RESUMO
Epigenetic modulation, including histone modification, alters gene expression and controls cell fate. Histone deacetylases (HDACs) are identified as important regulators of dental pulp cell (DPC) mineralisation processes. Currently, there is a paucity of information regarding the nature of histone modification and HDAC expression in the dentine-pulp complex during dentinogenesis. The aim of this study was to investigate post-translational histone modulation and HDAC expression during DPC mineralisation and the expression of Class I/II HDACs during tooth development and in adult teeth. HDAC expression (isoforms -1 to -6) was analysed in mineralising primary rat DPCs using qRT-PCR and Western blot with mass spectrometry being used to analyse post-translational histone modifications. Maxillary molar teeth from postnatal and adult rats were analysed using immunohistochemical (IHC) staining for HDACs (1-6). HDAC-1, -2, and -4 protein expression increased until days 7 and 11, but decreased at days 14 and 21, while other HDAC expression increased continuously for 21 days. The Class II mineralisation-associated HDAC-4 was strongly expressed in postnatal sample odontoblasts and DPCs, but weakly in adult teeth, while other Class II HDACs (-5, -6) were relatively strongly expressed in postnatal DPCs and adult odontoblasts. Among Class I HDACs, HDAC-1 showed high expression in postnatal teeth, notably in ameloblasts and odontoblasts. HDAC-2 and -3 had extremely low expression in the rat dentine-pulp complex. Significant increases in acetylation were noted during DPC mineralisation processes, while trimethylation H3K9 and H3K27 marks decreased, and the HDAC-inhibitor suberoylanilide hydroxamic acid (SAHA) enhanced H3K27me3. These results highlight a dynamic alteration in histone acetylation during mineralisation and indicate the relevance of Class II HDAC expression in tooth development and regenerative processes.
Assuntos
Polpa Dentária , Dentina , Dentinogênese , Histona Desacetilases , Animais , Acetilação , Ratos , Histona Desacetilases/metabolismo , Histona Desacetilases/genética , Dentina/metabolismo , Polpa Dentária/metabolismo , Polpa Dentária/citologia , Polpa Dentária/crescimento & desenvolvimento , Processamento de Proteína Pós-Traducional , Histonas/metabolismo , Dente Molar/metabolismo , Dente Molar/crescimento & desenvolvimento , Odontoblastos/metabolismo , MasculinoRESUMO
INTRODUCTION: Heparan sulfate (HS) is a major component of dental pulp tissue. We previously reported that inhibiting HS biosynthesis impedes endothelial differentiation of dental pulp stem cells (DPSCs). However, the underlying mechanisms by which exogenous HS induces DPSC differentiation and pulp tissue regeneration remain unknown. This study explores the impact of exogenous HS on vasculogenesis and dentinogenesis of DPSCs both in vitro and in vivo. METHODS: Human-derived DPSCs were cultured in endothelial and odontogenic differentiation media and treated with HS. Endothelial differentiation of DPSCs was investigated by real-time polymerase chain reaction and capillary sprouting assay. Odontogenic differentiation was assessed through real-time polymerase chain reaction and detection of mineralized dentin-like deposition. Additionally, the influence of HS on pulp tissue was assessed with a direct pulp capping model, in which HS was delivered to exposed pulp tissue in rats. Gelatin sponges were loaded with either phosphate-buffered saline or 101-102 µg/mL HS and placed onto the pulp tissue. Following a 28-day period, tissues were investigated by histological analysis and micro-computed tomography imaging. RESULTS: HS treatment markedly increased expression levels of key endothelial and odontogenic genes, enhanced the formation of capillary-like structures, and promoted the deposition of mineralized matrices. Treatment of exposed pulp tissue with HS in the in vivo pulp capping study induced formation of capillaries and reparative dentin. CONCLUSIONS: Exogenous HS effectively promoted vasculogenesis and dentinogenesis of DPSCs in vitro and induced reparative dentin formation in vivo, highlighting its therapeutic potential for pulp capping treatment.
Assuntos
Diferenciação Celular , Polpa Dentária , Dentinogênese , Heparitina Sulfato , Células-Tronco , Polpa Dentária/citologia , Polpa Dentária/irrigação sanguínea , Humanos , Dentinogênese/efeitos dos fármacos , Dentinogênese/fisiologia , Células-Tronco/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Animais , Ratos , Células Cultivadas , Neovascularização Fisiológica/efeitos dos fármacos , Odontogênese/efeitos dos fármacosRESUMO
MMP13 gene expression increases up to 2000-fold in mineralizing dental pulp cells (DPCs), with research previously demonstrating that global MMP13 deletion resulted in critical alterations in the dentine phenotype, affecting dentine-tubule regularity, the odontoblast palisade, and significantly reducing the dentine volume. Global MMP13-KO and wild-type mice of a range of ages had their molar teeth injured to stimulate reactionary tertiary dentinogenesis. The response was measured qualitatively and quantitatively using histology, immunohistochemistry, micro-CT, and qRT-PCR in order to assess changes in the nature and volume of dentine deposited as well as mechanistic links. MMP13 loss affected the reactionary tertiary dentine quality and volume after cuspal injury and reduced Nestin expression in a non-exposure injury model, as well as mechanistic links between MMP13 and the Wnt-responsive gene Axin2. Acute pulpal injury and pulp exposure to oral fluids in mice teeth showed upregulation of the MMP13 in vivo, with an increase in the gene expression of Mmp8, Mmp9, and Mmp13 evident. These results indicate that MMP13 is involved in tertiary reactionary dentine formation after tooth injury in vivo, potentially acting as a key molecule in the dental pulp during dentine-pulp repair processes.
