Involvement of Receptor Activator of Nuclear Factor-κB Ligand (RANKL)-induced Incomplete Cytokinesis in the Polyploidization of Osteoclasts.

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Takegahara, Noriko; Kim, Hyunsoo; Mizuno, Hiroki; Sakaue-Sawano, Asako; Miyawaki, Atsushi; Tomura, Michio; Kanagawa, Osami; Ishii, Masaru; Choi, Yongwon

2016-02-12

Osteoclasts are specialized polyploid cells that resorb bone. Upon stimulation with receptor activator of nuclear factor-κB ligand (RANKL), myeloid precursors commit to becoming polyploid, largely via cell fusion. Polyploidization of osteoclasts is necessary for their bone-resorbing activity, but the mechanisms by which polyploidization is controlled remain to be determined. Here, we demonstrated that in addition to cell fusion, incomplete cytokinesis also plays a role in osteoclast polyploidization. In in vitro cultured osteoclasts derived from mice expressing the fluorescent ubiquitin-based cell cycle indicator (Fucci), RANKL induced polyploidy by incomplete cytokinesis as well as cell fusion. Polyploid cells generated by incomplete cytokinesis had the potential to subsequently undergo cell fusion. Nuclear polyploidy was also observed in osteoclasts in vivo, suggesting the involvement of incomplete cytokinesis in physiological polyploidization. Furthermore, RANKL-induced incomplete cytokinesis was reduced by inhibition of Akt, resulting in impaired multinucleated osteoclast formation. Taken together, these results reveal that RANKL-induced incomplete cytokinesis contributes to polyploidization of osteoclasts via Akt activation. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Picrasidine I from Picrasma Quassioides Suppresses Osteoclastogenesis via Inhibition of RANKL Induced Signaling Pathways and Attenuation of ROS Production

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Lingbo Kong

2017-10-01

Full Text Available Background/Aims: Osteoporosis is a metabolic bone disorder that tortures about millions of people worldwide. Recent study demonstrated agents derived from picrasma quassioides is a promising drug for targets multiple signaling pathways. However its potential in treatment of bone loss has not been fully understood. Methods: The bone marrow macrophages (BMMs were cultured and induced with M-CSF and RANKL followed by picrasidine I (PI treatment. Then the effects of PI on osteoclast formation were evaluated by counting tartrate-resistant acid phosphatase (TRAP-positive multinucleated cells. Moreover, effects of PI on bone resorption activity of mature osteoclast were studied through bone resorption pit counting and actin ring structure analysis. Further, the involved potential signaling pathways cross-talking were investigated by performed Western blotting and quantitative real-time PCR examination. Results: Results demonstrated PI strongly inhibited RANKL induced osteoclast formation from its precursors. Mechanistically, the inhibitory effect of PI on osteoclast differentiation was due to the suppression of osteoclastogenic transcription factors, c-Fos and NFATc1. Moreover, PI markedly blocked the RANKL-induced osteoclastogenesis by attenuating MAPKs and NF-κB signaling pathways. In addition, PI decreased the ROS generation in osteoclast and osteoblast. Conclusion: Taken together our data demonstrate that PI has antiosteoclastogenic effect by inhibiting inflammation induced activation of MAPKs, NF-κB and ROS generation followed by suppressing the gene expression of c-Fos and NFATc1 in osteoclast precursors.

Low-magnitude high-frequency vibration inhibits RANKL-induced osteoclast differentiation of RAW264.7 cells.

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Wu, Song-Hui; Zhong, Zhao-Ming; Chen, Jian-Ting

2012-01-01

Osteoclasts are the key participants in regulation of bone mass. Low-magnitude high-frequency vibration (LMHFV) has been found to be anabolic to bone in vivo. This study aimed to investigate the effect of LMHFV on osteoclast differentiation in vitro. Murine monocyte cell line RAW264.7 cells in the presence of receptor activator of nuclear factor-kappaB ligand (RANKL) were treated with or without LMHFV at 45 Hz (0.3 g) for 15 min day(-1). Tartrate resistant acid phosphatase (TRAP)-positive multinucleated cells (MNCs) and actin ring formation were evaluated. Expression of the osteoclast-specific genes, such as cathepsin K, matrix metallopeptidase-9 (MMP-9) and TRAP, were analyzed using real time-PCR. c-Fos, an osteoclast-specific transcription factor, was determined using Western blot. We found that LMHFV significantly decreased the number of RANKL-induced TRAP-positive MNCs (P<0.01), and inhibited the actin ring formation. The mRNA expression of the cathepsin K, MMP-9 and TRAP were down-regulated by LMHFV intervention (all P<0.001). Furthermore, LMHFV also inhibited the expression of c-Fos protein in the RANKL-treated RAW264.7 cells (P<0.05). Our results suggest that LMHFV can inhibit the RANKL-induced osteoclast differentiation of RAW264.7 cells, which give some new insight into the anabolic effects of LMHFV on bone.

Niclosamide suppresses RANKL-induced osteoclastogenesis and prevents LPS-induced bone loss

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Cheon, Yoon-Hee [Center for Metabolic Function Regulation, Wonkwang University School of Medicine, Iksan, Jeonbuk 570-749 (Korea, Republic of); Kim, Ju-Young [Imaging Science-based Lung and Bone Diseases Research Center, Wonkwang University School of Medicine, Iksan, Jeonbuk 570-749 (Korea, Republic of); Baek, Jong Min; Ahn, Sung-Jun [Department of Anatomy, School of Medicine, Wonkwang University School of Medicine, Iksan, Jeonbuk 570-749 (Korea, Republic of); So, Hong-Seob, E-mail: jeanso@wku.ac.kr [Center for Metabolic Function Regulation, Wonkwang University School of Medicine, Iksan, Jeonbuk 570-749 (Korea, Republic of); Oh, Jaemin, E-mail: jmoh@wku.ac.kr [Imaging Science-based Lung and Bone Diseases Research Center, Wonkwang University School of Medicine, Iksan, Jeonbuk 570-749 (Korea, Republic of); Department of Anatomy, School of Medicine, Wonkwang University School of Medicine, Iksan, Jeonbuk 570-749 (Korea, Republic of); Institute for Skeletal Disease, Wonkwang University School of Medicine, Iksan, Jeonbuk 570-749 (Korea, Republic of)

2016-02-05

Niclosamide (5-chloro-salicyl-(2-chloro-4-nitro) anilide) is an oral anthelmintic drug used for treating intestinal infection of most tapeworms. Recently, niclosamide was shown to have considerable efficacy against some tumor cell lines, including colorectal, prostate, and breast cancers, and acute myelogenous leukemia. Specifically, the drug was identified as a potent inhibitor of signal transducer and activator of transcription 3 (STAT3), which is associated with osteoclast differentiation and function. In this study, we assessed the effect of niclosamide on osteoclastogenesis in vitro and in vivo. Our in vitro study showed that receptor activator of nuclear factor-kappaB ligand (RANKL)-induced osteoclast differentiation was inhibited by niclosamide, due to inhibition of serine–threonine protein kinase (Akt) phosphorylation, inhibitor of nuclear factor-kappaB (IκB), and STAT3 serine{sup 727}. Niclosamide decreased the expression of the major transcription factors c-Fos and NFATc1, and thereafter abrogated the mRNA expression of osteoclast-specific genes, including TRAP, OSCAR, αv/β3 integrin (integrin αv, integrin β3), and cathepsin K (CtsK). In an in vivo model, niclosamide prevented lipopolysaccharide-induced bone loss by diminishing osteoclast activity. Taken together, our results show that niclosamide is effective in suppressing osteoclastogenesis and may be considered as a new and safe therapeutic candidate for the clinical treatment of osteoclast-related diseases such as osteoporosis. - Highlights: • We first investigated the anti-osteoclastogenic effects of niclosamide in vitro and in vivo. • Niclosamide impairs the activation of the Akt-IκB-STAT3 ser{sup 727} signaling axis. • Niclosamide acts a negative regulator of actin ring formation during osteoclast differentiation. • Niclosamide suppresses LPS-induced bone loss in vivo. • Niclosamide deserves new evaluation as a potential treatment target in various bone diseases.

