• International Journal of Oral Biology
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• v.36 no.2
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• pp.51-57
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• 2011

Runx2 and Osterix, the transcription factors for osteoblast differentiation, are known as fundamental factors to regulate the development of calcified tissues. However, the biological functions of these factors in the development of the periodontal tissues remain unclear. In this study, we investigated the distribution of Runx2 and Osterix during periodontal tissue development of the mice. Mandibles from 14-day-old mice were prepared for paraffin section. Serial sections of the mandible containing $1^{st}$ molar tooth germs were obtained as a thickness of $7\;{\mu}m$. Some sections were stained with hematoxylin and eosin. Others were used for immunohistochemistry for PCNA, Runx2, and Osterix. Epithelial cells in growing end of Hertwig's epithelial root sheath (HERS) and mesenchymal cells adjacent to the growing end of HERS expressed PCNA. Undifferentiated mesenchymal cells and hard tissue forming cells like cementoblasts and osteoblasts in early stage of differentiation expressed Runx2. Fully differentiated cementoblasts and osteoblasts secreting matrix proteins expressed Osterix. However, the cells terminated the matrix formation did not express Osterix. Periodontal ligament cells expressed Runx2 and Osterix. Pulp cells expressed Runx2 only. These results suggest that Runx2 and Osterix might regulate the differentiation of cementoblasts in the same manner as osteoblasts. Runx2 might participate in the process of cementoblast differentiation in early stage, whether Osterix might regulate the maturation and matrix synthesis of the cells.

• Journal of Nutrition and Health
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• v.53 no.4
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• pp.347-355
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• 2020

Purpose: Zinc is known to be associated with osteoblast proliferation and differentiation. Osterix as zinc-finger transcription factor is also related to osteoblast differentiation and bone formation. In the present study, we aimed to investigate whether zinc modulates osterix gene and protein expression in osteoblastic MC3T3-E1 cells. Methods: MC3T3-E1 cells were cultured in zinc-dependent concentrations (0, 0.5, 1, 5, or 15 µM Zn), along with osteogenic control (normal osteogenic medium) for 1 and 3 days. The gene and protein expression levels of osterix were analyzed by real-time reverse transcription polymerase chain reaction and Western blotting, respectively. Results: Zinc increased osteoblast proliferation in a concentration-dependent manner at day 1 and 3. Similarly, zinc increased the activity of osteoblast marker enzyme alkaline phosphatase in cells and media in a zinc concentration-dependent manner. Moreover, our results showed that the pattern of osterix gene expression by zinc was down-regulated within the low levels of zinc treatments (0.5-1 µM) at day 1, but it was up-regulated after extended culture period at day 3. Osterix protein expression by zinc showed the similar pattern of gene expression, which down-regulated by low zinc levels at day 1 and up-regulated back at day 3 as the early stage of osteoblast differentiation. Conclusion: Our results suggest that zinc modulates osterix gene and protein expression in osteoblasts, particularly in low level of zinc at early stage of osteoblast differentiation period.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.4
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• pp.381-385
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• 2007

Bone is a dynamic organ that bone remodeling occurs throughout life and involves the process in which the bone matrix is broken down through resorption by osteoclasts and then built back again through bone formation by osteoblasts. Usually these two processes balance each other and a stable level of bone mass is maintained. We here discuss transcription factors involved in regulating the osteoblast differentiation pathway. Runx2 is a transcription factor which is essential in skeletal development by regulating osteoblast differentiation and chondrocyte maturation. Its companion subunit, Cbf${\beta}$ is needed for an early step in osteoblast differentiation pathway. Whereas Osterix(Osx) is a new identified osteoblast-specific transcription factor which is required for the differentiation of preosteoblasts into more mature and functional osteoblasts. We also discuss other transcription factors, Msx1 and 2, Dlx5 and 6, Twist, and Sp3 that affect skeletal patterning and development. Understanding the characteristics of mice in which these transcription factors are inactivated should help define their role in bone physiology and pathology of bone defects.

• Nutrition Research and Practice
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• v.15 no.5
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• pp.579-590
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• 2021

BACKGROUND/OBJECTIVES: Petasites japonicus Maxim (P. japonicus) has been used as an edible and medicinal plant and contains many bioactive compounds. The purpose of this study is to investigate the effect of P. japonicus on osteogenesis. MATERIALS/METHODS: The leaves and stems of P. japonicus were separated and extracted with hot water or ethanol, respectively. The total phenolic compound and total polyphenol contents of each extract were measured, and alkaline phosphatase (ALP) activity of each extract was evaluated to determine their effect on bone metabolism. To investigate the effect on osteoblast differentiation of the aqueous extract of P. japonicus leaves (AL), which produced the highest ALP activity among the tested extracts, collagen content was measured using the Sirius Red staining method, mineralization using the Alizarin Red S staining method, and osteocalcin production through enzyme-linked immunosorbent assay analysis. Also, real-time reverse transcription polymerase chain reaction was performed to investigate the mRNA expression levels of Runt-related transcriptional factor 2 (Runx2) and Osterix. RESULTS: Among the 4 P. japonicus extracts, AL had the highest values in all of the following measures: total phenolic compounds, total polyphenols, and ALP activity, which is a major biomarker of osteoblast differentiation. The AL-treated MC3T3-E1 cells showed significant increases in induced osteoblast differentiation, collagen synthesis, mineralization, and osteocalcin production. In addition, mRNA expressions of Runx2 and Osterix, transcription factors that regulate osteoblast differentiation, were significantly increased. CONCLUSIONS: These results suggest that AL can regulate osteoblasts differentiation, at least in part through Runx2 and Osterix. Therefore, it is highly likely that P. japonicus will be useful as an alternate therapeutic for the prevention and treatment of osteoporosis.

