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Journal of Dental Research Aug 2023Tooth enamel is generated by ameloblasts. Any failure in amelogenesis results in defects in the enamel, a condition known as amelogenesis imperfecta. Here, we report...
Tooth enamel is generated by ameloblasts. Any failure in amelogenesis results in defects in the enamel, a condition known as amelogenesis imperfecta. Here, we report that mice with deficient autophagy in epithelial-derived tissues ( and conditional knockout mice) exhibit amelogenesis imperfecta. Micro-computed tomography imaging confirmed that enamel density and thickness were significantly reduced in the teeth of these mice. At the molecular level, ameloblast differentiation was compromised through ectopic accumulation and activation of NRF2, a specific substrate of autophagy. Through bioinformatic analyses, we identified , , , , , and as candidate genes related to amelogenesis imperfecta and the NRF2-mediated pathway. To investigate the effects of the ectopic NRF2 pathway activation caused by the autophagy deficiency, we analyzed target gene expression and NRF2 binding to the promoter region of candidate target genes and found suppressed gene expression of , , , and but not of and . Taken together, our findings indicate that autophagy plays a crucial role in ameloblast differentiation and that its failure results in amelogenesis imperfecta through ectopic NRF2 activation.
Topics: Mice; Animals; Ameloblasts; Amelogenesis Imperfecta; X-Ray Microtomography; NF-E2-Related Factor 2; Amelogenesis; Mice, Knockout; Tumor Suppressor Proteins; Repressor Proteins
PubMed: 37249312
DOI: 10.1177/00220345231169220 -
Organogenesis Dec 2023It is known to all that Wnt signaling pathway plays an important role in the early development of tooth. Our previous research found that Wnt signaling pathway played... (Review)
Review
It is known to all that Wnt signaling pathway plays an important role in the early development of tooth. Our previous research found that Wnt signaling pathway played crucial roles in dental development, and mutations in antagonist of Wnt signaling pathway may lead to the formation of supernumerary teeth. However, the expression pattern of Wnt signaling molecules in early development of tooth, especially genes with stage specificity, remains unclear. Hence, we applied RNA-seq analysis to determine the expression levels of wnt signal molecules at five different stages of rat first molar tooth germ. In addition, after literature review we summarized the function of Wnt signaling molecules during tooth development and the relationship between Wnt signaling molecules variation and tooth agenesis. Our research may have implications for exploring the role of Wnt signaling molecules in different stages of tooth development.
Topics: Rats; Animals; Wnt Signaling Pathway; Odontogenesis; Wnt Proteins; Tooth; Molar
PubMed: 37194731
DOI: 10.1080/15476278.2023.2212583 -
BMC Oral Health May 2023To study the odontogenic potential of dental pulp stem cells (DPSCs) after induction with three different bioactive materials: activa bioactive (base/liner) (AB),...
BACKGROUND
To study the odontogenic potential of dental pulp stem cells (DPSCs) after induction with three different bioactive materials: activa bioactive (base/liner) (AB), TheraCal LC (TC), and mineral trioxide aggregate (MTA), when combined with two different types of scaffolds.
METHODS
DPSCs were isolated from freshly extracted premolars of young orthodontic patients, cultured, expanded to passage 4 (P), and characterized by flow cytometric analysis. DPSCs were seeded onto two scaffolds in contact with different materials (AB, TC, and MTA). The first scaffold contained polycaprolactone-nano-chitosan and synthetic hydroxyapatite (PCL-NC-HA), whereas the second scaffold contained polycaprolactone-nano-chitosan and synthetic Mg-substituted hydroxyapatite (PCL-NC-Mg-HA). DPSC viability and proliferation were evaluated at various time points. To assess odontoblastic differentiation, gene expression analysis of dentin sialophosphoprotein (DSPP) by quantitative real-time polymerase chain reaction (qRT-PCR) and morphological changes in cells were performed using inverted microscope phase contrast images and scanning electron microscopy. The fold-change in DSPP between subgroups was compared using a one-way ANOVA. Tukey's test was used to compare the fold-change in DSPP between the two subgroups in multiple comparisons, and P was set at p < 0.05.
RESULTS
DSPP expression was significantly higher in the PCL-NC-Mg-HA group than in the PCL-NC-HA group, and scanning electron microscopy revealed a strong attachment of odontoblast-like cells to the scaffold that had a stronger odontogenic differentiation effect on DPSCs than the scaffold that did not contain magnesium. MTA has a significantly higher odontogenic differentiation effect on cultured DPSCs than AB or TC does. The combination of scaffolds and bioactive materials improves DPSCs induction in odontoblast-like cells.
