RARE DISEASE
Dentinogenesis imperfecta type 3
Dentinogenesis imperfecta type 3
Dentinogenesis imperfecta type 3
Synonyms: Dentinogenesis imperfecta, Shields type 3
Synonyms: Dentinogenesis imperfecta, Shields type 3
Synonyms: Dentinogenesis imperfecta, Shields type 3
Drug discovery
102
papers
On emerging therapies
Overview
Dentinogenesis Imperfecta Type 3 (DGI-3) is a rare autosomal dominant genetic disorder caused by DSPP gene mutations, leading to defective dentin formation. Clinically, it presents with opalescent discoloration, severe tooth attrition, "shell teeth" (thin dentin with enlarged pulp chambers), and frequent periapical radiolucencies in non-carious teeth. Both primary and permanent dentitions are affected, with rapid enamel loss and structural fragility necessitating aggressive dental interventions [1][2][4][5].
Therapies
Preventive care: Early use of stainless steel crowns (primary teeth) and composite restorations to mitigate wear [3][12][15].
Advanced interventions: Full-mouth rehabilitation with bonded all-ceramic restorations or dental implants for non-restorable teeth [8][12].
Multidisciplinary approach: Coordination with pediatric dentistry, orthodontics, and prosthodontics to preserve occlusion and aesthetics [3][15].
Categories: rare genetic diseases, rare odontological diseases
Research Papers
102 drug discovery papers about Dentinogenesis imperfecta type 3. Recent publications:
102 drug discovery papers about Dentinogenesis imperfecta type 3. Recent publications:
categories:
Small molecules
small molecules
2025-12-24 | Inositol-requiring enzyme 1 alpha is essential for dentinogenesis.
Inositol-requiring enzyme 1 alpha (IRE1α), encoded by endoplasmic reticulum (ER) to nucleus signaling 1 (Ern1) gene, is the most conserved sensor of ER stress. IRE1α-initiated signaling pathways contribute to functional maturation of secretory cells and have been implicated in various human diseases. In this study, we examined the roles of IRE1α in odontoblast development and dentin formation in wild-type mice as well as in Dspp P19L mutant mice, which express a pathogenic variant of dentin sialophosphoprotein (P19L-DSPP) and exhibit a dentinogenesis imperfecta (DGI)-like phenotype. Western-blotting and stains-all staining analyses were used to assess whether secretion of mutant P19L-DSPP was impaired in dental pulp cells containing odontoblasts from Dspp P19L/P19L mice compared with Dspp +/+ controls. Immunohistochemistry and reverse-transcription PCR were performed to examine changes in IRE1α and its downstream target X-box binding protein 1 (XBP1) in P19L-DSPP mutant mice. To further investigate the roles of IRE1α in tooth development, we generated 2.3 Col1-Cre;Ern1 fl/fl and compound 2.3 Col1-Cre;Ern1 fl/fl ;Dspp P19L/+ mice. Structural and histological changes in mandibular molars were analyzed using plain X-ray radiography, micro-computed tomography (µCT), and histology. Additionally, in situ hybridization, quantitative real-time PCR, and immunohistochemistry were performed to compare molecular changes among these mice and Ern1 fl/fl and Ern1 fl/fl ;Dspp P19L/+ controls. Western-blotting and stains-all staining analyses support that mutant P19L-DSPP protein was not efficiently secreted into dentin matrix and was accumulated within odontoblasts. Further, immunostaining signals for phosphorylated IRE1α and total XBP1 were dramatically increased in odontoblasts and other dental pulp cells of Dspp P19L/+ and Dspp P19L/P19L mice, in comparison with Dspp +/+ mice. Consistently, there was a small increase in spliced XBP1S protein and Xbp1s mRNA levels in P19L-DSPP mutant mice. Moreover, loss of IRE1α function reduced dentin formation in 2.3 Col1-Cre;Ern1 fl/fl mice and exacerbated the dental defects of P19L-DSPP mutant mice. Notably, IRE1α deficiency did not restore the Dspp mRNA levels in the mutant mice but normalized the increased thickness of the dental pulp chamber floor dentin. These findings underscore the essential role of IRE1α in odontoblast function and dentinogenesis. Moreover, they reveal a context-dependent pathogenic role of IRE1α, providing new insights into ER stress in dental tissue development and disease.
2025-11-09 | Baseline Characteristics of the TOPaZ Study: Randomised Trial of Teriparatide and Zoledronic Acid Compared with Standard Care in Adults with Osteogenesis Imperfecta.
Osteogenesis imperfecta (OI) is a rare disorder causing multiple fractures throughout life. No treatment has been shown to reduce the risk of fractures in OI. Here, we present the baseline characteristics of participants in the Treatment of Osteogenesis Imperfecta with Parathyroid Hormone and Zoledronic Acid (TOPaZ) trial. The aim of the trial is to determine whether teriparatide and zoledronic acid are superior to standard care in reducing the risk of clinical fractures. We summarised data on the baseline characteristics of TOPaZ participants, including demographics, genetic diagnosis, clinical features, bone density measurements, previous treatments, and fracture history. We recruited 350 adults with a clinical diagnosis of OI in 27 European referral centres between June 2017 and October 2022. Overall, 266 (76.2%) had type I OI, 55 (15.8%) had type IV, and 19 (5.4%) had type III. The type was unknown in 9 (2.6%). Blue sclera were noted in 80.8%, and 35.8% had dentinogenesis imperfecta. Bisphosphonates had been administered to 28.1% in the 2 years prior to enrolment. Pathogenic variants in COL1A1 or COL1A2 were found in 87.6%. Fractures occurring in the 2 years prior to enrolment were not associated with bone density. The TOPaZ population represents a unique cohort with which to study the genetic epidemiology and outcome of OI in relation to bone density and biochemical markers of bone turnover. When the trial reports, it will also provide new insights into the effect of an anabolic therapy, followed by antiresorptive treatment in the management of OI.
2023-06-02 | Beneficial Effects of Zoledronic Acid on Tendons of the Osteogenesis Imperfecta Mouse (Oim)
Osteogenesis imperfecta (OI) is a genetic disorder of connective tissue characterized by spontaneous fractures, bone deformities, impaired growth and posture, as well as extra-skeletal manifestations. Recent studies have underlined an impairment of the osteotendinous complex in mice models of OI. The first objective of the present work was to further investigate the properties of tendons in the osteogenesis imperfecta mouse (oim), a model characterized by a mutation in the COL1A2 gene. The second objective was to identify the possible beneficial effects of zoledronic acid on tendons. Oim received a single intravenous injection of zoledronic acid (ZA group) at 5 weeks and were euthanized at 14 weeks. Their tendons were compared with those of untreated oim (oim group) and control mice (WT group) by histology, mechanical tests, western blotting and Raman spectroscopy. The ulnar epiphysis had a significantly lower relative bone surface (BV/TV) in oim than WT mice. The tendon of the triceps brachii was also significantly less birefringent and displayed numerous chondrocytes aligned along the fibers. ZA mice showed an increase in BV/TV of the ulnar epiphysis and in tendon birefringence. The tendon of the flexor digitorum longus was significantly less viscous in oim than WT mice; in ZA-treated mice, there was an improvement of viscoelastic properties, especially in the toe region of stress-strain curve, which corresponds to collagen crimp. The tendons of both oim and ZA groups did not show any significant change in the expression of decorin or tenomodulin. Finally, Raman spectroscopy highlighted differences in material properties between ZA and WT tendons. There was also a significant increase in the rate of hydroxyproline in the tendons of ZA mice compared with oim ones. This study highlighted changes in matrix organization and an alteration of mechanical properties in oim tendons; zoledronic acid treatment had beneficial effects on these parameters. In the future, it will be interesting to better understand the underlying mechanisms which are possibly linked to a greater solicitation of the musculoskeletal system.
2023-01-04 | The effects of 4-Phenylbutyric acid on ER stress during mouse tooth development
Introduction: During tooth development, proper protein folding and trafficking are significant processes as newly synthesized proteins proceed to form designated tissues. Endoplasmic reticulum (ER) stress occurs inevitably in tooth development as unfolded and misfolded proteins accumulate in ER. 4-Phenylbutyric acid (4PBA) is a FDA approved drug and known as a chemical chaperone which alleviates the ER stress. Recently, several studies showed that 4PBA performs therapeutic effects in some genetic diseases due to misfolding of proteins, metabolic related-diseases and apoptosis due to ER stress. However, the roles of 4PBA during odontogenesis are not elucidated. This study revealed the effects of 4PBA during molar development in mice. Methods: We employed in vitro organ cultivation and renal transplantation methods which would mimic the permanent tooth development in an infant period of human. The in vitro cultivated tooth germs and renal calcified teeth were examined by histology and immunohistochemical analysis. Results and Discussion: Our results revealed that treatment of 4PBA altered expression patterns of enamel knot related signaling molecules, and consequently affected cellular secretion and patterned formation of dental hard tissues including dentin and enamel during tooth morphogenesis. The alteration of ER stress by 4PBA treatment during organogenesis would suggest that proper ER stress is important for pattern formation during tooth development and morphogenesis, and 4PBA as a chemical chaperone would be one of the candidate molecules for dental and hard tissue regeneration.
2022-04-25 | Pamidronate Therapy Increases Trabecular Bone Complexity of Mandibular Condyles in Individuals with Osteogenesis Imperfecta.