Assuntos
Dentinogênese , Metaloproteinase 13 da Matriz , Traumatismos Dentários , Animais , Camundongos , Dentinogênese/genética , Metaloproteinase 13 da Matriz/genética , Dente Molar , OdontoblastosRESUMO
OBJECTIVE: This study intends to investigate the effect of a soft food diet on molar dentin formation during the occlusal establishment period. It can provide dietary guidance for infants to strengthen their dental structure. DESIGN: 60 BALB/c mice were used to obtain mandibles during lactation (P0.5, P7.5, P15.5, P21.5) and occlusal establishment (P27.5, P33.5, P60.5). The mice were randomly divided into soft or hard diet groups after weaning at day 21.5. Hematoxylin-eosin and aniline blue staining were used to observe the morphology and number of odontoblasts and the amount of molar dentin formation. Immunohistochemistry was performed to observe the proliferation and apoptosis of odontoblasts. The in vivo fluorescence double-labeling was applied to evaluate the rate of molar dentin formation. RESULTS: The soft diet group had poorer periodontal membrane development but more cervical dentin deposition. Alterations in morphology and the number of odontoblasts showed a stronger correlation with age rather than food hardness. There are no significant differences in proliferative and apoptotic behavior of dentin-forming cells between the two groups. Rather, it affected the rate of dentin deposition. The rate of dentin deposition was high in the soft diet group from P21.5 to P27.5, but it was surpassed by the hard diet group within P27.5-P33.5, and the difference between the two groups disappeared at P33.5-P60.5. CONCLUSIONS: A soft diet promotes molar early cervical dentin formation. This advantage is caused by an enhanced odontoblast secretion rate rather than affecting the morphology, number, proliferation, or apoptosis of odontoblasts.
Assuntos
Dentina , Dentinogênese , Humanos , Feminino , Camundongos , Animais , Odontoblastos , Dente Molar , Dieta , Diferenciação CelularRESUMO
OBJECTIVES: To investigate the genetic causes and teeth characteristics of dentin dysplasia Shields type II(DD-II) in three Chinese families. MATERIALS AND METHODS: Data from three Chinese families affected with DD-II were collected. Whole-exome sequencing (WES) and whole-genome sequencing (WGS) were conducted to screen for variations, and Sanger sequencing was used to verify mutation sites. The physical and chemical characteristics of the affected teeth including tooth structure, hardness, mineral content, and ultrastructure were investigated. RESULTS: A novel frameshift deletion mutation c.1871_1874del(p.Ser624fs) in DSPP was found in families A and B, while no pathogenic mutation was found in family C. The affected teeth's pulp cavities were obliterated, and the root canals were smaller than normal teeth and irregularly distributed comprising a network. The patients' teeth also had reduced dentin hardness and highly irregular dentinal tubules. The Mg content of the teeth was significantly lower than that of the controls, but the Na content was obviously higher than that of the controls. CONCLUSIONS: A novel frameshift deletion mutation, c.1871_1874del (p.Ser624fs), in the DPP region of the DSPP gene causes DD-II. The DD-II teeth demonstrated compromised mechanical properties and changed ultrastructure, suggesting an impaired function of DPP. Our findings expand the mutational spectrum of the DSPP gene and strengthen the understanding of clinical phenotypes related to the frameshift deletion in the DPP region of the DSPP gene. CLINICAL RELEVANCE: A DSPP mutation can alter the characteristics of the affected teeth, including tooth structure, hardness, mineral content, and ultrastructure.
