• 약학회지
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• 제58권3호
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• pp.165-170
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• 2014

We investigated the effect of Chenodeoxycholic acid (CDCA) on the proliferation of osteoclast precursor cells. CDCA decreased the proliferation of osteoclast precursor cells through the control of cell cycle regulators such as cyclin D1, p21 and p27. When we checked the signaling pathway, CDCA decreased Erk activation in osteoclast precursor cells. Furthermore, two bile acid receptors, FXR and TGR5, were involved in the suppressive effect of CDCA. Taken together, this study suggested that bile acid plays an important role in the proliferation of osteoclast precursor cells.

• 대한의생명과학회지
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• 제23권3호
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• pp.194-200
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• 2017

Bone-resorbing osteoclasts play a major role in maintaining bone homeostasis with bone-forming osteoblasts. Although it has been reported that A2B adenosine receptor (A2BAR) regulates osteoclast differentiation, its effects on apoptosis or proliferation of osteoclasts have been less-defined. Here, we demonstrate that A2BAR stimulation regulates macrophage-colony stimulating factor (M-CSF)-mediated osteoclast proliferation. Stimulation with a specific agonist of A2BAR, BAY 60-6583, significantly reduced M-CSF-mediated osteoclast proliferation in a time- and dose-dependent manner. In addition, A2BAR stimulation induced both apoptosis of the cells and cell arrest in the G1 phase with a decrease of cell number in the G2/M phase. Stimulation with BAY 60-6583 inhibited the activation of Akt by M-CSF, whereas M-CSF-induced ERK1/2 activation was not affected. These results suggest that the inhibition of M-CSF-mediated Akt activation by A2BAR stimulation increases apoptotic response of osteoclasts and induces cell cycle arrest in the G1 phase, thus contributing to the down-regulation of osteoclast proliferation.

• Molecules and Cells
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• 제38권3호
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• pp.279-284
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• 2015

Obatoclax, a pan-Bcl2 inhibitor, shows antitumor activities in various solid malignancies. Bcl2-deficient mice have shown the importance of Bcl2 in osteoclasts, as the bone mass of the mice was increased by the induced apoptosis of osteoclasts. Despite the importance of Bcl2, the effects of obatoclax on the proliferation and differentiation of osteoclast precursors have not been studied extensively. Here, we describe the anti-proliferative effects of obatoclax on osteoclast precursors and its negative role on fusion of the cells. Stimulation with low doses of obatoclax significantly suppressed the proliferation of osteoclast precursors in a dose-dependent manner while the apoptosis was markedly increased. Its stimulation was sufficient to block the activation of ERK MAP kinase by RANKL. The same was true when PD98059, an ERK inhibitor, was administered to osteoclast precursors. The activation of JNK1/2 and p38 MAP kinase, necessary for osteoclast differentiation, by RANKL was not affected by obatoclax. Interestingly, whereas the number of TRAP-positive mononuclear cells was increased by both obatoclax and PD98059, fused, multinucleated cells larger than $100{\pm}m$ in diameter containing more than 20 nuclei were completely reduced. Consistently, obatoclax failed to regulate the expression of osteoclast marker genes, including c-Fos, TRAP, RANK and CtsK. Instead, the expression of DC-STAMP and Atp6v0d2, genes that regulate osteoclast fusion, by RANKL was significantly abrogated by both obatoclax and PD98059. Taken together, these results suggest that obatoclax down-regulates the proliferation and fusion of osteoclast precursors through the inhibition of the ERK1/2 MAP kinase pathway.

