• Journal of Microbiology and Biotechnology
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• v.32 no.8
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• pp.1017-1025
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• 2022

Bone homeostasis is regulated by constant remodeling through osteogenesis by osteoblasts and osteolysis by osteoclasts and osteoporosis can be provoked when this balance is broken. Present pharmaceutical treatments for osteoporosis have harmful side effects and thus, our goal was to develop therapeutics from intrisincally safe natural products. Fucoidan is a polysaccharide extracted from many species of brown seaweed, with valuable pharmaceutical activities. To intensify the effect of fucoidan on bone homeostasis, we hydrolyzed fucoidan using AMG, Pectinex and Viscozyme. Of these, fucoidan biotransformed by Pectinex (Fu/Pec) powerfully inhibited the induction of tartrate-resistant acid phosphatase (TRAP) activity in osteoclasts differentiated from bone marrow macrophages (BMMs) by the receptor for activation of nuclear factor-κB ligand (RANKL). To investigate potential of lower molecular weight fucoidan it was separated into >300 kDa, 50-300 kDa, and <50 kDa Fu/Pec fractions by ultrafiltration system. The effects of these fractions on TRAP and alkaline phosphatase (ALP) activities were then examined in differentiated osteoclasts and MC3T3-E1 osteoblasts, respectively. Interestingly, 50-300 kDa Fu/Pec suppressed RANKL-induced osteoclasts differentiation from BMMs but did not synergistically enhance osteoblasts differentiation induced by osteogenic agents. In addition, this fraction inhibited the expressions of NFATc1, TRAP, OSCAR, and RANK, which are all key transcriptional factors involved in osteoclast differentiation, and those of Src, c-Fos and Mitf, as determined by RT-PCR. In conclusion, enzymatically low-molecularized 50-300 kDa Fu/Pec suppressed TRAP by downregulating RANKL-related signaling, contributing to the inhibition of osteoclasts differentiation, and represented a potential means of inducing bone remodeling in the background of osteoporosis.

• Journal of Veterinary Science
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• v.23 no.4
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• pp.47.1-47.11
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• 2022

Background: In lipopolysaccharide-induced RAW264.7 cells, Aster tataricus (AT) inhibits the nuclear factor kappa-light-chain-enhancer of activated B cells and MAPKs pathways and critical pathways of osteoclast development and bone resorption. Objectives: This study examined how aster saponin A2 (AS-A2) isolated from AT affects the processes and function of osteoclastogenesis induced by receptor activator of nuclear factor kappa-B ligand (RANKL) in RAW264.7 cells and bone marrow macrophages (BMMs). Methods: The cell viability, tartrate-resistant acid phosphatase staining, pit formation assay, polymerase chain reaction, and western blot were carried out to determine the effects of AS-A2 on osteoclastogenesis. Results: In RAW264.7 and BMMs, AS-A2 decreased RANKL-initiated osteoclast differentiation in a concentration-dependent manner. In AS-A2-treated cells, the phosphorylation of ERK1/2, JNK, and p38 protein expression were reduced considerably compared to the control cells. In RAW264.7 cells, AS-A2 suppressed the RANKL-induced activation of osteoclast-related genes. During osteoclast differentiation, AS-A2 suppressed the transcriptional and translational expression of NFATc1 and c-Fos. AS-A2 inhibited osteoclast development, reducing the size of the bone resorption pit area. Conclusion: AS-A2 isolated from AT appears to be a viable therapeutic therapy for osteolytic illnesses, such as osteoporosis, Paget's disease, and osteogenesis imperfecta.

• Korean Journal of Food Science and Technology
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• v.37 no.6
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• pp.997-1004
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• 2005

In bone remodeling imbalances that are caused by increased bone resorption over bone formation lead to adult skeletal diseases. Thus, we have screened various natural products for their ability to regulate the differentiation of osteoclasts to propose candidates for the prevention or treatment of osteoporosis. Scutellaria baicalensis Georgi and Zizyphus Jujuba Miller var. extracts of 140 natural products inhibited the differentiation of RAW264.7 cells into osteoclast, as showed by the reduced number of tartrate resistant acid phosphatase(TRAP)-positive multinucleated cells and decreased TRAP activity.