Patients with Osteogenesis Imperfecta (OI) present extra-skeletal manifestations, including important orodental and craniofacial features as dentinogenesis imperfecta, dental agenesis, failure of maxilla growth and hypotonia of masticatory muscles. These features may compromise vital functions speech and mastication. Studies have demonstrated that cyclic pamidronate infusion, the standard therapy for patients with moderate to severe OI, influences the histomorphometric pattern of different body bones. The present study aimed to investigate the condyle trabecular bone pattern in OI patients. We used fractal dimension (FD) analysis on dental panoramic radiographic images to characterize the mandibular condyle trabecular bone in adolescents diagnosed with OI and treated with pamidronate. Imaging exam of 33 adolescents of both sexes, aged between 12 and 17 years, were analyzed and compared with 99 age- and sex-matched healthy adolescents. FD in patients was significantly lower (1.23 ± 0.15) than in healthy controls (1.29 ± 0.11; p < 0.01). Type of OI, age at treatment onset, and the duration of therapy were variables that showed a statistically significant effect on the FD results. This study demonstrated that the bone architecture of mandibular condyles may be altered in pediatric patients with moderate and severe forms of OI. Also, pamidronate treatment seems to have a positive effect on condyle trabecular bone in these patients. This is supported by our finding that FD values were positively influenced by the length of cyclic pamidronate treatment at the time of imaging, as well as by the age of the individual at treatment onset.
proteins
2023-12-13 | CREB3L1 deficiency impairs odontoblastic differentiation and molar root dentin deposition partially through the TMEM30B
Odontoblasts are primarily responsible for synthesizing and secreting extracellular matrix proteins, which are crucial for dentinogenesis. Our previous single-cell profile and RNAscope for odontoblast lineage revealed that cyclic adenosine monophosphate responsive element-binding protein 3 like 1 (Creb3l1) was specifically enriched in the terminal differentiated odontoblasts. In this study, deletion of Creb3l1in the Wnt1+ lineage led to insufficient root elongation and root dentin deposition. Assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-seq) and RNA sequencing were performed to revealed that in CREB3L1-deficient mouse dental papilla cells (mDPCs), the genes near the closed chromatin regions were mainly associated with mesenchymal development and the downregulated genes were primarily related to biological processes including cell differentiation, protein biosynthesis and transport, all of which were evidenced by a diminished ability of odontoblastic differentiation, a significant reduction in intracellular proteins, and an even greater decline in extracellular supernatant proteins. Dentin matrix protein 1 (Dmp1) and transmembrane protein 30B (Tmem30b) were identified as direct transcriptional regulatory targets. TMEM30B was intensively expressed in the differentiated odontoblasts, and exhibited a significant decline in both CREB3L1-deficient odontoblasts in vivo and in vitro. Deletion of Tmem30b impaired the ability of odontoblastic differentiation, protein synthesis, and protein secretion in mDPCs. Moreover, overexpressing TMEM30B in CREB3L1-deficient mDPCs partially rescued the extracellular proteins secretion. Collectively, our findings suggest that CREB3L1 participates in dentinogenesis and facilitates odontoblastic differentiation by directly enhancing the transcription of Dmp1 and other differentiation-related genes and indirectly promoting protein secretion partially via TMEM30B.
2023-05-15 | Molecular study on gene and protein expression analysis of TGF beta1 - An in vitro model to develop drugs towards dentin tissue remodelling
Introduction: TGF-1-3 are one-of-a-kind multifunctional growth factors.TGF-beta1 is active in the reconstruction of the dental pulp tissue, according to recent reports.Furthermore, dental pulp cells can divide into odontoblast-like cells, which will then develop reparative dentine.Materials and Methods: DEMM were used to culture and preserve 3T3 cells.The cells were incubated with LPS after differentiation.3t3 Cells were used to extract total RNA.It was necessary to amplify cDNA.Using specific reagents, Rt PCR was used to measure the genes of interest.Results: TGF-beta1 mRNA has a role in protein expression in lipopolysaccharide (LPS) induced macrophage-like cells.TGF-β signals are largely related to the magnitude and duration and careful regulation of their ligand activation, both temporally and spatially.If appropriately activated, TGF-β signalling plays an important function in tissue remodelling.Conclusion: TGF-beta1 mRNA has a role in protein expression in lipopolysaccharide (LPS) induced macrophage-like cells.TGF-β signals are largely related to the magnitude and duration and careful regulation of their ligand activation, both temporally and spatially.If appropriately activated, TGF-β signalling plays an important function in tissue remodelling.The evidence suggests that hVEGF has a therapeutic potential in regeneration and other disorders of the pulp.
2022-11-01 | Effects of Dentin Phosphophoryn-Derived RGD Peptides on the Differentiation and Mineralization of Human Dental Pulp Stem Cells In Vitro
The purposes of this study were to investigate the in vitro effects of arginine-glycine-aspertic acid (RGD) peptides derived from human dentin phosphophoryn (DPP) on human dental pulp stem cell-proliferation, differentiation and mineralization, and to explore the mechanism of the peptides’ function. The 1 M concentration of soluble DPP-derived RGD peptides, RGD-1, RGD-2 and RGD-3 were coated onto non-tissue-culture polystyrene plates, and human dental pulp stem cells (hDPSCs) were cultured on them to examine the effects of the peptides on hDPSCs. In addition, 1 M arginine-alanine-aspertic acid (RAD) peptides were used as the control. Cell proliferation of hDPSCs was promoted by all three RGD peptides. All three RGD peptides had significantly higher alkaline phosphatase (ALP) activity compared to the control. RGD-3 induced the highest ALP activity compared to the control. RGD-3 also significantly promoted the mRNA expression of the following genes: 1.69-fold in dentine matrix protein-1 (DMP-1), 1.99-fold in dentine sialophosphoprotein (DSPP), 1.51-fold in ALP, and 2.31-fold in bone sialoprotein (BSP), as compared to the control group. Mineralization of hDPSCs was accelerated by all three RGD peptides, RGD-3 in particular. The MAPK p38 inhibitor SB202190 inhibited the effect of RGD-3 to a level comparable to the control, observed in both ALP activity assay and Arizarin red S (ARS) staining. It suggests that the p38 pathway may be responsible for eliciting the differentiation and mineralization effects of DPP-derived RGD peptides in the hDPSCs. The mRNA expression levels of the integrins ITGA1-5, ITGA7, ITGB1 and ITGB3 were significantly upregulated. Among them, expression of ITGA5 was promoted 1.9-fold, ITGA7 1.58-fold, ITGB1 1.75-fold and ITGB3 1.9-fold compared to the control. It suggests the possible involvement of these integrin channels in different subunit combinations facilitating signal transduction for differentiation of hDPSCs into odontoblasts. As conclusions, human DPP-derived RGD peptides RGD-1, RGD-2 and RGD-3 promoted the proliferation, differentiation and mineralization of hDPSCs in vitro. Among the three peptides, RGD-3 had the most significant effects. It is also suggested that RGD-3 binds to integrin receptors on the surface of hDPSCs and regulates the odontogenic gene expression and differentiation via activation of p38 of MAPK pathway. DPP-derived RGD-3 may be a promising choice in the formulation of a novel material for vital pulp therapy to induce dental pulp stem cells into odontoblasts and form reparative dentin on the exposed pulp tissue.
2021-05-12 | The Role of GH/IGF Axis in Dento-Alveolar Complex from Development to Aging and Therapeutics: A Narrative Review
The GH/IGF axis is a major regulator of bone formation and resorption and is essential to the achievement of normal skeleton growth and homeostasis. Beyond its key role in bone physiology, the GH/IGF axis has also major pleiotropic endocrine and autocrine/paracrine effects on mineralized tissues throughout life. This article aims to review the literature on GH, IGFs, IGF binding proteins, and their respective receptors in dental tissues, both epithelium (enamel) and mesenchyme (dentin, pulp, and tooth-supporting periodontium). The present review re-examines and refines the expression of the elements of the GH/IGF axis in oral tissues and their in vivo and in vitro mechanisms of action in different mineralizing cell types of the dento-alveolar complex including ameloblasts, odontoblasts, pulp cells, cementoblasts, periodontal ligament cells, and jaw osteoblasts focusing on cell-specific activities. Together, these data emphasize the determinant role of the GH/IGF axis in physiological and pathological development, morphometry, and aging of the teeth, the periodontium, and oral bones in humans, rodents, and other vertebrates. These advancements in oral biology have elicited an enormous interest among investigators to translate the fundamental discoveries on the GH/IGF axis into innovative strategies for targeted oral tissue therapies with local treatments, associated or not with materials, for orthodontics and the repair and regeneration of the dento-alveolar complex and oral bones.
2020-04-30 | Dentinogenesis and Tooth-Alveolar Bone Complex Defects in BMP9/GDF2 Knockout Mice.
Tooth development is regulated by sequential and reciprocal epithelium-mesenchymal interactions and their related molecular signaling pathways, such as bone morphogenetic proteins (BMPs). Among the 14 types of BMPs, BMP9 (also known as growth differentiation factor 2) is one of the most potent BMPs to induce osteogenic differentiation of mesenchymal stem cells. The purpose of this study was to examine potential roles of BMP9 signaling in tooth development. First, we detected the expression pattern of BMP9 in tooth germ during postnatal tooth development, and we found that BMP9 was widely expressed in odontoblasts, ameloblasts, dental pulp cells, and osteoblasts in alveolar bones. Then, we established a BMP9-KO mouse model. Gross morphological examination revealed that the tooth cusps of BMP9-KO mice were significantly abraded with shorter roots. Micro-computed tomography and three-dimensional reconstruction analysis indicated that the first molars of the BMP9-KO mice exhibited a reduced thickness dentin, enlarged pulp canals, and shortened roots, resembling the phenotypes of the common hereditary dental disease dentinogenesis imperfecta. Further, the alveolar bone of the BMP9-KO mutants was found to be shorter and had a decreased mineral density and trabecular thickness and bone volume fraction compared with that of the wild-type control. Mechanistically, we demonstrated that both dentin sialophosphoprotein and dentin matrix protein 1 were induced in dental stem cells by BMP9, whereas their expression was reduced when BMP9 was silenced. Further studies are required to determine whether loss of or decreased BMP9 expression is clinically associated with dentinogenesis imperfecta. Collectively, our results strongly suggest that BMP9 may play an important role in regulating dentinogenesis and tooth development. Further research is recommended into the therapeutic uses of BMP9 to regenerate traumatized and diseased tissues and for the bioengineering of replacement teeth.
cell therapies
2024-03-18 | From Pluripotent Stem Cells to Organoids and Bioprinting: Recent Advances in Dental Epithelium and Ameloblast Models to Study Tooth Biology and Regeneration
Abstract Ameloblasts are the specialized dental epithelial cell type responsible for enamel formation. Following completion of enamel development in humans, ameloblasts are lost and biological repair or regeneration of enamel is not possible. In the past, in vitro models to study dental epithelium and ameloblast biology were limited to freshly isolated primary cells or immortalized cell lines, both with limited translational potential. In recent years, large strides have been made with the development of induced pluripotent stem cell and organoid models of this essential dental lineage – both enabling modeling of human dental epithelium. Upon induction with several different signaling factors (such as transforming growth factor and bone morphogenetic proteins) these models display elevated expression of ameloblast markers and enamel matrix proteins. The advent of 3D bioprinting, and its potential combination with these advanced cellular tools, is poised to revolutionize the field – and its potential for tissue engineering, regenerative and personalized medicine. As the advancements in these technologies are rapidly evolving, we evaluate the current state-of-the-art regarding in vitro cell culture models of dental epithelium and ameloblast lineage with a particular focus toward their applicability for translational tissue engineering and regenerative/personalized medicine. Graphical Abstract Future perspectives for in vitro modeling of dental epithelium and ameloblasts. Development of iPSC and organoid models that can reliably generate dental epithelium and ameloblast-like cells, together with advances in 3D bioprinting, provide promising tools for enamel research. Advanced models will provide new avenues for development of enamel repair/regeneration approaches, for testing of dental materials or drugs, studying host-pathogen and/or cell-cell interactions, in vitro modeling of enamel diseases (e.g. amelogenesis imperfecta) and developing novel insights in fundamental tooth biology (e.g. regulation of amelogenesis, lineage specification). Abbreviations: iPSC: induced pluripotent stem cells; TO: tooth organoids; DE: dental epithelium; AB: ameloblast.
