• 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.

• International Journal of Oral Biology
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• v.41 no.3
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• pp.119-123
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• 2016

Acetylcholine receptors (AChR) including muscarinic and nicotinic AChR are widely expressed and mediate a variety of physiological cellular responses in neuronal and non-neuronal cells. Notably, a functional cholinergic system exists in oral epithelial cells, and nicotinic AChR (nAChR) mediates cholinergic anti-inflammatory responses. However, the pathophysiological roles of AChR in periodontitis are unclear. Here, we show that activation of AChR elicits increased cytosolic $Ca^{2+}([Ca^{2+}]_i)$, transient cytotoxicity, and induction of receptor activator of nuclear factor kappa-B ligand (RANKL) expression. Intracellular $Ca^{2+}$ mobilization in human gingival fibroblast-1 (hGF-1) cells was measured using the fluorescent $Ca^{2+}$ indicator, fura-2/AM. Cytotoxicity and induction of gene expression were evaluated by measuring the release of glucose-6-phosphate dehydrogenase and RT-PCR. Activation of AChR in hGF-1 cells by carbachol (Cch) induced $[Ca^{2+}]_i$ increase in a dose-dependent manner. Treatment with a high concentration of Cch on hGF-1 cells caused transient cytotoxicity. Notably, treatment of hGF-1 cells with Cch resulted in upregulated RANKL expression. The findings may indicate potential roles of AChR in gingival fibroblast cells in bone remodeling.

• The korean journal of orthodontics
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• v.48 no.4
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• pp.253-261
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• 2018

Objective: Orthodontic root resorption (ORR) due to orthodontic tooth movement is a difficult treatment-related adverse event. Caspases are important effector molecules for apoptosis. At present, little is known about the mechanisms underlying ORR and apoptosis in the cementum. The aim of the present in vivo study was to investigate the expression of tartrate-resistant acid phosphatase (TRAP), caspase 3, caspase 8, and receptor activator of nuclear factor kappa-B ligand (RANKL) in the cementum in response to a heavy or an optimum orthodontic force. Methods: The maxillary molars of male Wistar rats were subjected to an orthodontic force of 10 g or 50 g using a closed coil spring. The rats were sacrificed each experimental period on days 1, 3, 5, and 7 after orthodontic force application. And the rats were subjected to histopathological and immunohistochemical analyses. Results: On day 7 for the 50-g group, hematoxylin and eosin staining revealed numerous root resorption lacunae with odontoclasts on the root, while immunohistochemistry showed increased TRAP- and RANKL-positive cells. Caspase 3- and caspase 8-positive cells were increased on the cementum surfaces in the 50-g group on days 3 and 5. Moreover, the number of caspase 3- and caspase 8-positive cells and RANKL-positive cells was significantly higher in the 50-g group than in the 10-g group. Conclusions: In our rat model, ORR occurred after apoptosis was induced in the cementum by a heavy orthodontic force. These findings suggest that apoptosis of cementoblasts is involved in ORR.

• Molecules and Cells
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• v.37 no.8
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• pp.598-604
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• 2014

Fatty acids, important components of a normal diet, have been reported to play a role in bone metabolism. Osteoclasts are bone-resorbing cells that are responsible for many bone-destructive diseases such as osteoporosis. In this study, we investigated the impact of a medium-chain fatty acid, capric acid, on the osteoclast differentiation, function, and survival induced by receptor activator of NF-${\kappa}B$ ligand (RANKL) and macrophage colony-stimulating factor (M-CSF). Capric acid inhibited RANKL-mediated osteoclastogenesis in bone marrow-derived macrophages and suppressed RANKL-induced $I{\kappa}B{\alpha}$ phosphorylation, p65 nuclear translocation, and NF-${\kappa}B$ transcriptional activity. Capric acid further blocked the RANKL-stimulated activation of ERK without affecting JNK or p38. The induction of NFATc1 in response to RANKL was also attenuated by capric acid. In addition, capric acid abrogated M-CSF and RANKL-mediated cytoskeleton reorganization, which is crucial for the efficient bone resorption of osteoclasts. Capric acid also increased apoptosis in mature osteoclasts through the induction of Bim expression and the suppression of ERK activation by M-CSF. Together, our results reveal that capric acid has inhibitory effects on osteoclast development. We therefore suggest that capric acid may have potential therapeutic implications for the treatment of bone resorption-associated disorders.

• 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.

• 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.

• Molecules and Cells
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• v.28 no.3
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• pp.201-207
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• 2009

Silibinin is a polyphenolic flavonoid compound isolated from milk thistle (Silybum marianum), with known hepatoprotective, anticarcinogenic, and antioxidant effects. Herein, we show that silibinin inhibits receptor activator of $NF-{\kappa}B$ ligand (RANKL)-induced osteoclastogenesis from RAW264.7 cells as well as from bone marrow-derived monocyte/macrophage cells in a dose-dependent manner. Silibinin has no effect on the expression of RANKL or the soluble RANKL decoy receptor osteoprotegerin (OPG) in osteoblasts. However, we demonstrate that silibinin can block the activation of $NF-{\kappa}B$, c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein (MAP) kinase, and extracellular signal-regulated kinase (ERK) in osteoclast precursors in response to RANKL. Furthermore, silibinin attenuates the induction of nuclear factor of activated T cells (NFAT) c1 and osteoclast-associated receptor (OSCAR) expression during RANKL-induced osteoclastogenesis. We demonstrate that silibinin can inhibit $TNF-{\alpha}$-induced osteoclastogenesis as well as the expression of NFATc1 and OSCAR. Taken together, our results indicate that silibinin has the potential to inhibit osteoclast formation by attenuating the downstream signaling cascades associated with RANKL and $TNF-{\alpha}$.

