miR-214 inhibits the osteogenic differentiation of dental follicle cells in vitro / 口腔疾病防治

Objective @# To investigate the effect of miR-214 on the osteogenic differentiation of dental follicle cells (DFCs).@*Methods@#Purified DFCs were cultured in vitro by bidirectional differential passage, with the untransfected DFCs as the control group (DFCs group). The expression of miR-214-3p in DFCs was upregulated and downregulated by transfection of miR-214-3p(miR-214 mimics group) or miR-214-3p inhibitors(miR-214 inhibitor group) into DFCs. The expression levels of miR-214, alkaline phosphatase (ALP), osteonectin (OSN) and runt-related transcription factor-2(RUNX-2) were detected by qRT-PCR after 7 days of osteogenesis induction, the protein expression levels of RUNX-2 and β-catenin were detected by western blot, and the formation of mineralized nodules was observed with alizarin red staining after 14 days of osteogenesis induction. @*Results @# Compared with the DFCs group, in the miR-214 mimics group, the expression of miR-214 was upregulated after 7 days of osteogenesis induction. The mRNA expression of ALP, OSN and RUNX-2 in the miR-214 mimics group was lower than that in the DFCs group, but only ALP in the two groups was statistically significant (P > 0.05); the mRNA expression of ALP, OSN and RUNX-2 in the miR-214 inhibitor group was higher than that in the DFCs group, and the difference was statistically significant (P < 0.05). The protein expression of RUNX-2 and β-catenin in the miR-214 mimics group was lower than that in the miR-214 inhibitor group. The number of calcified nodules in the miR-214 mimics group was significantly less than that in the DFCs group, while that in the miR-214 inhibitor group was significantly higher than that in the DFCs group. @*Conclusion@#The upregulation of miR-214 can downregulate the expression of β-catenin, can inhibit the expression of ALP, OSN and RUNX-2 related to osteogenesis, and can inhibit osteogenic differentiation. The downregulation of miR-214 demonstrated the opposite results; miR-214 may downregulate the expression of β-catenin and inhibit the osteogenic differentiation of DFCs.

Neurotrophin 3 promotes osteogenic differentiation of human dental follicle cells / 华西口腔医学杂志

OBJECTIVE@#This study aims to investigate the effect of neurotrophin 3 (NT-3) on the osteogenic differentiation of human dental follicle cells (hDFCs).@*METHODS@#hDFCs were isolated and cultured in vitro. Immunocytochemical staining was used to identify the origin of hDFCs. The effects of different NT-3 concentrations on hDFCs proliferation were detected by using CCK-8 assay. The alkaline phosphatase (ALP) activities and mRNA expression levels of bone morphogenetic protein-2 (BMP-2) and osteocalcin (OCN) were determined to investigate the effects of NT-3 on hDFCs osteogenesis. The difference in the number of mineralized nodules was detected using alizarin red staining.@*RESULTS@#Vimentin and cytokeratin staining results showed that hDFCs originated from the mesenchymal cells. NT-3 exerted no evident effect on hDFCs proliferation. The ALP activity and the BMP-2 and OCN mRNA expression levels of hDFCs were significantly improved under treatment with different NT-3 concentrations (25, 50, and 100 ng·mL ⁻¹) compared with those in the control group. BMP-2 and OCN mRNA relative expression levels of hDFCs reached the highest when the NT-3 concentration was 100 ng·mL ⁻¹. The number of mineralized nodules reached the maximum when the hDFCs were treated with 50 and 100 ng·mL ⁻¹ NT-3.@*CONCLUSIONS@#Appropriate mass concentration of NT-3 can promote the osteogenic differentiation of hDFCs.

Naked cuticle homolog 2 positively regulates the osteogenic differentiation of rat dental follicle cells / 中华口腔医学杂志

