• Tissue Engineering and Regenerative Medicine
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• v.15 no.6
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• pp.793-801
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• 2018

BACKGROUND: The aim of this study was to evaluate the combined effect of low-level laser treatment (LLLT) and recombinant human bone morphological protein-2 (rhBMP-2) applied to hypoxic-cultured MC3T3-E1 osteoblastic cells and to determine possible signaling pathways underlying differentiation and mineralization of osteoblasts under hypoxia. METHODS: MC3T3-E1 cells were cultured under 1% oxygen tension for 72 h. Cell cultures were divided into four groups: normoxia control, low-level laser (LLL) alone, rhBMP-2 combined with LLLT, and rhBMP-2 under hypoxia. Laser irradiation was applied at 0, 24, and 48 h. Cells were treated with rhBMP-2 at 50 ng/mL. Alkaline phosphatase activity was measured at 3, 7, and 14 days to evaluate osteoblastic differentiation. Cell mineralization was determined with Alizarin red S staining at 7 and 14 days. Western blot assays were performed to evaluate whether p38/protein kinase D (PKD) signaling was involved. RESULTS: The results indicate that LLLT and rhBMP-2 synergistically increased alkaline phosphatase (ALP) activity and mineralization. Western blot analyses showed that expression of type I collagen, runt-related transcription factor 2 (RUNX2), and Osterix (Osx), increased and expression of hypoxia-inducible factor 1-alpha ($HIF-1{\alpha}$), decreased more in the LLLT and rhBMP-2 combined group than in the rhBMP-2 or LLL alone groups. Moreover, LLLT and rhBMP-2 stimulated p38 phosphorylation and rhBMP-2 and LLLT increased Prkd1 phosphorylation. CONCLUSION: Combined treatment with rhBMP-2 and LLL induced differentiation and mineralization of hypoxic-cultured MC3T3-E1 osteoblasts by activating p38/PKD signaling in vitro.

• Journal of Dental Rehabilitation and Applied Science
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• v.25 no.3
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• pp.293-306
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• 2009

In this study, the biological response of fetal rat calvarial cells on alkali- and heat-treated titanium was assessed. The results were as follows; Cell proliferation on alkali- and heat-treated surfaces showed significantly higher level than on the titanium-6aluminum-4vanadium (weight percentage: 6 % aluminum, 4 % vanadium, Ti-6Al-4V) surface (p<0.01). In ELISA analysis, concentration of $IL-1{\beta}$ and IL-6 were raised when the cells were grown to day 7. Pre-treatment with herbimycin, a known tyrosine kinase inhibitor, suppressed the production of IL-6 (p<0.01). In comparison to commercially pure titanium (grade II, cp-Ti) and Ti-6Al-4V alloy, alkali- and heat-treated titanium enhanced alkaline phosphatase activity (p<0.001). In RT-PCR analysis, alkaline phosphatase, bone sialoprotein, receptor activated nuclear factor ligand mRNA expression was increased alkali- and heat-treated titanium. Herbimycin and SB203580, p38 MAPK inhibitor, were repressed of $IL-1{\beta}-induced$ IL-6 mRNA expression. These results suggest that alkali- and heat-treated titanium stimulate osteoblasts differentiation and facilitate bone remodeling.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.4
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• pp.662-669
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• 2005

Nuclear factor I (NFI) exists in the odontoblast and osteoblast. NFI-C null mice demonstrated aberrant odontoblast differentiation, abnormal dentin formation, and molar lacking roots. The purpose of this study was to examine phenotype of the aberrant odontoblast in NFI-C null mice and to evaluate the expression of DSPP and BSP mRNAs in NFI-C null mice with in-situ hybridization. The results were as follows: 1. In the NFI-C (-/-) mice, the crown dentin of molar showed normally formation, but there was no root dentin. 2. In the NFI-C (-/-) mice, the labial dentin of mandibular incisors showed relatively a lot of dentin formation, but the lingual dentin showed defect. 3. In the NFI-C (-/-) mice, the odontoblast of mandibular incisors revealed abnormal shape and trapped in osteodentin-like mineralized tissue. 4. In the NFI-C (-/-) mice, the odontoblast in the crown dentin of molars showed strong expression of DSPP, the odontoblast in the root dentin of molars was not expression of DSPP. In the NFI-C (-/-) mice the odontoblast in the mandibular incisors showed weekly expression of DSPP 5. In the wild mice, the odontoblasts of mandibular incisors were not expression of BSP, but in the NFI-C (-/ -) mice the odontoblast of mandibular incisors showed strong expression of BSP These results suggest that odontoblast in the NFI-C (-/-) mice changes the phenotype into osteoblast.