• International Journal of Oral Biology
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• v.42 no.4
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• pp.163-168
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• 2017

Osteoporosis is a metabolic bone disease that is characterized by low bone mass resulting from an increase in bone resorption relative to bone formation. The most current therapies for osteoporosis have focused on inhibiting bone resorption by osteoclasts. The purpose of this study is to develop new anabolic agents for treatment of osteoporosis that have fewer risks compared to conventional therapies. We searched the natural products that were derived from the traditional Asian medicines which have been used for treatment of bone related diseases. Icaritin is a flavonoid glycoside derived from the herb Epimedium which has beneficial effects on bone formation. To determine the effect of icaritin on bone formation, we examined the effect of icaritin on MC3T3-E1 cell proliferation and differentiation. For determining the effects of icaritin on proliferation, we performed the MTT assay using MC3T3-E1 cells. To evaluate whether icaritin could promote the osteogenic differentiation of MC3T3-E1 cells, alkaline phosphatase (ALP) activity and mRNA expressions of Runx2, osteocalcin (OCN), RANKL, and osteoprotegerin (OPG) were determined. Icaritin increased MC3T3-E1 cell proliferation. Icaritin increased the ALP activity of MC3T3-E1 cells on 72 hour culture in osteogenic media. mRNA expression of Runx2 was increased after 24 hour culture with icaritin. mRNA expression of osteocalcin was increased after 72 hour culture with icaritin. In addition, icaritin increased the mRNA expressions of OPG and RANKL. However, icaritin increased the mRNA expression of OPG much more than that of RANKL, and then, it increased the OPG/RANKL ratio. These results suggest that icaritin promotes osteogenic differentiation of osteoblasts and decreases osteoclast formation regulated by osteoblasts.

• BMB Reports
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• v.53 no.4
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• pp.218-222
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• 2020

Excessive and hyperactive osteoclast activity causes bone diseases such as osteoporosis and periodontitis. Thus, the regulation of osteoclast differentiation has clinical implications. We recently reported that dehydrocostus lactone (DL) inhibits osteoclast differentiation by regulating a nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), but the underlying mechanism remains to be elucidated. Here we demonstrated that DL inhibits NFATc1 by regulating nuclear factor-κB (NF-κB), activator protein-1 (AP-1), and nuclear factor-erythroid 2-related factor 2 (Nrf2). DL attenuated IκBα phosphorylation and p65 nuclear translocation as well as decreased the expression of NF-κB target genes and c-Fos. It also inhibited c-Jun N-terminal kinase (JNK) but not p38 or extracellular signal-regulated kinase. The reporter assay revealed that DL inhibits NF-κB and AP-1 activation. In addition, DL reduced reactive oxygen species either by scavenging them or by activating Nrf2. The DL inhibition of NFATc1 expression and osteoclast differentiation was less effective in Nrf2-deficient cells. Collectively, these results suggest that DL regulates NFATc1 by inhibiting NF-κB and AP-1 via down-regulation of IκB kinase and JNK as well as by activating Nrf2, and thereby attenuates osteoclast differentiation.

• Korean Journal of Oriental Medicine
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• v.16 no.1
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• pp.149-155
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• 2010

Objective : Ssangwha-tang is a traditional medicine formula widely prescribed for a decrease of fatigue after an illness in Korea. The aim of this study is to investigate the effect of Ssangwha-tang fermented by Lactobacillus fermentum (SF) on osteoclast differentiation in vitro and on bone metabolism of an ovariectomized rat in vivo. Methods : Tartrate-resistant acid phosphatase activity and staining were applied to evaluate the formation of osteoclasts. Ovariectomized rats were orally administrated with SF (30 ml/kg/day) for 12 weeks. Serum aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total cholesterol, high-density lipoprotein-cholesterol, low-density lipoprotein-cholesterol, triglyceride, phosphate, calcium levels were determined. Effect of SF on bone loss were studied by histological analysis and the measurement of bone mineral density. Results : SF significantly inhibited tartrate-resistant acid phosphatase activity and formation of osteoclasts in RAW264.7 cells stimulated by receptor activator for nuclear factor ${\kappa}B$ (NF-${\kappa}B$) ligand (RANKL). In addition, SF significantly decreased the level of triglyceride and increased the level of low-density lipoprotein. Moreover, the decrease of trabeculae of the femur was partially prevented in ovariectomized rats administrated with SF. Conclusions : SF treatment could prevent ovariectomy induced bone loss and its effects could be medicated by the inhibition of osteoclastogenesis.

• 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.

