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Journal of Bone and Mineral Research :... Aug 2019Transcription factors bind to cell-specific cis-regulatory elements, such as enhancers and promoters, to initiate much of the gene expression program of different...
Transcription factors bind to cell-specific cis-regulatory elements, such as enhancers and promoters, to initiate much of the gene expression program of different biological process. Odontoblast differentiation is a necessary step for tooth formation and is also governed by a complex gene regulatory network. Our previous in vitro experiments showed that Krüppel-like factor 4 (KLF4) can promote odontoblastic differentiation of both mouse dental papillary cells (mDPCs) and human dental pulp cells; however, its mechanism remains unclear. We first used Wnt1-Cre; KLF4 (Klf4 cKO) mice to examine the role of KLF4 during odontoblast differentiation in vivo and demonstrated significantly impaired dentin mineralization and enlarged pulp/root canals. Additionally, combinatory analysis using RNA-seq and ATAC-seq revealed genomewide direct regulatory targets of KLF4 in mouse odontoblasts. We found that KLF4 can directly activate the TGF-β signaling pathway at the beginning of odontoblast differentiation with Runx2 as a cofactor. Furthermore, we found that KLF4 can directly upregulate the expression levels of Dmp1 and Sp7, which are markers of odontoblastic differentiation, through binding to their promoters. Interestingly, as a transcription factor, KLF4 can also recruit histone acetylase as a regulatory companion to the downstream target genes to positively or negatively regulate transcription. To further investigate other regulatory companions of KLF4, we chose histone acetylase HDAC3 and P300. Immunoprecipitation demonstrated that KLF4 interacted with P300 and HDAC3. Next, ChIP analysis detected P300 and HDAC3 enrichment on the promoter region of KLF4 target genes Dmp1 and Sp7. HDAC3 mainly interacted with KLF4 on day 0 of odontoblastic induction, whereas P300 interacted on day 7 of induction. These temporal-specific interactions regulated Dmp1 and Sp7 transcription, thus regulating dentinogenesis. Taken together, these results demonstrated that KLF4 regulates Dmp1 and Sp7 transcription via the modulation of histone acetylation and is vital to dentinogenesis. © 2019 American Society for Bone and Mineral Research.
Topics: Acetylation; Animals; Cell Differentiation; Core Binding Factor Alpha 1 Subunit; Dental Pulp; Extracellular Matrix Proteins; Gene Expression Regulation; Histone Deacetylase 2; Histones; Kruppel-Like Factor 4; Kruppel-Like Transcription Factors; Mice; Mice, Knockout; Odontoblasts; Sp7 Transcription Factor; Transcription, Genetic; Transforming Growth Factor beta
PubMed: 31112333
DOI: 10.1002/jbmr.3716 -
Journal of Dental Research Apr 2021WW domain-containing E3 Ub-protein ligase 2 (WWP2) belongs to the homologous to E6AP C-terminus (HECT) E3 ligase family. It has been explored to regulate osteogenic...
WW domain-containing E3 Ub-protein ligase 2 (WWP2) belongs to the homologous to E6AP C-terminus (HECT) E3 ligase family. It has been explored to regulate osteogenic differentiation, chondrogenesis, and palatogenesis. Odontoblasts are terminally differentiated mesenchymal cells, which contribute to dentin formation in tooth development. However, it remained unknown whether WWP2 participated in odontoblast differentiation. In this study, WWP2 was found to be expressed in mouse dental papilla cells (mDPCs), odontoblasts, and odontoblastic-induced mDPCs by immunohistochemistry and Western blotting. Besides, WWP2 expression was decreased in the cytoplasm but increased in the nuclei of differentiation-induced mDPCs. When was knocked down, the elevated expression of odontoblast marker genes ( and ) in mDPCs induced by differentiation medium was suppressed. Meanwhile, a decrease of alkaline phosphatase (ALP) activity was observed by ALP staining, and reduced formation of mineralized matrix nodules was demonstrated by Alizarin Red S staining. Overexpression of WWP2 presented opposite results to knockdown experiments, suggesting that WWP2 promoted odontoblastic differentiation of mDPCs. Further investigation found that WWP2 was coexpressed and interacted with KLF5 in the nuclei, leading to ubiquitination of KLF5. The PPPSY (PY2) motif of KLF5 was essential for its physical binding with WWP2. Also, cysteine 838 (Cys838) of WWP2 was the active site for ubiquitination of KLF5, which did not lead to proteolysis of KLF5. Then, KLF5 was confirmed to be monoubiquitinated and transactivated by WWP2, which promoted the expression of KLF5 downstream genes and . Deletion of the PY2 motif of KLF5 or mutation of Cys838 of WWP2 reduced the upregulation of and . Besides, lysine (K) residues K31, K52, K83, and K265 of KLF5 were verified to be crucial to WWP2-mediated KLF5 transactivation. Taken together, WWP2 promoted odontoblastic differentiation by monoubiquitinating KLF5.