Estrogen inhibits RANKL-stimulated osteoclastic differentiation of human monocytes through estrogen and RANKL-regulated interaction of estrogen receptor-α with BCAR1 and Traf6

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Robinson, Lisa J.; Yaroslavskiy, Beatrice B.; Griswold, Reed D.; Zadorozny, Eva V.; Guo, Lida; Tourkova, Irina L.; Blair, Harry C.

2009-01-01

The effects of estrogen on osteoclast survival and differentiation were studied using CD14-selected mononuclear osteoclast precursors from peripheral blood. Estradiol at ∼ 1 nM reduced RANKL-dependent osteoclast differentiation by 40-50%. Osteoclast differentiation was suppressed 14 days after addition of RANKL even when estradiol was withdrawn after 18 h. In CD14+ cells apoptosis was rare and was not augmented by RANKL or by 17-β-estradiol. Estrogen receptor-α (ERα) expression was strongly down-regulated by RANKL, whether or not estradiol was present. Mature human osteoclasts thus cannot respond to estrogen via ERα. However, ERα was present in CD14+ osteoclast progenitors, and a scaffolding protein, BCAR1, which binds ERα in the presence of estrogen, was abundant. Immunoprecipitation showed rapid (∼ 5 min) estrogen-dependent formation of ERα-BCAR1 complexes, which were increased by RANKL co-treatment. The RANKL-signaling intermediate Traf6, which regulates NF-κB activity, precipitated with this complex. Reduction of NF-κB nuclear localization occurred within 30 min of RANKL stimulation, and estradiol inhibited the phosphorylation of IκB in response to RANKL. Inhibition by estradiol was abolished by siRNA knockdown of BCAR1. We conclude that estrogen directly, but only partially, curtails human osteoclast formation. This effect requires BCAR1 and involves a non-genomic interaction with ERα.

Estrogen inhibits RANKL-stimulated osteoclastic differentiation of human monocytes through estrogen and RANKL-regulated interaction of estrogen receptor-{alpha} with BCAR1 and Traf6

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Robinson, Lisa J., E-mail: robinsonlj@msx.upmc.edu [Department of Pathology, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Yaroslavskiy, Beatrice B.; Griswold, Reed D.; Zadorozny, Eva V.; Guo, Lida; Tourkova, Irina L. [Department of Pathology, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Blair, Harry C. [Department of Pathology, University of Pittsburgh, Pittsburgh, PA 15261 (United States); Veteran' s Affairs Medical Center, Pittsburgh, PA 15243 (United States)

2009-04-15

The effects of estrogen on osteoclast survival and differentiation were studied using CD14-selected mononuclear osteoclast precursors from peripheral blood. Estradiol at {approx} 1 nM reduced RANKL-dependent osteoclast differentiation by 40-50%. Osteoclast differentiation was suppressed 14 days after addition of RANKL even when estradiol was withdrawn after 18 h. In CD14+ cells apoptosis was rare and was not augmented by RANKL or by 17-{beta}-estradiol. Estrogen receptor-{alpha} (ER{alpha}) expression was strongly down-regulated by RANKL, whether or not estradiol was present. Mature human osteoclasts thus cannot respond to estrogen via ER{alpha}. However, ER{alpha} was present in CD14+ osteoclast progenitors, and a scaffolding protein, BCAR1, which binds ER{alpha} in the presence of estrogen, was abundant. Immunoprecipitation showed rapid ({approx} 5 min) estrogen-dependent formation of ER{alpha}-BCAR1 complexes, which were increased by RANKL co-treatment. The RANKL-signaling intermediate Traf6, which regulates NF-{kappa}B activity, precipitated with this complex. Reduction of NF-{kappa}B nuclear localization occurred within 30 min of RANKL stimulation, and estradiol inhibited the phosphorylation of I{kappa}B in response to RANKL. Inhibition by estradiol was abolished by siRNA knockdown of BCAR1. We conclude that estrogen directly, but only partially, curtails human osteoclast formation. This effect requires BCAR1 and involves a non-genomic interaction with ER{alpha}.

Echinocystic acid inhibits RANKL-induced osteoclastogenesis by regulating NF-κB and ERK signaling pathways

Energy Technology Data Exchange (ETDEWEB)

Yang, Jian-hui, E-mail: jianhui_yangxa@163.com [Rehabilitation Center, First Affiliated Hospital of Health Science Center, Xi’an Jiaotong University, Xi’an, 710061, Shaanxi Province (China); Li, Bing [Department of Dermatology, the 451st Hospital of People’s Liberation Army, Xi’an 710054, Shaanxi Province (China); Wu, Qiong; Lv, Jian-guo; Nie, Hui-Yong [Rehabilitation Center, First Affiliated Hospital of Health Science Center, Xi’an Jiaotong University, Xi’an, 710061, Shaanxi Province (China)

2016-09-02

Receptor activator of nuclear factor-κB ligand (RANKL) is a key factor in the differentiation and activation of osteoclasts. Echinocystic acid (EA), a pentacyclic triterpene isolated from the fruits of Gleditsia sinensis Lam, was reported to prevent reduction of bone mass and strength and improve the cancellous bone structure and biochemical properties in ovariectomy rats. However, the molecular mechanism of EA on the osteoclast formation has not been reported. The purpose of this study was to investigate the effects and mechanism of EA on RANKL-induced osteoclastogenesis. Our results showed that EA inhibited the formation of osteoclast, as well as the expression of osteoclastogenesis-related marker proteins in bone marrow macrophages (BMMs). At molecular levels, EA inhibited RANKL-induced NF-κB activation and ERK phosphorylation in BMMs. In conclusion, the present study demonstrated that EA can suppress osteoclastogenesis in vitro. Moreover, we clarified that these inhibitory effects of EA occur through suppression of NF-κB and ERK activation. Therefore, EA may be a potential agent in the treatment of osteoclast-related diseases such as osteoporosis. - Highlights: • EA inhibited the formation of osteoclast in BMMs. • EA inhibits the expression of osteoclastogenesis-related marker proteins in BMMs. • EA inhibits RANKL-induced NF-κB activation in BMMs. • EA inhibits RANKL-induced ERK phosphorylation in BMMs.

Fucoidan, a Sulfated Polysaccharide, Inhibits Osteoclast Differentiation and Function by Modulating RANKL Signaling

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Young Woo Kim

2014-10-01

Full Text Available Multinucleated osteoclasts differentiate from hematopoietic progenitors of the monocyte/macrophage lineage. Because of its pivotal role in bone resorption, regulation of osteoclast differentiation is a potential therapeutic approach to the treatment of erosive bone disease. In this study, we have found that fucoidan, a sulfated polysaccharide extracted from brown seaweed, inhibited osteoclast differentiation. In particular, addition of fucoidan into the early stage osteoclast cultures significantly inhibited receptor activator of nuclear factor kappa B (NF-κB ligand (RANKL-induced osteoclast formation, thus suggesting that fucoidan affects osteoclast progenitors. Furthermore, fucoidan significantly inhibited the activation of RANKL-dependent mitogen-activated protein kinases (MAPKs such as JNK, ERK, and p38, and also c-Fos and NFATc1, which are crucial transcription factors for osteoclastogenesis. In addition, the activation of NF-κB, which is an upstream transcription factor modulating NFATc1 expression, was alleviated in the fucoidan-treated cells. These results collectively suggest that fucoidan inhibits osteoclastogenesis from bone marrow macrophages by inhibiting RANKL-induced p38, JNK, ERK and NF-κB activation, and by downregulating the expression of genes that partake in both osteoclast differentiation and resorption.