2022-11-18 | Effects of Sr2+, BO33−, and SiO32− on differentiation of human dental pulp stem cells into odontoblast-like cells
Abstract Objectives: This study aimed to clarify the effects of strontium (Sr 2⁺ ), borate (BO 3 3− ), and silicate (SiO 3 2− ) on cell proliferative capacity, the induction of differentiation into odontoblast-like cells (OLCs), and substrate formation of human dental pulp stem cells (hDPSCs). Methods: Sr 2+ , BO 3 3− , and SiO 3 2− solutions were added to the hDPSC culture medium at three different concentrations, totaling nine experimental groups. The effects of these ions on hDPSC proliferation, calcification, and collagen formation after 14, 21, and 28 days of culture were evaluated using a cell proliferation assay, a quantitative alkaline phosphatase (ALP) activity assay, and Alizarin red S and Sirius red staining, respectively. Further, the effects of these ions on hDPSC differentiation into OLCs were assessed via real-time polymerase chain reaction and immunohistochemistry. Results: Sr 2+ and SiO 3 2− increased the expression of odontoblast markers; i.e., nestin, DMP-1, dentin sialophospholipoprotein, and ALP genes, compared with the control group. BO 3 3− increased the ALP gene expression and activity. Significance: The results of this study suggested that Sr 2+ , BO 3 3− , and SiO₃²− may induce hDPSC differentiation into OLCs.
2018-01-01 | Establishment of an in vitro system to screen for substances to improve osteogenesis imperfecta osteoblasts functions
Background: Osteogenesis imperfecta (OI) is a heritable bone disorder caused mainly by dominant mutations in genes encoding collagen-related proteins which are COL1A1 and COL1A2. Genotype-phenotype correlation has some discrepancies which lead to the difficult prediction of the clinical outcome of OI patients. We identified a child with dentinogenesis imperfecta (DI) and OI who was homozygous for c.1009G>A (p.G337S) mutation in COL1A2. Her parents were heterozygous for the mutation and had only DI. This family provides the opportunity to explore the biochemical changes which are different between the homozygous with DI and OI and the heterozygous with DI only. Methods: We established patients-specific induced pluripotent stem cells (iPSCs) from the trio to use as an in vitro system to screen for biochemical substances. They were used to study the expression of the osteogenic marker genes (COL1A1, COL1A2, SPP1, OCN, ALP) and their products along the time course of osteoblast differentiation. Results: We successfully generated patient-specific iPSCs from the trio. They all showed the characteristic features of iPSCs. We then differentiated them to mesenchymal stem cells (MSCs) and osteoblasts. Their osteoblasts showed various defective expression of the osteogenic markers and calcium mineralization. Interestingly, osteopontin was�absent in iPSCs-derived osteoblasts of patients with OI, while it was significantly lower in those with DI-only compared to an unaffected control. In addition, osteocalcin was significantly lower in those with OI compared to DI-only and an unaffected control. Conclusion: Levels of osteopontin and osteocalcin in iPSCs-derived MSC of patients with OI were significantly low during osteoblasts differentiation. These cells could be used to screen for substances which can increase osteopontin and osteocalcin.
2017-07-12 | Minimally invasive orthodontics: elastodontic therapy in a growing patient affected by Dentinogenesis Imperfecta
The aim of the study was to report the use of an elastodontic therapy in a growing patient affected by Dentinogenesis Imperfecta, second class malocclusion, deep bite and lower arch crowding from the deciduous dentition to permanent one.At first, the 5-year-old patient was treated with an elastodontic device known as "Nite-Guide". When the patient was 7 years old, during her first permanent molars and incisors eruption and after optimal house-practices, an Occlus-o-Guide Series G was placed at night and on daylight (two hours a day) performing exercises aimed to activate facial muscles and facilitate the deep bite reopening. At 9 years of age, with totally deep bite resolution, she used the Occluso-Guide only at night to hold down previous results and follow patient's dental growth. At 11 years of age, after successful teeth switching, we prescribed an Occlus-o-Guide Series N, which is functional for permanent dentition and guaranteed an eruptive guide for last dental elements.This clinic case could be considered an example of approach for all those patients with systemic and/or dental diseases that do not allow adequate dental retention, which is necessary for most orthodontic appliances; elastodontic devices do not require adequate dental retention and define a minimum intervention on the surfaces of the teeth.
2009-06-25 | The performance of dental pulp stem cells on nanofibrous PCL/gelatin/nHA scaffolds
Abstract The aim of current study is to investigate the in vitro and in vivo behavior of dental pulp stem cells (DPSCs) seeded on electrospun poly(ε‐caprolactone) (PCL)/gelatin scaffolds with or without the addition of nano‐hydroxyapatite (nHA). For the in vitro evaluation, DNA content, alkaline phosphatase (ALP) activity and osteocalcin (OC) measurement showed that the scaffolds supported DPSC adhesion, proliferation, and odontoblastic differentiation. Moreover, the presence of nHA upregulated ALP activity and promoted OC expression. Real‐time PCR data confirmed these results. SEM micrographs qualitatively confirmed the proliferation and mineralization characteristics of DPSCs on both scaffolds. Subsequently, both scaffolds seeded with DPSCs were subcutaneously implanted into immunocompromised nude mice. Scaffolds with nHA but without cells were implanted as control. Histological evaluation revealed that all implants were surrounded by a thin fibrous tissue capsule without any adverse effects. The cell/scaffold composites showed obvious in vivo hard tissue formation, but there was no sign of tissue ingrowth. Further, the combination of nHA in scaffolds did upregulate the expression of specific odontogenic genes. In conclusion, the incorporation of nHA in nanofibers indeed enhanced DPSCs differentiation towards an odontoblast‐like phenotype in vitro and in vivo . © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
gene therapies
2022-05-25 | Comparative transcriptome profiles of human dental pulp stem cells from maxillary and mandibular teeth
Abstract The molecular control of tooth development is different between the maxilla and mandible, contributing to different tooth shapes and locations; however, whether this difference occurs in human permanent teeth is unknown. The aim of this study was to investigate and compare the transcriptome profiles of permanent maxillary and mandibular posterior teeth. Ten participants who had a pair of opposing premolars or molars extracted were recruited. The RNA obtained from cultured dental pulp stem cells underwent RNA-sequencing and qRT-PCR. The transcriptome profiles of two opposing premolar pairs and two molar pairs demonstrated that the upper premolars, lower premolars, upper molars, and lower molars expressed the same top-ranked genes, comprising FN1, COL1A1, COL1A2, ACTB, and EEFIA1, which are involved in extracellular matrix organization, immune system, signal transduction, hemostasis, and vesicle-mediated transport. Comparative transcriptome analyses of each/combined tooth pairs demonstrated that PITX1 was the only gene with different expression levels between upper and lower posterior teeth. PITX1 exhibited a 64-fold and 116-fold higher expression level in lower teeth compared with their upper premolars and molars, respectively. These differences were confirmed by qRT-PCR. Taken together, this study, for the first time, reveals that PITX1 is expressed significantly higher in mandibular posterior teeth compared with maxillary posterior teeth. The difference is more evident in the molars compared with premolars and consistent with its expression pattern in mouse developing teeth. We demonstrate that differences in lower versus upper teeth gene expression during odontogenesis occur in permanent teeth and suggest that these differences should be considered in molecular studies of dental pulp stem cells. Our findings pave the way to develop a more precise treatment in regenerative dentistry such as gene-based therapies for dentin/pulp regeneration and regeneration of different tooth types.
2021-05-26 | DSPP dosage affects tooth development and dentin mineralization
Dentin Sialoprotein (DSP) and phosphophoryn (PP) are two most dominant non-collagenous proteins in dentin, which are the cleavage products of the DSPP (dentin sialophosphoprotein) precursor protein. The absence of the DSPP gene in DSPP knock-out (KO) mice results in characteristics that are consistent with dentinogenesis imperfecta type III in humans. Symptoms include thin dentin, bigger pulp chamber with frequent pulp exposure as well as abnormal epithelial-mesenchymal interactions, and the appearance of chondrocyte-like cells in dental pulp. To better understand how DSPP influences tooth development and dentin formation, we used a bacterial artificial chromosome transgene construct (BAC-DSPP) that contained the complete DSPP gene and promoter to generate BAC-DSPP transgenic mice directly in a mouse DSPP KO background. Two BAC-DSPP transgenic mouse strains were generated and characterized. DSPP mRNA expression in BAC-DSPP Strain A incisors was similar to that from wild-type (wt) mice. DSPP mRNA expression in BAC-DSPP Strain B animals was only 10% that of wt mice. PP protein content in Strain A incisors was 25% of that found in wt mice, which was sufficient to completely rescue the DSPP KO defect in mineral density, since microCT dentin mineral density analysis in 21-day postnatal animal molars showed essentially identical mineral density in both strain A and wt mice. Strain B mouse incisors, with 5% PP expression, only partially rescued the DSPP KO defect in mineral density, as microCT scans of 21-day postnatal animal molars indicated a reduced dentin mineral density compared to wt mice, though the mineral density was still increased over that of DSPP KO. Furthermore, our findings showed that DSPP dosage in Strain A was sufficient to rescue the DSPP KO defect in terms of epithelial-mesenchymal interactions, odontoblast lineage maintenance, along with normal dentin thickness and normal mineral density while DSPP gene dosage in Strain B only partially rescued the aforementioned DSPP KO defect.
