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

• Molecules and Cells
• /
• v.26 no.5
• /
• pp.436-442
• /
• 2008

Osteoclasts are multinucleated cells with the unique ability to resorb bone. Elevated activity of these cells under pathologic conditions leads to the progression of bone erosion that occurs in osteoporosis, periodontal disease, and rheumatoid arthritis. Thus, the regulation of osteoclast apoptosis is important for bone homeostasis. In this study, we examined the effects of the Janus tyrosine kinase 2 specific inhibitor AG490 on osteoclast apoptosis. We found that AG490 greatly inhibited osteoclast apoptosis. AG490 stimulated the phosphorylation of Akt and ERK. Adenovirus-mediated expression of dominant negative (DN)-Akt and DN-Ras in osteoclasts inhibited the survival of osteoclasts despite the presence of AG490. Cytochrome c release during osteoclast apoptosis was inhibited by AG490 treatment, but this effect was inhibited in the presence of LY294002 or U0126. AG490 suppressed the pro-apoptotic proteins Bad and Bim, which was inhibited in osteoclasts infected with DN-Akt and DN-Ras adenovirus. In addition, constitutively active MEK and myristoylated-Akt adenovirus suppressed the cleavage of pro-caspase-9 and -3 and inhibited osteoclast apoptosis induced by etoposide. Taken together, our results suggest that AG490 inhibited cytochrome c release into the cytosol at least partly by inhibiting the pro-apoptotic proteins Bad and Bim, which in turn suppressed caspase-9 and -3 activation, thereby inhibiting osteoclast apoptosis.

• The korean journal of orthodontics
• /
• v.13 no.2
• /
• pp.147-154
• /
• 1983

This experiment was performed to study the effect of $PGE_2$ on the bone resorption at the tooth movement by orthodontic force. The experimental animals were the Sprague-Dawley strain rats. The orthodontic force was applied by the insertion of separating clamp made of 0.014' (0.356mm) wire to the interproximal site between the 2nd and the 3rd upper right molars. In experiment I, $0.2{\mu}g,\;0.4{\mu}g,\;0.8{\mu}g,\;and\;1.0{\mu}g\;PGE_2$ were locally injected at the submucosa near the 2nd molar of the maxilla each. The effect was detected by the count of the number of osteoclasts appeared at the compressed surface of interradicular bone. In experiment II, 1.0 mg/kg indomethacin (a specificc inhibitor of prostaglandin synthetas.) was subcutaneously injected. The effect was examined by the count of the number of cateoclasts appeared at the compressed surface of interradicular bone. The obtained results were follows; 1. The number of osteoclasts on the compressed surface of the interradicular bone increased in proportion to the increased dosage of $PGE_2$ administered. The number of osteoclasts increased significantly at the administration of $0.8{\mu}g\;and\;1.0{\mu}g\;PGE_2$ in contrast to the control (P<0.05). 2. The administration of 1.0 mg/kg indomethacin decreased the number of osteoclasts at the compressed bony surface significantly (P<0.01).

• BMB Reports
• /
• v.35 no.6
• /
• pp.609-614
• /
• 2002

The remodeling process of bone is accompanied by complex changes in the expression levels of various genes. Several approaches have been employed to detect differentially-expressed genes in regard to osteoclast differentiation. In order to identify the genes that are involved in osteoclast differentiation, we used a cDNA-array-nylon membrane. Among 1,200 genes that showed ameasurable signal, 19 genes were chosen for further study. Eleven genes were up-regulated; eight genes were down-regulated. TIS21 was one of the up-regulated genes which were highly expressed in mature osteoclasts. To verify the cDNA microarray results, we carried out RT-PCR and real-time RT-PCR for the TIS21 gene. The TIS21 mRNA level was higher in differentiated-osteoclasts when compared to undifferentiated bone-marrow macrophages. Furthermore, the treatment with $1\;{\mu}M$ of a TIS21 antisense oligonucleotide reduced the formation of osteoclasts from the bone-marrow-precursor cells by ~30%. These results provide evidence for the potential role of TIS21 in the differentiation of osteoclasts.