Andrographolide Inhibits Ovariectomy-Induced Bone Loss via the Suppression of RANKL Signaling Pathways

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Wang, Tao; Liu, Qian; Zhou, Lin; Yuan, Jin Bo; Lin, Xixi; Zeng, Rong; Liang, Xiaonan; Zhao, Jinmin; Xu, Jiake

2015-01-01

Osteoporosis is a debilitating skeletal disorder with an increased risk of low-energy fracture, which commonly occurs among postmenopausal women. Andrographolide (AP), a natural product isolated from Andrographis paniculata, has been found to have anti-inflammatory, anti-cancer, anti-asthmatic, and neuro-protective properties. However, its therapeutic effect on osteoporosis is unknown. In this study, an ovariectomy (OVX) mouse model was used to evaluate the therapeutic effects of AP on post-menopausal osteoporosis by using micro-computed tomography (micro-CT). Bone marrow-derived osteoclast culture was used to examine the inhibitory effect of AP on osteoclastogenesis. Real time PCR was employed to examine the effect of AP on the expression of osteoclast marker genes. The activities of transcriptional factors NF-κB and NFATc1 were evaluated using a luciferase reporter assay, and the IκBα protein level was analyzed by Western blot. We found that OVX mice treated with AP have greater bone volume (BV/TV), trabecular thickness (Tb.Th), and trabecular number (Tb.N) compared to vehicle-treated OVX mice. AP inhibited RANKL-induced osteoclastogenesis, the expression of osteoclast marker genes including cathepsin K (Ctsk), TRACP (Acp5), and NFATc1, as well as the transcriptional activities of NF-κB and NFATc1. In conclusion, our results suggest that AP inhibits estrogen deficiency-induced bone loss in mice via the suppression of RANKL-induced osteoclastogensis and NF-κB and NFATc1 activities and, thus, might have therapeutic potential for osteoporosis. PMID:26593901

Andrographolide Inhibits Ovariectomy-Induced Bone Loss via the Suppression of RANKL Signaling Pathways.

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Wang, Tao; Liu, Qian; Zhou, Lin; Yuan, Jin Bo; Lin, Xixi; Zeng, Rong; Liang, Xiaonan; Zhao, Jinmin; Xu, Jiake

2015-11-17

Osteoporosis is a debilitating skeletal disorder with an increased risk of low-energy fracture, which commonly occurs among postmenopausal women. Andrographolide (AP), a natural product isolated from Andrographis paniculata, has been found to have anti-inflammatory, anti-cancer, anti-asthmatic, and neuro-protective properties. However, its therapeutic effect on osteoporosis is unknown. In this study, an ovariectomy (OVX) mouse model was used to evaluate the therapeutic effects of AP on post-menopausal osteoporosis by using micro-computed tomography (micro-CT). Bone marrow-derived osteoclast culture was used to examine the inhibitory effect of AP on osteoclastogenesis. Real time PCR was employed to examine the effect of AP on the expression of osteoclast marker genes. The activities of transcriptional factors NF-κB and NFATc1 were evaluated using a luciferase reporter assay, and the IκBα protein level was analyzed by Western blot. We found that OVX mice treated with AP have greater bone volume (BV/TV), trabecular thickness (Tb.Th), and trabecular number (Tb.N) compared to vehicle-treated OVX mice. AP inhibited RANKL-induced osteoclastogenesis, the expression of osteoclast marker genes including cathepsin K (Ctsk), TRACP (Acp5), and NFATc1, as well as the transcriptional activities of NF-κB and NFATc1. In conclusion, our results suggest that AP inhibits estrogen deficiency-induced bone loss in mice via the suppression of RANKL-induced osteoclastogensis and NF-κB and NFATc1 activities and, thus, might have therapeutic potential for osteoporosis.

Andrographolide Inhibits Ovariectomy-Induced Bone Loss via the Suppression of RANKL Signaling Pathways

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Tao Wang

2015-11-01

Full Text Available Osteoporosis is a debilitating skeletal disorder with an increased risk of low-energy fracture, which commonly occurs among postmenopausal women. Andrographolide (AP, a natural product isolated from Andrographis paniculata, has been found to have anti-inflammatory, anti-cancer, anti-asthmatic, and neuro-protective properties. However, its therapeutic effect on osteoporosis is unknown. In this study, an ovariectomy (OVX mouse model was used to evaluate the therapeutic effects of AP on post-menopausal osteoporosis by using micro-computed tomography (micro-CT. Bone marrow-derived osteoclast culture was used to examine the inhibitory effect of AP on osteoclastogenesis. Real time PCR was employed to examine the effect of AP on the expression of osteoclast marker genes. The activities of transcriptional factors NF-κB and NFATc1 were evaluated using a luciferase reporter assay, and the IκBα protein level was analyzed by Western blot. We found that OVX mice treated with AP have greater bone volume (BV/TV, trabecular thickness (Tb.Th, and trabecular number (Tb.N compared to vehicle-treated OVX mice. AP inhibited RANKL-induced osteoclastogenesis, the expression of osteoclast marker genes including cathepsin K (Ctsk, TRACP (Acp5, and NFATc1, as well as the transcriptional activities of NF-κB and NFATc1. In conclusion, our results suggest that AP inhibits estrogen deficiency-induced bone loss in mice via the suppression of RANKL-induced osteoclastogensis and NF-κB and NFATc1 activities and, thus, might have therapeutic potential for osteoporosis.

Arctigenin inhibits osteoclast differentiation and function by suppressing both calcineurin-dependent and osteoblastic cell-dependent NFATc1 pathways.

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Yamashita, Teruhito; Uehara, Shunsuke; Udagawa, Nobuyuki; Li, Feng; Kadota, Shigetoshi; Esumi, Hiroyasu; Kobayashi, Yasuhiro; Takahashi, Naoyuki

2014-01-01

Arctigenin, a lignan-derived compound, is a constituent of the seeds of Arctium lappa. Arctigenin was previously shown to inhibit osteoclastogenesis; however, this inhibitory mechanism has yet to be elucidated. Here, we showed that arctigenin inhibited the action of nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), a key transcription factor for osteoclastogenesis. NFATc1 in osteoclast precursors was activated through two distinct pathways: the calcineurin-dependent and osteoblastic cell-dependent pathways. Among the several lignan-derived compounds examined, arctigenin most strongly inhibited receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclast-like cell formation in mouse bone marrow macrophage (BMM) cultures, in which the calcineurin-dependent NFATc1 pathway was activated. Arctigenin suppressed neither the activation of nuclear factor κB and mitogen-activated protein kinases nor the up-regulation of c-Fos expression in BMMs treated with RANKL. However, arctigenin suppressed RANKL-induced NFATc1 expression. Interestingly, the treatment of osteoclast-like cells with arctigenin converted NFATc1 into a lower molecular weight species, which was translocated into the nucleus even in the absence of RANKL. Nevertheless, arctigenin as well as cyclosporin A (CsA), a calcineurin inhibitor, suppressed the NFAT-luciferase reporter activity induced by ionomycin and phorbol 12-myristate 13-acetate in BMMs. Chromatin immunoprecipitation analysis confirmed that arctigenin inhibited the recruitment of NFATc1 to the promoter region of the NFATc1 target gene. Arctigenin, but not CsA suppressed osteoclast-like cell formation in co-cultures of osteoblastic cells and bone marrow cells, in which the osteoblastic cell-dependent NFATc1 pathway was activated. The forced expression of constitutively active NFATc1 rescued osteoclastogenesis in BMM cultures treated with CsA, but not that treated with arctigenin. Arctigenin also suppressed the pit

