• 한국세라믹학회지
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• 제40권6호
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• pp.601-607
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• 2003

재료의 선택에 따른 생체친화성을 고찰하기 위해서 조골세포의 세포배양실험을 실시하였으며, 이로부터 세포의 부착형상, 증식, 분화의 정도를 살펴보았다. 본 실험에서 세포배양모재는 체내식립재료로 주목을 받고 있는 TiO$_2$, 3Y-TZP, HA (Hydroxyapatite) 그리고 Ti를 사용하였으며 대조군으로 Thermanox를 선택하였다. 일반적으로 모든 시편들은 같은 세포배양시간일때 거의 유사한 세포부착형상을 보였다. 그러나, HA위의 세포들은 나머지 시편들보다 좀 더 두꺼운 형상을 보였으며 빠른 세포의 부착 및 퍼짐으로 인한 overlapping이 자주 관찰되었다. 세포의 증식 및 분화의 경우에도 생체활성의 특성을 지니는 HA가 가장 높은 값을 보였으며 생체불활성재료인 경우에는 Ti, TiO$_2$, 3Y-TZP모두 유의한 차이를 보이지 않고 비슷한 경향을 나타내었다.

• BMB Reports
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• 제52권7호
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• pp.469-474
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• 2019

Kruppel-like factor 2 (KLF2) has been implicated in the regulation of cell proliferation, differentiation, and survival in a variety of cells. Recently, it has been reported that KLF2 regulates the p65-mediated transactivation of $NF-{\kappa}B$. Although the $NF-{\kappa}B$ pathway plays an important role in the differentiation of osteoclasts and osteoblasts, the role of KLF2 in these bone cells has not yet been fully elucidated. In this study, we demonstrated that KLF2 regulates osteoclast and osteoblast differentiation. The overexpression of KLF2 in osteoclast precursor cells inhibited osteoclast differentiation by downregulating c-Fos, NFATc1, and TRAP expression, while KLF2 overexpression in osteoblasts enhanced osteoblast differentiation and function by upregulating Runx2, ALP, and BSP expression. Conversely, the downregulation of KLF2 with KLF2-specific siRNA increased osteoclast differentiation and inhibited osteoblast differentiation. Moreover, the overexpression of interferon regulatory protein 2-binding protein 2 (IRF2BP2), a regulator of KLF2, suppressed osteoclast differentiation and enhanced osteoblast differentiation and function. These effects were reversed by downregulating KLF2. Collectively, our data provide new insights and evidence to suggest that the IRF2BP2/KLF2 axis mediates osteoclast and osteoblast differentiation, thereby affecting bone homeostasis.

• Journal of Periodontal and Implant Science
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• 제40권1호
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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.

• 한국약용작물학회지
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• 제23권2호
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• pp.117-124
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• 2015

Osteoporosis induces a bone mineral density loss due to imbalance of bone homeostasis that is achieved by osteoclasts (which are involved in bone resorption) and osteoblasts (which are involved in bone formation). Thus, this study was performed to evaluate the effects of hot water extract of the Achyranthes bidentata Blume (ABB) and Panax ginseng (Gin) on osteoclast and osteoblast differentiation. In this study, there was no cytotoxicity by ABB, 50 and $100{\mu}g/ml$ of Gin significantly decreased cell viability of RANKL-induced osteoclast in RAW264.7 cell (p < 0.01). But, it was $50{\mu}g/ml$ of ABB and Gin mixtures increased due to protective action of ABB. Furthermore, Gin contained groups (Gin, ABB and Gin mixtures) were inhibitory effects on osteoclast differentiation and bone resorption, and increased in osteoblast differentiation activity. Gin clearly inhibited RANKL-induced osteoclast differentiation by decreased calcitonin and TRAP (p < 0.01). Also, these extracts significantly increased calcium accumulation formation of osteoblastic differentiation reagents-induced osteoblast in MC3T3-E1 cell (p < 0.05). These results suggest that ABB and Gin mixtures may be a potential as drug for the treatment of osteoporosis.

• 동의생리병리학회지
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• 제18권6호
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• pp.1821-1824
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• 2004

In order to investigate the effects of Radix Achyranthis Bidentatae (RAB) on the growth and differentiation of human osteoblast-like cells, we supplemented the culture medium of MG-63 cells with various concentrations of RAB water extracts. RAB extracts significantly stimulated cell growth, as confirmed by the colorimetric MTT (3-dimethylthiazol-2,5-diphenyltetrazolium bromide) assay. RAB extracts also increased the alkaline phosphatase (ALP) activity, which is a osteoblast differentiation marker. These results suggest that RAB can stimulate osteoblastic activity and may represent new pharmacological tools for the treatment of osteoporosis.

• 대한한방부인과학회지
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• 제25권2호
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• pp.23-42
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• 2012

Objectives: This study was performed to evaluate the effect of Samkieumgamibang (SKG) on osteoporosis. Methods: The osteoclastogenesis and gene expression were determined in RANKL-stimulated RAW 264.7 cell. And, osteoblastogenesis was also determined in rat calvarial cell. Results: SKG decreased the number of TRAP positive cell in osteoclast. It also decreased the expression of Cathepsin K, MMP-9, TRAP, c-fos, NAFTc1 and JNK1 in osteoclast. SKG increased the expression of iNOS in RANKL-stimulated in osteoclast. Otherwise, SKG inhibited TRAP activity in osteoclast. SKG increased cell proliferation, ALP activity, bone martix protein, collagen and nodule in osteoblast. Conclusions: It is concluded that SKG might decrease the bone resorption resulted from decrease of osteoclast differentiation and it's related gene expression. And, SKG might increase the bone formation resulted from increase of osteoblast function.