• 대한의생명과학회지
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• 제23권4호
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• pp.327-332
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• 2017

A2B adenosine receptor (A2BAR) is known to be a regulator of bone homeostasis, but the regulatory mechanism of A2BAR on the osteoclast proliferation are poorly explored. Recently, we have shown that stimulation with BAY 60-6583, a specific agonist of A2BAR, significantly reduced macrophage-colony stimulating factor (M-CSF)-induced osteoclast proliferation by inducing cell cycle arrest at G1 phase and increasing the apoptosis of osteoclasts. The objective of this study was to investigate the regulatory mechanisms of cell cycle and apoptosis by A2BAR stimulation. The expression of A2BAR and M-CSF receptor, c-Fms, was not changed by A2BAR stimulation whereas M-CSF effectively induced c-Fms expression during osteoclast proliferation. Interestingly, A2BAR stimulation remarkably increased the expression of $p27^{Kip-1}$, a cell cycle inhibitor, but the expression of Cyclin D1 and cdk4 was not affected. In addition, while BAY 60-6583 treatment reduced the expression of Bcl2, an anti-apoptotic oncogene, it failed to regulate the expression of Bax, a pro-apoptotic marker. Taken together, these results imply that the increase of $p27^{Kip-1}$ inducing cell cycle arrest at G1 phase and the decrease of Bcl2 inducing anti-apoptotic response by A2BAR stimulation contribute to the down-regulation of osteoclast proliferation.

• International Journal of Oral Biology
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• 제33권4호
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• pp.179-186
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• 2008

Several lines of evidence suggest that osteocytes play a critical role in bone remodeling. Both healthy and apoptotic osteocytes can send signals to other bone surface cells such as osteoblasts, osteoclasts, osteoclast precursors, and bone lining cells through canalicular networks. Osteocytes responding to mechanical strain may also send signals to other cells. To determine the role for osteocytes an mechanical strain in bone remodeling, we examined the effects of fluid flow shear stress on osteoclast precursor cell and osteoblast proliferation and recruitment induced by osteocytes. In addition, the effects of fluid flow shear stress on osteocyte M-CSF, RANKL, and OPG mRNA expression were also examined. MLO-Y4 cells were used as an in vitro model for osteocytes, RAW 264.7 cells and MOCP-5 cells as osteoclast precursors, and 2T3 cells as osteoblasts. MLO-Y4 cells conditioned medium (Y4-CM) was collected after 24h culture. For fluid flow experiments, MLO-Y4 cells were exposed to 2h of pulsatile fluid flow (PFF) at 2, 4, 8, $16{\pm}0.6\;dynes/cm^2$ using the Flexcell $Streamer^{TM}$ system. For proliferation assays, MOCP-5, RAW 264.7, and 2T3 cells were cultured with control media or 10-100% Y4 CM. Cells were cultured for 3d, and then cells were counted. RAW 264.7 and 2T3 cell migration was assayed using transwells with control media or 10-100% Y4-CM. M-CSF, RANKL and OPG in MLO-Y4 mRNA expression was determined by semiquantitative RT-PCR. Y4-CM increased osteoclast precursor proliferation and migration, but decreased 2T3 cell proliferation and migration. CM from MLO-Y4 cells exposed to PFF caused decreased RAW 267.4 cell proliferation and migration and 2T3 migration compared to control Y4-CM. However, Y4-CM from cells exposed to PFF had no effect on 2T3 osteoblastic cell proliferation. PFF decreased RNAKL mRNA and increased OPG mRNA in MLO-Y4 cells compared to control(without PFF). PFF had no effect on M-CSF mRNA expression in MLO-Y4 cells. These results suggest that osteocytes can regulate bone remodeling by communication with osteoclast precursors and osteoblasts and that osteocytes can communicate mechanical signals to other cells.