• Journal of Periodontal and Implant Science
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• v.30 no.1
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• pp.39-52
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• 2000

Polypeptide growth factor belong to a class of potent biologic mediator which regulate cell differentiation, proliferation, migration and metabolism. 1,25-dihydroxyvitamin $D_3$ decrease cell proliferation, and stimulate alkaline phosphatase activity which express in osteoblast during cell differentiation period. IGF-I is known to stimulate cell proliferation and differentiation too. 1,25-dihydroxyvitamin $D_3$ is known to increase IGF-I binding sites and IGF binding protein which inhibite the effect of IGF. The purpose of this study is to evaluate potential role of IGF-I as mediator that control the action of 1,25-dihydroxyvitamin $D_3$. MC3T3-E1 cell were seeded $5{\times}10^5/ml$ at 100mm culture plate in ${\alpha}-MEM$ containing 10% fetal bovine serum. After 48 hour incubation period, medium were changed ${\alpha}-MEM$ containing 5% fetal bovine serum. After 24 hours, $10^{-9}M$ 1,25-dihydroxyvitamin $D_3$ added. Total mRNA was extracted at 0, 6, 24, 48, 72 hour. PRPCR method was programed for the detection of IGF-I mRNA. In the both groups of 1,25-dihydroxy vitamin $D_3$ treated and control, alternative splicing form of IGF-I, IGF-IA and IGF-IB were expressed. In the 1,25-dihydroxyvitamin $D_3$ treated group, IGF-I mRNA expression was matained until 24 hour, there after expression was decresed. MC3T3-E1 cell were seeded $2.5{\times}10^4/ml$ at 24well plate in ${\alpha}-MEM$ containing 10% fetal bovine serum. After 48 hour incubation period, medium were changed ${\alpha}-MEM$ containing 3% fetal bovine serum. After 24 hours, $10^{-9}M$ 1,25-dihydroxyvitamin $D_3$ and 10 ng/ml IGF-I were added separately or together. Cell were cultured for 1 and 3 days, $2{\mu}Ci/ml\;[^3H]$ -thymidine was added for the last 24h of culture of each days. ${[^3H]}$-thymidine incorporation in to DNA was measured and expressed counter per minute(CPM). DNA synthetic activity was significantly decreased by 1,25-dihydroxyvitamin $D_3$ both at 1 day and 3 day, and in the combination group of 1,25-dihydroxyvitamin $D_3$ and IGF-I, DNA synthetic activity was also decreased both at 1 day and 3 days. IGF-I did not affect the DNA synthetic activity compared to control group both at 1 day and 3 day. From the above results, 1,25-dihydroxyvitamin $D_3$ was potent inhibitor of cell proliferaton in MC3T3-E1 cells. It assumed that the effect of 1,25-dihydroxyvitamin $D_3$ on osteoblast proliferation may be mediated in part by decreased level of IGF-I.

• Journal of Life Science
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• v.27 no.4
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• pp.456-463
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• 2017

The purpose of this study was to investigate the effect of 3 types of medicinal herbs (Glycyrrhizae radix, Astragali radix and Dioscorea rhizoma) extracts on estrogen-like activities, proliferation and differentiation in osteoblast. Human breast cancer cell line MCF7 was transfected using an estrogen responsive luciferase reporter plasmid for measure the estrogen-like activity. Estrogen-like activities of extracts were in the range of 1.11~5.73 fold to that of negative control. The extract of G. radix showed the strongest estrogen-like activities. The estrogen-like activities of 50 and $500{\mu}g/ml$ extracts of G. radix were similar to that of $10^{-8}$ and $10^{-7}$ M standard solution ($17{\beta}-estradiol$), respectively. G. radix extract showed no cytotoxicity against osteoblast MC3T3-E1 cells at $1{\sim}1,000{\mu}g/ml$. The extract of A. radix showed no significant proliferation of osteoblast. However, the extract of G. radix and D. rhizome showed maximum 148% and 133% proliferation effects. The extract of G. radix also increased alkaline phosphatase activity and the maximum was 122% at $100{\mu}g/ml$ compared to that of control. The nodule formation by the method of the Alizarin red S staining increased compared to control. These results suggest that G. radix is able to perform the bone formation and prevent osteoporosis.

• Journal of Periodontal and Implant Science
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• v.35 no.4
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• pp.839-850
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• 2005

The success of an implant is determined by its integration into the tissue surrounding the biomaterial. Surface roughness is considered to influence the behavior of adherent cells. The aim of this in vitro study was to determine the effect of surface roughness on Saos-2 osteoblast-like cells. Titanium disks blasted with 75 ${/mu}m$ aluminum oxide particles and machined titanium disks were prepared. Saos-2 were plated on the disks at a density of 50,000 cells per well in 48-well dishes. After 1 hour, 1 day, 6 days cell numbers were counted. One day, 6 days after plating, alkaline phosphatase(ALPase) activity was determined. Compared to experimental group, the number of cells was significantly higher on control group. The stimulatory effect of surface roughness on ALPase was more pronounced on the experimental group than on control group. These results demonstrate that surface roughness alters proliferation and differentiation of osteoblasts. The results also suggest that implant surface roughness may play a role in determining phenotypic expression of cells.