CONCLUSIONS
The PCL-NC-Mg-HA scaffold showed better odontogenic differentiation effects on cultured DPSCs. Compared to AB and TC, MTA is the most effective bioactive material for inducing the odontogenic differentiation of cultured DPSCs.
Topics: Humans; Cell Differentiation; Cell Proliferation; Cells, Cultured; Dental Pulp; Hydroxyapatites; Odontogenesis; Stem Cells; Bicuspid; Real-Time Polymerase Chain Reaction
PubMed: 37127635
DOI: 10.1186/s12903-023-02975-3 -
International Journal of Molecular... Apr 2023Heat shock proteins (HSPs) are a class of molecular chaperones with expression increased in response to heat or other stresses. HSPs regulate cell homeostasis by... (Review)
Review
Heat shock proteins (HSPs) are a class of molecular chaperones with expression increased in response to heat or other stresses. HSPs regulate cell homeostasis by modulating the folding and maturation of intracellular proteins. Tooth development is a complex process that involves many cell activities. During tooth preparation or trauma, teeth can be damaged. The damaged teeth start their repair process by remineralizing and regenerating tissue. During tooth development and injury repair, different HSPs have different expression patterns and play a special role in odontoblast differentiation and ameloblast secretion by mediating signaling pathways or participating in protein transport. This review explores the expression patterns and potential mechanisms of HSPs, particularly HSP25, HSP60 and HSP70, in tooth development and injury repair.
Topics: Heat-Shock Proteins; Molecular Chaperones; HSP70 Heat-Shock Proteins; Odontogenesis; HSP90 Heat-Shock Proteins
PubMed: 37108621
DOI: 10.3390/ijms24087455 -
Indian Journal of Pathology &... 2023Ameloblastoma is a benign epithelial odontogenic neoplasm that constitutes approximately 1% of all oral tumors and about 9 to 11% of all odontogenic tumors. They are...
INTRODUCTION
Ameloblastoma is a benign epithelial odontogenic neoplasm that constitutes approximately 1% of all oral tumors and about 9 to 11% of all odontogenic tumors. They are slow-growing, locally invasive, and demonstrate a potential for metastasis and malignant transformation. The molecular pathogenesis of ameloblastoma is attributed to aberrant activity of the signal transduction pathways relating to developmental stages of odontogenesis including the mitogen-activated protein kinase (MAPK) pathway. The BRAF V600E mutation was identified as the most frequently mutated gene in this neoplasm. Studies have shown that use of BRAF inhibitors in patients diagnosed with ameloblastomas led to a significant reduction in tumor volume.
AIMS
To detect the expression of BRAF V600E mutation in ameloblastomas in an Indian population using immunohistochemistry. To compare the difference in the occurrence of the BRAF V600E mutation between mandibular and maxillary cases.
MATERIALS AND METHODS
Thirty-three formalin-fixed paraffin-embedded tissues of histopathologically proven cases of ameloblastoma were assessed for the BRAF V600E mutation by immunohistochemistry using the BRAF V600E monoclonal antibody. Patient data such as age, sex, anatomical site, recurrence were documented.
STATISTICAL ANALYSIS
The statistical analysis was performed using the Pearson Chi-square test and Student's t-test.
RESULTS
The present study revealed a high expression of the BRAFV600E mutation in mandibular cases of ameloblastoma among Indians irrespective of the age, sex, site, recurrence or histological pattern.
CONCLUSIONS
The identification of this driver mutation opens the possibility of an adjuvant therapeutic modality to reduce the significant facial disfigurement and morbidity following surgical management.
Topics: Humans; Ameloblastoma; Proto-Oncogene Proteins B-raf; Odontogenic Tumors; Mutation; Mouth Neoplasms
PubMed: 37077063
DOI: 10.4103/ijpm.ijpm_398_21 -
BMC Oral Health Apr 2023Platelet concentrates combined with calcium silicate cements may promote reparative dentin formation. However, few studies have reported their effect on dental pulp...
BACKGROUND
Platelet concentrates combined with calcium silicate cements may promote reparative dentin formation. However, few studies have reported their effect on dental pulp inflammation. This study aimed to evaluate the effects of concentrated growth factor (CGF) combined with iRoot BP Plus on inflammatory human dental pulp stem cells (hDPSCs) in vitro and inflamed pulp in rats in vivo.