• The Journal of Korean Medicine
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• v.38 no.3
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• pp.59-72
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• 2017

Objectives: This study was performed to evaluate effects of Sochungryong-tang Extract(SRE) on osteoclast differentiation and bone resorptionin order to find out the possibility for clinical use in preventing and treating osteoporosis. Methods: To evaluate the effect of SRE on osteoclast differentiation, we induced RAW 264. 7 cells to be differentiated to osteoclasts by RANKL (receptor activator of nuclear $factor-{\kappa}B$ ligand). We measured effect on TRAP (Tartrate-resistant acid phosphatase), NFATc, cathepsin K, MMP-9, inflammation related factors, histogenesis factors and bone resorption. Results: SRE decreased osteoclast differentiation, and also decreased expression of bone resorbing factors such as MMP-9, cathepsin K, TRAP, NFATc1, MITF, c-Fos, osteoclast stimulatory transmembrane protein, calcitonin receptor in RANKL-induced osteoclast. SRE also decreased Cyclooxygenase-2, indusible nitric oxide synthase, $TNF-{\alpha}$, which are thought to be related with the inflammatory bone destruction. Conclusion: SRE inhibits osteoclast differentiation and bone resorption. The results indicate that the BHT extract can potentially be applied for preventing and treating osteoporosis.

• BMB Reports
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• v.52 no.11
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• pp.659-664
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• 2019

Vav1 is a Rho/Rac guanine nucleotide exchange factor primarily expressed in hematopoietic cells. In this study, we investigated the potential role of Vav1 in osteoclast (OC) differentiation by comparing the ability of bone marrow mononuclear cells (BMMCs) obtained from Vav1-deficient ($Vav1^{-/-}$) and wild-type (WT) mice to differentiate into mature OCs upon stimulation with macrophage colony stimulating factor and receptor activator of nuclear kappa B ligand in vitro. Our results suggested that Vav1 deficiency promoted the differentiation of BMMCs into OCs, as indicated by the increased expression of tartrate-resistant acid phosphatase, cathepsin K, and calcitonin receptor. Therefore, Vav1 may play a negative role in OC differentiation. This hypothesis was supported by the observation of more OCs in the femurs of $Vav1^{-/-}$ mice than in WT mice. Furthermore, the bone status of $Vav1^{-/-}$ mice was analyzed in situ and the femurs of $Vav1^{-/-}$ mice appeared abnormal, with poor bone density and fewer number of trabeculae. In addition, Vav1-deficient OCs showed stronger adhesion to vitronectin, an ${\alpha}_v{\beta}_3$ integrin ligand important in bone resorption. Thus, Vav1 may inhibit OC differentiation and protect against bone resorption.

• Journal of Acupuncture Research
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• v.32 no.3
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• pp.27-40
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• 2015

Objectives : This study was performed to evaluate the effects of water extract of Cervi Parvum Cornu(CPC), Aconiti Lateralis Radix Preparata(ALR), and Yongbu-tang(YBT) on suppression of the receptor activator of nuclear factor kappa-B ligand(RANKL)-induced osteoclast differentiation and bone resorption. Methods : The effects of CPC, ALR, YBT extracts on osteoclast differentiation were determined by culture of bone marrow macrophage(BMM). The mRNA expression levels of the nuclear factor of activated T-cells cytoplasmic 1(NFATc1), c-Fos and tartrate-resistant acid phosphatase(TRAP) in BMMs were analyzed by reverse transcriptase polymerase chain reaction(RT-PCR). Similarly, the protein expression levels of NFATc1, c-Fos, mitogen-activated protein kinase(MAPK)s and ${\beta}$-actin in cell lysates were measured by western blotting. In addition, effects of CPC, ALR and YBT extracts were determined by means of Lipopolysaccharide(LPS)-induced bone-loss with mice. Results : CPC, ALR and YBT extracts showed remarkable inhibition on RANKL-induced osteoclast differentiation without cytotoxicity. CPC and ALR extracts significantly reduced the protein expression level of NFATc1. YBT extract significantly reduced the mRNA expression levels of c-Fos, NFATc1 and the protein expression levels of c-Fos, NFATc1, AKT, p38, c-Jun N-terminal kinase(JNK). Further, YBT extract suppressed degradation of$ I-{\kappa}B$. And ALR extract significantly restored the bone erosion by LPS treatment in mice. Conclusions : YBT extract showed more remarkable inhibition on osteoclast differentiation than CPC and ALR extracts in vitro. ALR extract showed remarkable inhibition on bone resorption in vivo. Thus, YBT extract can be a useful treatment for bone-loss diseases such as osteoporosis.