Arctigenin Inhibits Osteoclast Differentiation and Function by Suppressing Both Calcineurin-Dependent and Osteoblastic Cell-Dependent NFATc1 Pathways

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Yamashita, Teruhito; Uehara, Shunsuke; Udagawa, Nobuyuki; Li, Feng; Kadota, Shigetoshi; Esumi, Hiroyasu; Kobayashi, Yasuhiro; Takahashi, Naoyuki

2014-01-01

Arctigenin, a lignan-derived compound, is a constituent of the seeds of Arctium lappa. Arctigenin was previously shown to inhibit osteoclastogenesis; however, this inhibitory mechanism has yet to be elucidated. Here, we showed that arctigenin inhibited the action of nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), a key transcription factor for osteoclastogenesis. NFATc1 in osteoclast precursors was activated through two distinct pathways: the calcineurin-dependent and osteoblastic cell-dependent pathways. Among the several lignan-derived compounds examined, arctigenin most strongly inhibited receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclast-like cell formation in mouse bone marrow macrophage (BMM) cultures, in which the calcineurin-dependent NFATc1 pathway was activated. Arctigenin suppressed neither the activation of nuclear factor κB and mitogen-activated protein kinases nor the up-regulation of c-Fos expression in BMMs treated with RANKL. However, arctigenin suppressed RANKL-induced NFATc1 expression. Interestingly, the treatment of osteoclast-like cells with arctigenin converted NFATc1 into a lower molecular weight species, which was translocated into the nucleus even in the absence of RANKL. Nevertheless, arctigenin as well as cyclosporin A (CsA), a calcineurin inhibitor, suppressed the NFAT-luciferase reporter activity induced by ionomycin and phorbol 12-myristate 13-acetate in BMMs. Chromatin immunoprecipitation analysis confirmed that arctigenin inhibited the recruitment of NFATc1 to the promoter region of the NFATc1 target gene. Arctigenin, but not CsA suppressed osteoclast-like cell formation in co-cultures of osteoblastic cells and bone marrow cells, in which the osteoblastic cell-dependent NFATc1 pathway was activated. The forced expression of constitutively active NFATc1 rescued osteoclastogenesis in BMM cultures treated with CsA, but not that treated with arctigenin. Arctigenin also suppressed the pit

Arctigenin inhibits osteoclast differentiation and function by suppressing both calcineurin-dependent and osteoblastic cell-dependent NFATc1 pathways.

Directory of Open Access Journals (Sweden)

Teruhito Yamashita

Full Text Available Arctigenin, a lignan-derived compound, is a constituent of the seeds of Arctium lappa. Arctigenin was previously shown to inhibit osteoclastogenesis; however, this inhibitory mechanism has yet to be elucidated. Here, we showed that arctigenin inhibited the action of nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1, a key transcription factor for osteoclastogenesis. NFATc1 in osteoclast precursors was activated through two distinct pathways: the calcineurin-dependent and osteoblastic cell-dependent pathways. Among the several lignan-derived compounds examined, arctigenin most strongly inhibited receptor activator of nuclear factor κB ligand (RANKL-induced osteoclast-like cell formation in mouse bone marrow macrophage (BMM cultures, in which the calcineurin-dependent NFATc1 pathway was activated. Arctigenin suppressed neither the activation of nuclear factor κB and mitogen-activated protein kinases nor the up-regulation of c-Fos expression in BMMs treated with RANKL. However, arctigenin suppressed RANKL-induced NFATc1 expression. Interestingly, the treatment of osteoclast-like cells with arctigenin converted NFATc1 into a lower molecular weight species, which was translocated into the nucleus even in the absence of RANKL. Nevertheless, arctigenin as well as cyclosporin A (CsA, a calcineurin inhibitor, suppressed the NFAT-luciferase reporter activity induced by ionomycin and phorbol 12-myristate 13-acetate in BMMs. Chromatin immunoprecipitation analysis confirmed that arctigenin inhibited the recruitment of NFATc1 to the promoter region of the NFATc1 target gene. Arctigenin, but not CsA suppressed osteoclast-like cell formation in co-cultures of osteoblastic cells and bone marrow cells, in which the osteoblastic cell-dependent NFATc1 pathway was activated. The forced expression of constitutively active NFATc1 rescued osteoclastogenesis in BMM cultures treated with CsA, but not that treated with arctigenin. Arctigenin also suppressed the

Monosodium Urate in the Presence of RANKL Promotes Osteoclast Formation through Activation of c-Jun N-Terminal Kinase

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Jung-Yoon Choe

2015-01-01

Full Text Available The aim of this study was to clarify the role of monosodium urate (MSU crystals in receptor activator of nuclear factor kB ligand- (RANKL- RANK-induced osteoclast formation. RAW 264.7 murine macrophage cells were incubated with MSU crystals or RANKL and differentiated into osteoclast-like cells as confirmed by staining for tartrate-resistant acid phosphatase (TRAP and actin ring, pit formation assay, and TRAP activity assay. MSU crystals in the presence of RANKL augmented osteoclast differentiation, with enhanced mRNA expression of NFATc1, cathepsin K, carbonic anhydrase II, and matrix metalloproteinase-9 (MMP-9, in comparison to RAW 264.7 macrophages incubated in the presence of RANKL alone. Treatment with both MSU crystals and RANKL induced osteoclast differentiation by activating downstream molecules in the RANKL-RANK pathway including tumor necrosis factor receptor-associated factor 6 (TRAF-6, JNK, c-Jun, and NFATc1. IL-1b produced in response to treatment with both MSU and RANKL is involved in osteoclast differentiation in part through the induction of TRAF-6 downstream of the IL-1b pathway. This study revealed that MSU crystals contribute to enhanced osteoclast formation through activation of RANKL-mediated pathways and recruitment of IL-1b. These findings suggest that MSU crystals might be a pathologic causative agent of bone destruction in gout.

Bropirimine inhibits osteoclast differentiation through production of interferon-β

International Nuclear Information System (INIS)

Suzuki, Hiroaki; Mochizuki, Ayako; Yoshimura, Kentaro; Miyamoto, Yoichi; Kaneko, Kotaro; Inoue, Tomio; Chikazu, Daichi; Takami, Masamichi; Kamijo, Ryutaro

2015-01-01

Bropirimine is a synthetic agonist for toll-like receptor 7 (TLR7). In this study, we investigated the effects of bropirimine on differentiation and bone-resorbing activity of osteoclasts in vitro. Bropirimine inhibited osteoclast differentiation of mouse bone marrow-derived macrophages (BMMs) induced by receptor activator of nuclear factor κB ligand (RANKL) in a concentration-dependent manner. Furthermore, it suppressed the mRNA expression of nuclear factor of activated T-cells, cytoplasmic, calcineurin-dependent 1 (NFATc1), a master transcription factor for osteoclast differentiation, without affecting BMM viability. Bropirimine also inhibited osteoclast differentiation induced in co-cultures of mouse bone marrow cells (BMCs) and mouse osteoblastic UAMS-32 cells in the presence of activated vitamin D_3. Bropirimine partially suppressed the expression of RANKL mRNA in UAMS-32 cells induced by activated vitamin D_3. Finally, the anti-interferon-β (IFN-β) antibody restored RANKL-dependent differentiation of BMMs into osteoclasts suppressed by bropirimine. These results suggest that bropirimine inhibits differentiation of osteoclast precursor cells into osteoclasts via TLR7-mediated production of IFN-β.