METHODS
The proliferation of LPS-stimulated hDPSCs treated with 50% CGF with/without 25% iRoot BP Plus was evaluated using Cell Counting Kit-8 on days 1, 4 and 7. The expression of genes associated with inflammation on day 1 and differentiation on day 14 was analysed by real-time polymerase chain reaction. The exposed pulp of rat maxillary molars was injected with 10 mg/mL LPS and directly capped with CGF membrane with/without iRoot BP Plus extract for 1, 7 and 28 days. The teeth were subjected to histologic analyses and immunohistochemistry.
RESULTS
The proliferation rates of the inflammatory hDPSCs after the combination treatment were significantly higher than those after the other treatments on days 4 and 7 (P < 0.05). IL-1β, IL-6, and TNF-α levels were increased in inflammatory hDPSCs but decreased after treatment with CGF combined with iRoot BP Plus extract, whereas IL-4 and IL-10 showed the opposite expression patterns. Expression of the odontogenesis-related genes OCN, Runx2, and ALP was dramatically enhanced by combined treatment with CGF and iRoot BP Plus extract. In rat pulp, the average inflammation scores of the CGF and CGF-iRoot BP Plus groups significantly decreased in comparison with those of the LPS group (P < 0.05), and the CGF-iRoot BP Plus group had more reparative dentin than the CGF and BP groups. Immunohistochemical staining showed fewer M1 macrophages on day 1 and more M2 macrophages on day 7 in the CGF-iRoot BP Plus group than in the other groups.
CONCLUSIONS
The combination of CGF and iRoot BP Plus showed a synergistic effect on anti-inflammatory potential and promoted greater pulp healing than CGF or iRoot BP Plus alone.
Topics: Humans; Rats; Animals; Dental Pulp; Lipopolysaccharides; Tooth; Intercellular Signaling Peptides and Proteins; Cell Differentiation; Cell Proliferation
PubMed: 37076830
DOI: 10.1186/s12903-023-02903-5 -
Proceedings of the National Academy of... Apr 2023Developmental complexity stemming from the dynamic interplay between genetic and biomechanic factors canalizes the ways genotypes and phenotypes can change in evolution....
Developmental complexity stemming from the dynamic interplay between genetic and biomechanic factors canalizes the ways genotypes and phenotypes can change in evolution. As a paradigmatic system, we explore how changes in developmental factors generate typical tooth shape transitions. Since tooth development has mainly been researched in mammals, we contribute to a more general understanding by studying the development of tooth diversity in sharks. To this end, we build a general, but realistic, mathematical model of odontogenesis. We show that it reproduces key shark-specific features of tooth development as well as real tooth shape variation in small-spotted catsharks . We validate our model by comparison with experiments in vivo. Strikingly, we observe that developmental transitions between tooth shapes tend to be highly degenerate, even for complex phenotypes. We also discover that the sets of developmental parameters involved in tooth shape transitions tend to depend asymmetrically on the direction of that transition. Together, our findings provide a valuable base for furthering our understanding of how developmental changes can lead to both adaptive phenotypic change and trait convergence in complex, phenotypically highly diverse, structures.
Topics: Animals; Sharks; Odontogenesis; Tooth; Phenotype; Mammals; Biological Evolution; Morphogenesis
PubMed: 37027430
DOI: 10.1073/pnas.2216959120 -
BMC Genomics Apr 2023Epithelium-mesenchymal interactions are involved in odontogenic processes. Previous studies have focused on the intracellular signalling regulatory network in tooth...
BACKGROUND
Epithelium-mesenchymal interactions are involved in odontogenic processes. Previous studies have focused on the intracellular signalling regulatory network in tooth development, but the functions of extracellular regulatory molecules have remained unclear. This study aims to explore the gene profile of extracellular proteoglycans and their glycosaminoglycan chains potentially involved in dental epithelium-mesenchymal interactions using high-throughput sequencing to provide new understanding of early odontogenesis.