• Journal of Dental Anesthesia and Pain Medicine
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• v.19 no.2
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• pp.91-99
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• 2019

Background: The imbalance between osteoblasts and osteoclasts can lead to pathological conditions such as osteoporosis. It has been reported that opioid adversely affect the skeletal system, but it is inconsistent. Remifentanil is currently used as an adjuvant analgesic drug in general anesthesia and sedation. The aim of the present study was to investigate the effect of remifentanil on the osteoblast differentiation and mechanism involved in this effect. Methods: The C2C12 cells (mouse pluripotent mesenchymal cell line) were used as preosteoblast. Osteoblastic differentiation potency was determined by alkaline phosphatase (ALP) staining. C2C12 cell migration by remifentanil was evaluated using Boyden chamber migration assay. The expression of Runx2 and osterix was evaluated by RT-PCT and western blot analysis to investigate the mechanism involved in remifentanil-mediated osteoblast differentiation. Results: ALP staining showed that remifentanil increased significantly osteoblast differentiation. In Boyden chamber migration assay, C2C12 cell migration was increased by remifentanil. RT-PCR and western blot analysis showed that the expression of Runx2 and osterix was upregulated by remifentanil. Conclusions: We demonstrated that remifentanil increased osteoblast differentiation in vitro by upregulation of Runx2 and osterix expression. Therefore, remifentanil has the potential for assisting with bone formation and bone healing.

• Journal of Nutrition and Health
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• v.51 no.1
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• pp.23-30
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• 2018

Purpose: Runx2 (runt-related transcription factor 2), a bone-specific transcription factor, is a key regulator of osteoblast differentiation and its expression is induced by the activation of BMP-2 signaling. This study examined whether zinc modulates BMP-2 signaling and therefore stimulates Runx2 and osteoblast differentiation gene expression. Methods: Two osteoblastic MC3T3-E1 cell lines (subclones 4 as a high osteoblast differentiation and subclone 24 as a low osteoblastic differentiation) were cultured in an osteogenic medium (OSM) as the normal control, Zn-($1{\mu}M$ Zn) or Zn+($15{\mu}M$ Zn) for 24 h. The genes and proteins for BMP-2 signaling (BMP-2, Smad-1/p-Smad-1), transcription factors (Runx2, osterix), and osteoblast differentiation marker proteins were assessed. Results: In both cell lines, BMP-2 mRAN and protein expression and extracellular BMP-2 secretion all decreased in Zn-. The expression of Smad-1 (downstream regulator of BMP-2 signaling) and p-Smad-1 (phosphorylated Smad-1) also downregulated in Zn-. Furthermore, the expression of the bone-specific transcription factors, Runx2 and osterix, decreased in Zn-, which might be due to the decreased BMP-2 expression and Smad-1 activation (p-Smad-1) by Zn-, because Runx2 and osterix both are downstream in BMP-2 signaling. Bone marker gene expression, such as alkaline phosphatase (ALP), collagen type I (COLI), osteocalcin, and osteopontin were also downregulated in Zn-. Conclusion: The results suggest that a zinc deficiency in osteoblasts suppresses the BMP-2 signaling pathway via the suppression of Smad-1 activation, and this suppressed BMP-2 signaling can cause poor osteoblast differentiation.

• International Journal of Industrial Entomology and Biomaterials
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• v.27 no.1
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• pp.159-165
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• 2013

