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ABSTRACT: It is suggested that dental pulp stem cells are involved in tooth regeneration and play an important role in maintaining pulp homeostasis. Previously, normal dental pulps were more widely used for experimental models than carious dental pulps. The aim of this study was to isolate and culture the dental pulp stem cells from carious and normal teeth and to evaluate stem cell parameters.
Pulp tissues were obtained and dissociated from normal and carious teeth. Single-cell suspensions were seeded into 6-well plates and purified by collecting multiple colonies. Normal dental pulp stem cells (DPSCs) and carious dental pulp stem cells (CDPSCs) were compared for morphologic appearance and for their capacity to differentiate into 3 lineages. Colony-forming and MTT assays, cell cycle analysis, gene expression, and alkaline phosphatase activity were also evaluated.
Stem cells were cultured successfully from normal and carious dental pulps. CDPSCs displayed increased proliferation ability compared with DPSCs. CDPSCs also showed enhanced ALP activity, mineralization ability, and expression of osteogenesis/dentinogenesis-related genes. All cultures differentiated into 3 cell types.
Our data suggest that caries as a local microenvironment should be taken into account when DPSCs are intended to be used for investigations and application. Furthermore, the mechanism of the underlying changes in cell properties requires further study.
Journal of endodontics 06/2012; 38(6):796-802. · 2.95 Impact Factor
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ABSTRACT: To investigate the effect of exogenous c-di-GMP in preventing dental caries formation in SD rats.
Twenty-day-old SD rats with dental caries induced by S. Mutans infection were randomly divided into 3 groups for treatment with dental application of exogenous c-di-GMP, NaF solution or 0.9% NaCl, and changes in the bacterial number and scores of dental caries following the treatments were recorded.
Compared with 0.9% NaCl treatment, exogenous c-di-GMP treatment significantly lowered the scores of dental caries on the occlusal surface and smooth surface (P<0.05) but produced no obvious effect on the number of bacterial plagues (P>0.05).
Exogenous c-di-GMP can be a novel agent for prevention and treatment of tooth decay.
Nan fang yi ke da xue xue bao = Journal of Southern Medical University 05/2012; 32(5):639-42.
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ABSTRACT: Members of the let-7 family have been shown to play a critical role in cell differentiation and tumorigenesis. However, potential targets of let-7 are still unclear. In the current study, we used bioinformatic analysis combined with DNA sequence analysis to identify potential let-7 targets. We discovered that dentin matrix protein 1 (DMP1), which is a non-collagenous protein essential in the mineralization of dentin and bone, has a let-7 binding site in its 3'-untranslated region. Furthermore, reporter assays demonstrated that the DMP1 3'-untranslated region can be regulated directly by the members of let-7. Gene expression levels of let-7 and DMP1 were validated by qRT-PCR of dental pulp cells cultured in a mineralizing medium. Our results suggest that DMP1 is regulated post-transcriptionally by let-7 during odontoblast differentiation.
International Journal of Molecular Medicine 04/2012; 30(2):295-301. · 1.98 Impact Factor
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ABSTRACT: Periodontal ligament-associated protein-1 (PLAP-1/asporin) is a special marker in periodontal ligament tissue. It is an important regulator of osteogenic differentiation of periodontal ligament cells (PDLCs). This marker is also a prerequisite for periodontal ligament development and mineralization in maintaining homeostasis of the periodontium. However, the molecular mechanisms of the regulation of PLAP-1 expression at the post-transcriptional level remain unknown. By contrast, microRNAs (miRNAs) provide an additional level of regulation beyond that of transcription factors via regulation of the post-transcriptional control of gene expression. This study was designed to analyze miRNA differential expression patterns of PDLCs at various osteoblastic differentiation stages and to determine the contribution of miRNAs in the regulation of PLAP-1 expression during osteoblast differentiation. Bioinformatic analysis was performed to predict miRNAs that potentially regulate the gene expression of PLAP-1. Dual luciferase reporter assay and qRT-PCR were performed to confirm the effects of these miRNAs on PLAP-1 gene expression. Our results indicated that mir-101 and mir-21 target PLAP-1 to regulate its expression during osteogenic differentiation of PDLCs.