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

• Biomolecules & Therapeutics
• /
• v.24 no.1
• /
• pp.9-18
• /
• 2016

Bone matrix is properly maintained by osteoclasts and osteoblasts. In the tumor microenvironment, osteoclasts are increasingly differentiated by the various ligands and cytokines secreted from the metastasized cancer cells at the bone metastasis niche. The activated osteoclasts generate osteolytic lesions. For this reason, studies focusing on the differentiation of osteoclasts are important to reduce bone destruction by tumor metastasis. The N-myc downstream-regulated gene 2 (NDRG2) has been known to contribute to the suppression of tumor growth and metastasis, but the precise role of NDRG2 in osteoclast differentiation induced by cancer cells has not been elucidated. In this study, we demonstrate that NDRG2 expression in breast cancer cells has an inhibitory effect on osteoclast differentiation. RAW 264.7 cells, which are monocytic preosteoclast cells, treated with the conditioned media (CM) of murine breast cancer cells (4T1) expressing NDRG2 are less differentiated into the multinucleated osteoclast-like cells than those treated with the CM of 4T1-WT or 4T1-mock cells. Interestingly, 4T1 cells stably expressing NDRG2 showed a decreased mRNA and protein level of intercellular adhesion molecule 1 (ICAM1), which is known to enhance osteoclast maturation. Osteoclast differentiation was also reduced by ICAM1 knockdown in 4T1 cells. In addition, blocking the interaction between soluble ICAM1 and ICAM1 receptors significantly decreased osteoclastogenesis of RAW 264.7 cells in the tumor environment. Collectively, these results suggest that the reduction of ICAM1 expression by NDRG2 in breast cancer cells decreases osteoclast differentiation, and demonstrate that excessive bone resorption could be inhibited via ICAM1 down-regulation by NDRG2 expression.

• The Korean Journal of Pain
• /
• v.30 no.2
• /
• pp.86-92
• /
• 2017

Osteoblasts, originating from mesenchymal cells, make the receptor activator of the nuclear factor kappa B ligand (RANKL) and osteoprotegerin (OPG) in order to control differentiation of activated osteoclasts, originating from hematopoietic stem cells. When the RANKL binds to the RANK of the pre-osteoclasts or mature osteoclasts, bone resorption increases. On the contrary, when OPG binds to the RANK, bone resorption decreases. Denosumab (AMG 162), like OPG (a decoy receptor), binds to the RANKL, and reduces binding between the RANK and the RANKL resulting in inhibition of osteoclastogenesis and reduction of bone resorption. Bisphosphonates (BPs), which bind to the bone mineral and occupy the site of resorption performed by activated osteoclasts, are still the drugs of choice to prevent and treat osteoporosis. The merits of denosumab are reversibility targeting the RANKL, lack of adverse gastrointestinal events, improved adherence due to convenient biannual subcutaneous administration, and potential use with impaired renal function. The known adverse reactions are musculoskeletal pain, increased infections with adverse dermatologic reactions, osteonecrosis of the jaw, hypersensitivity reaction, and hypocalcemia. Treatment with 60 mg of denosumab reduces the bone resorption marker, serum type 1 C-telopeptide, by 3 days, with maximum reduction occurring by 1 month. The mean time to maximum denosumab concentration is 10 days with a mean half-life of 25.4 days. In conclusion, the convenient biannual subcutaneous administration of 60 mg of denosumab can be considered as a first-line treatment for osteoporosis in cases of low compliance with BPs due to gastrointestinal trouble and impaired renal function.

• Restorative Dentistry and Endodontics
• /
• v.26 no.4
• /
• pp.285-295
• /
• 2001

The objective of this study was to investigate the inhibitory effect of taurine and alendronate on the osteoclast differentiation. Osteoblasts and bone marrow cells from 1-2 day old mouse were co-cultured in 10% fetal bovine serum - minimal essential media (FBS-MEM). Osteoclast differentiation was induced by adding the sonicated extracts of Porphyromonas gingivalis (P.gingivalis). Osteoclasts were identified using tartrate resistant acid phosphotase staining (TRAP). Alendronate of 10$^{-7}$, 10$^{-6}$, 10$^{-5}$M and taurine of 500, 1000, 1500$\mu\textrm{g}$/ml were added respectively. The cytotoxic effects of alendronate and taurine were examined using MTT(3-(4,5-dimethylthiazol -2-yl-2,5-diphenyltetrazo- lium bromide) method. After culturing with the sonicated extracts of P.gingivalis, the amounts of IL-6 in the culture supernatant were measured and compared using the ELISA method. The results were as follows : 1. Osteoclasts were differentiated at the concentration of 0.01~0.1$\mu\textrm{g}$/ml sonicated extracts of P.gingivalis. (P<0.05). 2. Alendronate inhibited osteoclasts differentiation at the concentration of 10$^{-5}$ M when the concentration of sonicated extracts of P.gingivalis was 0.01$\mu\textrm{g}$/ml. 3. Taurine inhibited osteoclasts differentiation at the concentration of 1500$\mu\textrm{g}$/ml when the concentration of sonicated extracts of P.gingivalis 0.01$\mu\textrm{g}$/ml. 4. In cytotoxic test (MTT test), no cytotoxic effect was evident in all concentrations of alendronate and taurine. 5. Taurine (10$^{-5}$M) and alendronate(1500$\mu\textrm{g}$/ml) did not change the amounts of IL-6 induced by sonicated extracts of P.gingivalis significantly.