Bropirimine inhibits osteoclast differentiation through production of interferon-β

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Suzuki, Hiroaki [Department of Biochemistry, Showa University School of Dentistry, Tokyo 142-8555 (Japan); Mochizuki, Ayako [Department of Oral Physiology, Showa University School of Dentistry, Tokyo 142-8555 (Japan); Yoshimura, Kentaro; Miyamoto, Yoichi [Department of Biochemistry, Showa University School of Dentistry, Tokyo 142-8555 (Japan); Kaneko, Kotaro [Department of Biochemistry, Showa University School of Dentistry, Tokyo 142-8555 (Japan); Department of Oral and Maxillofacial Surgery, Tokyo Medical University, Tokyo 160-0023 (Japan); Inoue, Tomio [Department of Oral Physiology, Showa University School of Dentistry, Tokyo 142-8555 (Japan); Chikazu, Daichi [Department of Oral and Maxillofacial Surgery, Tokyo Medical University, Tokyo 160-0023 (Japan); Takami, Masamichi [Department of Pharmacology, Showa University School of Dentistry, Tokyo 142-8555 (Japan); Kamijo, Ryutaro, E-mail: kamijor@dent.showa-u.ac.jp [Department of Biochemistry, Showa University School of Dentistry, Tokyo 142-8555 (Japan)

2015-11-06

Bropirimine is a synthetic agonist for toll-like receptor 7 (TLR7). In this study, we investigated the effects of bropirimine on differentiation and bone-resorbing activity of osteoclasts in vitro. Bropirimine inhibited osteoclast differentiation of mouse bone marrow-derived macrophages (BMMs) induced by receptor activator of nuclear factor κB ligand (RANKL) in a concentration-dependent manner. Furthermore, it suppressed the mRNA expression of nuclear factor of activated T-cells, cytoplasmic, calcineurin-dependent 1 (NFATc1), a master transcription factor for osteoclast differentiation, without affecting BMM viability. Bropirimine also inhibited osteoclast differentiation induced in co-cultures of mouse bone marrow cells (BMCs) and mouse osteoblastic UAMS-32 cells in the presence of activated vitamin D{sub 3}. Bropirimine partially suppressed the expression of RANKL mRNA in UAMS-32 cells induced by activated vitamin D{sub 3}. Finally, the anti-interferon-β (IFN-β) antibody restored RANKL-dependent differentiation of BMMs into osteoclasts suppressed by bropirimine. These results suggest that bropirimine inhibits differentiation of osteoclast precursor cells into osteoclasts via TLR7-mediated production of IFN-β.

Effects of interleukin-7/interleukin-7 receptor on RANKL-mediated osteoclast differentiation and ovariectomy-induced bone loss by regulating c-Fos/c-Jun pathway.

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Zhao, Ji-Jun; Wu, Zhao-Feng; Yu, Ying-Hao; Wang, Ling; Cheng, Li

2018-09-01

To explore the effects of IL-7/IL-7R on the RANKL-mediated osteoclast differentiation in vitro and OVX-induced bone loss in vivo. BMMs and RAW264.7 were transfected with IL-7, IL-7R siRNA, c-Fos siRNA, and c-jun siRNA and later stimulated by RANKL. TRAP and toluidine blue staining were used to observe osteoclast formation and bone resorption, respectively. HE and TRAP staining were used to detect trabecular bone microstructure and osteoclasts of mice, respectively. qRT-PCR and Western blot analysis were used to examine expression. IL-7 unregulated the expression of CTSK, NFATc1, MMP9, and the phosphorylation of p38 and Akt by activating the c-Fos/c-Jun pathway, which increased osteoclast numbers and bone resorption in RANKL-stimulated macrophages. While IL-7R siRNA and c-Fos siRNA decreased the expression, as well as and the phosphorylation of p38 and Akt.IL-7 decreased the BMD and OPG expression in OVX-induced mice and increased the TRAP positive cells, the mRNA expression of c-fos, c-jun, and RANKL, which was contradictory to IL-7R siRNA, and c-Fos siRNA. Furthermore, IL-7R siRNA and c-Fos siRNA caused thicker trabeculae, increased trabecular number, and decreased osteolysis in OVX mice. IL-7/IL-7R can promote RANKL-mediated osteoclast formation and bone resorption by activating the c-Fos/c-Jun pathway, as well as inducing bone loss in OVX mice. © 2018 Wiley Periodicals, Inc.

Attenuated RANKL-induced cytotoxicity by Portulaca oleracea ethanol extract enhances RANKL-mediated osteoclastogenesis.

Science.gov (United States)

Erkhembaatar, Munkhsoyol; Choi, Eun-Joo; Lee, Hak-Yong; Lee, Choong Hun; Lee, Young-Rae; Kim, Min Seuk

2015-07-14

Portulaca oleracea (PO) has been widely used as traditional medicine because of its pharmacological activities. However, the effects of PO on osteoclasts that modulate bone homeostasis are still elusive. In this study, we examined the effects of PO ethanol extract (POEE) on receptor activator of nuclear factor-κB ligand (RANKL)-mediated Ca(2+) mobilization, nuclear factor of activated T-cell c1 (NFATc1) amplification, tartrate-resistant acid phosphatase-positive (TRAP+) multinucleated cell (MNC) formation, and cytotoxicity. Our results demonstrated that POEE suppressed RANKL-induced Ca(2+) oscillations by inhibition of Ca(2+) release from internal Ca(2+) stores, resulting in reduction of NFATc1 amplification. Notably, POEE attenuated RANKL-mediated cytotoxicity and cleavage of polyadenosine 5'-diphosphate-ribose polymerase (PARP), resulted in enhanced formation of TRAP+ MNCs. These results present in vitro effects of POEE on RANKL-mediated osteoclastogenesis and suggest the possible use of PO in treating bone disorders, such as osteopetrosis.

The plant limonoid 7-oxo-deacetoxygedunin inhibits RANKL-induced osteoclastogenesis by suppressing activation of the NF-{kappa}B and MAPK pathways

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Wisutsitthiwong, Chonnaree; Buranaruk, Chayanit [Graduate Program in Industrial Microbiology, Department of Microbiology, Faculty of Science, Chulalongkorn University, Phayathai Road, Bangkok 10330 (Thailand); Pudhom, Khanitha [Department of Chemistry, Faculty of Science and Center for Petroleum, Petrochemicals and Advanced Materials, Chulalongkorn University, Phayathai Road, Bangkok 10330 (Thailand); Palaga, Tanapat, E-mail: tanapat.p@chula.ac.th [Graduate Program in Industrial Microbiology, Department of Microbiology, Faculty of Science, Chulalongkorn University, Phayathai Road, Bangkok 10330 (Thailand)

2011-11-18

Highlights: Black-Right-Pointing-Pointer A gedunin type limonoid from seeds of mangroves, 7-oxo-7-deacetoxygedunin, exhibits strong anti-osteoclastogenic activity. Black-Right-Pointing-Pointer Treatment with this limonoid results in significant decrease in expression of NFATc1 and osteoclast-related genes. Black-Right-Pointing-Pointer The mode of action of this limonoid is by inhibiting activation of the NF-{kappa}B and MAPK pathways which are activated by RANKL. -- Abstract: Osteoclasts together with osteoblasts play pivotal roles in bone remodeling. Aberrations in osteoclast differentiation and activity contribute to osteopenic disease. Osteoclasts differentiate from monocyte/macrophage progenitors, a process that is initiated by the interaction between receptor activator of NF-{kappa}B (RANK) and its ligand, RANKL. In this study, we identified 7-oxo-7-deacetoxygedunin (7-OG), a gedunin type limonoid from seeds of the mangrove Xylocarpus moluccensis, as a potent inhibitor of osteoclastogenesis. Additionally, 7-OG showed strong anti-osteoclastogenic activity with low cytotoxicity against the monocyte/macrophage progenitor cell line, RAW264.7. The IC50 for anti-osteoclastogenic activity was 4.14 {mu}M. Treatment with 7-OG completely abolished the appearance of multinucleated giant cells with tartrate-resistant acid phosphatase activity in RAW264.7 cells stimulated with RANKL. When the expression of genes related to osteoclastogenesis was investigated, a complete downregulation of NFATc1 and cathepsin K and a delayed downregulation of irf8 were observed upon 7-OG treatment in the presence of RANKL. Furthermore, treatment with this limonoid suppressed RANKL-induced activation of p38, MAPK and Erk and nuclear localization of NF-{kappa}B p65. Taken together, we present evidence indicating a plant limonoid as a novel osteoclastogenic inhibitor that could be used for osteoporosis and related conditions.

