may be involved in neural invasion during tooth development. These findings suggest that histone lysine lactylation may play important roles in regulating tooth development.


Assuntos
Histonas , Lisina , Camundongos , Animais , Odontogênese , Germe de Dente , Ameloblastos
7.
Biochem Biophys Res Commun ; 679: 167-174, 2023 10 30.
Artigo em Inglês | MEDLINE | ID: mdl-37703759

RESUMO

Murine tooth germ development proceeds in continuous sequential steps with reciprocal interactions between the odontogenic epithelium and the adjacent mesenchyme, and several growth factor signaling pathways and their activation are required for tooth germ development. The expression of ADP-ribosylation factor (Arf)-like 4c (Arl4c) has been shown to induce cell proliferation, and is thereby involved in epithelial morphogenesis and tumorigenesis. In contrast, the other functions of Arl4c (in addition to cellular growth) are largely unknown. Although we recently demonstrated the involvement of the upregulated expression of Arl4c in the proliferation of ameloblastomas, which have the same origin as odontogenic epithelium, its effect on tooth germ development remains unclear. In the present study, single-cell RNA sequencing (scRNA-seq) analysis revealed that the expression of Arl4c, among 17 members of the Arf-family, was specifically detected in odontogenic epithelial cells, such as those of the stratum intermedium, stellate reticulum and outer enamel epithelium, of postnatal day 1 (P1) mouse molars. scRNA-seq analysis also demonstrated the higher expression of Arl4c in non-ameloblast and inner enamel epithelium, which include immature cells, of P7 mouse incisors. In the mouse tooth germ rudiment culture, treatment with SecinH3 (an inhibitor of the ARNO/Arf6 pathway) reduced the size, width and cusp height of the tooth germ and the thickness of the eosinophilic layer, which would involve the synthesis of dentin and enamel matrix organization. In addition, loss-of-function experiments using siRNAs and shRNA revealed that the expression of Arl4c was involved in cell proliferation and osteoblastic cytodifferentiation in odontogenic epithelial cells. Finally, RNA-seq analysis with a gene set enrichment analysis (GSEA) and Gene Ontology (GO) analysis showed that osteoblastic differentiation-related gene sets and/or GO terms were downregulated in shArl4c-expressing odontogenic epithelial cells. These results suggest that the Arl4c-ARNO/Arf6 pathway axis contributes to tooth germ development through osteoblastic/ameloblastic differentiation.


Assuntos
Ameloblastoma , Dente , Camundongos , Animais , Germe de Dente , Células Epiteliais/metabolismo , Epitélio/metabolismo , Ameloblastoma/metabolismo , Diferenciação Celular , Dente/metabolismo
8.
PeerJ ; 11: e15896, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37692112

RESUMO

The retinoic acid (RA) pathway was shown to be important for tooth development in mammals, and suspected to play a key role in tooth evolution in teleosts. The general modalities of development of tooth and "tooth-like" structures (collectively named odontodes) seem to be conserved among all jawed vertebrates, both with regard to histogenesis and genetic regulation. We investigated the putative function of RA signalling in tooth and scale initiation in a cartilaginous fish, the small-spotted catshark Scyliorhinus canicula. To address this issue, we identified the expression pattern of genes from the RA pathway during both tooth and scale development and performed functional experiments by exposing small-spotted catshark embryos to exogenous RA or an inhibitor of RA synthesis. Our results showed that inhibiting RA synthesis affects tooth but not caudal primary scale development while exposure to exogenous RA inhibited both. We also showed that the reduced number of teeth observed with RA exposure is probably due to a specific inhibition of tooth bud initiation while the observed effects of the RA synthesis inhibitor is related to a general delay in embryonic development that interacts with tooth development. This study provides data complementary to previous studies of bony vertebrates and support an involvement of the RA signalling pathway toolkit in odontode initiation in all jawed vertebrates. However, the modalities of RA signalling may vary depending on the target location along the body, and depending on the species lineage.


Assuntos
Elasmobrânquios , Tretinoína , Feminino , Animais , Tretinoína/farmacologia , Transdução de Sinais , Odontogênese , Germe de Dente , Mamíferos
9.
STAR Protoc ; 4(3): 102377, 2023 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-37379218

RESUMO

Subcapsular transplantation of developing tissues and organs into the richly vascularized murine kidney provides the necessary trophic support, thus ensuring proper completion of their growth.1,2,3 Here, we provide a protocol for kidney capsule transplantation that allows the full differentiation of embryonic teeth previously exposed to chemicals. We describe steps for dissection and in vitro culture of embryonic teeth, followed by transplantation of tooth germs. We then detail harvesting of kidneys for further analysis. For complete details on the use and execution of this protocol, please refer to Mitsiadis et al.4.