Assuntos
Dentinogênese Imperfeita , Dente , Humanos , Dentina/patologia , Dentinogênese , Dentinogênese Imperfeita/genética , Proteínas da Matriz Extracelular/genética , Mutação , FenótipoRESUMO
BACKGROUND: The dentinogenesis differentiation of dental pulp stem cells (DPSCs) is controlled by the spatio-temporal expression of differentiation related genes. RNA N6-methyladenosine (m6A) methylation, one of the most abundant internal epigenetic modification in mRNA, influences various events in RNA processing, stem cell pluripotency and differentiation. Methyltransferase like 3 (METTL3), one of the essential regulators, involves in the process of dentin formation and root development, while mechanism of METTL3-mediated RNA m6A methylation in DPSC dentinogenesis differentiation is still unclear. METHODS: Immunofluorescence staining and MeRIP-seq were performed to establish m6A modification profile in dentinogenesis differentiation. Lentivirus were used to knockdown or overexpression of METTL3. The dentinogenesis differentiation was analyzed by alkaline phosphatase, alizarin red staining and real time RT-PCR. RNA stability assay was determined by actinomycin D. A direct pulp capping model was established with rat molars to reveal the role of METTL3 in tertiary dentin formation. RESULTS: Dynamic characteristics of RNA m6A methylation in dentinogenesis differentiation were demonstrated by MeRIP-seq. Methyltransferases (METTL3 and METTL14) and demethylases (FTO and ALKBH5) were gradually up-regulated during dentinogenesis process. Methyltransferase METTL3 was selected for further study. Knockdown of METTL3 impaired the DPSCs dentinogenesis differentiation, and overexpression of METTL3 promoted the differentiation. METTL3-mediated m6A regulated the mRNA stabiliy of GDF6 and STC1. Furthermore, overexpression of METTL3 promoted tertiary dentin formation in direct pulp capping model. CONCLUSION: The modification of m6A showed dynamic characteristics during DPSCs dentinogenesis differentiation. METTL3-mediated m6A regulated in dentinogenesis differentiation through affecting the mRNA stability of GDF6 and STC1. METTL3 overexpression promoted tertiary dentin formation in vitro, suggesting its promising application in vital pulp therapy (VPT).
Assuntos
Polpa Dentária , Dentinogênese , Animais , Ratos , Diferenciação Celular , Metiltransferases/genética , Metiltransferases/metabolismo , RNA/metabolismo , Estabilidade de RNA , RNA Mensageiro/metabolismo , Células-Tronco/metabolismoRESUMO
INTRODUCTION: Substance P (SP) is a neuropeptide released from the nervous fibers in response to injury. In addition to its association with pain and reactions to anxiety and stress, SP exerts various physiological functions by binding to the neurokinin-1 receptor (NK1R). However, the expression and role of SP in reparative dentinogenesis remain elusive. Here, we explored whether SP is involved in odontoblastic differentiation during reparative dentinogenesis. METHODS: Dental pulp stem cells (DPSCs) were isolated from healthy human dental pulp tissues and subjected to odontoblastic differentiation. The expression of SP and NK1R during odontoblastic differentiation was investigated in vitro. The effects of SP on odontoblastic differentiation of DPSCs were evaluated using alizarin red staining, alkaline phosphatase staining, and real-time polymerase chain reaction. After direct pulp capping with mineral trioxide aggregate, the expression of SP and NK1R during reparative dentin formation in rats were identified using histological and immunohistochemical staining. RESULTS: SP and NK1R expression increased during the odontoblastic differentiation of DPSCs. SP translocated to the nucleus when DPSCs were exposed to differentiation medium. NK1R was always present in the nuclei of DPSCs and odontoblast-like cells. Additionally, we discovered that 10-8 M SP marginally enhanced the odontoblastic differentiation of DPSCs, and that these effects could be impaired by the NK1R antagonist. Furthermore, SP and NK1R were expressed in odontoblast-like and dental pulp cells during reparative dentin formation in vivo. CONCLUSIONS: SP contributes to odontoblastic differentiation during reparative dentin formation by binding to the NK1R.
Assuntos
Dentina Secundária , Proteínas da Matriz Extracelular , Ratos , Humanos , Animais , Proteínas da Matriz Extracelular/farmacologia , Substância P/farmacologia , Polpa Dentária , Dentinogênese , Odontoblastos , Diferenciação Celular , Células Cultivadas , Células-TroncoRESUMO
WW domain-containing E3 Ubiquitin-protein ligase 2 (WWP2) has been found to positively regulate odontoblastic differentiation by monoubiquitinating the transcription factor Kruppel-like factor 5 (KLF5) in a cell culture system. However, the in vivo role of WWP2 in mouse teeth remains unknown. To explore this, here we generated Wwp2 knockout (Wwp2 KO) mice. We found that molars in Wwp2 KO mice exhibited thinner dentin, widened predentin, and reduced numbers of dentinal tubules. In addition, expression of the odontoblast differentiation markers Dspp and Dmp1 was decreased in the odontoblast layers of Wwp2 KO mice. These findings demonstrate that WWP2 may facilitate odontoblast differentiation and dentinogenesis. Furthermore, we show for the first time that phosphatase and tensin homolog (PTEN), a tumor suppressor, is expressed in dental papilla cells and odontoblasts of mouse molars and acts as a negative regulator of odontoblastic differentiation. Further investigation indicated that PTEN is targeted by WWP2 for degradation during odontoblastic differentiation. We demonstrate PTEN physically interacts with and inhibits the transcriptional activity of KLF5 on Dspp and Dmp1. Finally, we found WWP2 was able to suppress the interaction between PTEN and KLF5, which diminished the inhibition effect of PTEN on KLF5. Taken together, this study confirms the essential role of WWP2 and the WWP2-PTEN-KLF5 signaling axis in odontoblast differentiation and dentinogenesis in vivo.