• Journal of Korean Medicine Rehabilitation
• /
• v.30 no.4
• /
• pp.1-16
• /
• 2020

Objectives The main purpose of this study was to evaluate the bone healing effect of Pahyeolsandong-tang (PHT)(Poxiesanteng-tang) extract in tibia fracture-induced mice. Methods PHT was extracted using a solution of 35% ethanol in 60℃ for 8 hours. Mice were randomly divided into 4 groups (normal, control, PHT 50 and PHT 100). Mice of experimental groups were medicated with PHT 50 or 100 mg/kg for 7 to 21 days. To clarify the effect of bone fracture healing, relative messenger RNA (mRNA) expressions of osteocalcin (OCN), runt-related transcription factor 2 (Runx2), osterix (OSX), Sox9, collagen type II alpha 1 chain (Col2a1), receptor activator of nuclear factor kappa-B ligand (RANKL), osteoprotegerin (OPG) were examined. Results In in vitro experiment, relative mRNA expression of OCN, Runx2, Col2a1 was significantly increased in PHT treated group to compare with control differentiation group. In in vivo experiment, relative mRNA expression of OCN, Runx2, OSX, Sox9, Col2a1, RANKL, OPG was significantly increased in PHT treated group. Conclusions This study showed that PHT accelerates bone fracture healing through the activation of osteoclasts and osteoblasts. It was showed that PHT significantly promotes osteoblasts differentiation by osteoblast differentiation markers such as OCN, Runx2, Col1a2. Also it was investigated that PHT had stimulatory effect on osteoblasts function through enhancing OCN, Runx2, OSX, Sox9, Col2a1 and, osteoclasts function through enhancing RANKL and OPG markers. PHT effectively promotes bone fracture healing process through activation of osteoblasts and osteoclasts.

• Journal of Acupuncture Research
• /
• v.22 no.2
• /
• pp.55-70
• /
• 2005

Objective: Ulmus davidiana Planch (Ulmaceae) has long been known to have anti-inflammnatory in the traditional Korean medicine. UD has been reported as a good enhancer for bone healing. Methods : In this experiment, we investigate the Inhibitory effects of UD on bone resorption using the bone cells culture. Different concentrations of crude extract of UD were added to mouse bone cells culture. The mitochondria activity of the bone cells after exposure was determined by colorimetric MIT assay. It was demonstrated that UD has potential effects on bone cells culture without any cytotoxicity. The most effective concentration of UD on bone cells were $100\;{\mu}g/ml$. Cathepsin K (Cat K) is the major cysteine protease expressed in osteoclasts and is thought to play a key role in matrix degradation during bone resorption. Results : When mouse long bone cells including osteoclasts and osteoblast were treated with the PI3-Kinase inhibitor, wortmannin (WT), WT prevented the osteoclast-mediated intracellular processing of Cat K. Similarly, treatment of osteoclasts-containing long bone cells with UD extracts prevented the intracellular maturation of Cat K, suggesting that UD may disrupt the intracellular trafficking of pro Cat K. This is similar to that of WT. Since secreted proenzymes have the potential to reenter the cell via mannose-6-phosphate (M6P) receptor, to prevent this possibility, we tested WT and UD in the absence or presence of M6P. Inhibition of Cat K processing by WT or UD was observed in a dose-dependent manner. Furthermore, the addition of M6P resulted in enhanced potency of WT and UD. Conclusion : UD dose-dependently inhibited in vitro bone resorption with a potency similar to that observed for inhibition of Cat K processing.