Assuntos
Germe de Dente , Dente , Animais , Camundongos , Dente/cirurgia , Rim/cirurgia , Epitélio
10.
J Dent Res ; 102(7): 825-834, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37246809

RESUMO

The enamel knot (EK), located at the center of cap stage tooth germs, is a transitory cluster of nondividing epithelial cells. The EK acts as a signaling center that provides positional information for tooth morphogenesis and regulates the growth of tooth cusps. To identify species-specific cuspal patterns, this study analyzed the cellular mechanisms in the EK that were related to bone morphogenetic protein (Bmp), which plays a crucial role in cell proliferation and apoptosis. To understand the cellular mechanisms in the EK, the differences between 2 species showing different cuspal patterning, mouse (pointy bunodont cusp) and gerbil (flat lophodont cusp), were analyzed with quantitative reverse transcriptase polymerase chain reaction and immunofluorescent staining. Based on these, we performed protein-soaked bead implantation on tooth germs of the 2 different EK regions and compared the cellular behavior in the EKs of the 2 species. Many genes related with cell cycle, cell apoptosis, and cell proliferation were involved in BMP signaling in the EK during tooth development. A comparison of the cell proliferation and apoptosis associated with Bmp revealed distinctive patterns of the cellular mechanisms. Our findings indicate that the cellular mechanisms, such as cell proliferation and apoptosis, in the EK are related to Bmp4 and play an important role in tooth morphogenesis.


Assuntos
Dente , Animais , Camundongos , Esmalte Dentário/metabolismo , Odontogênese/genética , Germe de Dente , Proteínas Morfogenéticas Ósseas/metabolismo , Proliferação de Células , Apoptose , Proteína Morfogenética Óssea 4/metabolismo
11.
J Anat ; 243(3): 534-544, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37038912

RESUMO

Our understanding of the initiation and cellular mechanisms underlying endochondral resorption of Meckel's cartilage (MC) remains limited. Several studies have shown that the resorption site of MC and the mandibular incisor tooth germ are located close to each other. However, whether incisor tooth germ development is involved in MC resorption remains unclear. In this study, we aimed to elucidate the spatio-temporal interaction between the initiation site of MC resorption and the development of incisor tooth germs in an embryonic mouse model. To this effect, we developed a histology-based three-dimensional (3D) reconstruction technique using paraffin-embedded serial sections of various tissues in the jaw. The serial sections were cut in the frontal section and the tissue constituents (e.g., MC, incisor, and mineralized mandible) were studied using conventional and enzyme-based histochemistry. The outline of each component was marked on the frontal sectional images and 3D structures were constructed. To assess the vascular architecture at the site of MC resorption, immunohistochemical staining using anti-laminin, anti-factor VIII, and anti-VEGF antibodies was performed. MC resorption was first observed on the lateral incisor-facing side of the cartilage rods at sites anterior to the mental foramen on E16.0. The 3D analysis suggested that: (a) the posterior region of the clastic cartilage resorption corresponds to the cervical loop of the incisor; (b) the cervical portion of the tooth germ inflates probably due to temporal cellular congestion prior to differentiation into matrix-producing cells; (c) the incisor tooth germ tissue is present in close proximity to MC even in mouse with continuously growing tooth and determines the disappearance of MC as the tooth development.


Assuntos
Cartilagem , Incisivo , Camundongos , Animais , Germe de Dente , Diferenciação Celular , Histocitoquímica , Mandíbula
12.
Artigo em Inglês | MEDLINE | ID: mdl-36925450

RESUMO

OBJECTIVE: The aim of this study was to investigate and compare the immunohistochemical expression of connexin 43 (Cx43) in tooth germs (TGs), ameloblastic fibromas (AFs), ameloblastic fibro-odontomas (AFOs), and conventional ameloblastomas (AMs). STUDY DESIGN: Nine TGs, 12 AFs, 12 AFOs, and 27 AMs were evaluated for Cx43 expression by immunohistochemistry. RESULTS: Most of the TGs expressed Cx43 in the mesenchyme (77.6%) and in the late stages of odontogenesis. Cx43 was more highly expressed (P < .05) in the mesenchymal layer of all groups than in the epithelial layer except for the AFOs. When comparing the expression of Cx43 in the different layers of the analyzed groups, statistically significant differences were observed between AFO vs AM (*P = .0158) in the epithelial layer and between AF vs AFO (P** = .0046) in the mesenchymal layer. CONCLUSIONS: The results obtained in this study showed that Cx43 is a protein with important expression in the mesenchymal layer of the embryonic and odontogenic tissues studied. It could be speculated that Cx43 participates in mineralization events based on the relationship of the expression of this protein between the epithelial and mesenchymal layers of odontogenic tissues.


