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Differentiation; Research in Biological... 2023Epithelial-mesenchymal interactions occur during tooth development. The dental epithelium (DE) is regarded as the signal center that regulates tooth morphology. However,...
Epithelial-mesenchymal interactions occur during tooth development. The dental epithelium (DE) is regarded as the signal center that regulates tooth morphology. However, the mechanism by which DE regulates the differentiation of mesenchyme-derived dental papilla (DP) into odontoblasts remains unclear. Using miniature pigs as a model, we analyzed the expression profiles of the DE and DP during odontoblast differentiation using high-throughput RNA sequencing. The phosphatidylinositol-3-kinase (PI3K)/AKT pathway is one of the most enriched pathways in both DE and DP. The PI3K/AKT pathway was first activated in the inner enamel epithelium but not in the DP on embryonic day 50. This pathway was then activated in the odontoblast layer on embryonic day 60. We showed that AKT activation promoted odontoblast differentiation of DP cells. We further demonstrated that activation of PI3K/AKT signaling in the DE effectively increased the expression levels of AKT and dentin sialophosphoprotein in DP cells. Additionally, we found that DE cells secreted collagen type IV alpha 6 chain (COL4A6) downstream of epithelial AKT signaling to positively regulate mesenchymal AKT levels. Therefore, our data suggest that PI3K/AKT signaling from the DE to the DP promotes odontoblast differentiation via COL4A6 secretion.
Topics: Animals; Swine; Odontoblasts; Proto-Oncogene Proteins c-akt; Phosphatidylinositol 3-Kinases; Cell Differentiation; Epithelium
PubMed: 37898102
DOI: 10.1016/j.diff.2023.10.002 -
F1000Research 2018Primordial odontogenic tumors are a rare recently described mixed odontogenic tumor composed histopathologically of dental papilla like tissue and enamel organ like...
Primordial odontogenic tumors are a rare recently described mixed odontogenic tumor composed histopathologically of dental papilla like tissue and enamel organ like tissue. Only nine cases have been documented worldwide and we are reporting the tenth case which is from Egypt. A 2-year-old Egyptian boy that presented with an asymptomatic swelling of the mandible which appeared with multilocular radiolucency associated with an impacted developing tooth on a computerized tomography (CT) scan. The lesion was excised and diagnosed as a primordial odontogenic tumor. The patient was followed up for two years with no recurrence. Differentiation of primordial odontogenic tumors from other odontogenic tumors, which resemble it histopathologically is crucial to avoid unnecessary aggressive treatment.
PubMed: 29904598
DOI: 10.12688/f1000research.14735.1 -
The International Journal of... May 2021SIRT4 is a mitochondrial sirtuin. Owing to its dependance on the cofactor nicotinamide adenine dinucleotide (NAD), SIRT4 can act as a mitochondrial metabolic sensor of...
INTRODUCTION
SIRT4 is a mitochondrial sirtuin. Owing to its dependance on the cofactor nicotinamide adenine dinucleotide (NAD), SIRT4 can act as a mitochondrial metabolic sensor of cellular energy status. We have previously shown that enhancement of mitochondrial functions is vital for the odontogenic diff ;erentiation of dental papilla cells (DPCs) during dentinogenesis. However, whether SIRT4 serves as an effective regulator of DPC diff ;erentiation by affecting mitochondrial functions remains unexplored.
METHODS
Primary DPCs obtained from the first molar dental papilla of neonatal Sprague-Dawley rats were used in this study. The expression pattern of SIRT4 was observed by immunohistochemistry in the first molar of postnatal day 1 (P1) rats. The changes in SIRT4 expression during odontogenic DPC differentiation were evaluated using real-time quantitative polymerase chain reaction (PCR), western blotting, and immunofluorescence. DPCs with loss (small interfering RNA-mediated knockdown) and gain (plasmid transfection-induced overexpression) of SIRT4 function were used to explore the role of SIRT4 in odontogenic differentiation. Mitochondrial function assays were performed using ATP, reactive oxygen species (ROS), and NAD/NADH kits to investigate the potential mechanisms involved in SIRT4-mediated dentinogenesis.