2018-04-19 | Transgenic expression of dentin phosphoprotein (DPP) partially rescued the dentin defects of DSPP-null mice
Mutations in the dentin sialophosphoprotein (DSPP) gene cause dentinogenesis imperfecta. After synthesis, DSPP is proteolytically processed into NH2- and COOH-terminal fragments. The NH2-terminal fragment of DSPP is highly glycosylated but not phosphorylated, whereas the COOH-terminal fragment (named “dentin phosphoprotein” or “DPP”) is highly phosphorylated but not glycosylated. These two fragments are believed to perform distinct roles in dentin formation. To analyze the functions of DPP in dentinogenesis, we created “Dspp-/-;DPP Tg mice”, which expressed transgenic DPP driven by a Type I collagen promoter but lacked the endogenous Dspp gene. We characterized the dentin of the Dspp-/-;DPP Tg mice using X-ray radiography, histology, scanning electron microscopy, double fluorochrome labeling, immunohistochemistry and in situ hybridization. Micro-computed tomography analyses revealed that at postnatal 6 months, the transgenic expression of DPP increased the dentin thickness of the Dspp-null mice by 97.1% and restored the dentin material density by 29.5%. Histological analyses showed that the Dspp-null mice manifested an abnormal widening of the predentin while the predentin in Dspp-/-;DPP Tg mice was narrower than in the Dspp-null mice. Scanning electron microscopy analyses showed that the dentinal tubules in the Dspp-/-;DPP Tg mice were better organized than in the Dspp-null mice. The double fluorochrome labeling analyses demonstrated that the dentin mineral deposition rate in the Dspp-/-;DPP Tg mice was significantly improved compared to that in the Dspp-null mice. These findings indicate that the transgenic expression of DPP partially rescued the dentin defects of the DSPP-null mice, suggesting that DPP may promote dentin formation and that the coordinated actions between DPP and the NH2-terminal fragment of DSPP may be necessary for dentinogenesis.
2017-04-25 | Klf5 Mediates Odontoblastic Differentiation through Regulating Dentin-Specific Extracellular Matrix Gene Expression during Mouse Tooth Development
Abstract Klf5, a member of the Krüppel-like transcription factor family, has essential roles during embryonic development, cell proliferation, differentiation, migration and apoptosis. This study was to define molecular mechanism of Klf5 during the odontoblastic differentiation. The expression of Klf5, odontoblast-differentiation markers, Dspp and Dmp1 was co-localized in odontoblastic cells at different stages of mouse tooth development and mouse dental papilla mesenchymal cells. Klf5 was able to promote odontoblastic differentiation and enhance mineral formation of mouse dental papilla mesenchymal cells. Furthermore, overexpression of Klf5 could up-regulate Dspp and Dmp1 gene expressions in mouse dental papilla mesenchymal cells. In silico analysis identified that several putative Klf5 binding sites in the promoter and first intron of Dmp1 and Dspp genes that are homologous across species lines. Electrophoretic mobility shift assay and chromatin immunoprecipitation analysis indicated that Klf5 bound to these motifs in vitro and in intact cells. The responsible regions of Dmp1 gene were located in the promoter region while effect of Klf5 on Dspp activity was in the first intron of Dspp gene. Our results identify Klf5 as an activator of Dmp1 and Dspp gene transcriptions by different mechanisms and demonstrate that Klf5 plays a pivotal role in odontoblast differentiation.
2015-12-17 | Transgenic expression of Dspp partially rescued the long bone defects of Dmp1-null mice
Dentin matrix protein 1 (DMP1) and dentin sialophosphoprotein (DSPP) belong to the Small Integrin-Binding Ligand N-linked Glycoprotein (SIBLING) family. In addition to the features common to all SIBLING members, DMP1 and DSPP share several unique similarities in chemical structure, proteolytic activation and tissue localization. Mutations in, or deletion of DMP1, cause autosomal recessive hypophosphatemic rickets along with dental defects; DSPP mutations or its ablation are associated with dentinogenesis imperfecta. While the roles and functional mechanisms of DMP1 in osteogenesis have been extensively studied, those of DSPP in long bones have been studied only to a limited extent. Previous studies by our group revealed that transgenic expression of Dspp completely rescued the dentin defects of Dmp1-null (Dmp1(-/-)) mice. In this investigation, we assessed the effects of transgenic Dspp on osteogenesis by analyzing the formation and mineralization of the long bones in Dmp1(-/-) mice that expresses a transgene encoding full-length DSPP driven by a 3.6-kb rat Col1a1 promoter (referred as "Dmp1(-/-);Dspp-Tg mice"). We characterized the long bones of the Dmp1(-/-);Dspp-Tg mice at different ages and compared them with those from Dmp1(-/-) and Dmp1(+/-) (normal control) mice. Our analyses showed that the long bones of Dmp1(-/-);Dspp-Tg mice had a significant increase in cortical bone thickness, bone volume and mineral density along with a remarkable restoration of trabecular thickness compared to those of the Dmp1(-/-) mice. The long bones of Dmp1(-/-);Dspp-Tg mice underwent a dramatic reduction in the amount of osteoid, significant improvement of the collagen fibrillar network, and better organization of the lacunocanalicular system, compared to the Dmp1(-/-) mice. The elevated levels of biglycan, bone sialoprotein and osteopontin in Dmp1(-/-) mice were also noticeably corrected by the transgenic expression of Dspp. These findings suggest that DSPP and DMP1 may function synergistically within the complex milieus of bone matrices.
other
2023-10-27 | Osteoporosis Improved by Romosozumab Therapy in a Patient With Type I Osteogenesis Imperfecta
Osteogenesis imperfecta (OI) is a genetic disorder that affects type 1 collagen synthesis causing increased bone fragility, low bone mass, and skeletal deformity. Bisphosphonates are recommended for treatment of OI patients; however, the efficacy of sclerostin inhibitors such as romosozumab has not been determined in OI patients with osteoporosis.A 52-year-old G2P2 clinically diagnosed with OI, with a history of multiple fractures beginning in childhood presented with low bone mass. On physical examination, blue sclera was observed. She was previously treated with alendronate therapy from April 2014 to June 2015 without significant improvement in bone mineral density (BMD). After the onset of menopause, she began romosozumab 210 mg subcutaneous therapy once a month for 12 months. Repeat dual-energy X-ray absorptiometry showed an increase of 10.3% in BMD of the spine and a 5.4% increase in BMD of the right hip. The trabecular bone score increased by 5.2%.Current literature is limited regarding the use of sclerostin inhibitors in OI patients. Our patient's improvement in BMD of the spine and right hip after romosozumab therapy was significant at a 95% confidence level, compared to treatment initiation. Her trabecular bone score also improved significantly. Six months into our patient's treatment course, a case in Japan of a male with severe osteoporotic OI and recurrent fractures showed improvement in BMD after romosozumab therapy.This case highlights our patient's significant response to romosozumab and warrants further investigation of romosozumab as a potential treatment option for OI patients with osteoporosis.
2022-07-12 | MACF1 Deficiency Suppresses Tooth Mineralization through IGF1 mediated Crosstalk Between Odontoblasts and Ameloblasts
Abstract Tooth mineralization is a ubiquitous and tightly regulated process in vertebrates which usually share the similar mechanisms of bone mineralization. However, key molecules in tooth mineralization remain poorly identified. Previously, we showed the crucial roles of MACF1 in promoting osteoblast differentiation and bone formation. In this study, odontoblast-specific Osx -Cre; Macf1 f/f mice and in vitro cell culture systems were used to investigate the roles of MACF1 in tooth formation. We found that deficiency of MACF1 in odontoblast caused delayed development, abnormal morphology, decreased mineral density and deteriorated microarchitecture in both dentin and enamel of mice. The expression of odontoblast marker genes and ALP activity were suppressed in in vitro cultured Macf1 deficiency odontoblasts. Meanwhile, the ameloblast marker genes and ALP activity were also inhibited in ameloblasts co-cultured with the Macf1 deficiency odontoblasts, indicating the key roles of MACF1 in modulating the process of formation and mineralization in enamel and dentin. Transcriptome sequencing analysis of tooth germs and cytokine antibody array analysis of odontoblast mineralization-inducing medium proved that MACF1 deficiency in odontoblasts inhibited crosstalk between odontoblasts and ameloblasts through IGF1. Altogether, our studies have revealed a novel key molecule MACF1 in tooth mineralization and provided a new target for diseases related to dental development.
2022-03-08 | Cell surface accumulation of intracellular leucine proline-enriched proteoglycan 1 enhances odontogenic potential of human dental pulp stem cells
Abstract Primary dental pulp cells can be differentiated into odontoblasts, which are responsible for dentin formation and mineralization. Successful differentiation has been verified using a few markers. However, odontoblast-specific cell surface markers have not been fully studied yet. Previously, we have constructed monoclonal antibodies to identify cell surface molecules of odontoblasts by decoy immunization. Mass spectrometry confirmed that one of these antibodies, the anti-OD40 antibody, recognized LEucine PRoline-Enriched Proteoglycan 1 (LEPRE1) as a specific antigen. Among three alternative splicing isoforms of LEPRE1, this new antibody showed the most stable antigenic affinity for LEPRE1a, a canonical transcript. Anti-OD40 antibody could strongly bind to the cell surface as odontogenic differentiation progressed. Intracellular and cell surface accumulation of this protein completely disappeared during dentin maturation and mineralization. Overexpression and knock-down experiments showed that intracellular LEPRE1/OD40 should not accumulate too much and that it should move from ER to the cell surface for efficient odontogenic differentiation. Indeed, when LEPRE1/OD40 already located on the cell surface was blocked with antibody, odontogenic differentiation of human dental pulp cells was inhibited. In addition to its role in differentiation, our new antibody which only recognizes LEPRE1a isoform specifically will be useful in studying differentiated functions between LEPRE1a and other isoforms found in osteogenesis imperfecta and dentinogenesis imperfecta.
2021-08-10 | Gender-Related Impact of Sclerostin Antibody on Bone in the Osteogenesis Imperfecta Mouse
Osteogenesis imperfecta (OI), which is most often due to a collagen type 1 gene mutation, is characterized by low bone density and bone fragility. In OI patients, gender-related differences were reported, but data in the literature are not convergent. We previously observed that sclerostin antibody (Scl-Ab), which stimulates osteoblast Wnt pathway via sclerostin inactivation, improved spine and long-bone parameters and biomechanical strength in female oim/oim mice, a validated model of human type 3 OI. Here, we wanted to highlight the effect of Scl-Ab on male oim/oim bones in order to identify a possible distinct therapeutic effect from that observed in females. According to the same protocol as our previous study with female mice, male wild-type (Wt) and oim/oim mice received vehicle or Scl-Ab from 5 to 14 weeks of age. Clinimetric and quantitative bone parameters were studied using X-rays, peripheral quantitative computed tomography, microradiography, and dynamic histomorphometry and compared to those of females. Contrary to Wt mice, male oim/oim had significantly lower weight, snout–sacrum length, and bone mineral content than females at 5 weeks. No significant difference in these clinimetric parameters was observed at 14 weeks, whereas male oim showed significantly more long-bone fractures than females. Scl-Ab improved bone mineral density and bone volume/total volume ratio (BV/TV) of vertebral body in Wt and oim/oim, without significant difference between male and female at 14 weeks. Male vehicle oim/oim had a significantly lower cortical thickness (Ct.Th) and BV/TV of tibial diaphysis than female and showed a higher number of fractures at 14 weeks. Scl-Ab increased midshaft periosteal apposition rate in such a way that tibial Ct.Th of male oim/oim was not significantly different from the female one at 14 weeks. The number of fractures was lower in male than female oim/oim after 14 weeks of Scl-Ab treatment, but this difference was not significant. Nevertheless, Scl-Ab–treated oim/oim male and female mice remained smaller than the Wt ones. In conclusion, our results highlighted differences between male and female oim/oim at 4 and 14 weeks of age, as well as some male-specific response of cortical bone to Scl-Ab. These gender-related particularities of oim/oim should be considered when testing experimental treatments.
small molecules
2025-12-24 | Inositol-requiring enzyme 1 alpha is essential for dentinogenesis.