Assuntos
Ameloblastoma , Tumores Odontogênicos , Odontoma , Humanos , Conexina 43/metabolismo , Tumores Odontogênicos/patologia , Ameloblastoma/metabolismo , Germe de Dente/metabolismo , Germe de Dente/patologia , Odontoma/metabolismo
13.
Int J Oral Sci ; 15(1): 14, 2023 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-36927863

RESUMO

Tooth germ injury can lead to abnormal tooth development and even tooth loss, affecting various aspects of the stomatognathic system including form, function, and appearance. However, the research about tooth germ injury model on cellular and molecule mechanism of tooth germ repair is still very limited. Therefore, it is of great importance for the prevention and treatment of tooth germ injury to study the important mechanism of tooth germ repair by a tooth germ injury model. Here, we constructed a Tg(dlx2b:Dendra2-NTR) transgenic line that labeled tooth germ specifically. Taking advantage of the NTR/Mtz system, the dlx2b+ tooth germ cells were depleted by Mtz effectively. The process of tooth germ repair was evaluated by antibody staining, in situ hybridization, EdU staining and alizarin red staining. The severely injured tooth germ was repaired in several days after Mtz treatment was stopped. In the early stage of tooth germ repair, the expression of phosphorylated 4E-BP1 was increased, indicating that mTORC1 is activated. Inhibition of mTORC1 signaling in vitro or knockdown of mTORC1 signaling in vivo could inhibit the repair of injured tooth germ. Normally, mouse incisors were repaired after damage, but inhibition/promotion of mTORC1 signaling inhibited/promoted this repair progress. Overall, we are the first to construct a stable and repeatable repair model of severe tooth germ injury, and our results reveal that mTORC1 signaling plays a crucial role during tooth germ repair, providing a potential target for clinical treatment of tooth germ injury.


Assuntos
Transdução de Sinais , Dente , Animais , Camundongos , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Alvo Mecanístico do Complexo 1 de Rapamicina/farmacologia , Dente/metabolismo , Germe de Dente/metabolismo , Odontogênese
14.
Odontology ; 111(4): 839-853, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36792749

RESUMO

Various growth and transcription factors are involved in tooth development and developmental abnormalities; however, the protein dynamics do not always match the mRNA expression level. Using a proteomic approach, this study comprehensively analyzed protein expression in epithelial and mesenchymal tissues of the tooth germ during development. First molar tooth germs from embryonic day 14 and 16 Crlj:CD1 (ICR) mouse embryos were collected and separated into epithelial and mesenchymal tissues by laser microdissection. Mass spectrometry of the resulting proteins was carried out, and three types of highly expressed proteins [ATP synthase subunit beta (ATP5B), receptor of activated protein C kinase 1 (RACK1), and calreticulin (CALR)] were selected for immunohistochemical analysis. The expression profiles of these proteins were subsequently evaluated during all stages of amelogenesis using the continuously growing incisors of 3-week-old male ICR mice. Interestingly, these three proteins were specifically expressed depending on the stage of amelogenesis. RACK1 was highly expressed in dental epithelial and mesenchymal tissues during the proliferation and differentiation stages of odontogenesis, except for the pigmentation stage, whereas ATP5B and CALR immunoreactivity was weak in the enamel organ during the early stages, but became intense during the maturation and pigmentation stages, although the timing of the increased protein expression was different between the two. Overall, RACK1 plays an important role in maintaining the cell proliferation and differentiation in the apical end of incisors. In contrast, ATP5B and CALR are involved in the transport of minerals and the removal of organic materials as well as matrix deposition for CALR.


