• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.1
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• pp.64-70
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• 2010

Soybean is of particular interest as a food supplement of isoflavones for inhibiting bone resorption in postmenopausal woman. These beneficial effects of isoflavones are caused by functioning as partial agonists or antagonists of estrogen, of which anti-resorptive effect is mediated indirectly through paracrine factors produced by osteoblasts that act on osteoclasts. In this study, the indirect effect of soybean on osteoclastic differentiation of RAW264.7 cells were investigated. The conditioned medium was collected from MC3T3-E1 osbeoblasts treated with 0.001 mg/mL~0.1 mg/mL soybean extracts for 6 days, mixed in 1:1 ratio with osteoclast medium, and then added into RAW264.7 cells with receptor activator of nuclear factor kappa B ligand (RANKL), a differentiation inducer for 3 days. Of paracrine factors in the conditioned medium, the protein expression of osteoprotegerin (OPG) with soybean extract was specifically higher in a dose dependent manner than with $10^{-9}$ M~$10^{-6}$ M of estrogen, genistein or daidzein standards. In RAW264.7 cells, the conditioned medium with soybean inhibited RANKL induced osteoclastic differentiation as total number of multinucleated tartrateresistant alkaline phosphatase (TRAP)-positive osteoclasts and protein expression of MMP-9 were significantly decreased. Coupled with the low expression of estrogen receptor $\alpha$ and $\beta$ proteins in RANKL treated RAW264.7 cells, we demonstrate that the conditioned medium of soybean treated osteoblasts inhibits RANKL induced differentiation of osteoclasts with the selective expression of OPG in osteoblasts.

• The korean journal of orthodontics
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• v.25 no.6 s.53
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• pp.705-714
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• 1995

Due to the great deal of effort that has gone into the study of osteoclastic differentiation and activation over the last few decades, the mechanisms of these two events have been discovered gradually. Nitric oxide($NO^-$), which is produced from arginine by a nitric oxide synthase, opened up a new area of biological research. Recently, it has been reported that $NO^-$ is produced by osteoblasts stimulated by lipopolysaccharide and several other cytokines. In this study, the effect of sodium nitroprusside(SNP), a donor of nitric oxide($NO^-$), on osteoclast-like cell formation and on mature osteoclast function was examined. To determine the mechanism of the inhibitory effects of SNP decreased not only the basal $^{45}Ca$ release but also thee bone resorption induced by PTH and 1,25-dihydroxyvitamin $D_3\;(1,25[OH]_{2}D_3)$. The inhibitory effect of SNP on bone resorption induced by PTH appeared 2 dyas after treatment, whereas SNP effect on inhibiting bone resorption induced by $1,25[OH]_{2}D_3$ appeared at the thhird days. When chicken and rat osteeoclasts were cultured on dentin slices, treatment of $300{\mu}M$ SNP resulted in a significant decrease in dentin resorption by osteoclasts in terms of total resolution area and average individual area. We also examind the effect of SNP on formation of osteoclast-like cells that is TRAP-positive multinucleated cells from chicken and rat bone marrow cells in the presence or absence of $10^{-8}\;M\;1,25[OH]_{2}D_3$. The addition of $300{\mu}M$ SNP inhibiteed the formation of TRAP-positive multinucleated cells. The present data suggest that SNP, possibly as a $NO^-$ donor, inhibits the osteoclastic differentiation and osteoclastic activity.

• International Journal of Oral Biology
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• v.44 no.1
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• pp.1-7
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• 2019

Osteoporosis is a common disease characterized by bone mass reduction, leading to an increased risk of bone fracture, and it is caused by an imbalance of osteoblastic bone formation and osteoclastic bone resorption. Current osteoporosis drugs aim to reduce the risk of bone fracture, either by increasing osteoblastic bone formation or decreasing osteoclastic bone resorption. However, osteoblasts and osteoclasts are closely coupled, such that any reagent altering the differentiation or activity of one eventually affects the other. This tight coupling between osteoblasts and osteoclasts not only limits the therapeutic efficacy but also threatens the safety of osteoporosis drugs. This review will discuss the biological mechanisms of action of currently approved medications for osteoporosis treatment, focusing on the osteoblast-osteoclast coupling.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.8
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• pp.992-997
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• 2008