Topics: Animals; Cell Differentiation; Dental Pulp; Extracellular Matrix Proteins; Kruppel-Like Transcription Factors; Mesenchymal Stem Cells; Mice; Odontoblasts; Odontogenesis; Osteogenesis; Phosphoproteins; Ubiquitin-Protein Ligases
PubMed: 33164644
DOI: 10.1177/0022034520970866 -
Frontiers in Physiology 2023Mouse and human genetic studies indicate key roles of the ligand in odontogenesis. Previous studies have identified effectors and regulators of the Wnt signaling...
Mouse and human genetic studies indicate key roles of the ligand in odontogenesis. Previous studies have identified effectors and regulators of the Wnt signaling pathway actively expressed during key stages of tooth morphogenesis. However, limitations in multiplexing and spatial resolution hindered a more comprehensive analysis of these signaling molecules. Here, profiling of transcriptomes using fluorescent multiplex hybridization and single-cell RNA-sequencing (scRNA-seq) provide robust insight into the synchronized expression patterns of , , and simultaneously during tooth development. First, we identified transcripts restricted to the epithelium at the stage of tooth bud morphogenesis, contrasting that of and localization to the dental mesenchyme. By embryonic day 15.5 (E15.5), a marked shift of expression from dental epithelium to mesenchyme was noted, while and expression remained enriched in the mesenchyme. By postnatal day 0 (P0), co-localization patterns of , , and were observed in both terminally differentiating and secreting odontoblasts of molars and incisors. Interestingly, exhibited robust expression in fully differentiated ameloblasts at the developing cusp tip of both molars and incisors, an observation not previously noted in prior studies. At P7 and 14, after the mineralization of dentin and enamel, expression was limited to odontoblasts. Meanwhile, Wnt modulators showed reduced or absent signals in molars. In contrast, strong signals persisted in ameloblasts (for ) and odontoblasts (for , , and ) towards the proximal end of incisors, near the cervical loop. Our scRNA-seq analysis used CellChat to further contextualize Wnt pathway-mediated communication between cells by examining ligand-receptor interactions among different clusters. The co-localization pattern of , , and in both terminally differentiating and secreting odontoblasts of molars and incisors potentially signifies the crucial ligand-modulator interaction along the gradient of cytodifferentiation starting from each cusp tip towards the apical region. These data provide cell type-specific insight into the role of Wnt ligands and mediators during epithelial-mesenchymal interactions in odontogenesis.
PubMed: 38274045
DOI: 10.3389/fphys.2023.1316635 -
Swiss Dental Journal 2016
Topics: Animals; Dental Caries; Dental Pulp Capping; Dentin; Dentinogenesis; Humans; Microscopy, Electron, Scanning; Odontoblasts
PubMed: 27874915
DOI: 10.61872/sdj-2016-11-02 -
Calcified Tissue International May 2024Osteogenesis Imperfecta is a rare, hereditary bone condition with an incidence of 1/15,000-20,000. Symptoms include bone fragility, long bone deformity, scoliosis,... (Review)
Review
Osteogenesis Imperfecta is a rare, hereditary bone condition with an incidence of 1/15,000-20,000. Symptoms include bone fragility, long bone deformity, scoliosis, hypermobility, alongside secondary features such as short stature, basilar invagination, pulmonary and cardiac complications, hearing loss, dentinogenesis imperfecta and malocclusion. Osteogenesis Imperfecta can have a large impact on the child and their family; this impact starts immediately after diagnosis. Fractures, pain, immobility, hospital admissions and the need for equipment and adaptations all influence the health-related quality of life of the individual and their family. This narrative review article aims to examine the impact the diagnosis and management of osteogenesis imperfecta has on the health-related quality of life of a child. It will touch on the effect this may have on the quality of life of their wider family and friends and identify strategies to optimise health-related quality of life in this population. Optimising health-related quality of life in children with Osteogenesis Imperfecta is often a complicated, multifaceted journey that involves the child, their extended family, school, extracurricular staff and numerous health professionals.
PubMed: 38695871
DOI: 10.1007/s00223-024-01205-4 -
Dentistry Journal Apr 2021Osteogenesis imperfecta (OI) is a genetic disorder characterized by increased bone fragility and low bone mass, caused mainly by mutations in collagen type I encoding...