Objective@#To examine the expression of naked cuticle homolog 2 (Nkd2) in the process of root development and osteogenic differentiation of dental follicle cells of rat (rDFC), in order to explore the molecular mechanisms of Nkd2 on the osteoblast differentiation of rDFCs.@*Methods@#Immunohistochemical analysis was used to detect the expression of Nkd2 in the base dental follicle of the mandibular first molar of rat at 1, 3, 5, 7, 9, 11 and 13 days postnatal. Mineralization nodule formation of rDFCs was detected by alizarin red staining and cetylpyridine. The change of Nkd2 during osteogenic differentiation of rDFCs was evaluated by Western blotting and the associations between Nkd2 and osteogenic cytokines of alkaline phosphatase (ALP), Runt-related transcription factor-2 (RUNX2) and osteocalcin (OCN) were examined. The rDFCs were transfected with small interfering RNA (siRNA) to knock down the expression of Nkd2 and Western blotting and quantitative real-time PCR (qPCR) were adopted to explore the effects of Nkd2 on osteogenic differentiation by detecting variations of Nkd2 and osteogenic factors ALP, RUNX2, OCN among silencing group (Si), negative control RNA group (Nc) and mock control group (Mock), respectively.@*Results@#The expression of Nkd2 in the base dental follicle of the mandibular first molar of rat was time dependent. Mineralization nodules of rDFCs and absorbance of cetylpyridine after osteogenic induction increased gradually (the absorbances of cetylpyridine were 0 week: 0.017±0.005, 1 week: 0.702±0.044, 2 weeks: 1.812±0.531, 3 weeks: 2.767±0.253, respectively). Results of Western blotting showed that Nkd2 (1.60±0.23) of mineralization group was significantly higher than that of control group (1) (P<0.05) at the early stage of osteogenic differentiation along with the expression of other osteogenic factors. The protein and mRNA of Nkd2 and osteogenic factors were significantly decreased in Si group compared with Nc and Mock groups (P<0.05), and no changes between Nc and Mock groups were observed. The changes of protein in Si, Nc and Mock groups were Nkd2: 0.42±0.10, 1.12±0.07, 1, ALP: 0.70±0.15, 1.11±0.14, 1, RUNX2: 0.58±0.08, 0.93±0.08, 1 and OCN: 0.64±0.06, 0.99±0.02, 1, respectively. The mRNA variances in Si, Nc and Mock groups were Nkd2: 0.39±0.05, 0.96±0.10, 1, ALP: 0.15±0.13, 1.01±0.07, 1, RUNX2: 0.39±0.31, 0.97±0.13, 1, OCN: 0.17±0.08, 1.08±0.21, 1, respectively.@*Conclusions@#Nkd2 participates in the root development process in rat and may acts as a positive role in the early stage of osteogenic differentiation of rDFCs in rat.

Effect of hypoxia on the biological characteristics of human dental follicle cells / 华西口腔医学杂志

<p><b>OBJECTIVE</b>This study aimed to investigate the effects of hypoxia on the characteristics of human dental follicle cells (hDFCs).</p><p><b>METHODS</b>The tissue explant collagenase method was used to isolate hDFCs from young permanent teeth. The immunofluorescence technique was used to detect cell surface markers, and the multi-differentiation potential was detected by multilineage differentiation induction assay. Then, the hypoxic microenvironment was physically mimicked, and the cells were divided into the normoxia group (20%O₂) and the hypoxia group (2%O₂). The effects of hypoxia on cell migration and proliferation were examined by Transwell chamber test and CCK-8 assay, respectively. The gene and protein expression levels of stemness-related markers at both oxygen concentrations were measured by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot, respectively. After osteogenic induction of both groups, qRT-PCR was performed to evaluate the osteogenesis-related gene, and alizarin red staining was used to assess the formation of mineralized nodules.</p><p><b>RESULTS</b>With the multi-differentiation capacity of osteogenic cells, adipogenic cells, and nerves, hDFCs demonstrate strong stem cell characteristics and possess the criteria of mesenchymal stem cells, which can meet the requirements of seed cells in dental tissue engineering. Hypoxia was conducive to the maintenance of hDFC stemness. Hypoxia promoted the migration and proliferation of hDFCs. The hDFCs were induced to osteogenic differentiation under hypoxic conditions, thereby enhancing osteogenesis.</p><p><b>CONCLUSIONS</b>Hypoxic microenvironment plays an important role in maintaining the stemness and promoting the proliferation, migration, and differentiation of hDFCs. Thus, this microenvironment could also serve several important functions in future clinical applications.</p>

Progress in the study of dental tissue-derived stem cells / 实用口腔医学杂志

Dental stem cells(DSCs)possess the characteristics of stem cells and can be effectively obtained from iatro-waste products (such as impacted wisdom tooth and the extracted teeth for orthodontic reason).It has been proved that DSCs are the important sources of stem cells for tissue engineering and regenerative medicine research.Research of these stem cells will create broader space for tissue engi-neering and regenerative medicine and will have important values in translational research.This review gives an overview of the research pro-gress of dental stem cells,and presents some new findings of several common dental stem cells as well as the application in tissue regenera-tion.