Inositol-requiring enzyme 1 alpha (IRE1α), encoded by endoplasmic reticulum (ER) to nucleus signaling 1 (Ern1) gene, is the most conserved sensor of ER stress. IRE1α-initiated signaling pathways contribute to functional maturation of secretory cells and have been implicated in various human diseases. In this study, we examined the roles of IRE1α in odontoblast development and dentin formation in wild-type mice as well as in Dspp P19L mutant mice, which express a pathogenic variant of dentin sialophosphoprotein (P19L-DSPP) and exhibit a dentinogenesis imperfecta (DGI)-like phenotype. Western-blotting and stains-all staining analyses were used to assess whether secretion of mutant P19L-DSPP was impaired in dental pulp cells containing odontoblasts from Dspp P19L/P19L mice compared with Dspp +/+ controls. Immunohistochemistry and reverse-transcription PCR were performed to examine changes in IRE1α and its downstream target X-box binding protein 1 (XBP1) in P19L-DSPP mutant mice. To further investigate the roles of IRE1α in tooth development, we generated 2.3 Col1-Cre;Ern1 fl/fl and compound 2.3 Col1-Cre;Ern1 fl/fl ;Dspp P19L/+ mice. Structural and histological changes in mandibular molars were analyzed using plain X-ray radiography, micro-computed tomography (µCT), and histology. Additionally, in situ hybridization, quantitative real-time PCR, and immunohistochemistry were performed to compare molecular changes among these mice and Ern1 fl/fl and Ern1 fl/fl ;Dspp P19L/+ controls. Western-blotting and stains-all staining analyses support that mutant P19L-DSPP protein was not efficiently secreted into dentin matrix and was accumulated within odontoblasts. Further, immunostaining signals for phosphorylated IRE1α and total XBP1 were dramatically increased in odontoblasts and other dental pulp cells of Dspp P19L/+ and Dspp P19L/P19L mice, in comparison with Dspp +/+ mice. Consistently, there was a small increase in spliced XBP1S protein and Xbp1s mRNA levels in P19L-DSPP mutant mice. Moreover, loss of IRE1α function reduced dentin formation in 2.3 Col1-Cre;Ern1 fl/fl mice and exacerbated the dental defects of P19L-DSPP mutant mice. Notably, IRE1α deficiency did not restore the Dspp mRNA levels in the mutant mice but normalized the increased thickness of the dental pulp chamber floor dentin. These findings underscore the essential role of IRE1α in odontoblast function and dentinogenesis. Moreover, they reveal a context-dependent pathogenic role of IRE1α, providing new insights into ER stress in dental tissue development and disease.
2025-11-09 | Baseline Characteristics of the TOPaZ Study: Randomised Trial of Teriparatide and Zoledronic Acid Compared with Standard Care in Adults with Osteogenesis Imperfecta.
Osteogenesis imperfecta (OI) is a rare disorder causing multiple fractures throughout life. No treatment has been shown to reduce the risk of fractures in OI. Here, we present the baseline characteristics of participants in the Treatment of Osteogenesis Imperfecta with Parathyroid Hormone and Zoledronic Acid (TOPaZ) trial. The aim of the trial is to determine whether teriparatide and zoledronic acid are superior to standard care in reducing the risk of clinical fractures. We summarised data on the baseline characteristics of TOPaZ participants, including demographics, genetic diagnosis, clinical features, bone density measurements, previous treatments, and fracture history. We recruited 350 adults with a clinical diagnosis of OI in 27 European referral centres between June 2017 and October 2022. Overall, 266 (76.2%) had type I OI, 55 (15.8%) had type IV, and 19 (5.4%) had type III. The type was unknown in 9 (2.6%). Blue sclera were noted in 80.8%, and 35.8% had dentinogenesis imperfecta. Bisphosphonates had been administered to 28.1% in the 2 years prior to enrolment. Pathogenic variants in COL1A1 or COL1A2 were found in 87.6%. Fractures occurring in the 2 years prior to enrolment were not associated with bone density. The TOPaZ population represents a unique cohort with which to study the genetic epidemiology and outcome of OI in relation to bone density and biochemical markers of bone turnover. When the trial reports, it will also provide new insights into the effect of an anabolic therapy, followed by antiresorptive treatment in the management of OI.
2023-06-02 | Beneficial Effects of Zoledronic Acid on Tendons of the Osteogenesis Imperfecta Mouse (Oim)
Osteogenesis imperfecta (OI) is a genetic disorder of connective tissue characterized by spontaneous fractures, bone deformities, impaired growth and posture, as well as extra-skeletal manifestations. Recent studies have underlined an impairment of the osteotendinous complex in mice models of OI. The first objective of the present work was to further investigate the properties of tendons in the osteogenesis imperfecta mouse (oim), a model characterized by a mutation in the COL1A2 gene. The second objective was to identify the possible beneficial effects of zoledronic acid on tendons. Oim received a single intravenous injection of zoledronic acid (ZA group) at 5 weeks and were euthanized at 14 weeks. Their tendons were compared with those of untreated oim (oim group) and control mice (WT group) by histology, mechanical tests, western blotting and Raman spectroscopy. The ulnar epiphysis had a significantly lower relative bone surface (BV/TV) in oim than WT mice. The tendon of the triceps brachii was also significantly less birefringent and displayed numerous chondrocytes aligned along the fibers. ZA mice showed an increase in BV/TV of the ulnar epiphysis and in tendon birefringence. The tendon of the flexor digitorum longus was significantly less viscous in oim than WT mice; in ZA-treated mice, there was an improvement of viscoelastic properties, especially in the toe region of stress-strain curve, which corresponds to collagen crimp. The tendons of both oim and ZA groups did not show any significant change in the expression of decorin or tenomodulin. Finally, Raman spectroscopy highlighted differences in material properties between ZA and WT tendons. There was also a significant increase in the rate of hydroxyproline in the tendons of ZA mice compared with oim ones. This study highlighted changes in matrix organization and an alteration of mechanical properties in oim tendons; zoledronic acid treatment had beneficial effects on these parameters. In the future, it will be interesting to better understand the underlying mechanisms which are possibly linked to a greater solicitation of the musculoskeletal system.
2023-01-04 | The effects of 4-Phenylbutyric acid on ER stress during mouse tooth development
Introduction: During tooth development, proper protein folding and trafficking are significant processes as newly synthesized proteins proceed to form designated tissues. Endoplasmic reticulum (ER) stress occurs inevitably in tooth development as unfolded and misfolded proteins accumulate in ER. 4-Phenylbutyric acid (4PBA) is a FDA approved drug and known as a chemical chaperone which alleviates the ER stress. Recently, several studies showed that 4PBA performs therapeutic effects in some genetic diseases due to misfolding of proteins, metabolic related-diseases and apoptosis due to ER stress. However, the roles of 4PBA during odontogenesis are not elucidated. This study revealed the effects of 4PBA during molar development in mice. Methods: We employed in vitro organ cultivation and renal transplantation methods which would mimic the permanent tooth development in an infant period of human. The in vitro cultivated tooth germs and renal calcified teeth were examined by histology and immunohistochemical analysis. Results and Discussion: Our results revealed that treatment of 4PBA altered expression patterns of enamel knot related signaling molecules, and consequently affected cellular secretion and patterned formation of dental hard tissues including dentin and enamel during tooth morphogenesis. The alteration of ER stress by 4PBA treatment during organogenesis would suggest that proper ER stress is important for pattern formation during tooth development and morphogenesis, and 4PBA as a chemical chaperone would be one of the candidate molecules for dental and hard tissue regeneration.
2022-04-25 | Pamidronate Therapy Increases Trabecular Bone Complexity of Mandibular Condyles in Individuals with Osteogenesis Imperfecta.
Patients with Osteogenesis Imperfecta (OI) present extra-skeletal manifestations, including important orodental and craniofacial features as dentinogenesis imperfecta, dental agenesis, failure of maxilla growth and hypotonia of masticatory muscles. These features may compromise vital functions speech and mastication. Studies have demonstrated that cyclic pamidronate infusion, the standard therapy for patients with moderate to severe OI, influences the histomorphometric pattern of different body bones. The present study aimed to investigate the condyle trabecular bone pattern in OI patients. We used fractal dimension (FD) analysis on dental panoramic radiographic images to characterize the mandibular condyle trabecular bone in adolescents diagnosed with OI and treated with pamidronate. Imaging exam of 33 adolescents of both sexes, aged between 12 and 17 years, were analyzed and compared with 99 age- and sex-matched healthy adolescents. FD in patients was significantly lower (1.23 ± 0.15) than in healthy controls (1.29 ± 0.11; p < 0.01). Type of OI, age at treatment onset, and the duration of therapy were variables that showed a statistically significant effect on the FD results. This study demonstrated that the bone architecture of mandibular condyles may be altered in pediatric patients with moderate and severe forms of OI. Also, pamidronate treatment seems to have a positive effect on condyle trabecular bone in these patients. This is supported by our finding that FD values were positively influenced by the length of cyclic pamidronate treatment at the time of imaging, as well as by the age of the individual at treatment onset.
proteins
2023-12-13 | CREB3L1 deficiency impairs odontoblastic differentiation and molar root dentin deposition partially through the TMEM30B
Odontoblasts are primarily responsible for synthesizing and secreting extracellular matrix proteins, which are crucial for dentinogenesis. Our previous single-cell profile and RNAscope for odontoblast lineage revealed that cyclic adenosine monophosphate responsive element-binding protein 3 like 1 (Creb3l1) was specifically enriched in the terminal differentiated odontoblasts. In this study, deletion of Creb3l1in the Wnt1+ lineage led to insufficient root elongation and root dentin deposition. Assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-seq) and RNA sequencing were performed to revealed that in CREB3L1-deficient mouse dental papilla cells (mDPCs), the genes near the closed chromatin regions were mainly associated with mesenchymal development and the downregulated genes were primarily related to biological processes including cell differentiation, protein biosynthesis and transport, all of which were evidenced by a diminished ability of odontoblastic differentiation, a significant reduction in intracellular proteins, and an even greater decline in extracellular supernatant proteins. Dentin matrix protein 1 (Dmp1) and transmembrane protein 30B (Tmem30b) were identified as direct transcriptional regulatory targets. TMEM30B was intensively expressed in the differentiated odontoblasts, and exhibited a significant decline in both CREB3L1-deficient odontoblasts in vivo and in vitro. Deletion of Tmem30b impaired the ability of odontoblastic differentiation, protein synthesis, and protein secretion in mDPCs. Moreover, overexpressing TMEM30B in CREB3L1-deficient mDPCs partially rescued the extracellular proteins secretion. Collectively, our findings suggest that CREB3L1 participates in dentinogenesis and facilitates odontoblastic differentiation by directly enhancing the transcription of Dmp1 and other differentiation-related genes and indirectly promoting protein secretion partially via TMEM30B.