Osteogenesis imperfecta (OI) is a genetic disorder characterized by increased bone fragility and low bone mass, caused mainly by mutations in collagen type I encoding genes. The current study aimed to evaluate dentinogenesis imperfecta (DI), oral manifestations and caries status of OI children. Sixty-eight children (41 males, 27 females) aged from 3 to 17 years old (mean 9 ± 4.13) participated in the study. Participants were classified into three OI type groups (I-2 cases, III-31 cases and IV-35 cases). Clinical examination and an orthopantomogram were used to obtain prevalences and associations of DI, caries status, malocclusion, crossbite, open bite, eruption, impaction and missing teeth with OI. The prevalence of DI among OI patients was 47.1%, more common in OI type III than type IV. The yellow-brown discoloration type was more vulnerable to attrition than the opalescent-grey one in the primary dentition. OI seemed not to have a high risk of caries; the prevalence of caries was 69.1%. A high incidence of malocclusion, crossbite and open bite was observed. In-depth oral information would provide valuable data for better dental management in OI patients. Parents and general doctors should pay more attention to dental care to prevent caries and premature tooth loss.
PubMed: 33925433
DOI: 10.3390/dj9050049 -
The Journal of Biological Chemistry Aug 2022WW domain-containing E3 Ubiquitin-protein ligase 2 (WWP2) has been found to positively regulate odontoblastic differentiation by monoubiquitinating the transcription...
WW domain-containing E3 Ubiquitin-protein ligase 2 (WWP2) has been found to positively regulate odontoblastic differentiation by monoubiquitinating the transcription factor Kruppel-like factor 5 (KLF5) in a cell culture system. However, the in vivo role of WWP2 in mouse teeth remains unknown. To explore this, here we generated Wwp2 knockout (Wwp2 KO) mice. We found that molars in Wwp2 KO mice exhibited thinner dentin, widened predentin, and reduced numbers of dentinal tubules. In addition, expression of the odontoblast differentiation markers Dspp and Dmp1 was decreased in the odontoblast layers of Wwp2 KO mice. These findings demonstrate that WWP2 may facilitate odontoblast differentiation and dentinogenesis. Furthermore, we show for the first time that phosphatase and tensin homolog (PTEN), a tumor suppressor, is expressed in dental papilla cells and odontoblasts of mouse molars and acts as a negative regulator of odontoblastic differentiation. Further investigation indicated that PTEN is targeted by WWP2 for degradation during odontoblastic differentiation. We demonstrate PTEN physically interacts with and inhibits the transcriptional activity of KLF5 on Dspp and Dmp1. Finally, we found WWP2 was able to suppress the interaction between PTEN and KLF5, which diminished the inhibition effect of PTEN on KLF5. Taken together, this study confirms the essential role of WWP2 and the WWP2-PTEN-KLF5 signaling axis in odontoblast differentiation and dentinogenesis in vivo.
Topics: Animals; Cell Differentiation; Dentin; Dentinogenesis; Extracellular Matrix Proteins; Kruppel-Like Transcription Factors; Mice; Mice, Knockout; Odontoblasts; PTEN Phosphohydrolase; Phosphoproteins; Sialoglycoproteins; Signal Transduction; Transcription Factors; Ubiquitin-Protein Ligases
PubMed: 35780838
DOI: 10.1016/j.jbc.2022.102220 -
Journal of Translational Medicine May 2022Sclerostin is the protein product of the SOST gene and is known for its inhibitory effects on bone formation. The monoclonal antibody against sclerostin has been... (Review)
Review
Sclerostin is the protein product of the SOST gene and is known for its inhibitory effects on bone formation. The monoclonal antibody against sclerostin has been approved as a novel treatment method for osteoporosis. Oral health is one of the essential aspects of general human health. Hereditary bone dysplasia syndrome caused by sclerostin deficiency is often accompanied by some dental malformations, inspiring the therapeutic exploration of sclerostin in the oral and dental fields. Recent studies have found that sclerostin is expressed in several functional cell types in oral tissues, and the expression level of sclerostin is altered in pathological conditions. Sclerostin not only exerts similar negative outcomes on the formation of alveolar bone and bone-like tissues, including dentin and cementum, but also participates in the development of oral inflammatory diseases such as periodontitis, pulpitis, and peri-implantitis. This review aims to highlight related research progress of sclerostin in oral cavity, propose necessary further research in this field, and discuss its potential as a therapeutic target for dental indications and regenerative dentistry.