Assuntos
Dentinogênese , Fatores de Transcrição Kruppel-Like , Odontoblastos , PTEN Fosfo-Hidrolase , Ubiquitina-Proteína Ligases , Animais , Diferenciação Celular , Dentina/metabolismo , Proteínas da Matriz Extracelular/genética , Proteínas da Matriz Extracelular/metabolismo , Fatores de Transcrição Kruppel-Like/genética , Fatores de Transcrição Kruppel-Like/metabolismo , Camundongos , Camundongos Knockout , Odontoblastos/metabolismo , PTEN Fosfo-Hidrolase/genética , PTEN Fosfo-Hidrolase/metabolismo , Fosfoproteínas/metabolismo , Sialoglicoproteínas/metabolismo , Transdução de Sinais , Fatores de Transcrição/metabolismo , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismoRESUMO
Dentin is a major mineralized component of teeth. Odontoblasts are responsible for synthesis and secretion of dentin matrix. Previously, it has been demonstrated in a cell culture system that the E3 ubiquitin ligase, murine double minute 2 (Mdm2), promotes odontoblast-like differentiation of mouse dental papilla cells (mDPCs) by ubiquitinating p53 and the odontoblast-specific substrate Dlx3. However, whether Mdm2 plays an essential role in vivo in odontoblast differentiation and dentin formation remains unknown. In this study, we investigated the in vivo functions of Mdm2 using Dmp1-Cre;Mdm2flox/flox mice combined with multiple histological and molecular biological methods. The results showed that Mdm2 deletion in the odontoblast layer led to defects in odontoblast differentiation and dentin formation. Unexpectedly, specific inhibition of the Mdm2-p53 axis in wild-type mice by injection of a small-molecule inhibitor Nutlin-3a indicated that the role of Mdm2 in dentinogenesis was p53 independent, which was inconsistent with the previous in vitro study. In situ proximity ligation assay (PLA) showed that Mdm2 interacted with and ubiquitinated Dlx3 in the odontoblast nucleus of mouse molars. Dlx3 promoted the translocation of Mdm2 to the nucleus, and in turn, the nuclear Mdm2 mediated ubiquitination of Dlx3 and promoted the odontoblast-like differentiation of mDPCs. Dlx3 interacted with Mdm2 through its C-terminal domain. Deletion of the C-terminal domain of Dlx3 reversed the enhanced odontoblast-like differentiation and the activation of Dspp promoter mediated by overexpression of wild-type or nuclear Mdm2. Our findings suggest that nuclear Mdm2 mediates ubiquitination of the transcription factor Dlx3, which is essential for Dlx3 transcriptional activity on Dspp as well as subsequent odontoblast differentiation and dentin formation.
Assuntos
Dentinogênese , Proteínas de Homeodomínio , Proteínas Proto-Oncogênicas c-mdm2 , Fatores de Transcrição , Ubiquitinação , Animais , Diferenciação Celular , Dentina/metabolismo , Proteínas da Matriz Extracelular/metabolismo , Proteínas de Homeodomínio/metabolismo , Camundongos , Odontoblastos/metabolismo , Fosfoproteínas/metabolismo , Sialoglicoproteínas/genética , Fatores de Transcrição/metabolismo , Proteína Supressora de Tumor p53RESUMO
The development and repair of dentin are strictly regulated by hundreds of genes. Abnormal dentin development is directly caused by gene mutations and dysregulation. Understanding and mastering this signal network is of great significance to the study of tooth development, tissue regeneration, aging, and repair and the treatment of dental diseases. It is necessary to understand the formation and repair mechanism of dentin in order to better treat the dentin lesions caused by various abnormal properties, whether it is to explore the reasons for the formation of dentin defects or to develop clinical drugs to strengthen the method of repairing dentin. Molecular biology of genes related to dentin development and repair are the most important basis for future research.