The plant limonoid 7-oxo-deacetoxygedunin inhibits RANKL-induced osteoclastogenesis by suppressing activation of the NF-κB and MAPK pathways

International Nuclear Information System (INIS)

Wisutsitthiwong, Chonnaree; Buranaruk, Chayanit; Pudhom, Khanitha; Palaga, Tanapat

2011-01-01

Highlights: ► A gedunin type limonoid from seeds of mangroves, 7-oxo-7-deacetoxygedunin, exhibits strong anti-osteoclastogenic activity. ► Treatment with this limonoid results in significant decrease in expression of NFATc1 and osteoclast-related genes. ► The mode of action of this limonoid is by inhibiting activation of the NF-κB and MAPK pathways which are activated by RANKL. -- Abstract: Osteoclasts together with osteoblasts play pivotal roles in bone remodeling. Aberrations in osteoclast differentiation and activity contribute to osteopenic disease. Osteoclasts differentiate from monocyte/macrophage progenitors, a process that is initiated by the interaction between receptor activator of NF-κB (RANK) and its ligand, RANKL. In this study, we identified 7-oxo-7-deacetoxygedunin (7-OG), a gedunin type limonoid from seeds of the mangrove Xylocarpus moluccensis, as a potent inhibitor of osteoclastogenesis. Additionally, 7-OG showed strong anti-osteoclastogenic activity with low cytotoxicity against the monocyte/macrophage progenitor cell line, RAW264.7. The IC50 for anti-osteoclastogenic activity was 4.14 μM. Treatment with 7-OG completely abolished the appearance of multinucleated giant cells with tartrate-resistant acid phosphatase activity in RAW264.7 cells stimulated with RANKL. When the expression of genes related to osteoclastogenesis was investigated, a complete downregulation of NFATc1 and cathepsin K and a delayed downregulation of irf8 were observed upon 7-OG treatment in the presence of RANKL. Furthermore, treatment with this limonoid suppressed RANKL-induced activation of p38, MAPK and Erk and nuclear localization of NF-κB p65. Taken together, we present evidence indicating a plant limonoid as a novel osteoclastogenic inhibitor that could be used for osteoporosis and related conditions.

Dioscin inhibits osteoclast differentiation and bone resorption though down-regulating the Akt signaling cascades

International Nuclear Information System (INIS)

Qu, Xinhua; Zhai, Zanjing; Liu, Xuqiang; Li, Haowei; Ouyang, Zhengxiao; Wu, Chuanlong; Liu, Guangwang; Fan, Qiming; Tang, Tingting; Qin, An; Dai, Kerong

2014-01-01

Highlights: •A natural-derived compound, dioscin, suppresses osteoclast formation and bone resorption. •Dioscin inhibits osteolytic bone loss in vivo. •Dioscin impairs the Akt signaling cascades pathways during osteoclastogenesis. •Dioscin have therapeutic value in treating osteoclast-related diseases. -- Abstract: Bone resorption is the unique function of osteoclasts (OCs) and is critical for both bone homeostasis and pathologic bone diseases including osteoporosis, rheumatoid arthritis and tumor bone metastasis. Thus, searching for natural compounds that may suppress osteoclast formation and/or function is promising for the treatment of osteoclast-related diseases. In this study, we for the first time demonstrated that dioscin suppressed RANKL-mediated osteoclast differentiation and bone resorption in vitro in a dose-dependent manner. The suppressive effect of dioscin is supported by the reduced expression of osteoclast-specific markers. Further molecular analysis revealed that dioscin abrogated AKT phosphorylation, which subsequently impaired RANKL-induced nuclear factor-kappaB (NF-κB) signaling pathway and inhibited NFATc1 transcriptional activity. Moreover, in vivo studies further verified the bone protection activity of dioscin in osteolytic animal model. Together our data demonstrate that dioscin suppressed RANKL-induced osteoclast formation and function through Akt signaling cascades. Therefore, dioscin is a potential natural agent for the treatment of osteoclast-related diseases

Dioscin inhibits osteoclast differentiation and bone resorption though down-regulating the Akt signaling cascades

Energy Technology Data Exchange (ETDEWEB)

Qu, Xinhua; Zhai, Zanjing; Liu, Xuqiang; Li, Haowei [Shanghai Key Laboratory of Orthopaedic Implants, Department of Orthopaedics, Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai (China); Ouyang, Zhengxiao [Shanghai Key Laboratory of Orthopaedic Implants, Department of Orthopaedics, Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai (China); Department of Orthopaedics, Hunan Provincial Tumor Hospital and Tumor Hospital of Xiangya School of Medicine, Central South University, Changsha (China); Wu, Chuanlong [Shanghai Key Laboratory of Orthopaedic Implants, Department of Orthopaedics, Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai (China); Liu, Guangwang [Department of Orthopaedic Surgery, The Central Hospital of Xuzhou, Affiliated Hospital of Medical Collage of Southeast University, Xuzhou (China); Fan, Qiming; Tang, Tingting [Shanghai Key Laboratory of Orthopaedic Implants, Department of Orthopaedics, Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai (China); Qin, An, E-mail: dr.qinan@gmail.com [Shanghai Key Laboratory of Orthopaedic Implants, Department of Orthopaedics, Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai (China); Dai, Kerong, E-mail: krdai@163.com [Shanghai Key Laboratory of Orthopaedic Implants, Department of Orthopaedics, Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai (China)

2014-01-10

Highlights: •A natural-derived compound, dioscin, suppresses osteoclast formation and bone resorption. •Dioscin inhibits osteolytic bone loss in vivo. •Dioscin impairs the Akt signaling cascades pathways during osteoclastogenesis. •Dioscin have therapeutic value in treating osteoclast-related diseases. -- Abstract: Bone resorption is the unique function of osteoclasts (OCs) and is critical for both bone homeostasis and pathologic bone diseases including osteoporosis, rheumatoid arthritis and tumor bone metastasis. Thus, searching for natural compounds that may suppress osteoclast formation and/or function is promising for the treatment of osteoclast-related diseases. In this study, we for the first time demonstrated that dioscin suppressed RANKL-mediated osteoclast differentiation and bone resorption in vitro in a dose-dependent manner. The suppressive effect of dioscin is supported by the reduced expression of osteoclast-specific markers. Further molecular analysis revealed that dioscin abrogated AKT phosphorylation, which subsequently impaired RANKL-induced nuclear factor-kappaB (NF-κB) signaling pathway and inhibited NFATc1 transcriptional activity. Moreover, in vivo studies further verified the bone protection activity of dioscin in osteolytic animal model. Together our data demonstrate that dioscin suppressed RANKL-induced osteoclast formation and function through Akt signaling cascades. Therefore, dioscin is a potential natural agent for the treatment of osteoclast-related diseases.

Safflower bud inhibits RANKL-induced osteoclast differentiation and prevents bone loss in ovariectomized mice.