2023-05-15 | Molecular study on gene and protein expression analysis of TGF beta1 - An in vitro model to develop drugs towards dentin tissue remodelling
Introduction: TGF-1-3 are one-of-a-kind multifunctional growth factors.TGF-beta1 is active in the reconstruction of the dental pulp tissue, according to recent reports.Furthermore, dental pulp cells can divide into odontoblast-like cells, which will then develop reparative dentine.Materials and Methods: DEMM were used to culture and preserve 3T3 cells.The cells were incubated with LPS after differentiation.3t3 Cells were used to extract total RNA.It was necessary to amplify cDNA.Using specific reagents, Rt PCR was used to measure the genes of interest.Results: TGF-beta1 mRNA has a role in protein expression in lipopolysaccharide (LPS) induced macrophage-like cells.TGF-β signals are largely related to the magnitude and duration and careful regulation of their ligand activation, both temporally and spatially.If appropriately activated, TGF-β signalling plays an important function in tissue remodelling.Conclusion: TGF-beta1 mRNA has a role in protein expression in lipopolysaccharide (LPS) induced macrophage-like cells.TGF-β signals are largely related to the magnitude and duration and careful regulation of their ligand activation, both temporally and spatially.If appropriately activated, TGF-β signalling plays an important function in tissue remodelling.The evidence suggests that hVEGF has a therapeutic potential in regeneration and other disorders of the pulp.
2022-11-01 | Effects of Dentin Phosphophoryn-Derived RGD Peptides on the Differentiation and Mineralization of Human Dental Pulp Stem Cells In Vitro
The purposes of this study were to investigate the in vitro effects of arginine-glycine-aspertic acid (RGD) peptides derived from human dentin phosphophoryn (DPP) on human dental pulp stem cell-proliferation, differentiation and mineralization, and to explore the mechanism of the peptides’ function. The 1 M concentration of soluble DPP-derived RGD peptides, RGD-1, RGD-2 and RGD-3 were coated onto non-tissue-culture polystyrene plates, and human dental pulp stem cells (hDPSCs) were cultured on them to examine the effects of the peptides on hDPSCs. In addition, 1 M arginine-alanine-aspertic acid (RAD) peptides were used as the control. Cell proliferation of hDPSCs was promoted by all three RGD peptides. All three RGD peptides had significantly higher alkaline phosphatase (ALP) activity compared to the control. RGD-3 induced the highest ALP activity compared to the control. RGD-3 also significantly promoted the mRNA expression of the following genes: 1.69-fold in dentine matrix protein-1 (DMP-1), 1.99-fold in dentine sialophosphoprotein (DSPP), 1.51-fold in ALP, and 2.31-fold in bone sialoprotein (BSP), as compared to the control group. Mineralization of hDPSCs was accelerated by all three RGD peptides, RGD-3 in particular. The MAPK p38 inhibitor SB202190 inhibited the effect of RGD-3 to a level comparable to the control, observed in both ALP activity assay and Arizarin red S (ARS) staining. It suggests that the p38 pathway may be responsible for eliciting the differentiation and mineralization effects of DPP-derived RGD peptides in the hDPSCs. The mRNA expression levels of the integrins ITGA1-5, ITGA7, ITGB1 and ITGB3 were significantly upregulated. Among them, expression of ITGA5 was promoted 1.9-fold, ITGA7 1.58-fold, ITGB1 1.75-fold and ITGB3 1.9-fold compared to the control. It suggests the possible involvement of these integrin channels in different subunit combinations facilitating signal transduction for differentiation of hDPSCs into odontoblasts. As conclusions, human DPP-derived RGD peptides RGD-1, RGD-2 and RGD-3 promoted the proliferation, differentiation and mineralization of hDPSCs in vitro. Among the three peptides, RGD-3 had the most significant effects. It is also suggested that RGD-3 binds to integrin receptors on the surface of hDPSCs and regulates the odontogenic gene expression and differentiation via activation of p38 of MAPK pathway. DPP-derived RGD-3 may be a promising choice in the formulation of a novel material for vital pulp therapy to induce dental pulp stem cells into odontoblasts and form reparative dentin on the exposed pulp tissue.
2021-05-12 | The Role of GH/IGF Axis in Dento-Alveolar Complex from Development to Aging and Therapeutics: A Narrative Review
The GH/IGF axis is a major regulator of bone formation and resorption and is essential to the achievement of normal skeleton growth and homeostasis. Beyond its key role in bone physiology, the GH/IGF axis has also major pleiotropic endocrine and autocrine/paracrine effects on mineralized tissues throughout life. This article aims to review the literature on GH, IGFs, IGF binding proteins, and their respective receptors in dental tissues, both epithelium (enamel) and mesenchyme (dentin, pulp, and tooth-supporting periodontium). The present review re-examines and refines the expression of the elements of the GH/IGF axis in oral tissues and their in vivo and in vitro mechanisms of action in different mineralizing cell types of the dento-alveolar complex including ameloblasts, odontoblasts, pulp cells, cementoblasts, periodontal ligament cells, and jaw osteoblasts focusing on cell-specific activities. Together, these data emphasize the determinant role of the GH/IGF axis in physiological and pathological development, morphometry, and aging of the teeth, the periodontium, and oral bones in humans, rodents, and other vertebrates. These advancements in oral biology have elicited an enormous interest among investigators to translate the fundamental discoveries on the GH/IGF axis into innovative strategies for targeted oral tissue therapies with local treatments, associated or not with materials, for orthodontics and the repair and regeneration of the dento-alveolar complex and oral bones.
2020-04-30 | Dentinogenesis and Tooth-Alveolar Bone Complex Defects in BMP9/GDF2 Knockout Mice.
Tooth development is regulated by sequential and reciprocal epithelium-mesenchymal interactions and their related molecular signaling pathways, such as bone morphogenetic proteins (BMPs). Among the 14 types of BMPs, BMP9 (also known as growth differentiation factor 2) is one of the most potent BMPs to induce osteogenic differentiation of mesenchymal stem cells. The purpose of this study was to examine potential roles of BMP9 signaling in tooth development. First, we detected the expression pattern of BMP9 in tooth germ during postnatal tooth development, and we found that BMP9 was widely expressed in odontoblasts, ameloblasts, dental pulp cells, and osteoblasts in alveolar bones. Then, we established a BMP9-KO mouse model. Gross morphological examination revealed that the tooth cusps of BMP9-KO mice were significantly abraded with shorter roots. Micro-computed tomography and three-dimensional reconstruction analysis indicated that the first molars of the BMP9-KO mice exhibited a reduced thickness dentin, enlarged pulp canals, and shortened roots, resembling the phenotypes of the common hereditary dental disease dentinogenesis imperfecta. Further, the alveolar bone of the BMP9-KO mutants was found to be shorter and had a decreased mineral density and trabecular thickness and bone volume fraction compared with that of the wild-type control. Mechanistically, we demonstrated that both dentin sialophosphoprotein and dentin matrix protein 1 were induced in dental stem cells by BMP9, whereas their expression was reduced when BMP9 was silenced. Further studies are required to determine whether loss of or decreased BMP9 expression is clinically associated with dentinogenesis imperfecta. Collectively, our results strongly suggest that BMP9 may play an important role in regulating dentinogenesis and tooth development. Further research is recommended into the therapeutic uses of BMP9 to regenerate traumatized and diseased tissues and for the bioengineering of replacement teeth.
cell therapies
2024-03-18 | From Pluripotent Stem Cells to Organoids and Bioprinting: Recent Advances in Dental Epithelium and Ameloblast Models to Study Tooth Biology and Regeneration
Abstract Ameloblasts are the specialized dental epithelial cell type responsible for enamel formation. Following completion of enamel development in humans, ameloblasts are lost and biological repair or regeneration of enamel is not possible. In the past, in vitro models to study dental epithelium and ameloblast biology were limited to freshly isolated primary cells or immortalized cell lines, both with limited translational potential. In recent years, large strides have been made with the development of induced pluripotent stem cell and organoid models of this essential dental lineage – both enabling modeling of human dental epithelium. Upon induction with several different signaling factors (such as transforming growth factor and bone morphogenetic proteins) these models display elevated expression of ameloblast markers and enamel matrix proteins. The advent of 3D bioprinting, and its potential combination with these advanced cellular tools, is poised to revolutionize the field – and its potential for tissue engineering, regenerative and personalized medicine. As the advancements in these technologies are rapidly evolving, we evaluate the current state-of-the-art regarding in vitro cell culture models of dental epithelium and ameloblast lineage with a particular focus toward their applicability for translational tissue engineering and regenerative/personalized medicine. Graphical Abstract Future perspectives for in vitro modeling of dental epithelium and ameloblasts. Development of iPSC and organoid models that can reliably generate dental epithelium and ameloblast-like cells, together with advances in 3D bioprinting, provide promising tools for enamel research. Advanced models will provide new avenues for development of enamel repair/regeneration approaches, for testing of dental materials or drugs, studying host-pathogen and/or cell-cell interactions, in vitro modeling of enamel diseases (e.g. amelogenesis imperfecta) and developing novel insights in fundamental tooth biology (e.g. regulation of amelogenesis, lineage specification). Abbreviations: iPSC: induced pluripotent stem cells; TO: tooth organoids; DE: dental epithelium; AB: ameloblast.