• Molecules and Cells
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• 제39권5호
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• pp.389-394
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• 2016

Dovitinib (TKI258) is a small molecule multi-kinase inhibitor currently in clinical phase I/II/III development for the treatment of various types of cancers. This drug has a safe and effective pharmacokinetic/pharmacodynamic profile. Although dovitinib can bind several kinases at nanomolar concentrations, there are no reports relating to osteoporosis or osteoblast differentiation. Herein, we investigated the effect of dovitinib on human recombinant bone morphogenetic protein (BMP)-2-induced osteoblast differentiation in a cell culture model. Dovitinib enhanced the BMP-2-induced alkaline phosphatase (ALP) induction, which is a representative marker of osteoblast differentiation. Dovitinib also stimulated the translocation of phosphorylated Smad1/5/8 into the nucleus and phosphorylation of mitogen-activated protein kinases, including ERK1/2 and p38. In addition, the mRNA expression of BMP-4, BMP-7, ALP, and OCN increased with dovitinib treatment. Our results suggest that dovitinib has a potent stimulating effect on BMP-2-induced osteoblast differentiation and this existing drug has potential for repositioning in the treatment of bone-related disorders.

• BMB Reports
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• 제55권12호
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• pp.627-632
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• 2022

Dickkopf-1 (DKK1) is a secreted protein that acts as an antagonist of the canonical WNT/β-catenin pathway, which regulates osteoblast differentiation. However, the role of DKK1 on osteoblast differentiation has not yet been fully clarified. Here, we investigate the functional role of DKK1 on osteoblast differentiation. Primary osteoprogenitor cells were isolated from human spinal bone tissues. To examine the role of DKK1 in osteoblast differentiation, we manipulated the expression of DKK1, and the cells were differentiated into mature osteoblasts. DKK1 overexpression in osteoprogenitor cells promoted matrix mineralization of osteoblast differentiation but did not promote matrix maturation. DKK1 increased Ca⁺ influx and activation of the Ca⁺/calmodulin-dependent protein kinase II Alpha (CAMK2A)-cAMP response element-binding protein 1 (CREB1) and increased translocation of p-CREB1 into the nucleus. In contrast, stable DKK1 knockdown in human osteosarcoma cell line SaOS2 exhibited reduced nuclear translocation of p-CREB1 and matrix mineralization. Overall, we suggest that manipulating DKK1 regulates the matrix mineralization of osteoblasts by Ca⁺-CAMK2A-CREB1, and DKK1 is a crucial gene for bone mineralization of osteoblasts.

• 대한한방부인과학회지
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• 제29권2호
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• pp.66-82
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• 2016

Objectives : This study was conducted to evaluate the effect of Kanghwalsokdan-tang Gamibang water extract (KSG) on osteoporosis. Methods : RANKL-stimulated RAW 264.7 was used to evaluate inhibitory effect of KSG osteoclast differentiation and gene expression. We counted TRAP (+) multinucleated cells and measured TRAP activity and mRNA expressions of osteoclastogenesis-related genes (NFATc1, MITF, JNK1, cathepsin K, MMP-9) to figure out the effect of KSG on osteoclast. Osteoblastogenesis was also determined in rat calvarial cell. Alkaline phosphatase (ALP) activity, bone matrix protein and collagen synthesis were measured by using murine calvarial cell. Results : KSG inhibited the differentiation of osteoclast precursor cell and expression of genes related osteoclastogenesis like NAFTc1, MITF, c-fos, JNK1, Cathepsin K, MMP-9 and TRAP. KSG increased cell division and function of osteoblast separated from the skull of a rat and ALP synthesis, biosynthesis of bone matrix protein and collagen. Conclusions : Reviewing these results, KSG has efficacy on osteoclast inhibition and osteoblast activation. After further study, KSG will be able to apply for osteoporosis treatment and prevention.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제28권2호
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• pp.114-125
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• 2002

This study was designed to evaluate the influence of fibroblasts or connective tissue from mouse oral mucosa on differentiation of neonatal mouse calvaria-derived osteoblasts and mineralization of bone nodules. Primary cell cultures from mouse calvarial osteoblasts and 2-4 passaged fibroblasts from oral mucosa were co-cultured in monolayer cultures, devided into 6 experimental group according to cell density or cell confluency. Osteoblasts were also co-cultured with fibroblasts in $Transwell^{(R)}$ culture plate with different co-cultured period according to osteoblast differentiation. The alkaline phosphatase activity were measured in monolayer cultures and cultures using $Transwell^{(R)}$. The mineralized bone nodules were presented by Von Kossa staining and density of mineralized nodules was measured by image analysis. The connective tissues with or without osteoblast seeding were cultured and examined histologically by Von Kossa and Trichrome Goldner staining. The results were as follows; 1. Prolonged maturation of matrix and delayed mineralization of bone nodules were resulted in monolayer cultures. 2. Co-culture of fibroblast with osteoblast using $Transwell^{(R)}$ during osteoblast proliferation stage stimulated proliferation of osteoblasts and increased alkaline phosphatase activity and mineralization of bone nodules. 3. Co-culture of fibroblast with osteoblast using $Transwell^{(R)}$ during matrix mineralization stage decreased and delayed mineralization of bone nodules. 4. In vitro cultured connective tissue with osteoblast seeding resulted in proliferation of osteoblasts and matrix formation with mineralization.