Science.gov (United States)

Choi, Joo-Hee; Lim, Seul-Ki; Kim, Dong-Il; Park, Min-Jung; Kim, Young-Kuk; Lee, An-Chul; Kim, Young-Min; Yang, Soo-Jin; Park, Jong-Hwan

2017-10-15

The powder and extract of safflower seeds are known to be effective in the prevention of bone loss in ovariectomized animals. However, the inhibitory effect and molecular mechanisms of safflower bud (SB), the germinated safflower, on bone destruction is unclear. The present study was designed to investigate the inhibitory effect and molecular mechanism of SB on osteoclastic differentiation and on bone loss in ovarietomized (OVX) mice. Osteoclastogenesis was determined by TRAP staining, F-actin ring formation, and bone resorption assay. NF-κB and MAPKs activation was analyzed by transfection assay and Western blot, respectively. Real-time PCR was performed to examine the expression of osteoclastogenesis-related genes. Histological changes, increases in TRAP-positive cells, and cathepsin K expression were examined in the metaphysis of OVX mice. Density of bone marrow was evaluated by µCT. SB inhibited the RANKL-induced differentiation of BMDMs into osteoclasts in a dose-dependent manner. F-actin ring formation and bone resorption were also reduced by SB in RANKL-treated BMDMs. In addition, SB decreased the activation of NF-κB and MAPKs and the expression of osteoclastogenesis-related genes in BMDMs treated with RANKL. Feeding of SB-included diet prevented bone loss in OVX mice. The number of TRAP-positive cells and level of protein expression of cathepsin K was reduced and bone mineral density was increased in the metaphysis of mice fed SB compared with OVX mice. These findings suggest that SB can be a preventive and therapeutic candidate for destructive bone diseases. Copyright © 2017. Published by Elsevier GmbH.

Ebselen Is a Potential Anti-Osteoporosis Agent by Suppressing Receptor Activator of Nuclear Factor Kappa-B Ligand-Induced Osteoclast Differentiation In vitro and Lipopolysaccharide-Induced Inflammatory Bone Destruction In vivo.

Science.gov (United States)

Baek, Jong Min; Kim, Ju-Young; Yoon, Kwon-Ha; Oh, Jaemin; Lee, Myeung Su

2016-01-01

Ebselen is a non-toxic seleno-organic drug with anti-inflammatory and antioxidant properties that is currently being examined in clinical trials to prevent and treat various diseases, including atherosclerosis, stroke, and cancer. However, no reports are available for verifying the pharmacological effects of ebselen on major metabolic bone diseases such as osteoporosis. In this study, we observed that ebselen suppressed the formation of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells in an osteoblast/osteoclast co-culture by regulating the ratio of receptor activator of nuclear factor kappa-B ligand (RANKL)/osteoprotegerin secreted by osteoblasts. In addition, ebselen treatment in the early stage of osteoclast differentiation inhibited RANKL-dependent osteoclastogenesis by decreasing the phosphorylation of IκB, PI3K, and Akt in early signaling pathways and by subsequently inducing c-Fos and nuclear factor of activated T-cells c1. Further, ebselen induced apoptosis of osteoclasts in the late stage of osteoclast differentiation. In addition, ebselen treatment suppressed filamentous actin ring formation and bone resorption activity of mature osteoclasts. Reflecting these in vitro effects, administration of ebselen recovered bone loss and its µ-CT parameters in lipopolysaccharide-mediated mouse model. Histological analysis confirmed that ebselen prevented trabecular bone matrix degradation and osteoclast formation in the bone tissues. Finally, it was proved that the anti-osteoclastogenic action of ebselen is achieved through targeting N-methyl-D-aspartate (NMDA) receptor. These results indicate that ebselen is a potentially safe drug for treating metabolic bone diseases such as osteoporosis.

Fisetin antagonizes cell fusion, cytoskeletal organization and bone resorption in RANKL-differentiated murine macrophages.

Science.gov (United States)

Kim, Yun-Ho; Kim, Jung-Lye; Lee, Eun-Jung; Park, Sin-Hye; Han, Seon-Young; Kang, Soon Ah; Kang, Young-Hee

2014-03-01

Osteoclastogenesis is comprised of several stage s including progenitor survival, differentiation to mononuclear preosteoclasts, cell fusion to multinuclear mature osteoclasts, and activation to osteoclasts with bone resorbing activity. Botanical antioxidants are now being increasingly investigated for their health-promoting effects on bone. This study investigated that fisetin, a flavonol found naturally in many fruits and vegetables, suppressed osteoclastogenesis by disturbing receptor activator of nuclear factor (NF)-κB ligand (RANKL)-mediated signaling pathway and demoting osteoclastogenic protein induction. Nontoxic fisetin at ≤10 μM inhibited the induction of RANK, tumor necrosis factor receptor associated factor 6 (TRAF6) and the activation of NF-κB in RANKL-stimulated RAW 264.7 macrophages. In RANKL-differentiated osteoclasts cell fusion protein of E-cadherin was induced, which was dampened by fisetin. The formation of tartrate-resistance acid phosphatase-positive multinucleated osteoclasts was suppressed by adding fisetin to RANKL-exposed macrophages. It was also found that fisetin reduced actin ring formation and gelsolin induction of osteclasts enhanced by RANKL through disturbing c-Src-proline-rich tyrosine kinase 2 signaling. Fisetin deterred preosteoclasts from the cell-cell fusion and the organization of the cytoskeleton to seal the resorbing area and to secret protons for bone resorption. Consistently, the 5 day-treatment of fisetin diminished RANKL-induced cellular expression of carbonic anhydrase II and integrin β3 concurrently with a reduction of osteoclast bone-resorbing activity. Therefore, fisetin was a natural therapeutic agent retarding osteoclast fusion and cytoskeletal organization such as actin rings and ruffled boarder, which is a property of mature osteoclasts and is required for osteoclasts to resorb bone. Copyright © 2014 Elsevier Inc. All rights reserved.

Water extract of Acer tegmentosum reduces bone destruction by inhibiting osteoclast differentiation and function.

Science.gov (United States)

Ha, Hyunil; Shim, Ki-Shuk; Kim, Taesoo; An, Hyosun; Lee, Chung-Jo; Lee, Kwang Jin; Ma, Jin Yeul

2014-04-01

The stem of Acer tegmentosum has been widely used in Korea for the treatment of hepatic disorders. In this study, we investigated the bone protective effect of water extract of the stem of Acer tegmentosum (WEAT). We found that WEAT inhibits osteoclast differentiation induced by receptor activator of nuclear factor-κB ligand (RANKL), an essential cytokine for osteoclast differentiation. In osteoclast precursor cells, WEAT inhibited RANKL-induced activation of JNK, NF-κB, and cAMP response element-binding protein, leading to suppression of the induction of c-Fos and nuclear factor of activated T cells cytoplasmic 1, key transcription factors for osteoclast differentiation. In addition, WEAT inhibited bone resorbing activity of mature osteoclasts. Furthermore, the oral administration of WEAT reduced RANKL-induced bone resorption and trabecular bone loss in mice. Taken together, our study demonstrates that WEAT possesses a protective effect on bone destruction by inhibiting osteoclast differentiation and function.

RANKL signaling and osteoclastogenesis is negatively regulated by cardamonin.

Directory of Open Access Journals (Sweden)

Bokyung Sung

Full Text Available Bone loss/resorption or osteoporosis is a disease that is accelerated with aging and age-associated chronic diseases such as cancer. Bone loss has been linked with human multiple myeloma, breast cancer, and prostate cancer and is usually treated with bisphosphonates, and recently approved denosumab, an antibody against receptor activator of NF-κB ligand (RANKL. Because of the numerous side effects of the currently available drugs, the search continues for safe and effective therapies for bone loss. RANKL, a member of the TNF superfamily, has emerged as a major mediator of bone loss via activation of osteoclastogenesis. We have identified cardamonin, a chalcone isolated from Alpinia katsumadai Hayata that can affect osteoclastogenesis through modulation of RANKL. We found that treatment of monocytes with cardamonin suppressed RANKL-induced NF-κB activation and this suppression correlated with inhibition of IκBα kinase and of phosphorylation and degradation of IκBα, an inhibitor of NF-κB. Furthermore, cardamonin also downregulated RANKL-induced phosphorylation of MAPK including ERK and p38 MAPK. Cardamonin suppressed the RANKL-induced differentiation of monocytes to osteoclasts in a dose-dependent and time-dependent manner. We also found that an inhibitor of NF-κB essential modulator (NEMO blocked RANKL-induced osteoclastogenesis, indicating a direct link with NF-κB. Finally, osteoclastogenesis induced by human breast cancer cells or human multiple myeloma cells were completely suppressed by cardamonin. Collectively, our results indicate that cardamonin suppresses osteoclastogenesis induced by RANKL and tumor cells by suppressing activation of the NF-κB and MAPK pathway.

