• Journal of Periodontal and Implant Science
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• v.40 no.1
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• pp.39-44
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• 2010

Purpose: Bone tissues for clinical application can be improved by studies on osteoblast differentiation. Runx2 is known to be an important transcription factor for osteoblast differentiation. However, bone morphogenetic protein (BMP)-2 treatment to stimulate Runx2 is not sufficient to acquire enough bone formation in osteoblasts. Therefore, it is necessary to find other regulatory factors which can improve the transcriptional activity of Runx2. The erythroblast transformation-specific (ETS) transcription factor family is reported to be involved in various aspects of cellular proliferation and differentiation. Methods: We have noticed that the promoters of osteoblast differentiation markers such as alkaline phosphatase (Alp), osteopontin (Opn), and osteocalcin (Oc) contain Ets binding sequences which are also close to Runx2 binding elements. Luciferase assays were performed to measure the promoter activities of these osteoblast differentiation markers after the transfection of Runx2, myeloid Elf-1-like factor (MEF), and Runxs+MEF. Reverse-transcription polymerase chain reaction was also done to check the mRNA levels of Opn after Runx2 and MEF transfection into rat osteoblast (ROS) cells. Results: We have found that MEF, an Ets transcription factor, increased the transcriptional activities of Alp, Opn, and Oc. The addition of Runx2 resulted in the 2- to 6-fold increase of the activities. This means that these two transcription factors have a synergistic effect on the osteoblast differentiation markers. Furthermore, early introduction of these two Runx2 and MEF factors significantly elevated the expression of the Opn mRNA levels in ROS cells. We also showed that Runx2 and MEF proteins physically interact with each other. Conclusions: Runx2 interacts with MEF proteins and binds to the promoters of the osteoblast markers such as Opn nearby MEF to increase its transcriptional activity. Our results also imply that osteoblast differentiation and bone formation can be increased by activating MEF to elicit the synergistic effect of Runx2 and MEF.

• Journal of Periodontal and Implant Science
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• v.29 no.2
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• pp.277-289
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• 1999

The ultimate aim of periodontal treatment is periodontal regeneration, which necessiates the regeneration of bone tissues. To evaluate the effects of Dex growth and differentiation of MC3T3-E1 cells, cells were seeded in alpha-modified eagle medium containing 10% fetal bovine serum, 10mM beta-glycerophosphate , $50{\mu}g/ml$ of ascorbic acid, with or without $10^{-7}M$ Dex and examined cell proliferation activities, alkaline phosphatase activities, and bone nodule formation until 25days. The results were as follows : 1. In Dex group, cell proliferation activities were lower until 15 days compared to control group. Bone nodules formation were showed at 10 days. 2. In the time-response effect, ALP activities were increased until the 10 days in control groups thereafter decreased and ALP activities of Dex group were lower aspect than control group until the 10 days In this study, bone nodule formation of osteoblast-like cells were accelerated by Dex and cell proliferation activities, ALP activity of Dex group showed lower than control group. Dex was considered that it did suppress initial growth, but accerelate mineralization of osteoblast-like cells.

• The korean journal of orthodontics
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• v.25 no.6 s.53
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• pp.697-704
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• 1995

Chicken calvarial bone is known to contain various cell types, but their exact composition is unknown. By characterizing the chicken calvarial bone biochemically, it can be used to study biochemical, histochemical actions of bone cells in general. Calvaria of 18-day-old white leg horn embryo was aseptically dissected and bone cell populations were isolated by sequential enzymatic digestion. Histochemical study for osteoclast-like bone cell. population was performed with tartrate resistant acid phosphatase(TRAP) stain and for osteoblast-like bone cell population, alkaline phosphatase(ALP) stain was performed. Biochemical study for osteoblast-like bone cell population was performed using alkaline phosphatase(ALP) assay. Following conclusions were obtained from this study. 1. TRAP positive multi and mononuclear cells were mostly observed in group I and II, indicating that osteoclast-like bone cell population is mostly found in these groups. 2. All the cultured groups showed almost equal ALP activities and were positive for ALP stain, indicating that osteoblast-like bone cell population is evenly dispersed in all culture groups. 3. Experimental group treated with $1,25(OH)_{2}D_3$ showed increase in ALP activity in contrast to the control group, confirming previous studies that $1,25(OH)_{2}D_3$ increases ALP activities in in vitro bone cultures. 4. Results from von Kossa's stain indicated that in vitro bone formation had occured after 3 weeks of culture with beta-glycero phosphate.