Assuntos
Proteômica , Dente , Camundongos , Animais , Masculino , Camundongos Endogâmicos ICR , Odontogênese/genética , Germe de Dente/metabolismo , Órgão do Esmalte/metabolismo , Proteínas/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Dente/metabolismo
15.
Biomed Res Int ; 2023: 4038278, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36820224

RESUMO

Hard tissues make up the vast majority of teeth and are mineralized from the surrounding matrix. If the development of tooth germ is affected during mineralization, hypoplasia of the tooth tissue can occur. To better understand the mechanisms mediating hypoplasia, we need to first study normal development. Using a rodent model, we highlight the transcriptomic changes that occur from the differentiation to secretion stages of mandibular molar germs. The tooth germ was dissected from rats at postnatal day 1.5 or 3.5 for high-throughput sequencing. Combining transcriptome analysis and DNA methylation, we identified 590 differentially expressed genes (436 upregulated and 154 downregulated) and 551 differentially expressed lncRNAs (long noncoding RNA; 369 upregulated and 182 downregulated) which were linked to the biological processes of odontogenesis, amelogenesis, tooth mineralization, and the alteration of extracellular matrix (ECM), especially matrix metalloproteinases (MMPs) and elastin. We found DNA methylation changes in 32 selected fragments involved in 5 chromosomes, 26 targets, and 2 haplotypes. Finally, three novel genes were identified: MMP20, Tgfb3, and Dusp1. Further analysis revealed that MMP20 has a role in odontogenesis and amelogenesis by influencing Slc24a4 and DSPP; Tgfb3 is involved in epithelial cell proliferation, cellular component disassembly process, ECM cellular component, and decomposition of cell components. But lncRNA expression could affect DNA methylation and mRNA expression. Moreover, the degree of DNA methylation could also affect the transcriptome level. Thus, Tgfb3 had no difference in DNA methylation, and Dusp1 conferred no difference at the transcriptome level. These three genes were all enriched in the MAPK pathway and played an important role in ECM remodeling. These data suggest that during the period of the bell differentiation stage to the secretory stage, along with enamel/dentin matrix secretion and hard tissue occurrence, the ECM is remodeled via MAPK signaling.


Assuntos
Transcriptoma , Fator de Crescimento Transformador beta3 , Ratos , Animais , Metaloproteinase 20 da Matriz , Germe de Dente , Odontogênese , Diferenciação Celular , Matriz Extracelular , Perfilação da Expressão Gênica , Transdução de Sinais
16.
Compend Contin Educ Dent ; 44(1): 32-34, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36696276

RESUMO

The autotransplantation of a third molar represents an alternative treatment solution for filling an edentulous space that may exist because of traumatic avulsion, agenesis, large carious processes, or other reasons, particularly in young patients. Autotransplantation can offer many benefits, including maintenance of a normally functioning periodontium, preservation of pulp vitality, and completion of root formation. This case report describes a successful autotransplantation of an open-apex maxillary third molar germ to replace a hopeless mandibular first molar in a growing patient. After 24 months of follow-up, the donor tooth showed physiological mobility, absence of infection and ankylosis, positive pulp vitality, and fully formed periodontal integration. Radiographic examination confirmed a remarkable radicular edification.


Assuntos
Dente Serotino , Dente Molar , Humanos , Transplante Autólogo , Dente Molar/diagnóstico por imagem , Dente Molar/cirurgia , Dente Serotino/cirurgia , Dente Serotino/transplante , Germe de Dente , Seguimentos
17.
J Oral Pathol Med ; 52(2): 181-187, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36207782

RESUMO

BACKGROUND: Primordial odontogenic tumour is a benign mixed neoplasm of recent description, which has histological similarities with other odontogenic tumours such as the ameloblastic fibroma. In this article, we investigate the architecture of the sub-epithelial layer of mesenchymal cells expressing the marker CD34 in primordial odontogenic tumour. OBJECTIVE: Analyse the spatial patterns of CD34 expression in primordial odontogenic tumour and compare them with those in ameloblastic fibroma and the normal tooth germ by means of objective imaging approaches, to better characterise these lesions. METHODS: Two cases of primordial odontogenic tumour, four cases of ameloblastic fibroma and two cases of tooth germ in cap and bell stages were used for morphological, structural and immunohistochemical analyses. RESULTS: CD34 expression was found in vascular endothelium of primordial odontogenic tumour, ameloblastic fibroma and tooth germ. In addition, a characteristic sub-epithelial expression was observed only in primordial odontogenic tumour, corresponding to 84%-86% of the sample boundaries. Moreover, the zone expressing CD34 corresponded with a higher cellularity, which was absent in ameloblastic fibroma and tooth germ. CONCLUSION: Image analysis of the primordial odontogenic tumour architecture revealed characteristics absent in other odontogenic tumours and tooth germs. This study provides additional information to support the idea that this neoplasm is a distinct entity from early stage AF or developing odontoma.