Assuntos
Dentinogênese , Odontoblastos , Dentina , Dentinogênese/genética , Odontogênese/genéticaRESUMO
O desenvolvimento do dente depende de uma série de interações sinalizadoras recíprocas entre o epitélio oral (EO) e o ectomesênquima derivado da crista neural, a via WNT com o TGF-ß e BMP4 tem sido implicada na tumorigênese. A via de sinalização tipo Wingless (Wnt) / ß-catenina é essencial para a ativação precoce da odontogênese e no desenvolvimento de tumores odontogênicos. O TGF-ß e as BMPs tem sido associadas aos processos de dentinogênese reacionária e reparadora. A sinalização de Shh pode regular a proliferação celular no ectomesênquima dentário, controlando assim a morfogênese dentária. O objetivo da pesquisa foi investigar a atuação de algumas proteínas das vias na odontogênese e na formação de odontomas e tumores odontogênicos mistos benignos, para isto, foi desenvolvido um estudo seccional restrospectivo e imuno-histoquímico contendo 23 odontomas compostos, 21 odontomas complexos, 17 germes dentários, 05 fibro-odontomas ameloblásticos e 01 fibroma ameloblástico. Os resultados encontrados demonstraram maiores imunoexpressões da via WNT/ß-catenina no epitélio dos germes dentários (p<0,001) e no fibroma ameloblástico, enquanto que, esteve no ectomesênquima dos odontomas (p<0,001) e fibro-odontomas ameloblásticos. A via WNT/ßcatenina correlacionou-se moderadamente e significativamente com a CK14 no epitélio (p = 0,007) dos odontomas. A BMP4 foi imunoexpressa, especialmente, no ectomesênquima dos odontomas complexos (mediana = 33,7; p<0,001). A via Shh foi mais imunoexpressa no epitélio dos germes dentários (p<0,001) e no ectomesênquima dos odontomas complexos (p=0,029). De forma similar, o TGFß apresentou maior imunoexpressão no epitélio dos germes dentários (p<0,001) e no ectomesênquima dos odontomas complexos (p = 0,002). O dente em desenvolvimento exibiu maiores concentrações para estas proteínas no epitélio odontogênico nas fases de botão e capuz e a expressão diferencial ocorreu, principalmente, no ectomesênquima dos tumores, o que indica que esse componente é de fato mais proliferativo (AU).
Tooth development depends on a series of reciprocal signaling interactions between oral epithelium (EO) and neural crest-derived ectomesenchyme, the WNT pathway with TGF-ß and BMP4 has been implicated in tumorigenesis. The Wingless (Wnt)/ß-catenin signaling pathway is essential for the early activation of odontogenesis and the development of odontogenic tumors. TGF-ß and BMPs have been associated with reactionary and reparative dentinogenesis processes. Shh signaling can regulate cell proliferation in dental ectomesenchyme, thus controlling dental morphogenesis. The objective of the research was to investigate the role of some proteins in the pathways in odontogenesis and in the formation of odontomas and benign mixed odontogenic tumors. tooth germs, 05 ameloblastic fibro-odontomas and 01 ameloblastic fibroma. The results found showed higher immunoexpressions of the WNT/ß-catenin pathway in the epithelium of tooth germs (p<0.001) and in ameloblastic fibroma, while it was in the ectomesenchyme of odontomas (p<0.001) and ameloblastic fibroodontomas. The WNT/ß-catenin pathway correlated moderately and significantly with CK14 in the epithelium (p = 0.007) of odontomas. BMP4 was immunoexpressed, especially in the ectomesenchyme of complex odontomas (median = 33.7; p<0.001). The Shh pathway was more immunoexpressed in the epithelium of tooth germs (p<0.001) and in the ectomesenchyme of complex odontomas (p=0.029). Similarly, TGF-ß showed higher immunoexpression in the epithelium of tooth germs (p<0.001) and in the ectomesenchyme of complex odontomas (p = 0.002). The developing tooth exhibited higher concentrations of these proteins in the odontogenic epithelium in the bud and cap phases and the differential expression occurred mainly in the ectomesenchyme of the tumors, which indicates that this component is in fact more proliferative (AU).
Assuntos
Humanos , Masculino , Feminino , Odontoma/patologia , Fator de Crescimento Transformador beta , Proteínas Hedgehog , Via de Sinalização Wnt , Odontogênese , Imuno-Histoquímica , Tumores Odontogênicos/patologia , Estudos Transversais/métodos , Estatísticas não Paramétricas , DentinogêneseRESUMO
Small-molecule drugs targeting glycogen synthase kinase 3 (GSK3) as inhibitors of the protein kinase activity are able to stimulate reparative dentine formation. To develop this approach into a viable clinical treatment for exposed pulp lesions, we synthesized a novel, small-molecule noncompetitive adenosine triphosphate (ATP) drug that can be incorporated into a biodegradable hydrogel for placement by syringe into the tooth. This new drug, named NP928, belongs to the thiadiazolidinone (TDZD) family and has equivalent activity to similar drugs of this family such as tideglusib. However, NP928 is more water soluble than other TDZD drugs, making it more suitable for direct delivery into pulp lesions. We have previously reported that biodegradable marine collagen sponges can successfully deliver TDZD drugs to pulp lesions, but this involves in-theater preparation of the material, which is not ideal in a clinical context. To improve surgical handling and delivery, here we incorporated NP928 into a specifically tailored hydrogel that can be placed by syringe into a damaged tooth. This hydrogel is based on biodegradable hyaluronic acid and can be gelled in situ upon dental blue light exposure, similarly to other common dental materials. NP928 released from hyaluronic acid-based hydrogels upregulated Wnt/ß-catenin activity in pulp stem cells and fostered reparative dentine formation compared to marine collagen sponges delivering equivalent concentrations of NP928. This drug-hydrogel combination has the potential to be rapidly developed into a therapeutic procedure that is amenable to general dental practice.