• Archives of Pharmacal Research
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• 제26권11호
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• pp.929-936
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• 2003

Methanol extract (MeOH), n-hexane (Hx), chloroform ($CHCl_3$), ethyl acetate (EA), butanol (BuOH) and aqueous ($H_2O$) fractions of Eucommiae Cortex including geniposidic acid (GA), geniposide (GP) and aucubin (AU) were tested for their therapeutic efficacy on osteoporosis. The contents of GA, GP and AU in the cortex and leaf of Eucommia ulmoides Oliver were quantified by HPLC. The effect of Eucommiae Cortex on the induction of growth hormone (GH) release was studied by using rat pituitary cells. The proliferation of osteoblast-like cells increased by herbal extracts was assayed using a tetrazolium (MTT), alkaline phosphatase (ALP) activity, and [$^3H$]-proline incorporation assays. The inhibition of osteoclast was studied by using the coculture of mouse bone marrow cells and ST-2 cells. As a result, the GA, GP and AU were present in the cortex more than in the leaf of E. ulmoides Oliver. The MeOH (1mg/mL), Hx, $CHCl_3$ and EA fractions (each 20 $\mu$ g/mL) had potent induction of GH release. The $CHCl_3$ exhibited the potent proliferation of osteoblasts. The AU, GP and GA were increased proliferation of osteoblasts. In addition, GA ($IC_{50}: 4.43{\times}10^{-7}$M), AU and GP were significantly inhibited proliferation of osteoclast. In summary, it is thought that the components in a part of the fractions of Eucommiae Cortex participate in each step of mechanism for activating osteoblast to facilitate osteogenesis, and suppress osteoclast activity to inhibit osteolysis.

• 대한한방부인과학회지
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• 제27권3호
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• pp.12-27
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• 2014

Objectives: This study was performed to evaluate the effect of Guibi-tang water extract (GB) on osteoporosis. Methods: We examined the effect of GB on osteoclast differentiation using murine pre-osteoclastic RAW 264.7 cells treated with receptor activator of nuclear factor kappa-B ligand (RANKL). The effect of GB on osteoclast was measured by counting TRAP (+) multinucleated cells and measuring TRAP activity. The mRNA expressions of osteoclastogenesis-related genes (Cathepsin K, MMP-9, TRAP, NFATc1, MITF, TNF-${\alpha}$, IL-6, COX-2) were measured by real-time PCR. We examined the effect of GB on osteoblast proliferation, ALP activity, bone matrix protein synthesis and collagen synthesis using murine calvarial cell. Results: GB decreased the number of TRAP (+) multinucleated cells and inhibited TRAP activity in RANKL-stimulated RAW 264.7 cell. GB decreased the expression of genes related osteoclastogenesis such as Cathepsin K, MMP-9, TRAP, NFATc1, MITF, COX-2 in RANKL-stimulated RAW 264.7 cell. But GB did not decrease the expression of iNOS and increased the expression of TNF-${\alpha}$, IL-6 in RANKL-stimulated RAW 264.7 cell. These genes (iNOS, TNF-${\alpha}$, IL-6) are thought to be related with the inflammatory bone destruction. GB increased cell proliferation of rat calvarial cell and also increased ALP activity in rat calvarial cell. GB did not increase bone matrix protein synthesis but increased collagen synthesis in rat calvarial cell. Conclusions: This study suggests that GB may be effective in treating osteoporosis by inhibiting osteoclast differentiation and its related gene expression and by increasing osteoblast proliferation.

• International Journal of Oral Biology
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• 제30권2호
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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.

• 대한한의학방제학회지
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• 제19권2호
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• pp.61-71
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• 2011

Objectives : Kyungok-go(KOG), the first herbal formulation of donguibogam, has been used for treating of many symptoms of yin deficiency. In this study, we examined the effect of KOG on bone resorption. Methods : We determined the effects of water extract of KOG in RANKL(Receptor Activator for Nuclear Factor ${\kappa}B$ Ligand)-induced osteoclast differentiation culture system and osteoblast proliferation. In addition, we determined the effects of water extract of ABR on LPS-induced bone-loss with mice. Results : Water extract of KOG showed proliferation effect on osteoblast without cytotoxicity and no effect on RANKL-treated osteoclast differentiation. KOG rescued bone erosion by LPS induction in vivo study. Conclusions : These results demonstrated that KOG can be a useful remedy for treating of bone-loss disease such as 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.