Molecular Medicine Reports 02/2012; 5(5):1340-6. · 0.42 Impact Factor
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ABSTRACT: Dentin sialophosphoprotein (DSPP), an important marker of odontoblast differentiation, is a prerequisite for tooth development and mineralization; however, the molecular mechanisms of both temporal and spatial regulation remain unknown. MicroRNAs (miRNAs) provide an additional level of control beyond that of transcription factors, which regulate post-transcriptional control of gene expression. The present study was designed to provide a first attempt at an in-depth analysis of dental pulp cells at various odontoblastic differentiation stages to obtain miRNA differential expression patterns, and to determine the contribution of miRNAs in the expression of DSPP during odontoblast differentiation. Dual luciferase reporter assays and qRT-PCR were used to validate miRNAs identified from bioinformatic analyses to determine whether they were able to regulate the DSPP gene in dental pulp cells cultured in a mineralizing medium. The results presented here suggest that DSPP is regulated post-transcriptionally by mir32, mir885-5p and mir586 during odontoblast differentiation.
International Journal of Molecular Medicine 06/2011; 28(4):659-67. · 1.98 Impact Factor
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ABSTRACT: Depending on a biofilm lifestyle, Streptococcus mutans (S. mutans) is thought to be one of the primary causative agents of dental caries. Biofilm formation and adhesion are crucial physiological functions and virulence factors for S. mutans. Thus, attempts to control the development of dental caries only by inhibiting one of the several virulence factors are not effective. Cyclic diguanylate (c-di-GMP) [bis(3',5')-cyclic diguanylic acid] is a prokaryotic cyclic dinucleotide second messenger that has been implicated in determining the timing and amplitude of complex biological processes from biofilm formation and virulence to photosynthesis. Here, we demonstrate that this signaling molecule also plays a role in the ability of S. mutans to initiate biofilm formation and adhere to tooth surfaces. To test this hypothesis, S. mutans UA159 and its gcp gene knockout mutant were assayed for their ability to initiate biofilm formation and adherence. The spatial distribution and architecture of the biofilms were examined by scanning electron microscopy. These results show that inactivation of the gcp gene resulted in the formation of an abnormal biofilm. We confirmed that c-di-GMP was effective in preventing biofilm formation of S. mutans UA159. We also found that extracellular c-di-GMP inhibited the adherence of S. mutans to tooth surfaces and reduced (>50%) biofilm formation compared to the untreated control. These results indicate that c-di-GMP attenuates the caries-inducing virulence factors of S. mutans. This suggests that c-di-GMP may be used alone or in combination with other antimicrobial agents, and that such a treatment could be developed into a novel method to prevent tooth decay.
Microbiological Research 01/2009; 165(2):87-96. · 2.31 Impact Factor
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ABSTRACT: An osteoblast-specific transcription factor, core binding factor alpha1 (Cbfalpha1), is critical for osteoblast and odontoblast differentiation. In this study, the role of Cbfalpha1 in human dentin matrix protein1 (DMP1) gene expression in human dental pulp stem cells (HDPSCs) was investigated. The desired promoter fragments were obtained and cloned into the pGL3-basic vector. It was found that Cbfalpha1 isoforms were predominantly expressed in the cytoplasm of the HDPSCs and reached to the maximum after transfection for 48h. Furthermore, forced overexpression of Cbfalpha1 induced the increase of the luciferase activities of pGL3-P1-6, especially those of pGL3-P(-505to+86) (p<0.05) were the most significant. Then the site-directed mutagenesis of Cbfalpha1 binding sites in the promoter region of nt -505 to +86 resulted in a marked decline of luciferase activities. Thus, our results suggest that Cbfalpha1 upregulates DMP1 gene expression differentially that may contribute to the spatial-temporal expression pattern of DMP1 during odontoblast differentiation.
Biochemical and Biophysical Research Communications 06/2007; 357(2):505-10. · 2.48 Impact Factor
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ABSTRACT: Recombinant Streptococcus mutans glucan-binding protein D (rGbpD) was incorporated into poly(lactic-co-glycolic acid) (PLGA) microspheres which then were surface-coated with chitosan. The microspheres, with a mean diameter of ca. 1.8 microm, were intranasally administered in rats. There were elevated salivary immunoglobulin A and serum immunoglobulin G antibody responses to rGbpD, as well as lower molar caries scores in immunized animals as compared to sham immunized ones. The chitosan-coated PLGA microspheres are thus potentially useful for antigen delivery in dental caries vaccination.
Biotechnology Letters 09/2006; 28(16):1299-304. · 1.68 Impact Factor
