miR-342-5p inhibits odonto/osteogenic differentiation of human dental pulp stem cells via targeting Wnt7b.

OBJECTIVE: Human dental pulp stem cells (hDPSCs) constitute a promising source of stem cells in tissue engineering. However, the molecular mechanism of differentiation in hDPSCs remains largely unclear. MicroRNAs (miRNAs) play crucial roles in lineage-specific differentiation of stem cells. The present study investigated the function of miRNA-342-5p in the odonto/osteogenic differentiation of hDPSCs. METHODS: The miRNA array profiling and quantitative real-time reverse transcriptase-polymerase chain reaction (qRT-PCR) revealed the expression of miR-342-5p during odonto/osteogenic differentiation of hDPSCs. hDPSCs were treated with miR-342-5p mimic and inhibitor to investigate the regulatory roles of miR-342-5p in the differentiation of hDPSCs. Moreover, miR-342-5p inhibitor and small interference RNA (siRNA) targeting Wnt7b were applied to explore the regulatory mechanism of miR-342-5p. RESULTS: Downregulated miR-342-5p was observed during odonto/osteogenic differentiation of hDPSCs. The overexpression of miR-342-5p inhibited the odonto/osteogenic potential of DPSCs, as indicated by low levels of alkaline phosphatase activity, calcium deposition formation, and odonto/osteogenic differentiation markers, whereas silencing of miR-342-5p exhibited the opposite effect. When co-treated with siRNA targeting Wnt7b and miR-342-5p inhibitor in hDPSCs, the odonto/osteogenic potential and activation of Wnt7b/ß-catenin pathway were attenuated. CONCLUSIONS: This study showed that miR-342-5p inhibits the odonto/osteogenic differentiation of hDPSCs by interfering with Wnt/ß-catenin signaling via targeting Wnt7b.

Effect of high-fructose corn syrup on Streptococcus mutans virulence gene expression and on tooth demineralization.

High-fructose corn syrup-55 (HFCS-55) has been widely welcomed in recent years as a substitute for sucrose on the basis of its favourable properties and price. The objective of this study was to determine the influence of HFCS-55 on the expression of Streptococcus mutans UA159 virulence genes and on tooth demineralization. Real-time reverse-transcription PCR (real-time RT-PCR) and microhardness evaluations were performed to examine gene expression and enamel demineralization, respectively, after treatment with HFCS-55 and/or sucrose. Significant up-regulation of glucosyltransferase B (gtfB) by HFCS-55 was found. A mixture of HFCS-55 and sucrose could positively enhance expression of glucan-binding protein (gbp) genes. Regarding acidogenicity, expression of the lactate dehydrogenase (ldh) gene was unaffected by HFCS-55. A notable finding in this study was that 5% HFCS-55 significantly enhanced expression of the intracellular response gene of the two-component VicRK signal transduction system (vicR). Demineralization testing showed that the microhardness of teeth decreased by a greater extent in response to HFCS-55 than in response to sucrose. The results indicate that HFCS-55 can enhance S. mutans biofilm formation indirectly in the presence of sucrose and that HFCS-55 has a more acidogenic potential than does sucrose. Summing up the real-time PCR and demineralization results, HFCS-55 appears to be no less cariogenic than sucrose in vitro - at least, not under the conditions of our experiments.

Nicolau Syndrome with Severe Facial Ischemic Necrosis after Endodontic Treatment: A Case Report.

Nicolau syndrome (NS) is a rare complication resulting from intramuscular injections. It is characterized by severe pain at the injection site and the development of purplish discoloration. Only a limited number of case reports have been published documenting the adverse effects associated with the injection of calcium hydroxide (CH) beyond the apex during endodontic treatment. Here, we present the case of a 16-year-old female with NS after the injection of CH during the root canal treatment. The radiography examination revealed distal occlusion of the right maxillary and facial arteries. This caused a substantial area of skin necrosis to develop on the patient's face, resulting in permanent scarring. NS is associated with the displacement of CH beyond the apex. To minimize the risk of NS, dentists should exercise caution by avoiding forced injection of CH during treatment, particularly when the root canal is actively bleeding.