RESULTS
In the present study, we found that SIRT4 expression increased in a time-dependent manner during odontogenic differentiation bothin vivo and in vitro. Sirt4 knockdown resulted in reduced odontogenic differentiation and mineralization, whereas an opposite effect was observed with SIRT4 overexpression. Furthermore, our results verified that in addition to reducing DPC differentiation, Sirt4 knockdown could also significantly reduce ATP levels, elevate the NAD/NADH ratio, and increase ROS levels.
CONCLUSION
SIRT4 regulates mitochondrial functions and the antioxidant capacity of DPCs, thereby influencing dentin formation and tooth development, a phenomenon that may provide a foundation for better understanding the specific molecular mechanisms underlying dentin regeneration.
Topics: Animals; Animals, Newborn; Cell Differentiation; Dental Papilla; Mitochondria; Models, Animal; Odontogenesis; Primary Cell Culture; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Sirtuins
PubMed: 33636397
DOI: 10.1016/j.biocel.2021.105962 -
European Review For Medical and... Jul 2019The aim of this study was to investigate the effect of melatonin on mitochondria of dental papilla cells (DPCs) during the odontogenic differentiation process.
OBJECTIVE
The aim of this study was to investigate the effect of melatonin on mitochondria of dental papilla cells (DPCs) during the odontogenic differentiation process.
MATERIALS AND METHODS
Primary DPCs were obtained from the first molar dental papilla of neonatal rats and cultured in osteogenic (OS) or basal medium supplemented with melatonin at different concentrations (0, 1 pM, 0.1 nM, 10 nM, and 1 μM) for differentiation in vitro. Effects of melatonin on differentiation, mitochondrial respiratory function, and mitochondrial biogenesis of DPCs were analyzed.
RESULTS
Upon odontogenic induction, Alkaline phosphatase (ALP) activity, dentin sialophosphoprotein (DSPP), and dentin matrix protein (DMP1) expression were significantly enhanced, with a peaked expression at 10 nM of melatonin treatment. During DPCs differentiation, 10 nM melatonin could significantly induce the increase of intracellular Adenosine triphosphate (ATP), the decrease of the oxidized form of nicotinamide adenine dinucleotide (NAD+)/NADH ratio and reactive oxygen species (ROS). The mRNA and protein levels of peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), nuclear respiratory factor 1 (NRF-1), and mitochondrial transcription factor A (TFAM) were significantly increased, and the peak level of expression was found in cells treated with 10 nM of melatonin. Furthermore, the mitochondria DNA (mtDNA) copy number was significantly decreased during DPCs differentiation.
CONCLUSIONS
These findings suggest that melatonin can promote the differentiation of rat DPCs and regulate mitochondrial energy metabolism, ROS scavenging, and mitochondrial biogenesis.
Topics: Animals; Cell Differentiation; Cells, Cultured; Dental Papilla; Dose-Response Relationship, Drug; Melatonin; Mitochondria; Organelle Biogenesis; Rats; Rats, Sprague-Dawley
PubMed: 31298348
DOI: 10.26355/eurrev_201907_18343 -
Journal of Pharmacy & Bioallied Sciences Aug 2015Dental stem cells have recently become one of the widely researched areas in dentistry. Ever since the identification of stem cells from various dental tissues like... (Review)
Review
Dental stem cells have recently become one of the widely researched areas in dentistry. Ever since the identification of stem cells from various dental tissues like deciduous teeth, dental papilla, periodontal ligament and third molars, storing them for future use for various clinical applications was being explored. Dental stem cells were harvested and isolated using various techniques by different investigators and laboratories. This article explains the technical aspects of preparing the patient, atraumatic and aseptic removal of the tooth and its safe transportation and preservation for future expansion.