2022-11-18 | Effects of Sr2+, BO33−, and SiO32− on differentiation of human dental pulp stem cells into odontoblast-like cells
Abstract Objectives: This study aimed to clarify the effects of strontium (Sr 2⁺ ), borate (BO 3 3− ), and silicate (SiO 3 2− ) on cell proliferative capacity, the induction of differentiation into odontoblast-like cells (OLCs), and substrate formation of human dental pulp stem cells (hDPSCs). Methods: Sr 2+ , BO 3 3− , and SiO 3 2− solutions were added to the hDPSC culture medium at three different concentrations, totaling nine experimental groups. The effects of these ions on hDPSC proliferation, calcification, and collagen formation after 14, 21, and 28 days of culture were evaluated using a cell proliferation assay, a quantitative alkaline phosphatase (ALP) activity assay, and Alizarin red S and Sirius red staining, respectively. Further, the effects of these ions on hDPSC differentiation into OLCs were assessed via real-time polymerase chain reaction and immunohistochemistry. Results: Sr 2+ and SiO 3 2− increased the expression of odontoblast markers; i.e., nestin, DMP-1, dentin sialophospholipoprotein, and ALP genes, compared with the control group. BO 3 3− increased the ALP gene expression and activity. Significance: The results of this study suggested that Sr 2+ , BO 3 3− , and SiO₃²− may induce hDPSC differentiation into OLCs.
2018-01-01 | Establishment of an in vitro system to screen for substances to improve osteogenesis imperfecta osteoblasts functions
Background: Osteogenesis imperfecta (OI) is a heritable bone disorder caused mainly by dominant mutations in genes encoding collagen-related proteins which are COL1A1 and COL1A2. Genotype-phenotype correlation has some discrepancies which lead to the difficult prediction of the clinical outcome of OI patients. We identified a child with dentinogenesis imperfecta (DI) and OI who was homozygous for c.1009G>A (p.G337S) mutation in COL1A2. Her parents were heterozygous for the mutation and had only DI. This family provides the opportunity to explore the biochemical changes which are different between the homozygous with DI and OI and the heterozygous with DI only. Methods: We established patients-specific induced pluripotent stem cells (iPSCs) from the trio to use as an in vitro system to screen for biochemical substances. They were used to study the expression of the osteogenic marker genes (COL1A1, COL1A2, SPP1, OCN, ALP) and their products along the time course of osteoblast differentiation. Results: We successfully generated patient-specific iPSCs from the trio. They all showed the characteristic features of iPSCs. We then differentiated them to mesenchymal stem cells (MSCs) and osteoblasts. Their osteoblasts showed various defective expression of the osteogenic markers and calcium mineralization. Interestingly, osteopontin was�absent in iPSCs-derived osteoblasts of patients with OI, while it was significantly lower in those with DI-only compared to an unaffected control. In addition, osteocalcin was significantly lower in those with OI compared to DI-only and an unaffected control. Conclusion: Levels of osteopontin and osteocalcin in iPSCs-derived MSC of patients with OI were significantly low during osteoblasts differentiation. These cells could be used to screen for substances which can increase osteopontin and osteocalcin.
2017-07-12 | Minimally invasive orthodontics: elastodontic therapy in a growing patient affected by Dentinogenesis Imperfecta
The aim of the study was to report the use of an elastodontic therapy in a growing patient affected by Dentinogenesis Imperfecta, second class malocclusion, deep bite and lower arch crowding from the deciduous dentition to permanent one.At first, the 5-year-old patient was treated with an elastodontic device known as "Nite-Guide". When the patient was 7 years old, during her first permanent molars and incisors eruption and after optimal house-practices, an Occlus-o-Guide Series G was placed at night and on daylight (two hours a day) performing exercises aimed to activate facial muscles and facilitate the deep bite reopening. At 9 years of age, with totally deep bite resolution, she used the Occluso-Guide only at night to hold down previous results and follow patient's dental growth. At 11 years of age, after successful teeth switching, we prescribed an Occlus-o-Guide Series N, which is functional for permanent dentition and guaranteed an eruptive guide for last dental elements.This clinic case could be considered an example of approach for all those patients with systemic and/or dental diseases that do not allow adequate dental retention, which is necessary for most orthodontic appliances; elastodontic devices do not require adequate dental retention and define a minimum intervention on the surfaces of the teeth.
2009-06-25 | The performance of dental pulp stem cells on nanofibrous PCL/gelatin/nHA scaffolds
Abstract The aim of current study is to investigate the in vitro and in vivo behavior of dental pulp stem cells (DPSCs) seeded on electrospun poly(ε‐caprolactone) (PCL)/gelatin scaffolds with or without the addition of nano‐hydroxyapatite (nHA). For the in vitro evaluation, DNA content, alkaline phosphatase (ALP) activity and osteocalcin (OC) measurement showed that the scaffolds supported DPSC adhesion, proliferation, and odontoblastic differentiation. Moreover, the presence of nHA upregulated ALP activity and promoted OC expression. Real‐time PCR data confirmed these results. SEM micrographs qualitatively confirmed the proliferation and mineralization characteristics of DPSCs on both scaffolds. Subsequently, both scaffolds seeded with DPSCs were subcutaneously implanted into immunocompromised nude mice. Scaffolds with nHA but without cells were implanted as control. Histological evaluation revealed that all implants were surrounded by a thin fibrous tissue capsule without any adverse effects. The cell/scaffold composites showed obvious in vivo hard tissue formation, but there was no sign of tissue ingrowth. Further, the combination of nHA in scaffolds did upregulate the expression of specific odontogenic genes. In conclusion, the incorporation of nHA in nanofibers indeed enhanced DPSCs differentiation towards an odontoblast‐like phenotype in vitro and in vivo . © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010
gene therapies
2022-05-25 | Comparative transcriptome profiles of human dental pulp stem cells from maxillary and mandibular teeth
Abstract The molecular control of tooth development is different between the maxilla and mandible, contributing to different tooth shapes and locations; however, whether this difference occurs in human permanent teeth is unknown. The aim of this study was to investigate and compare the transcriptome profiles of permanent maxillary and mandibular posterior teeth. Ten participants who had a pair of opposing premolars or molars extracted were recruited. The RNA obtained from cultured dental pulp stem cells underwent RNA-sequencing and qRT-PCR. The transcriptome profiles of two opposing premolar pairs and two molar pairs demonstrated that the upper premolars, lower premolars, upper molars, and lower molars expressed the same top-ranked genes, comprising FN1, COL1A1, COL1A2, ACTB, and EEFIA1, which are involved in extracellular matrix organization, immune system, signal transduction, hemostasis, and vesicle-mediated transport. Comparative transcriptome analyses of each/combined tooth pairs demonstrated that PITX1 was the only gene with different expression levels between upper and lower posterior teeth. PITX1 exhibited a 64-fold and 116-fold higher expression level in lower teeth compared with their upper premolars and molars, respectively. These differences were confirmed by qRT-PCR. Taken together, this study, for the first time, reveals that PITX1 is expressed significantly higher in mandibular posterior teeth compared with maxillary posterior teeth. The difference is more evident in the molars compared with premolars and consistent with its expression pattern in mouse developing teeth. We demonstrate that differences in lower versus upper teeth gene expression during odontogenesis occur in permanent teeth and suggest that these differences should be considered in molecular studies of dental pulp stem cells. Our findings pave the way to develop a more precise treatment in regenerative dentistry such as gene-based therapies for dentin/pulp regeneration and regeneration of different tooth types.
2021-05-26 | DSPP dosage affects tooth development and dentin mineralization
Dentin Sialoprotein (DSP) and phosphophoryn (PP) are two most dominant non-collagenous proteins in dentin, which are the cleavage products of the DSPP (dentin sialophosphoprotein) precursor protein. The absence of the DSPP gene in DSPP knock-out (KO) mice results in characteristics that are consistent with dentinogenesis imperfecta type III in humans. Symptoms include thin dentin, bigger pulp chamber with frequent pulp exposure as well as abnormal epithelial-mesenchymal interactions, and the appearance of chondrocyte-like cells in dental pulp. To better understand how DSPP influences tooth development and dentin formation, we used a bacterial artificial chromosome transgene construct (BAC-DSPP) that contained the complete DSPP gene and promoter to generate BAC-DSPP transgenic mice directly in a mouse DSPP KO background. Two BAC-DSPP transgenic mouse strains were generated and characterized. DSPP mRNA expression in BAC-DSPP Strain A incisors was similar to that from wild-type (wt) mice. DSPP mRNA expression in BAC-DSPP Strain B animals was only 10% that of wt mice. PP protein content in Strain A incisors was 25% of that found in wt mice, which was sufficient to completely rescue the DSPP KO defect in mineral density, since microCT dentin mineral density analysis in 21-day postnatal animal molars showed essentially identical mineral density in both strain A and wt mice. Strain B mouse incisors, with 5% PP expression, only partially rescued the DSPP KO defect in mineral density, as microCT scans of 21-day postnatal animal molars indicated a reduced dentin mineral density compared to wt mice, though the mineral density was still increased over that of DSPP KO. Furthermore, our findings showed that DSPP dosage in Strain A was sufficient to rescue the DSPP KO defect in terms of epithelial-mesenchymal interactions, odontoblast lineage maintenance, along with normal dentin thickness and normal mineral density while DSPP gene dosage in Strain B only partially rescued the aforementioned DSPP KO defect.
2018-04-19 | Transgenic expression of dentin phosphoprotein (DPP) partially rescued the dentin defects of DSPP-null mice
Mutations in the dentin sialophosphoprotein (DSPP) gene cause dentinogenesis imperfecta. After synthesis, DSPP is proteolytically processed into NH2- and COOH-terminal fragments. The NH2-terminal fragment of DSPP is highly glycosylated but not phosphorylated, whereas the COOH-terminal fragment (named “dentin phosphoprotein” or “DPP”) is highly phosphorylated but not glycosylated. These two fragments are believed to perform distinct roles in dentin formation. To analyze the functions of DPP in dentinogenesis, we created “Dspp-/-;DPP Tg mice”, which expressed transgenic DPP driven by a Type I collagen promoter but lacked the endogenous Dspp gene. We characterized the dentin of the Dspp-/-;DPP Tg mice using X-ray radiography, histology, scanning electron microscopy, double fluorochrome labeling, immunohistochemistry and in situ hybridization. Micro-computed tomography analyses revealed that at postnatal 6 months, the transgenic expression of DPP increased the dentin thickness of the Dspp-null mice by 97.1% and restored the dentin material density by 29.5%. Histological analyses showed that the Dspp-null mice manifested an abnormal widening of the predentin while the predentin in Dspp-/-;DPP Tg mice was narrower than in the Dspp-null mice. Scanning electron microscopy analyses showed that the dentinal tubules in the Dspp-/-;DPP Tg mice were better organized than in the Dspp-null mice. The double fluorochrome labeling analyses demonstrated that the dentin mineral deposition rate in the Dspp-/-;DPP Tg mice was significantly improved compared to that in the Dspp-null mice. These findings indicate that the transgenic expression of DPP partially rescued the dentin defects of the DSPP-null mice, suggesting that DPP may promote dentin formation and that the coordinated actions between DPP and the NH2-terminal fragment of DSPP may be necessary for dentinogenesis.