• Biomolecules & Therapeutics
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• v.24 no.6
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• pp.589-594
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• 2016

Insulin is a peptide hormone of the endocrine pancreas and exerts a wide variety of physiological actions in insulin sensitive tissues, such as regulation of glucose homeostasis, cell growth, differentiation, learning and memory. However, the role of insulin in osteoblast cells remains to be fully characterized. In this study, we demonstrated that the insulin (100 nM) has the ability to stimulate the phosphorylation of protein kinase B (Akt/PKB) and extracellular signal-regulated kinase (ERK) and the levels of inhibin-${\beta}E$ in the osteoblast-like UMR-106 cells. This insulin-stimulated activities were abolished by the PI3K and MEK1 inhibitors LY294002 and PD98059, respectively. This is the first report proving that insulin is a potential candidate that enables the actions of inhibin-${\beta}E$ subunit of the TGF-${\beta}$ family. The current investigation provides a foundation for the realization of insulin as a potential stimulator in survival signaling pathways in osteoblast-like UMR-106 cells.

• The korean journal of orthodontics
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• v.27 no.6 s.65
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• pp.929-941
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• 1997

Optimal force for orthodontic treatment is the force that produces a rapid rate of tooth movement without discomfort to the Patient or ensuing tissue damage. Recently considerable interest has been generated in the application of magnets as a way to obtain an optimal force. The purpose of the present study was to investigate the effect of static magnetic fields of Sm-Co magnets on molecular and cellular activities. The distance of erythrocyte sedimentation was measured directly, and the activities and the syntheses of $Fe^{2+}$-related enzymes (catalase and NO synthase) and non $Fe^{2+}$-related enzyme (lactic dehydrogenase) were assayed by the spectrophotometer. The growth and the proliferation of osteoblast-like cells $MC_3T_3-E_1$ were determined by the crystal violet staining and the ${^3}H$-thymidine incorporation. The erythrocytes were exposed to the pole face flux density of 1,400 G (gauss), and the enzymes and osteoblast-like cells $MC_{3}T_3-E_1$ were exposed to the flux density of 7,000 G. The results obtained were as follows: 1. The distance of sedimentation of erythrocyte was not affected by the static magnetic fields. 2. The activities of catalase and lactic dehydrogenase were not affected by the static magnetic fields. 3. The intracellular syntheses of NO synthase and lactic dehydrogenase were not affected by the static magnetic fields. 4. The growth and the proliferation of cultured osteoblast-like cells $MC_{3}T_3-E_1$ were not affected by the static magnetic fields. These results suggested that the molecular and cellular activities were not significantly influenced by the static magnetic fields.

• Journal of Life Science
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• v.30 no.5
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• pp.468-475
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• 2020

The purpose of this study was to investigate antioxidant activity and cell differentiation effects of Monascus purpureus pigment on osteoblast-like MC3T3-E1 cell. In order to examine the antioxidant activities of Monascus purpureus pigment, DPPH radical scavenging, ABTS radical scavenging and SOD-like activities were investigated. DPPH radical and ABTS radical scavenging activities of Monascus purpureus pigment were increased in a dose-dependent manner, and maximum activity were 94% and 99% at a concentration of 1,000 ㎍/ml, respectively. Additionally, SOD-like activity of Monascus purpureus pigment showed 62% at a concentration of 1,000 ㎍/ml. MC3T3-E1 cells did not show cytotoxicity in the concentration range of Monascus purpureus pigment 1~100 ㎍/ml. The ALP activity was increased by addition of Monascus purpureus pigment, and the maximum activity was 124% as compared with control. In addition, nodule formation, a late differentiation factor for bone formation, was increased by adding Monascus purpureus pigment compared to control. These results suggest that Monascus purpureus pigment is expected to be a natural source for developing functional materials to prevent bone-related diseases by osteoblast differentiation.