• Molecules and Cells
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• v.37 no.11
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• pp.827-832
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• 2014

The balance between bone formation by osteoblasts and destruction of mineralized bone matrix by osteoclasts is important for bone homeostasis. The increase of osteoclast differentiation by RANKL induces bone diseases such as osteoporosis. Recent studies have shown that insulin is one of main factors mediating the cross-talk between bone remodeling and energy metabolism. However, the systemic examination of insulin-induced differential gene expression profiles in osteoclasts has not been extensively studied. Here, we investigated the global effects of insulin on osteoclast precursors at the level of gene transcription by microarray analysis. The number of genes that were up-regulated by ${\geq}1.5$ fold after insulin treatment for 6 h, 12 h, or 24 h was 76, 73, and 39; and 96, 83, and 54 genes were down-regulated, respectively. The genes were classified by 20 biological processes or 24 molecular functions and the number of genes involved in 'development processes' and 'cell proliferation and differentiation' was 25 and 18, respectively, including Inhba, Socs, Plk3, Tnfsf4, and Plk1. The microarray results of these genes were verified by real-time RT-PCR analysis. We also compared the effects of insulin and RANKL on the expression of these genes. Most genes had a very similar pattern of expressions in insulin- and RANKL-treated cells. Interestingly, Tnfsf4 and Inhba genes were affected by insulin but not by RANKL. Taken together, these results suggest a potential role for insulin in osteoclast biology, thus contributing to the understanding of the pathogenesis and development of therapeutics for numerous bone and metabolic diseases.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.6
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• pp.539-546
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• 1999

Bone is a complex tissue in which resorption and formation continue throughout life. The bone tissue contains various types of cells, of which the bone forming osteoblasts and bone resorbing osteoclasts are mainly responsible for bone remodeling. Periodontal disease represents example of abnormal bone remodeling. Osteoclasts are multinucleated cells present only in bone. It is believed that osteoclast progenitors are hematopoietic origin, and they are recruited from hematopoietic tissues such as bone marrow and circulating blood to bone. Cells present in the osteoclast microenvironment include marrow stromal cells, osteoblasts, macrophages, T-lymphocytes, and marrow cells. These cells produce cytokines that can affect osteoclast formation. In vitro model systems using bone marrow cultures have demonstrated that $IL-l{\beta},\;IL-3,\;TNF-{\alpha},$ bFGF can stimulate the formation of osteoclasts. In contrast, IL-4 inhibits osteoclast formation. Knowledge of cytokines and bFGF that affect osteoclast formation and their capacity to modulate the bone-resorbing process should provide critical insights into normal calcium homeostasis and disorders of bone turnover such as periodontal disease, osteoporosis and Paget's disease.

• Nutritional Sciences
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• v.8 no.3
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• pp.159-168
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• 2005

Phytoestrogens, especially Yak-kong or soybean-derived isoflavones have been traditionally used as a supplement of estrogen for preventing postmemopausal osteoporosis in oriental folk medicine. In our previous study, the treatment of Yak-kong and soybean increased estrogen receptor-a (ERa) expression and proliferation of MG-63 osteoblastic cells. In contrast, the increase of estrogen receptor-$\beta$ (ER$\beta$) expression in proliferating MG-63 cells with Yak-kong and soybean treatment was less pronounced, which suggested that ER$\beta$ may play a role rather in the regulation of bone cell differentiation To determine the role of ER$\beta$ in Yak-kong or soybean mediated regulation of bone cell differentiation, we established MG-63 cell lines stably expressing either ER$\beta$ or antisense ER$\beta$ RNAs. Increased expression of ER$\beta$ did not affect ERa expression and proliferation of MG-63 cells. However, increased expression of ER$\beta$ in MG-63 cells (ER$\beta$-MG63 cells) selectively enhanced Yak-kong or soybean induced expression of osteoprotegerin (OPG), a novel soluble glycoprotein which is secreted from osteoblasts and mediates the signal for osteoclast differentiation. Inhibition of ER$\beta$ expression by antisense ER$\beta$ RNAs (As-ER$\beta$-MG63) caused these cells to insensitize Yak-kong or soybean induced expression of OPG but increased MG-63 cell proliferation. Furthermore, the comparable effects between Yak-kong and the combined treatment of genistein and daidzein at $0.5{\times}l0^{-8}$ M, which is a concentration of these two isoflavones similar to Yak-kong at 0.001 mg/mL, on OPG expression in ER$\beta$-MG63 cell demonstrate that the enhanced expression of OPG with Yak-kong treatment is mediated by the synergistic effect of low leveled isoflavones in the extracts. Together, coupled with low level of ER expression in osteoclasts, our data demonstrate that ER$\beta$ in osteoblasts plays an important role in Yak-kong and soybean mediated inhibition of osteoclast differentiation indirectly by enhancing the expression of OPG.