RESULTS
Whole transcriptome profiles of the mouse dental epithelium and mesenchyme were investigated by RNA sequencing (RNA-seq). A total of 1,281 and 1,582 differentially expressed genes were identified between the dental epithelium and mesenchyme at E11.5 and E13.5, respectively. Enrichment analysis showed that extracellular regions and ECM-receptor interactions were significantly enriched at both E11.5 and E13.5. Polymerase chain reaction analysis confirmed that the extracellular proteoglycan family exhibited distinct changes during epithelium-mesenchymal interactions. Most proteoglycans showed higher transcript levels in the dental mesenchyme, whereas only a few were upregulated in the epithelium at both stages. In addition, 9 proteoglycans showed dynamic expression changes between these two tissue compartments. Gpc4, Sdc2, Spock2, Dcn and Lum were expressed at higher levels in the dental epithelium at E11.5, whereas their expression was significantly higher in the dental mesenchyme at E13.5, which coincides with the odontogenic potential shift. Moreover, the glycosaminoglycan biosynthetic enzymes Ext1, Hs3st1/5, Hs6st2/3, Ndst3 and Sulf1 also exhibited early upregulation in the epithelium but showed markedly higher expression in the mesenchyme after the odontogenic potential shift.
CONCLUSION
This study reveals the dynamic expression profile of extracellular proteoglycans and their biosynthetic enzymes during the dental epithelium-mesenchymal interaction. This study offers new insight into the roles of extracellular proteoglycans and their distinct sulfation underlying early odontogenesis.
Topics: Mice; Animals; Epithelium; Odontogenesis; Proteoglycans; Signal Transduction; Glycosaminoglycans; Tooth
PubMed: 37013486
DOI: 10.1186/s12864-023-09140-8 -
Research Advances on Hydrogel-Based Materials for Tissue Regeneration and Remineralization in Tooth.Gels (Basel, Switzerland) Mar 2023Tissue regeneration and remineralization in teeth is a long-term and complex biological process, including the regeneration of pulp and periodontal tissue, and... (Review)
Review
Tissue regeneration and remineralization in teeth is a long-term and complex biological process, including the regeneration of pulp and periodontal tissue, and re-mineralization of dentin, cementum and enamel. Suitable materials are needed to provide cell scaffolds, drug carriers or mineralization in this environment. These materials need to regulate the unique odontogenesis process. Hydrogel-based materials are considered good scaffolds for pulp and periodontal tissue repair in the field of tissue engineering due to their inherent biocompatibility and biodegradability, slow release of drugs, simulation of extracellular matrix, and the ability to provide a mineralized template. The excellent properties of hydrogels make them particularly attractive in the research of tissue regeneration and remineralization in teeth. This paper introduces the latest progress of hydrogel-based materials in pulp and periodontal tissue regeneration and hard tissue mineralization and puts forward prospects for their future application. Overall, this review reveals the application of hydrogel-based materials in tissue regeneration and remineralization in teeth.
PubMed: 36975694
DOI: 10.3390/gels9030245 -
The Journal of Biological Chemistry May 2023Lipid rafts are membrane microdomains rich in cholesterol, sphingolipids, glycosylphosphatidylinositol-anchored proteins (GPI-APs), and receptors. These lipid raft...
Lipid rafts are membrane microdomains rich in cholesterol, sphingolipids, glycosylphosphatidylinositol-anchored proteins (GPI-APs), and receptors. These lipid raft components are localized at the plasma membrane and are essential for signal transmission and organogenesis. However, few reports have been published on the specific effects of lipid rafts on tooth development. Using microarray and single-cell RNA sequencing methods, we found that a GPI-AP, lymphocyte antigen-6/Plaur domain-containing 1 (Lypd1), was specifically expressed in preodontoblasts. Depletion of Lypd1 in tooth germ using an ex vivo organ culture system and in mouse dental pulp (mDP) cells resulted in the inhibition of odontoblast differentiation. Activation of bone morphogenetic protein (BMP) signaling by BMP2 treatment in mDP cells promoted odontoblast differentiation via phosphorylation of Smad1/5/8, while this BMP2-mediated odontoblast differentiation was inhibited by depletion of Lypd1. Furthermore, we created a deletion construct of the C terminus containing the omega site in LYPD1; this site is necessary for localizing GPI-APs to the plasma membrane and lipid rafts. We identified that this site is essential for odontoblast differentiation and morphological change of mDP cells. These findings demonstrated that LYPD1 is a novel marker of preodontoblasts in the developing tooth; in addition, they suggest that LYPD1 is important for tooth development and that it plays a pivotal role in odontoblast differentiation by regulating Smad1/5/8 phosphorylation through its effect as a GPI-AP in lipid rafts.
Topics: Animals; Mice; Bone Morphogenetic Proteins; Cell Differentiation; Cell Membrane; Gene Expression Regulation, Developmental; Glycosylphosphatidylinositols; GPI-Linked Proteins; Membrane Microdomains; Odontoblasts; Odontogenesis; Protein Domains
PubMed: 36963497
DOI: 10.1016/j.jbc.2023.104638