Bone morphogenetic proteins (BMPs) belong to the transforming growth factor (TGF-${\beta}$) superfamily and are involved in osteoblastic differentiation. The largest TGF-${\beta}$ superfamily subgroup shares genetic homology with human BMPs (hBMPs) and silkworm decapentaplegic (dpp). In addition, hBMPs are functionally interchangeable with Drosophila dpp. Bombyx mori dpp may induce bone formation in mammalian cells. To test this hypothesis, we synthesized the 1,285-base pairs cDNA of full-length B. mori dpp using total RNAs obtained from the fat body of 3-day-old of the $5^{th}$ instar larvae and cloned the cDNA into the pCEP4 mammalian expression vector. Next, B. mori dpp was expressed in C3H10T1/2 cells. The target cells transfected with the pCEP4-Bm dpp plasmid showed biological functions similar to those of osteogenic differentiation induction growth factors such as hBMPs. We determined the relative mRNA expression rates of Runt-related transcription factor 2 (RUNX2), osterix, osteocalcin, and alkaline phosphatase (ALP) to validate the osteoblast-specific differentiation effects of B. mori dpp by performing quantitative real-time RT-PCR. Interestingly, mRNA expression levels of the 3 marker genes except RUNX2, in cells expressing B. mori dpp were much higher than those in control cells and C3H10T1/2 cells transfected with pCEP4. These results suggested that B. mori dpp signaling regulates osterix expression during osteogenic differentiation via RUNX2-independent mechanisms.

• International Journal of Oral Biology
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• v.41 no.2
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• pp.53-62
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• 2016

In the present study, we evaluated the effect of CGM on osteogenic differentiation of cultured osteoblasts, and determined whether combination treatment with LLLT had synergistic effects on osteogenic differentiation. The results indicated that CGM promoted proliferation, differentiation, and mineralization of osteoblasts at the threshold concentration of $10{\mu}g/ml$; whereas, CGM showed cytotoxic properties at concentrations above $100{\mu}g/ml$. ALP activity and mineralization were increased at concentrations above $10{\mu}g/ml$. CGM in concentrations up to $10{\mu}g/ml$ also increased the expression of osteoblast-activated factors including type I collagen, BMP-2, RUNX2, and Osterix. The CGM ($50{\mu}g/ml$) and LLLT (80 mW for 15 sec) combination treatment group showed the highest proliferation levels, ALP activity, and mineralization ratios. The combination treatment also increased the levels of phosphorylated forms of p38, ATF2, PKD, ERK, and JNK. In addition, the osteoblast differentiation factors including type I collagen, BMP-2, RUNX2, and Osterix protein levels were clearly increased in the combination treatment group. These results suggested that the combination treatment of CGM and LLLT has synergistic effects on the differentiation and mineralization of osteoblastic cells.

• Journal of Korean Medicine Rehabilitation
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• v.30 no.4
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• pp.17-30
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• 2020

Objectives The purpose of this study is to evaluate the healing effect of Yukmijihwang-tang (YM) on femur fractured mice. Methods Mice were randomly divided into 6 groups: normal, control, positive control, YM with low, medium, high dosage each. All groups were prepared with femur fracture and treated diffrently. In order to measure bone regeneration effects, we analysed the levels of cyclooxygenase-2 (COX2), bone morphogenetic protein-2 (BMP2), collagen type II alpha 1 chain (Col2a1), Sox9, runt-related transcription factor 2 (Runx2), and osterix genes expressed in bone. For morphological analysis, muscles were removed and femur was observed with naked eye. Results COX2 gene expression in bone marrow significantly decreased. BMP2 gene expression significantly increased. Col2a1 gene expression significantly increased. Sox9 gene expression increased as well. Runx2 gene expression in bone marrow increased, but there was no statistical significance. Osterix gene expression significantly increased. Union of the fracture site progressed more in YM group compared to the control group. The fracture union score was significantly decreased in YM group compared to the control group. Conclusions YM showed anti-inflammatory effect, promoted bone regeneration by stimulating the bone regeneration factor. In conclusion, YM can help fracture healing and it well be applied clinically to patients with fracture.

• Journal of Korean Medicine Rehabilitation
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• v.31 no.1
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• pp.1-16
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• 2021

Objectives This study was designed to evaluate the effects of Danggwisu-san (Dangguixu-san, DG) on bone repair from femur fracture in mice. Methods Mice were randomly divided into 4 groups (normal, control, positive control and DG 300 mg/kg-treated group). In order to investigate the effects of DG on gene expressions in experimental animals with fracture, we measured the levels of bone morphogenetic protein-2 (BMP2), cyclooxygenase-2 (COX2), Sox9, collagen type II alpha 1 chain (Col2a1), runt-related transcription factor 2 (Runx2), osterix genes. After the cytotoxicity test, we analyzed the levels of expression of osteocalcin and Runx2, and tumor necrosis factor-α (TNF-α), a pro-inflammatory cytokine. The process of fusion in the fracture was also investigated by gross examination. Results Through in vivo BMP2, COX2 gene expression significantly decreased. Sox9 significantly increased. Col2a1, Runx2, osterix gene expression also increased as well, but there was no statistical significance. The degree of unilateral fracture fusion investigated by gross examination was significantly faster than those of the other groups. Through in vitro the level of TNF-α in macrophages was increased by DG in a dose-dependent mannerand and 250 and 500 ㎍/mL showed statistical significance. Osteocalcin and Runx2 genes expressions increased when DG was treated in osteoblasts. Conclusions DG promotes the healing of the fracture through the expression of bone repair-related genes and TNF-α production. This study may set the foundation for the clinical application of DG to the patients with bone fractures.