• Korean Journal of Oriental Medicine
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• v.13 no.1 s.19
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• pp.139-145
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• 2007

Emodin is one of the main active components of a traditional Korean medicine isolated from the root and rhizomes of Rheum palmatum L. In this study, of 222 natural compounds to evaluate the anabolic activities, emodin activated bone morphogenetic protein (BMP)-2 promoter in the differentiation process of mouse osteoblastic MC3T3-E1 cells. Emodin was shown to significantly stimulate the activity and expression of alkaline phosphatase, an earlyphase marker of osteoblastic differentiation, on the differentiation day 7, and induce the osteopontin mRNA expression from the differentiation day 14. In addition, low concentration (up to 5 M) of emodin dramatically promoted the induction of mineralization in MC3T3-E1 subclone 4 cells. The stimulatory effect of emodin on the osteoblast differentiation/mineralization could be associated with its potential to stimulate the BMP-2 gene expression. Although further studies are needed to determine the precise mechanism, this study suggests that the use of herbal medicine containing natural compounds with anabolic activity such as emodin could have a beneficial effect on bone health.

• Korean Journal of Plant Resources
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• v.27 no.6
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• pp.593-600
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• 2014

Osteoporosis is a progressive bone disease characterized by low bone mass which is caused by disturbance in the balance between the activities of osteoblasts and osteoclasts. Postmenopausal osteoporosis is one of the most common disorders in women after menopause, which is linked to an estrogen deficiency and characterized by an excessive loss of trabecular bone. Rubus coreanus has been used for their various pharmacological properties in Asia as a traditional medicine. To investigate the effect of unripe fruits of R. coreanus 30% ethanol extract (RCE) on osteoblast-like cells (MG63) differentiation, we examined the effects of RCE on in vitro osteoblastic differentiation markers, alkaline phosphatase (ALP) activity and receptor activator of nuclear factor ${\kappa}$-B ligand (RANKL) and osteoprotegerin (OPG) expression. The high concentration (50 and $100{\mu}g/mL$) of RCE markedly increased ALP activity, whereas decreased the RANKL/OPG. We also investigated the effect of RCE on M-CSF plus RANKL-induced differentiation of pre-osteoclast cells (RAW 264.7). RCE treatment remarkably inhibited M-CSF/RANKL-induced formation of osteoclast-like multinuclear cells from RAW 264.7 cells. Moreover, the inhibitory effect of RCE was reduced by selective estrogen receptor-${\alpha}$ antagonist. Our research suggests that suggested that unripe fruits of R. coreanus may act beneficial effects on bone mass by regulating both osteoblast and osteoclast.

• Journal of Microbiology and Biotechnology
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• v.26 no.6
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• pp.1063-1066
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• 2016

Longan (Dimocarpus longan Lour.) has been used as a traditional oriental medicine and possesses a number of physiological activities. In this study, we used cell-based herbal extract screening to identify longan fruit extract (LFE) as an activator of osteoblast differentiation. LFE up-regulated alkaline phosphatase (ALP) activity, induced mineralization, and activated Runx2 gene expression in MC3T3-E1 cells. Furthermore, treatment of MC3T3-E1 cells with LFE promoted the phosphorylation of extracellular signal-regulated kinase1/2 (Erk1/2); however, abrogation of Erk1/2 activation with PD98059 resulted in down-regulation of the phospho-SMAD1/5/8 and Runx2 levels, which in turn reduced the ALP activity. Our findings suggest that LFE exerts its osteogenic activity through activation of the ERK signaling pathway and may have potential as an herbal therapeutic or a preventive agent for the treatment of osteoporosis.

• International Journal of Oral Biology
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• v.30 no.2
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• pp.39-45
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• 2005

The present study was performed to investigate whether Achyranthes Radix extracts play roles in the bone metabolism. Three kinds of Achyranthes Radix extracts (methylene chloride (MC), ethylacetate (Ea), and water (W)) were used for bioassay. We examined cellular activities of osteoblasts by measurement of cell proliferation rate, alkaline phosphatase (ALP) activity, and calcified nodule formation. Osteoclast generation was assayed by measuring the number of tartrate-resistant acid phosphatase (TRAP) (+) multinucleated cells after culture of osteoclast precursor cells. There was a maximum 20% increase in proliferation rate of osteoblastic cells after treatment with MC. First and second subfraction of MC layer increased proliferation of osteoblast. Ea layer and second subfraction of MC layer increased ALP activity. Also MC layer and second subfraction of MC layer from Achyranthes Radix extracts increased the calcified nodule. MC layer and second subfraction of MC layer from Achyranthes Radix extracts significantly decreased in the number of TRAP (+) multinucleated cells. Taken together, Achyranthes Radix stimulates the proliferation and bioactivities of bone-forming osteoblasts, and inhibits activities of bone-resorbing osteoclasts.