Assuntos
Dentina Secundária , Dentinogênese , Quinase 3 da Glicogênio Sintase/antagonistas & inibidores , Tiadiazóis/farmacologia , Polpa Dentária , Dentinogênese/efeitos dos fármacos , Humanos , HidrogéisRESUMO
La dentina se compone de un mineral de fosfato de calcio identificado como dahllita, que se dispone en pequeños cristales de hidroxiapatita carbonatada con dimensiones de 36 × 25 × 4 nm, y por una fase orgánica cuyo principal componente es el colágeno tipo 1 en 90%, que se orienta en forma de malla. Esta conformación corresponde a los dientes permanentes. Dentro de las estructuras, encontramos túbulos dentinarios que miden, aproximadamente, entre 0.5-1 µm de diámetro en la periferia y hasta 3-5 µm cerca de la pulpa. En el presente estudio, realizado en dentina de dientes temporales, el lumen de dichos túbulos es más grande cuando se encuentra cerca de la pulpa dental. Asimismo, se encontraron cambios elementales importantes de acuerdo con las diferentes profundidades en las que se observó, encontrando un aumento en el peso porcentual de carbono cuando se encuentra a mayor profundidad, lo que indica una composición orgánica mayor en la dentina pulpar. En estudios de dientes permanentes esta composición es disminuida y con mayor concentración en la dentina cercana a la unión amelodentinaria. En dentina de dientes temporales se encontraron diferencias en el recuento de túbulos dentinarios por mm2, comparado a la dentina de dientes permanentes, donde el número de túbulos no varía mucho (AU)
Dentin is composed of a calcium phosphate mineral identified as dahllite, which is arranged in small crystals of carbonated hydroxyapatite with dimensions of 36 × 25 × 4 nm, and by an organic phase whose main component is type l collagen in 90%, which is oriented in the form of a mesh. This conformation corresponds to permanent teeth. Within the structures, we find dentin tubules that measure approximately 0.5-1 µm in diameter at the periphery and up to 3-5 µm near the pulp. In the present study, carried out in dentin of primary teeth, the lumen of these tubules is larger when it is close to the dental pulp. Likewise, important elemental changes were found according to the different depths in which it was observed, finding an increase in the percentage weight of carbon when it is at a greater depth, indicating a greater organic composition in the pulp dentin. In studies of permanent teeth, this composition is decreased and with a higher concentration in the dentin near the amelodentinal junction. In dentin of primary teeth, differences were found in the count of dentin tubules per mm2, compared to dentin of permanent teeth, where the number of tubules did not vary much (AU)
Assuntos
Humanos , Dente Decíduo , Dentina/ultraestrutura , Dentinogênese , Fosfatos , Ácidos Fosfóricos , Condicionamento Ácido do Dente , Microscopia Eletrônica de Varredura , Cálcio , Colágeno , Durapatita , Dentição Permanente , Colágeno Tipo I , MineraisRESUMO
Direct pulp capping is an effective treatment for preserving dental pulp against carious or traumatic pulp exposure via the formation of protective reparative dentin by odontoblast-like cells. Reparative dentin formation can be stimulated by several signaling molecules; therefore, we investigated the effects of secreted frizzled-related protein (SFRP) 1 that was reported to be strongly expressed in odontoblasts of newborn molar tooth germs on odontoblastic differentiation and reparative dentin formation. In developing rat incisors, cells in the dental pulp, cervical loop, and inner enamel epithelium, as well as ameloblasts and preodontoblasts, weakly expressed Sfrp1; however, Sfrp1 was strongly expressed in mature odontoblasts. Human dental pulp cells (hDPCs) showed stronger expression of SFRP1 compared with periodontal ligament cells and gingival cells. SFRP1 knockdown in hDPCs abolished calcium chloride-induced mineralized nodule formation and odontoblast-related gene expression and decreased BMP-2 gene expression. Conversely, SFRP1 stimulation enhanced nodule formation and expression of BMP-2. Direct pulp capping treatment with SFRP1 induced the formation of a considerable amount of reparative dentin that has a structure similar to primary dentin. Our results indicate that SFRP1 is crucial for dentinogenesis and is important in promoting reparative dentin formation in response to injury.
Assuntos
Polpa Dentária/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Odontoblastos/metabolismo , Adolescente , Animais , Diferenciação Celular/genética , Polpa Dentária/fisiologia , Dentina/metabolismo , Dentina/fisiologia , Dentina Secundária/fisiologia , Dentinogênese/genética , Dentinogênese/fisiologia , Feminino , Expressão Gênica/genética , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/genética , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/genética , Peptídeos e Proteínas de Sinalização Intracelular/fisiologia , Masculino , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Odontoblastos/fisiologia , Ratos , Ratos Wistar , Transdução de Sinais/genética , Adulto JovemRESUMO
Dental pulp vitality is a desideratum for preserving the health and functionality of the tooth. In certain clinical situations that lead to pulp exposure, bioactive agents are used in direct pulp-capping procedures to stimulate the dentin-pulp complex and activate reparative dentinogenesis. Hydraulic calcium-silicate cements, derived from Portland cement, can induce the formation of a new dentin bridge at the interface between the biomaterial and the dental pulp. Odontoblasts are molecularly activated, and, if necessary, undifferentiated stem cells in the dental pulp can differentiate into odontoblasts. An extensive review of literature was conducted on MedLine/PubMed database to evaluate the histological outcomes of direct pulp capping with hydraulic calcium-silicate cements performed on animal models. Overall, irrespective of their physico-chemical properties and the molecular mechanisms involved in pulp healing, the effects of cements on tertiary dentin formation and pulp vitality preservation were positive. Histological examinations showed different degrees of dental pulp inflammatory response and complete/incomplete dentin bridge formation during the pulp healing process at different follow-up periods. Calcium silicate materials have the ability to induce reparative dentinogenesis when applied over exposed pulps, with different behaviors, as related to the animal model used, pulpal inflammatory responses, and quality of dentin bridges.