PubMed: 26538883
DOI: 10.4103/0975-7406.163461 -
Journal of Endodontics Jan 2024Stem cell-based dental pulp regeneration has been extensively studied, mainly focusing on exploiting dental stem cells' osteogenic and angiogenic potentials. Dental stem...
Interactions of Neuronally Induced Stem Cells from Apical Papilla Spheres, Stems Cells from Apical Papilla, and Human Umbilical Vascular Endothelial Cells on Vasculogenesis and Neurogenesis.
INTRODUCTION
Stem cell-based dental pulp regeneration has been extensively studied, mainly focusing on exploiting dental stem cells' osteogenic and angiogenic potentials. Dental stem cells' neurogenic role is often overlooked. Stem cells from apical papilla (SCAPs), originating from the neural crest and capable of sphere formation, display potent neurogenic capacity. This study aimed to investigate the interactions of neuronally induced stem cells from apical papilla (iSCAP) spheres, SCAPs, and human umbilical vascular endothelial cells (HUVECs) on vasculogenesis and neurogenesis.
METHODS
SCAPs were isolated and characterized using flow cytometry and multilineage differentiation assays. SCAP monolayer culture and spheres were neuronally induced by a small molecule neural induction medium, and the neural gene expression and neurite formation at days 0, 3, and 7 were evaluated by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and using phase-contrast light and fluorescence microscopy. Direct coculture or pulp-on-chip was used to investigate iSCAP sphere interaction with SCAPs and HUVECs. RT-qPCR, fluorescence microscopy, and immunostaining with β-tubulin III, alpha-smooth muscle actin, and CD31 were used to study neural gene expression, neurite formation, and neurovascular cell interactions.
RESULTS
Neural induction medium with small molecules rapidly induced SCAP differentiation toward neural-like cells. Gene expression of Nestin, β-tubulin III, microtubule-associated protein 2, neuron-specific enolase, and NeuN was higher in iSCAP spheres than in iSCAPs. iSCAP spheres formed more and longer neurites compared with iSCAPs. iSCAP sphere, HUVEC, and SCAP direct coculture significantly enhanced vessel formation along with up-regulated VEGF (P < .001) and multiple neural markers, such as Nestin (P < .01), microtubule-associated protein 2 (P < .001), S100 (P < .001), and NG2 (P < .001). iSCAP spheres, SCAPs, and HUVECs cultured in a pulp-on-chip system promoted endothelial and neural cell migration toward each other and alpha-smooth muscle actin-positive and CD31-positive cells assembling for the vascular constitution.
CONCLUSIONS
iSCAP-formed spheres interact with SCAPs and HUVECs, promoting vasculogenesis and neurogenesis.
Topics: Humans; Endothelial Cells; Dental Pulp; Nestin; Dental Papilla; Tubulin; Actins; Regeneration; Stem Cells; Cell Differentiation; Neurogenesis; Cells, Cultured; Microtubule-Associated Proteins; Osteogenesis
PubMed: 37866800
DOI: 10.1016/j.joen.2023.10.006 -
Theranostics 2020Hertwig's epithelial root sheath (HERS) plays indispensable roles in tooth root development, including controlling the shape and number of roots, dentin formation, and...
Hertwig's epithelial root sheath (HERS) plays indispensable roles in tooth root development, including controlling the shape and number of roots, dentin formation, and helping generate the cementum. Based on these characteristics, HERS cell is a potential seed cell type for tooth-related tissue regeneration. However, the application is severely limited by a lack of appropriate culture methods and small cell numbers. Here, we constructed a 3D culture method to expand functional HERS cells into spheroids, and investigated characteristics and application of dental tissue regeneration of these spheroids. HERS spheroids and HERS cells (2D monolayer culture) were compared in terms of biological characteristics (such as proliferation, self-renewal capacity, and stemness) and functions (including differentiation potential and inductive ability of dentin formation) both and . Further, transcriptome analysis was utilized to reveal the molecular mechanisms of their obvious differences. HERS spheroids showed obvious superiority in biological characteristics and functions compared to 2D monolayers of HERS cells . , HERS spheroids generated more mineralized tissue; when combined with dental papilla cells (DPCs), HERS spheroids contributed to dentin-like tissue formation. Moreover, the generation and expansion of HERS spheroids rely to some degree on the HIF-1 pathway. HERS spheroid generation is beneficial for functional HERS cell expansion and can provide a useful cell source for further tooth regeneration and mechanistic research. Notably, HIF-1 pathway plays a critical role in HERS spheroid formation and function.