In this study, we investigated the indirect effect of silk-fibroin on osteoclastic differentiation of RAW264.7 cells. The conditioned medium were collected from MC3T3-E1 osbeoblasts treated with $0.001\;mg/mL{\sim}0.1\;mg/mL$ silk fibroin for 6 days, mixed in 1:1 ratio with osteoclast medium, and then added into RAW264.7 cells with receptor activator of nuclear factor kappa B ligand (RANKL), a differentiation inducer for 3 days. Of osteoclastic cytokines in the conditioned medium, the protein expression of osteoprotegerin (OPG) with silk-fibroin was not significantly different. However, the protein expression of interleukin (IL)-$1{\beta}$ was specifically lower in a dose dependent manner. In RAW264.7 cells, the conditioned medium with silk-fibroin inhibited RANKL induced osteoclastic differentiation as total number of multinucleated tartrate-resistant alkaline phosphatase (TRAP)-positive osteoclasts in a dose dependent manner. Taken together, we demonstrated that the conditioned medium of silk-fibroin treated osteoblasts inhibits RANKL induced differentiation of osteoclasts with inhibiting selective expression of IL-$1{\beta}$.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.1
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• pp.74-79
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• 2010

Osteoclasts are bone-resorbing giant cells that differentiate from hematopoietic cells of the monocyte/macrophages. Excessive osteoclast differentiation leads to gradual loss of bone mass causing fracture of the skeleton. The aim of this study was to develop a drug candidates for the treatment of osteoporosis. RANKL-induced osteoclast differentiation was dose-dependently inhibited by myricetin. Myricetin inhibited the expression of c-Fos, NFATc1, and TRAP in BMMs treated with RANKL. Myricetin disrupted the structure of actin ring and suppressed osteoclastic bone resorption. Also, myricetin induced apoptosis in mature osteoclasts. Myricetin inhibited the phosphorylation of ERK in mature osteoclasts treated with M-CSF. The activation of caspase-9 and caspase-3 was increased by myricetin treatment. Our results suggest that myricetin may be an effective agent to prevent bone diseases such as osteoporosis.

• Molecules and Cells
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• v.40 no.5
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• pp.371-377
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• 2017

Despite the importance of the receptor activator of nuclear factor (NF)-kappaB ligand (RANKL)-RANK signaling mechanisms on osteoclast differentiation, little has been studied on how RANK expression is regulated or what regulates its expression during osteoclastogenesis. We show here that insulin signaling increases RANK expression, thus enhancing osteoclast differentiation by RANKL. Insulin stimulation induced RANK gene expression in time- and dose-dependent manners and insulin receptor shRNA completely abolished RANK expression induced by insulin in bone marrow-derived monocyte/macrophage cells (BMMs). Moreover, the addition of insulin in the presence of RANKL promoted RANK expression. The ability of insulin to regulate RANK expression depends on extracellular signal-regulated kinase 1/2 (ERK1/2) since only PD98059, an ERK1/2 inhibitor, specifically inhibited its expression by insulin. However, the RANK expression by RANKL was blocked by all three mitogen-activated protein (MAP) kinases inhibitors. The activation of RANK increased differentiation of BMMs into tartrate-resistant acid phosphatase-positive ($TRAP^+$) osteoclasts as well as the expression of dendritic cell-specific transmembrane protein (DC-STAMP) and d2 isoform of vacuolar ($H^+$) ATPase (v-ATPase) Vo domain (Atp6v0d2), genes critical for osteoclastic cell-cell fusion. Collectively, these results suggest that insulin induces RANK expression via ERK1/2, which contributes to the enhancement of osteoclast differentiation.