Assuntos
Materiais Biocompatíveis/química , Compostos de Cálcio/química , Capeamento da Polpa Dentária , Dentinogênese/efeitos dos fármacos , Silicatos/química , Compostos de Alumínio , Animais , Cerâmica , Materiais Dentários , Polpa Dentária/efeitos dos fármacos , Dentina/química , Dentina Secundária/efeitos dos fármacos , Cães , Combinação de Medicamentos , Humanos , Inflamação , Modelos Animais , Óxidos/farmacologiaRESUMO
BACKGROUND: Extracellular matrix molecules (ECMM) expression during tertiary dentinogenesis provides useful information for regenerative applications and efficacy of pulp capping materials. AIM: To identify and review the expression and roles of non-collagenous ECMM after successful direct pulp capping (DPC), following mechanical pulp exposures, via immunohistochemistry (IHC). The study addressed the question of where will successful DPC impact the IHC expression of these molecules. DATA SOURCES: In vivo animal and human original clinical studies reporting on ECMM in relation to different follow-up periods were screened and evaluated via descriptive analysis. The electronic literature search was carried out in three databases (MEDLINE/PubMed, Web of Science, Scopus), followed by manual screening of relevant journals and cross-referencing, up to December 2018. STUDY ELIGIBILITY CRITERIA, PARTICIPANTS, AND INTERVENTIONS: Randomized and non-randomized controlled trials, conducted in humans and animals, were selected. Histological evidence for tertiary dentine formation was a prerequisite for IHC evaluation. STUDY APPRAISAL AND SYNTHESIS METHODS: The methodological quality of the included articles was independently assessed using the Systematic Review Centre for Laboratory animal Experimentation (SYRCLE) and the Cochrane risk of bias tool (RoB 1), respectively. RESULTS: From a total of 1534 identified studies, 18 were included. Thirteen papers evaluated animal subjects and five studies were carried out on humans. In animals and humans, fibronectin and tenascin expressions were detected in pulp and odontoblast-like cells (OLC); dentine sialoprotein was expressed in both soft and newly-formed mineralized tissue. In animals, bone sialoprotein was early expressed, in association with OLC and predentin; the immunoreactivity for dentine sialophosphoprotein and dentine matrix protein-1 was associated with the OLC and dentine bridge; osteopontin was expressed in OLC, predentine and reparative dentine. A considerable heterogeneity was found in the methodologies of the included studies, as well as interspecies variability of results in terms of time. CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS: Within the limited scientific evidence, all non-collagenous ECMM expressions during tertiary dentinogenesis are active and related to soft and hard tissues. There is a shortage of human studies, and future research directions should focus more on them. PROSPERO Protocol: CRD42019121304.
Assuntos
Dentina Secundária , Dentinogênese , Animais , Polpa Dentária , Capeamento da Polpa Dentária , Matriz Extracelular , Humanos , OdontoblastosRESUMO
INTRODUCTION: Oxytocin (OT) is a neurohypophysial hormone that plays a role in lactation and parturition and exerts diverse biological actions via the OT receptor. Recently, several studies have reported that OT stimulates bone formation by osteoblasts in osteoporosis. We focused on OT and hypothesized that OT can stimulate the differentiation of odontoblasts as well as osteoblasts. The aim of this study was to verify whether OT is an essential factor in dentinogenesis; we examined the effects of OT on dentinogenesis using a long-term culture system of rat dental pulp cells. METHODS: Using a culture system of rat dental pulp cells with Otr knocked out by CRISPR-Cas9 genome editing, we examined the effects of OT on odontoblastlike cell differentiation as reflected by dentin formation. RESULTS: We confirmed that OT stimulated mineralized nodule formation and the expression of both dentin sialoprotein and bone Gla protein messenger RNAs (mRNAs) in the culture system. Interestingly, the cultured cells treated with OT also exhibited an increase of both Wnt10a and Lef-1 mRNA. The Otr knockout cells showed inhibition of nodule formation and mRNA expression, and these phenomena remained despite OT treatment. These results indicate the following: OT regulates odontoblastlike cell differentiation via the OT receptor, it stimulates dentin formation, and the Wnt canonical pathway is closely related to these effects. CONCLUSIONS: The present results suggest that OT can promote odontoblastlike cell differentiation, resulting in increased dentin formation, and that OT could be an important factor for dentinogenesis.