Isolation and characterization of human dental tissue-derived stem cells in the impacted wisdom teeth: comparison of dental follicle, dental pulp, and root apical papilla-derived cells

INTRODUCTION: The first aim of this study was to isolate the dental tissue-derived stem cells from the dental follicle (DF), dental pulp (DP), and root apical papilla (RAP) of the extracted wisdom teeth. Second was to evaluate their characterization with the expressions of transcription factors and cell surface markers. Finally, their ability of the in vitro multi-lineage differentiations into osteogenic and adipogenic cells were compared, respectively. MATERIALS AND METHODS: Dental tissues, including dental follicle, dental pulp, and root apical papilla, were separated in the extracted wisdom teeth. These three dental tissues were cultured in Dulbecco's modified Eagle's medium (DMEM) with supplements, respectively. After passage 3, the homogeneous shaped dental tissue-derived cells were analyzed the expression of transcription factors (Oct-4, Nanog and Sox-2) and cell surface markers (CD44, CD90 and CD105) with reverse transcription polymerase chain reaction (RT-PCR) and fluorescence-activated cell sorting (FACS) analysis. In order to evaluate in vitro multi-lineage differentiations, the culture media were changed to the osteogenic and adipogenic induction mediums when the dental tissue-derived cells reached to passage 3. The characteristics of these three dental tissue-derived cells were compared with immunohistochemistry. RESULTS: During primary culture, heterogenous and colony formatted dental tissue-derived cells were observed in the culture plates. After passage 2 or 3, homogenous spindle-like cells were observed in all culture plates. Transcription factors and mesenchymal stem cell markers were positively observed in all three types of dental tissue-derived cells. However, the quantity of expressed transcription factors was most large in RAP-derived cells. In all three types of dental tissue-derived cells, osteogenic and adipogenic differentiations were observed after treatment of specific induction media. In vitro adipogenic differentiation was similar among these three types of cells. In vitro osteogenic differentiation was most strongly and frequently observed in the RAP-derived cells, whereas rarely osteogenic differentiation was observed in the DP-derived cells. CONCLUSION: These findings suggest that three types of human dental tissue-derived cells from extracted wisdom teeth were multipotent mesenchymal stem cells, have the properties of multi-lineage differentiations. Especially, stem cells from root apical papilla (SCAP) have much advantage in osteogenic differentiation, whereas dental follicle cells (DFCs) have a characteristic of easy adipogenic differentiation.

Effects of IGF-1 on the biological characteristics of mouse dental follicle cells / 实用口腔医学杂志

Objective:To study the effects of IGF-1 on the proliferation,total protein amount and cytodifferentiation of mouse dental follicle cells.Methods:The dental follicle cells of passage 3 were incubated with different concentrations((0.005),0.01,0.05,0.1 and 0.5 mg/L)of IGF-1 respectively,cell proliferation,alkaline phosphatase(ALP),total protein amount were measured by MTT assay and spectrophotometer respectively.Effects of 0.05 and 0.1 mg/L IGF-1 on mineralization potential were studied by Von Kossa staining.Results:IGF-1(ml/L) at 0.005~0.1 increased the proliferation and total protein amount(P

Purification of rat dental follicle cells by differential passage / 实用口腔医学杂志

Objective:To develop a simple culture and purifying method for rat dental follicle cells.Methods:The upper and lower first and second intact molar germs of SD rat were separated. Then, dental follicle and enamel organ were stripped together, minced into little pieces, digested with collagenase and cultured. Dental follicular cells were purified by differential passage and indentified by immunohistochemical staining of vimentin and cytokeratin. Results:The primary cells were mixed, consisting of dental follicle cells and enamel organ cells. After differential passage, the cells of fourth passage became purified dental follicle cells. Purified dental follicle cells were elongated spindle or triangle in shape, positive for vimentin and negative for cytokeratin.Conclusion:Dental follicle cells can be purified by several differential passages from the mixed primarily cultured cells.

The effects of enamel matrix proteins on biological characteristics of human dental follicle cells in vitro / 实用口腔医学杂志

Objective:To investigate the effects of enamel matrix proteins(EMPs) on proliferation and alkaline phosphotase (ALP) activity of human dental follicle cells(HDFCs) in vitro. Methods:HDFCs were dissected and cultured by digestion with bacterial collagenase. MTT method and enzyme kinetics method were used to examine the proliferation and ALP activity of HDFCs treated with EMPs.Results:EMPs at 25~200 mg/L increased the proliferation of HDFCs and EMPs at 100 mg/L showed the strongest effects in 7-day-culture.EMPs at 100 mg/L increased ALP activity of HDFCs in 3- and 7-day cultures.Conclusion:EMPs may stimulate the proliferation and the ALP activity of HDFCs.