• BMB Reports
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• v.50 no.2
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• pp.103-108
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• 2017

Heme oxygenase (HO-1) catalyzes heme to carbon monoxide (CO), biliverdin/bilirubin, and iron and is known to prevent the pathogenesis of several human diseases. We assessed the beneficial effect of heme degradation products on osteoclastogenesis induced by receptor activator of NF-${\kappa}B$ ligand (RANKL). Treatment of RAW264.7 cells with CORM-2 (a CO donor) and bilirubin, but not with iron, decreased RANKL-induced osteoclastogenesis, with CORM-2 having a more potent anti-osteogenic effect. CORM-2 also inhibited RANKL-induced osteoclastogenesis and osteoclastic resorption activity in marrow-derived macrophages. Treatment with hemin, a HO-1 inducer, strongly inhibited RANKL-induced osteoclastogenesis in wild-type macrophages, but was ineffective in $HO-1^{+/-}$ cells. CORM-2 reduced RANKL-induced NFATc1 expression by inhibiting IKK-dependent NF-${\kappa}B$ activation and reactive oxygen species production. These results suggest that CO potently inhibits RANKL-induced osteoclastogenesis by inhibiting redox-sensitive NF-${\kappa}B$-mediated NFATc1 expression. Our findings indicate that HO-1/CO can act as an anti-resorption agent and reduce bone loss by blocking osteoclast differentiation.

• Biomolecules & Therapeutics
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• v.28 no.4
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• pp.337-343
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• 2020

Activation of osteoclast and inactivation of osteoblast result in loss of bone mass with bone resorption, leading to the pathological progression of osteoporosis. The receptor activator of NF-κB ligand (RANKL) is a member of the TNF superfamily, and is a key mediator of osteoclast differentiation. A flavanone glycoside isolated from the fruit of Poncirus trifoliata, poncirin has anti-allergic, hypocholesterolemic, anti-inflammatory and anti-platelet activities. The present study investigates the effect of poncirin on osteoclast differentiation of RANKL-stimulated RAW264.7 cells. We observed reduced formation of RANKL-stimulated TRAP-positive multinucleated cells (a morphological feature of osteoclasts) after poncirin exposure. Real-time qPCR analysis showed suppression of the RANKL-mediated induction of key osteoclastogenic molecules such as NFATc1, TRAP, c-Fos, MMP9 and cathepsin K after poncirin treatment. Poncirin also inhibited the RANKL-mediated activation of NF-κB and, notably, JNK, without changes in ERK and p38 expression in RAW264.7 cells. Furthermore, we assessed the in vivo efficacy of poncirin in the lipopolysaccharide (LPS)-induced bone erosion model. Evaluating the micro-CT of femurs revealed that bone erosion in poncirin treated mice was markedly attenuated. Our results indicate that poncirin exerts anti-osteoclastic effects in vitro and in vivo by suppressing osteoclast differentiation. We believe that poncirin is a promising candidate for inflammatory bone loss therapeutics.

• 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 Physiology & Pathology in Korean Medicine
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• v.25 no.1
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• pp.65-70
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• 2011

Osteoclasts play a critical role in bone-related diseases such as osteoporosis and rheumatoid arthritis by resorbing the bone. Recently, natural products from plants have been extensively studied as therapeutic drugs to treat and prevent various diseases. Here, we examined the effects of rhizoma arisaematis on ostoclast differentiation and bone resorption. We showed that rhizoma arisaematis significantly suppressed receptor activator of nuclear factor-${\kappa}B$ ligand (RANKL)-induced osteoclast differentiation in bone marrow-derived macrophages (BMMs) in a dose dependent manner but have little or no effect on the cytotoxicity of BMMs and RAW264.7 cells. We found that rhizoma arisaematis iarrow-ed the RANKL-induced c-Fos and nuclear factor of activated T cells (NFAT)c1, which is a master regulator of osteoclast differentiation. Furthermore, rhizoma arisaematis suppressed the mRNA expression of tartrate resistant-acid phosphatase and cathepsin K iaduced by RANKL in BMMs. in y chanistic studies, rhizoma arisaematis considerably iarrow-ed I-${\kappa}B$ degradation, which is a negative regulator of NF-${\kappa}B$, but iaduced the phosphderlation of p-38, ERK, and JNK.MMlso, we found that rhizoma arisaematis significantly iarrow-ed osteoclastic bone resorption. Taken tarether, our results suggest that rhizoma arisaematis suppresses osteoclast differentiation through down-regulatd the mRANKL-induced c-Fos and NFATc1 expression and iarrow-s bone resorption.