Assuntos
Polpa Dentária , Dentinogênese , Animais , Diferenciação Celular , Dentina , Feminino , Fator 1 de Ligação ao Facilitador Linfoide , Odontoblastos , Ocitocina/farmacologia , Fosfoproteínas/genética , Ratos , Sialoglicoproteínas , Proteínas WntRESUMO
Odontoblast differentiation is a complex and multistep process regulated by signaling pathways, including the Wnt/ß-catenin signaling pathway. Both positive and negative effects of Wnt/ß-catenin signaling on dentinogenesis have been reported, but the underlying mechanisms of these conflicting results are still unclear. To gain a better insight into the role of Wnt/ß-catenin in dentinogenesis, we used dental pulp cells from a panel of transgenic mice, in which fluorescent protein expression identifies cells at different stages of odontoblast and osteoblast differentiation. Our results showed that exposure of pulp cells to WNT3a at various times and durations did not induce premature differentiation of odontoblasts. These treatments supported the survival of undifferentiated cells in dental pulp and promoted the formation of 2.3GFP+ preodontoblasts and their rapid transition into differentiated odontoblasts expressing DMP1-Cherry and DSPP-Cerulean transgenes. WNT3a also promoted osteogenesis in dental pulp cultures. These findings provide critical information for the development of improved treatments for vital pulp therapy and dentin regeneration.
Assuntos
Dentinogênese , Via de Sinalização Wnt , Animais , Diferenciação Celular , Polpa Dentária/metabolismo , Camundongos , Odontoblastos/metabolismo , beta Catenina/metabolismoRESUMO
Pulp-capping materials are commonly adopted in the clinic to form reparative dentin and thus protect dental pulp tissues from cases of deep caries, accidentally exposed pulps or partial pulpotomy. Some traditional pulp capping materials used in the clinic include calcium hydroxide and mineral trioxide aggregates. However, there are limitations to thin restorative dentin, and a long period of time is needed to cause degenerative changes in dental pulp. In this paper, injectable colloidal gels were developed to induce the formation of reparative dentin through a simple UV method from methacrylic acid functionalized gelatin loaded with notoginsenoside R1 (Gel-MA/NGR1). The results of the physicochemical property examinations showed that the prepared Gel-MA/NGR1 hydrogel possessed an appropriate interconnected porous microarchitecture with a pore size of 10.5 micrometres and suitable mechanical properties with a modulus of 50-60 kPa, enabling cell adhesion and proliferation. The hydrogel remained hydrophilic with sustained drug release performance. In addition, Gel-MA/NGR1 significantly enhanced the odontogenetic differentiation of mouse dental papilla cells by elevating the expression levels of the dentinogenic markers ALP and OCN and extracellular matrix mineralization. In vivo stimulation was carried out by injecting the precursors into the predrilled alveolar cavity of Sprague-Dawley rats followed by immediate in situ UV crosslinking. The results showed that Gel-MA/NGR1 has a strong capacity to promote reparative dentin formation. Haematoxylin& eosin, Masson, and immunohistochemical staining (DMP-1, DSPP, OCN and RUNX2) and micro-CT were employed to illustrate the effectiveness of dentinogenesis, and the relative volumes of calcification were found to have increased ~175-fold. All of the results showed that the Gel-MA/NGR1 hydrogel promoted reparative dentin formation, which suggests that this hydrogel provides great potential as a pulp-capping material to induce dentin formation.
Assuntos
Dentinogênese , Gelatina , Animais , Polpa Dentária , Ginsenosídeos , Hidrogéis/farmacologia , Camundongos , Ratos , Ratos Sprague-DawleyRESUMO
Odontoblast processes are thin cytoplasmic projections that extend from the cell body at the periphery of the pulp toward the dentin-enamel junction. The odontoblast processes function in the secretion, assembly and mineralization of dentin during development, participate in mechanosensation, and aid in dentin repair in mature teeth. Because they are small and densely arranged, their three-dimensional organization is not well documented. To gain further insight into how odontoblast processes contribute to odontogenesis, we used serial section electron microscopy and three-dimensional reconstructions to examine these processes in the predentin region of mouse molars and incisors. In molars, the odontoblast processes are tubular with a diameter of ~1.8 µm. The odontoblast processes near the incisor tip are similarly shaped, but those midway between the tip and apex are shaped like plates. The plates are radially aligned and longitudinally oriented with respect to the growth axis of the incisor. The thickness of the plates is approximately the same as the diameter of molar odontoblast processes. The plates have an irregular edge; the average ratio of width (midway in the predentin) to thickness is 2.3 on the labial side and 3.6 on the lingual side. The plate geometry seems likely to be related to the continuous growth of the incisor and may provide a clue as to the mechanisms by which the odontoblast processes are involved in tooth development.