2017-04-25 | Klf5 Mediates Odontoblastic Differentiation through Regulating Dentin-Specific Extracellular Matrix Gene Expression during Mouse Tooth Development
Abstract Klf5, a member of the Krüppel-like transcription factor family, has essential roles during embryonic development, cell proliferation, differentiation, migration and apoptosis. This study was to define molecular mechanism of Klf5 during the odontoblastic differentiation. The expression of Klf5, odontoblast-differentiation markers, Dspp and Dmp1 was co-localized in odontoblastic cells at different stages of mouse tooth development and mouse dental papilla mesenchymal cells. Klf5 was able to promote odontoblastic differentiation and enhance mineral formation of mouse dental papilla mesenchymal cells. Furthermore, overexpression of Klf5 could up-regulate Dspp and Dmp1 gene expressions in mouse dental papilla mesenchymal cells. In silico analysis identified that several putative Klf5 binding sites in the promoter and first intron of Dmp1 and Dspp genes that are homologous across species lines. Electrophoretic mobility shift assay and chromatin immunoprecipitation analysis indicated that Klf5 bound to these motifs in vitro and in intact cells. The responsible regions of Dmp1 gene were located in the promoter region while effect of Klf5 on Dspp activity was in the first intron of Dspp gene. Our results identify Klf5 as an activator of Dmp1 and Dspp gene transcriptions by different mechanisms and demonstrate that Klf5 plays a pivotal role in odontoblast differentiation.
2015-12-17 | Transgenic expression of Dspp partially rescued the long bone defects of Dmp1-null mice
Dentin matrix protein 1 (DMP1) and dentin sialophosphoprotein (DSPP) belong to the Small Integrin-Binding Ligand N-linked Glycoprotein (SIBLING) family. In addition to the features common to all SIBLING members, DMP1 and DSPP share several unique similarities in chemical structure, proteolytic activation and tissue localization. Mutations in, or deletion of DMP1, cause autosomal recessive hypophosphatemic rickets along with dental defects; DSPP mutations or its ablation are associated with dentinogenesis imperfecta. While the roles and functional mechanisms of DMP1 in osteogenesis have been extensively studied, those of DSPP in long bones have been studied only to a limited extent. Previous studies by our group revealed that transgenic expression of Dspp completely rescued the dentin defects of Dmp1-null (Dmp1(-/-)) mice. In this investigation, we assessed the effects of transgenic Dspp on osteogenesis by analyzing the formation and mineralization of the long bones in Dmp1(-/-) mice that expresses a transgene encoding full-length DSPP driven by a 3.6-kb rat Col1a1 promoter (referred as "Dmp1(-/-);Dspp-Tg mice"). We characterized the long bones of the Dmp1(-/-);Dspp-Tg mice at different ages and compared them with those from Dmp1(-/-) and Dmp1(+/-) (normal control) mice. Our analyses showed that the long bones of Dmp1(-/-);Dspp-Tg mice had a significant increase in cortical bone thickness, bone volume and mineral density along with a remarkable restoration of trabecular thickness compared to those of the Dmp1(-/-) mice. The long bones of Dmp1(-/-);Dspp-Tg mice underwent a dramatic reduction in the amount of osteoid, significant improvement of the collagen fibrillar network, and better organization of the lacunocanalicular system, compared to the Dmp1(-/-) mice. The elevated levels of biglycan, bone sialoprotein and osteopontin in Dmp1(-/-) mice were also noticeably corrected by the transgenic expression of Dspp. These findings suggest that DSPP and DMP1 may function synergistically within the complex milieus of bone matrices.
other
2023-10-27 | Osteoporosis Improved by Romosozumab Therapy in a Patient With Type I Osteogenesis Imperfecta
Osteogenesis imperfecta (OI) is a genetic disorder that affects type 1 collagen synthesis causing increased bone fragility, low bone mass, and skeletal deformity. Bisphosphonates are recommended for treatment of OI patients; however, the efficacy of sclerostin inhibitors such as romosozumab has not been determined in OI patients with osteoporosis.A 52-year-old G2P2 clinically diagnosed with OI, with a history of multiple fractures beginning in childhood presented with low bone mass. On physical examination, blue sclera was observed. She was previously treated with alendronate therapy from April 2014 to June 2015 without significant improvement in bone mineral density (BMD). After the onset of menopause, she began romosozumab 210 mg subcutaneous therapy once a month for 12 months. Repeat dual-energy X-ray absorptiometry showed an increase of 10.3% in BMD of the spine and a 5.4% increase in BMD of the right hip. The trabecular bone score increased by 5.2%.Current literature is limited regarding the use of sclerostin inhibitors in OI patients. Our patient's improvement in BMD of the spine and right hip after romosozumab therapy was significant at a 95% confidence level, compared to treatment initiation. Her trabecular bone score also improved significantly. Six months into our patient's treatment course, a case in Japan of a male with severe osteoporotic OI and recurrent fractures showed improvement in BMD after romosozumab therapy.This case highlights our patient's significant response to romosozumab and warrants further investigation of romosozumab as a potential treatment option for OI patients with osteoporosis.
2022-07-12 | MACF1 Deficiency Suppresses Tooth Mineralization through IGF1 mediated Crosstalk Between Odontoblasts and Ameloblasts
Abstract Tooth mineralization is a ubiquitous and tightly regulated process in vertebrates which usually share the similar mechanisms of bone mineralization. However, key molecules in tooth mineralization remain poorly identified. Previously, we showed the crucial roles of MACF1 in promoting osteoblast differentiation and bone formation. In this study, odontoblast-specific Osx -Cre; Macf1 f/f mice and in vitro cell culture systems were used to investigate the roles of MACF1 in tooth formation. We found that deficiency of MACF1 in odontoblast caused delayed development, abnormal morphology, decreased mineral density and deteriorated microarchitecture in both dentin and enamel of mice. The expression of odontoblast marker genes and ALP activity were suppressed in in vitro cultured Macf1 deficiency odontoblasts. Meanwhile, the ameloblast marker genes and ALP activity were also inhibited in ameloblasts co-cultured with the Macf1 deficiency odontoblasts, indicating the key roles of MACF1 in modulating the process of formation and mineralization in enamel and dentin. Transcriptome sequencing analysis of tooth germs and cytokine antibody array analysis of odontoblast mineralization-inducing medium proved that MACF1 deficiency in odontoblasts inhibited crosstalk between odontoblasts and ameloblasts through IGF1. Altogether, our studies have revealed a novel key molecule MACF1 in tooth mineralization and provided a new target for diseases related to dental development.
2022-03-08 | Cell surface accumulation of intracellular leucine proline-enriched proteoglycan 1 enhances odontogenic potential of human dental pulp stem cells
Abstract Primary dental pulp cells can be differentiated into odontoblasts, which are responsible for dentin formation and mineralization. Successful differentiation has been verified using a few markers. However, odontoblast-specific cell surface markers have not been fully studied yet. Previously, we have constructed monoclonal antibodies to identify cell surface molecules of odontoblasts by decoy immunization. Mass spectrometry confirmed that one of these antibodies, the anti-OD40 antibody, recognized LEucine PRoline-Enriched Proteoglycan 1 (LEPRE1) as a specific antigen. Among three alternative splicing isoforms of LEPRE1, this new antibody showed the most stable antigenic affinity for LEPRE1a, a canonical transcript. Anti-OD40 antibody could strongly bind to the cell surface as odontogenic differentiation progressed. Intracellular and cell surface accumulation of this protein completely disappeared during dentin maturation and mineralization. Overexpression and knock-down experiments showed that intracellular LEPRE1/OD40 should not accumulate too much and that it should move from ER to the cell surface for efficient odontogenic differentiation. Indeed, when LEPRE1/OD40 already located on the cell surface was blocked with antibody, odontogenic differentiation of human dental pulp cells was inhibited. In addition to its role in differentiation, our new antibody which only recognizes LEPRE1a isoform specifically will be useful in studying differentiated functions between LEPRE1a and other isoforms found in osteogenesis imperfecta and dentinogenesis imperfecta.
2021-08-10 | Gender-Related Impact of Sclerostin Antibody on Bone in the Osteogenesis Imperfecta Mouse
Osteogenesis imperfecta (OI), which is most often due to a collagen type 1 gene mutation, is characterized by low bone density and bone fragility. In OI patients, gender-related differences were reported, but data in the literature are not convergent. We previously observed that sclerostin antibody (Scl-Ab), which stimulates osteoblast Wnt pathway via sclerostin inactivation, improved spine and long-bone parameters and biomechanical strength in female oim/oim mice, a validated model of human type 3 OI. Here, we wanted to highlight the effect of Scl-Ab on male oim/oim bones in order to identify a possible distinct therapeutic effect from that observed in females. According to the same protocol as our previous study with female mice, male wild-type (Wt) and oim/oim mice received vehicle or Scl-Ab from 5 to 14 weeks of age. Clinimetric and quantitative bone parameters were studied using X-rays, peripheral quantitative computed tomography, microradiography, and dynamic histomorphometry and compared to those of females. Contrary to Wt mice, male oim/oim had significantly lower weight, snout–sacrum length, and bone mineral content than females at 5 weeks. No significant difference in these clinimetric parameters was observed at 14 weeks, whereas male oim showed significantly more long-bone fractures than females. Scl-Ab improved bone mineral density and bone volume/total volume ratio (BV/TV) of vertebral body in Wt and oim/oim, without significant difference between male and female at 14 weeks. Male vehicle oim/oim had a significantly lower cortical thickness (Ct.Th) and BV/TV of tibial diaphysis than female and showed a higher number of fractures at 14 weeks. Scl-Ab increased midshaft periosteal apposition rate in such a way that tibial Ct.Th of male oim/oim was not significantly different from the female one at 14 weeks. The number of fractures was lower in male than female oim/oim after 14 weeks of Scl-Ab treatment, but this difference was not significant. Nevertheless, Scl-Ab–treated oim/oim male and female mice remained smaller than the Wt ones. In conclusion, our results highlighted differences between male and female oim/oim at 4 and 14 weeks of age, as well as some male-specific response of cortical bone to Scl-Ab. These gender-related particularities of oim/oim should be considered when testing experimental treatments.
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