• Molecules and Cells
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• v.44 no.8
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• pp.557-568
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• 2021

Global knockout of the BK channel has been proven to affect bone formation; however, whether it directly affects osteoblast differentiation and the mechanism are elusive. In the current study, we further investigated the role of BK channels in bone development and explored whether BK channels impacted the differentiation and proliferation of osteoblasts via the canonical Wnt signaling pathway. Our findings demonstrated that knockout of Kcnma1 disrupted the osteogenesis of osteoblasts and inhibited the stabilization of β-catenin. Western blot analysis showed that the protein levels of Axin1 and USP7 increased when Kcnma1 was deficient. Together, this study confirmed that BK ablation decreased bone mass via the Wnt/β-catenin signaling pathway. Our findings also showed that USP7 might have the ability to stabilize the activity of Axin1, which would increase the degradation of β-catenin in osteoblasts.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.3
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• pp.337-344
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• 2002

Runx2, a Runt-related osteoblast-specific transcription factor, is essential for osteoblast differentiation and function. Runx2 was identified as a key regulator of osteoblast-specific gene expression through its binding to the OSE2 element present in these genes. However, little is known about the signaling mechanism regulating Runx2 activity. This study examines the role of protein kinase C (PKC) pathway and mitogen-activated protein kinase (MAPK) pathway in regulating Runx2 and bone marker genes (osteopontin; OP, osteocalcin; OC). Luciferase assay and Northern blot analysis suggested that the stimulation of PKC by PMA increased transcription activity of Runx2 and bone marker genes (OP and OC) and also increased expression of Runx2. The stimulation of MAPK by okadaic acid increased transcription activity of Runx2 and bone marker genes (OP and OC). Pretreatment with PD98059 (Erk pathway inhibitor) and SB203580 (P38 pathway inhibitor) prior to PMA treatment decreased PMA stimulated Runx2 activity. Together these results indicate that both PKC and MAPKs are involved in the regulation of Runx2 activity and also the stimulation of Runx2 transcriptional activity by the PKC pathway is through activation of MAPK pathway.

• Journal of Life Science
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• v.26 no.3
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• pp.331-337
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• 2016

Although fibroblast growth factor 23 (FGF23) is exclusively produced in osteoblasts and osteocytes, its main target is the kidney, where it decreases phosphate reabsorption by suppressing Na-phosphate cotransporters. Independently of its action on phosphate homeostasis, FGF23 also inhibits bone formation in vivo. In a calvarial osteoblastic cell model, FGF23 was shown to negatively affect extracellular matrix mineralization. This study investigated whether FGF23 had similar effects on osteoblast maturation, including differentiation and mineralization of bone marrow-derived mesenchymal stem cells (MSCs). D1 MSCs were cultured in an osteogenic medium containing β-glycerophosphate, ascorbic acid, and dexamethazone. Osteoblastic differentiation was evaluated by alkaline phosphatase (Alp) staining, and matrix mineralization was evaluated by alizarin red staining and calcium deposition. The expression of differentiation-stimulating genes Runx2, Alp, and osteocalcin and mineralization-inhibiting genes Enpp1 and Ank was analyzed using semiquantitative RT-PCR. Supraphysiological doses of FGF23 did not stimulate proliferation or osteoblastic differentiation of MSCs. Matrix mineralization 1, 2, and 3 weeks after the FGF23 treatment did not vary between control and FGF23 groups, although time-dependent enhancement of mineralization was obvious. Calcium deposition was also unchanged after the FGF23 treatment. mRNA expression levels of differentiation- and mineralization-related genes were also similar between the groups. Despite these negative findings, FGF23 signaling through FGF receptors seemed to function normally, with phosphorylation of the Erk protein more evident in the FGF23 group than in controls. These findings suggest that unlike calvarial osteoblasts, FGF23 is not likely to affect osteoblastic differentiation and mineralization of MSCs.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.11
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• pp.1532-1536
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• 2011

In this study, the antioxidative activity of Artemisia capillaris T. extract on the proliferation and differentiation of MC3T3-E1 cells under $H_2O_2$-induced oxidative stress was investigated in order to determine its protective effect against oxidative stress as well as its availability as an antioxidant material related to treatment of bone diseases. As a result, the total polyphenol content of A. capillaris extract was 90.10 mg/g, whereas the flavonoid content was 4.45 mg/g. A. capillaris extract increased proliferation of MC3T3-E1 cells under $H_2O_2$-induced oxidative stress, and also increased the proliferation of differentiated osteoblast cells under oxidative stress. In addition, two differentiation markers, alkaline phosphatase activity and mineralization level, in A. capillaris extract tended to increase. These results indicate that A. capillaris extract suppresses the damage to osteoblasts caused by oxidative stress, which demonstrates its availability as an antioxidant material for preventing bone diseases.