Topics: Bone and Bones; Dentistry; Humans; Inflammation; Osteogenesis; Osteoporosis
PubMed: 35562828
DOI: 10.1186/s12967-022-03417-4 -
Frontiers in Physiology 2019mTORC1 signaling plays an important role in extracellular and intracellular signals, including growth factors, nutrients, energy metabolism, and stress. However, the...
mTORC1 signaling plays an important role in extracellular and intracellular signals, including growth factors, nutrients, energy metabolism, and stress. However, the functional role of mTORC1 in dentinogenesis is unknown. To study the role of Raptor/mTORC1 in dentinogenesis, an Raptor; Osx-Cre (Rap-Osx) mouse, in which Raptor was conditionally deleted in odontoblasts and dental mesenchymal cells, was generated, and postnatal tooth development was compared between Rap-Osx mice and control littermates. Rap-Osx mice presented a phenotype known as dentinogenesis imperfecta and had smaller tooth volume, a thinner dentin layer and a larger pulp chamber. The proliferation and differentiation of odontoblasts/preodontoblasts were attenuated in mutant mice, which was likely responsible for the defects in dentinogenesis. Raptor/mTORC1-pS6K1 signaling was inactivated during tooth development in Rap-Osx mice, whereas it was activated in control mice. These results indicate that Raptor/mTORC1 plays a critical role in dentinogenesis promoting odontoblasts/preodontoblasts proliferation and differentiation. Raptor/mTORC1 might regulate tooth development through the pS6K1 signaling pathway.
PubMed: 30984011
DOI: 10.3389/fphys.2019.00250 -
Acta Biomaterialia Mar 2023Hard dental tissue pathologies, such as caries, are conventionally managed through replacement by tooth-colored inert biomaterials. Tissue engineering provides novel...
Hard dental tissue pathologies, such as caries, are conventionally managed through replacement by tooth-colored inert biomaterials. Tissue engineering provides novel treatment approaches to regenerate lost dental tissues based on bioactive materials and/or signaling molecules. While regeneration in the form of reparative dentin (osteo-dentin) is feasible, the recapitulation of the tubular microstructure of ortho-dentin and its special features is sidelined. This study characterized in vitro, and in vivo human EDTA-treated, freeze-dried dentin matrices (HTFD scaffolds) conditioned with calcium phosphate nanoparticles (NPs) bearing plasmids encoding dentinogenesis-inducing factors (pBMP2/NPs or pDMP1/NPs). The uptake and transfection efficiency of the synthesized NPs on dental pulp stem cells (DPSCs) increased in a concentration- and time-dependent manner, as evaluated qualitatively by confocal laser microscopy and transmission electron microscopy, and quantitatively by flow cytometry, while, in parallel, cell viability decreased. HTFD scaffolds conditioned with the optimal transfectability-to-viability concentration at 4 µg Ca/mL of each of the pBMP2/NPs or pDMP1/NPs preserved high levels of cell viability, evidenced by live/dead staining in vitro and caused no adverse reactions after implantation on C57BL6 mice in vivo. HTFD/NPs constructs induced rapid and pronounced odontogenic shift of the DPSCs, as evidenced by relevant gene expression patterns of RunX2, ALP, BGLAP, BMP-2, DMP-1, DSPP by real-time PCR, and acquirement of polarized meta-mitotic phenotype with cellular protrusions entering the dentinal tubules as visualized by scanning electron microscopy. Taken together, HTFD/NPs constitute a promising tool for customized reconstruction of the ortho-dentin/odontoblastic layer barrier and preservation of pulp vitality. STATEMENT OF SIGNIFICANCE: In clinical dentistry, the most common therapeutic approach for the reconstruction of hard dental tissue defects is the replacement by resin-based restorative materials. Even modern bioactive materials focus on reparative dentinogenesis, leading to amorphous dentin-bridge formation in proximity to the pulp. Therefore, the natural microarchitecture of tubular ortho-dentin is not recapitulated, and the sensory and defensive role of odontoblasts is sidelined. This study approaches the reconstruction at the dentin-pulp interface using a construct of human treated dentin (HTFD) scaffold and plasmid-carrying nanoparticles (NPs) encoding dentinogenic factors (DMP-1 or BMP-2) with excellent in vitro and in vivo properties. As a future perspective, the HTFD/NPs constructs could act as bio-fillings for personalized reconstruction of the dentin-pulp interface.
Topics: Humans; Animals; Mice; Tissue Engineering; Tissue Scaffolds; Cell Differentiation; Cells, Cultured; Stem Cells; Mice, Inbred C57BL; DNA; Nanoparticles; Calcium Phosphates; Dentin; Plasmids; Dental Pulp; Bone Morphogenetic Protein 2
PubMed: 36708852
DOI: 10.1016/j.actbio.2023.01.044