Topics: Animals; Cell Differentiation; Cell Proliferation; Cell Self Renewal; Dentin; Epithelial Cells; Female; Hypoxia-Inducible Factor 1; Models, Animal; Odontogenesis; Primary Cell Culture; Rats; Regeneration; Regenerative Endodontics; Spheroids, Cellular; Stem Cells; Tooth Root
PubMed: 32642002
DOI: 10.7150/thno.44782 -
Swiss Dental Journal Sep 2021Tooth development begins in the human embryo 28 to 40 days after ovulation. Epithelial cells grow into the ectomesenchymal parts of the jaw. An epithelial protrusion...
Tooth development begins in the human embryo 28 to 40 days after ovulation. Epithelial cells grow into the ectomesenchymal parts of the jaw. An epithelial protrusion develops. Further penetration of the epithelial cells into the ectomesenchyma results in the formation of the dental papilla (Figs. 1, 2 and 3). At this point, the cells for the formation of the tooth hard substance are differentiated.
PubMed: 34472765
DOI: 10.61872/sdj-2021-09-04 -
Frontiers in Physiology 2021circular RNAs (circRNAs) is a broad and diverse endogenous subfamily of non-coding RNAs, regulating the gene expression by acting as a microRNA (miRNA) sponge. However,...
circular RNAs (circRNAs) is a broad and diverse endogenous subfamily of non-coding RNAs, regulating the gene expression by acting as a microRNA (miRNA) sponge. However, the biological functions of circRNAs in odontoblast differentiation remain largely unknown. Our preliminary study identified an unknown mouse circRNA by circRNA sequencing generated from mouse dental papilla and we termed it circKLF4. In this study, quantitative real-time PCR and hybridization were used and demonstrated that circKLF4 was upregulated during odontoblastic differentiation. Gene knockdown and overexpression assays indicated that circKLF4 promoted odontoblastic differentiation of mouse dental papilla cells (mDPCs). Mechanistically, we found that circKLF4 increased the linear KLF4 expression in a microRNA-dependent manner. By mutating the binding sites of microRNA and circKLF4, we further confirmed that circKLF4 acted as sponge of miRNA-1895 and miRNA-5046 to promote the expression of KLF4. We then also found that ENDOGLIN was also up-regulated by circKLF4 by transfection of circKLF4 overexpression plasmids with or without microRNA inhibitor. In conclusion, circKLF4 increases the expression of KLF4 and ENDOGLIN to promote odontoblastic differentiation sponging miRNA-1895 and miRNA-5046.
PubMed: 35222058
DOI: 10.3389/fphys.2021.760223 -
Journal of Oral Science Oct 2022Primordial odontogenic tumor (POT) is a rare mixed odontogenic tumor composed of primitive ectomesenchyme similar to the dental papilla. The outer surface consists of...
Primordial odontogenic tumor (POT) is a rare mixed odontogenic tumor composed of primitive ectomesenchyme similar to the dental papilla. The outer surface consists of columnar/cuboidal odontogenic epithelium similar to the inner enamel epithelium, and there is no hard tissue formation. Until now, 27 cases have been reported in the English literature. This article describes the clinicopathological characteristics of one case of POT, representing the oldest patient (aged 26 years) reported to date.
Topics: Adult; Calcinosis; Epithelium; Humans; Jaw Neoplasms; Male; Odontogenic Tumors
PubMed: 36070922
DOI: 10.2334/josnusd.22-0028