EVL Promotes Osteo-/Odontogenic Differentiation of Dental Pulp Stem Cells via Activating JNK Signaling Pathway.

Objective: Human dental pulp stem cells (hDPSCs) were recognized as a suitable and promising source of stem cells in dental pulp regeneration. However, the mechanism by which hDPSCs differentiation into osteo-/odontogenic lineage remains unclear. Ena/VASP-like protein (EVL) has been found to be involved in diverse biological processes. In this study, we explored the role and underlying mechanism of EVL in osteo-/odontogenic differentiation of hDPSCs. Methods: Expression of EVL was detected in hDPSCs by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blot (WB) analyses during osteo-/odontogenic differentiation. The function of EVL in osteo-/odontogenic differentiation and involvement of MAPK signaling pathways were evaluated by alkaline phosphatase (ALP) staining and activity, alizarin red staining (ARS), and qRT-PCR and western blot analyses. Results: The expression of EVL was upregulated during osteo-/odontogenic differentiation of hDPSCs. Overexpression of EVL significantly increased osteo-/odontogenic capacity of hDPSCs, which was reflected in increased alkaline phosphatase (ALP) staining, ALP activity, mineralized nodule formation, and the expressions of genes related to osteo-/odontogenic differentiation, while downregulation of EVL inhibited it. In addition, EVL activated the JNK pathway and phosphorylation of p38 MAPK during differentiation procedure of hDPSCs. The EVL-enhanced differentiation of DPSCs was suppressed by blocking the JNK pathway, rather than the p38 MAPK pathway. Conclusion: EVL promotes the osteo-/odontogenic differentiation of hDPSCs by activating the JNK pathway, providing a future target for osteo-/odontogenic differentiation and dental pulp regeneration.

The Antimicrobial Peptide LL-37 Promotes Migration and Odonto/Osteogenic Differentiation of Stem Cells from the Apical Papilla through the Akt/Wnt/ß-catenin Signaling Pathway.

INTRODUCTION: The antimicrobial peptide LL-37, in addition to its broad spectrum of antibacterial function, can promote odontogenesis and osteogenesis. Stem cells from the apical papilla (SCAPs) are essential for the formation of dentin/bonelike tissues. However, little information on these cells is available in regenerative endodontics. This study aimed to evaluate the effects of LL-37 on the proliferation, migration, and differentiation of SCAPs. METHODS: SCAPs were isolated, cultured, and characterized. Cell viability was analyzed by Cell Counting Kit-8 assays (Dojindo, Kumamoto, Japan). Cell migration was investigated by transwell assays. Dentin sialophosphoprotein, dentin matrix protein 1, runt-related transcription factor 2, and osterix were assessed by quantitative polymerase chain reaction and Western blots. Alkaline phosphatase (ALP) activity and ALP staining were assessed to determine the in vitro potential for osteogenic differentiation. The involvement of the Akt/Wnt/ß-catenin signaling pathway was also studied. RESULTS: In the 2.5-µg/mL LL-37 -treated group, cell proliferation and migration were up-regulated. Quantitative polymerase chain reaction and Western blot assays both revealed that LL-37 at 2.5 µg/mL up-regulated odonto/osteogenic markers (dentin sialophosphoprotein, dentin matrix protein 1, runt-related transcription factor 2, and osterix). LL-37 at 2.5 µg/mL significantly promoted ALP activity and increased the staining in SCAPs. In addition, the p-Akt and p-glycogen synthase kinase-3ß levels were increased in LL-37-treated SCAPs. The migratory and odonto/osteogenic differentiation capacities of SCAPs were inhibited after treatment with inhibitors LY294002 and XAV-939. CONCLUSIONS: Our study showed that LL-37 at 2.5 µg/mL promoted the migration and odonto/osteogenic differentiation of SCAPs by activating the Akt/Wnt/ß-catenin signaling pathway.