Assuntos
Fibroma , Tumores Odontogênicos , Odontoma , Humanos , Tumores Odontogênicos/patologia , Germe de Dente , Odontoma/patologia , Moléculas de Adesão Celular/análise
18.
Dev Biol ; 495: 8-18, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36565838

RESUMO

In the echidna, after development in utero, the egg is laid in the pouch and incubated for 10 days. During this time, the fetuses develop an egg tooth and caruncle to help them hatch. Using rare and unprecedented access to limited echidna pre- and post-hatching tissues, development of the egg tooth and caruncle were assessed by micro-CT, histology and immunofluorescence. Unlike therian tooth germs that develop by placode invagination, the echidna egg tooth developed by evagination, similar to the first teeth in some reptiles and fish. The egg tooth ankylosed to the premaxilla, rather than forming a tooth root with ligamentous attachment found in other mammals, with loss of the egg tooth associated with high levels of activity odontoclasts and apoptosis. The caruncle formed as a separate mineralisation from the adjacent nasal capsule, and as observed in birds and turtles, the nasal region epithelium on top of the nose expressed markers of cornification. Together, this highlights that the monotreme egg tooth shares many similarities with typical reptilian teeth, suggesting that this tooth has been conserved from a common ancestor of mammals and reptiles.


Assuntos
Tachyglossidae , Dente , Animais , Tachyglossidae/genética , Mamíferos , Répteis , Germe de Dente
19.
Leg Med (Tokyo) ; 60: 102171, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36375422

RESUMO

BACKGROUND: Although dental radiography is a valuable tool for age estimation in forensic anthropology and odontology, very limited radiological data are available regarding tooth development in healthy newborn babies during the first month of life. AIM: This study aimed to describe the radiological findings of tooth development in babies aged 0 days to 1 month. DESIGN: We analyzed the postmortem findings of five newborn babies with no known natural cause of death who had undergone autopsy, computed tomography (CT), and dental radiography. We estimated the gestational age for the babies aged 0 days and analyzed the condition of mandibular symphysis, existence of tooth germs, and presence or absence of calcification of the first permanent molars of all the babies. RESULTS: The calcified form of 20 deciduous teeth, tooth germs of the permanent upper and lower first molars, and non-calcified mandibular symphysis were observed in each case. However, calcification of the first permanent molar was observed in only two 1-month-old babies. CONCLUSION: The dental radiographic findings and anthropometric measurements of non-skeletonized, non-mummified term babies confirmed calcification of all the deciduous teeth and the first permanent molar at the age of 0 days and 1 month, respectively.


Assuntos
Dente Molar , Odontogênese , Lactente , Recém-Nascido , Humanos , Japão , Radiografia , Germe de Dente
20.
Artigo em Inglês | WPRIM (Pacífico Ocidental) | ID: wpr-971602

RESUMO

Tooth germ injury can lead to abnormal tooth development and even tooth loss, affecting various aspects of the stomatognathic system including form, function, and appearance. However, the research about tooth germ injury model on cellular and molecule mechanism of tooth germ repair is still very limited. Therefore, it is of great importance for the prevention and treatment of tooth germ injury to study the important mechanism of tooth germ repair by a tooth germ injury model. Here, we constructed a Tg(dlx2b:Dendra2-NTR) transgenic line that labeled tooth germ specifically. Taking advantage of the NTR/Mtz system, the dlx2b+ tooth germ cells were depleted by Mtz effectively. The process of tooth germ repair was evaluated by antibody staining, in situ hybridization, EdU staining and alizarin red staining. The severely injured tooth germ was repaired in several days after Mtz treatment was stopped. In the early stage of tooth germ repair, the expression of phosphorylated 4E-BP1 was increased, indicating that mTORC1 is activated. Inhibition of mTORC1 signaling in vitro or knockdown of mTORC1 signaling in vivo could inhibit the repair of injured tooth germ. Normally, mouse incisors were repaired after damage, but inhibition/promotion of mTORC1 signaling inhibited/promoted this repair progress. Overall, we are the first to construct a stable and repeatable repair model of severe tooth germ injury, and our results reveal that mTORC1 signaling plays a crucial role during tooth germ repair, providing a potential target for clinical treatment of tooth germ injury.


Assuntos
Animais , Camundongos , Alvo Mecanístico do Complexo 1 de Rapamicina/farmacologia , Transdução de Sinais , Dente/metabolismo , Germe de Dente/metabolismo , Odontogênese
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