Salicortin inhibits osteoclast differentiation and bone resorption by down-regulating JNK and NF-κB/NFATc1 signaling pathways

Energy Technology Data Exchange (ETDEWEB)

Nie, Shaobo [Department of Orthopaedics, PLA General Hospital, Beijing 100853 (China); Xu, Jiawei [Department of Orthopaedics, Shanghai Ninth People' s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011 (China); Zhang, Chenghua [Department of Orthopaedics, Changle County Hospital of Traditional Chinese Medicine, Weifang 262400 (China); Xu, Chen [Department of Orthopaedics, Shanghai Ninth People' s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011 (China); Liu, Ming, E-mail: ming_li4717@sina.com [Department of Orthopaedics, Shanghai Ninth People' s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011 (China); Yu, Degang, E-mail: ydg163@126.com [Department of Orthopaedics, Shanghai Ninth People' s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011 (China)

2016-01-29

Receptor activator of nuclear factor (NF)-κB ligand (RANKL)-activated signaling is essential for osteoclast differentiation, activation, and survival. Salicortin is a phenolic glycoside that has been isolated from many plants such as Populus and Salix species, and has been shown to have anti-amnesic and anti-adipogenic effects. In this study, we investigated the effect of salicortin on RANKL-induced osteoclasts formation, bone resorption, and activation of osteoclast-related signaling pathways. Salicortin suppressed RANKL-induced osteoclastogenesis in bone marrow macrophage cultures in a dose-dependent manner, and inhibited osteoclastic bone resorption activity without any cytotoxicity. Salicortin inhibited RANKL-induced c-Jun N-terminal kinase and NF-κB activation, concomitant with retarded IκBα phosphorylation and inhibition of p65 nuclear translocation, leading to impaired transcription of nuclear factor of activated T cells c1 (NFATc1) and expression of osteoclastic-specific genes. Taken together, our findings demonstrate that salicortin inhibits NF-κB and NFATc1 activation, leading to attenuation of osteoclastogenesis and bone resorption. Thus, salicortin may be of interest in developments of treatment for osteoclast related diseases. - Highlights: • Salicortin suppresses osteoclastogenesis in vitro. • Salicortin impairs the JNK and NF-κB/NFATc1 signaling pathway. • Salicortin may be of interest in developments of osteoporosis treatment.

Salicortin inhibits osteoclast differentiation and bone resorption by down-regulating JNK and NF-κB/NFATc1 signaling pathways

International Nuclear Information System (INIS)

Nie, Shaobo; Xu, Jiawei; Zhang, Chenghua; Xu, Chen; Liu, Ming; Yu, Degang

2016-01-01

Receptor activator of nuclear factor (NF)-κB ligand (RANKL)-activated signaling is essential for osteoclast differentiation, activation, and survival. Salicortin is a phenolic glycoside that has been isolated from many plants such as Populus and Salix species, and has been shown to have anti-amnesic and anti-adipogenic effects. In this study, we investigated the effect of salicortin on RANKL-induced osteoclasts formation, bone resorption, and activation of osteoclast-related signaling pathways. Salicortin suppressed RANKL-induced osteoclastogenesis in bone marrow macrophage cultures in a dose-dependent manner, and inhibited osteoclastic bone resorption activity without any cytotoxicity. Salicortin inhibited RANKL-induced c-Jun N-terminal kinase and NF-κB activation, concomitant with retarded IκBα phosphorylation and inhibition of p65 nuclear translocation, leading to impaired transcription of nuclear factor of activated T cells c1 (NFATc1) and expression of osteoclastic-specific genes. Taken together, our findings demonstrate that salicortin inhibits NF-κB and NFATc1 activation, leading to attenuation of osteoclastogenesis and bone resorption. Thus, salicortin may be of interest in developments of treatment for osteoclast related diseases. - Highlights: • Salicortin suppresses osteoclastogenesis in vitro. • Salicortin impairs the JNK and NF-κB/NFATc1 signaling pathway. • Salicortin may be of interest in developments of osteoporosis treatment.

TRAF family member-associated NF-κB activator (TANK) induced by RANKL negatively regulates osteoclasts survival and function.

Science.gov (United States)

Wu, Mengrui; Wang, Yiping; Deng, Lianfu; Chen, Wei; Li, Yi-Ping

2012-01-01

Osteoclasts are the principle bone-resorbing cells. Precise control of balanced osteoclast activity is indispensable for bone homeostasis. Osteoclast activation mediated by RANK-TRAF6 axis has been clearly identified. However, a negative regulation-machinery in osteoclast remains unclear. TRAF family member-associated NF-κB activator (TANK) is induced by about 10 folds during osteoclastogenesis, according to a genome-wide analysis of gene expression before and after osteoclast maturation, and confirmed by western blot and quantitative RT-PCR. Bone marrow macrophages (BMMs) transduced with lentivirus carrying tank-shRNA were induced to form osteoclast in the presence of RANKL and M-CSF. Tank expression was downregulated by 90% by Tank-shRNA, which is confirmed by western blot. Compared with wild-type (WT) cells, osteoclastogenesis of Tank-silenced BMMs was increased, according to tartrate-resistant acid phosphatase (TRAP) stain on day 5 and day 7. Number of bone resorption pits by Tank-silenced osteoclasts was increased by 176% compared with WT cells, as shown by wheat germ agglutinin (WGA) stain and scanning electronic microscope (SEM) analysis. Survival rate of Tank-silenced mature osteoclast is also increased. However, acid production of Tank-knockdown cells was not changed compared with control cells. IκBα phosphorylation is increased in tank-silenced cells, indicating that TANK may negatively regulate NF-κB activity in osteoclast. In conclusion, Tank, whose expression is increased during osteoclastogenesis, inhibits osteoclast formation, activity and survival, by regulating NF-κB activity and c-FLIP expression. Tank enrolls itself in a negative feedback loop in bone resorption. These results may provide means for therapeutic intervention in diseases of excessive bone resorption.

Inhibition of matrix metalloproteinase-9 activity by doxycycline ameliorates RANK ligand-induced osteoclast differentiation in vitro and in vivo

International Nuclear Information System (INIS)

Franco, Gilson C.N.; Kajiya, Mikihito; Nakanishi, Tadashi; Ohta, Kouji; Rosalen, Pedro L.; Groppo, Francisco C.; Ernst, Cory W.O.; Boyesen, Janie L.; Bartlett, John D.; Stashenko, Philip; Taubman, Martin A.; Kawai, Toshihisa

2011-01-01

Tetracycline antibiotics, including doxycycli/e (DOX), have been used to treat bone resorptive diseases, partially because of their activity to suppress osteoclastogenesis induced by receptor activator of nuclear factor kappa B ligand (RANKL). However, their precise inhibitory mechanism remains unclear. Therefore, the present study examined the effect of Dox on osteoclastogenesis signaling induced by RANKL, both in vitro and in vivo. Although Dox inhibited RANKL-induced osteoclastogenesis and down-modulated the mRNA expression of functional osteoclast markers, including tartrate-resistant acid phosphatase (TRAP) and cathepsin K, Dox neither affected RANKL-induced MAPKs phosphorylation nor NFATc1 gene expression in RAW264.7 murine monocytic cells. Gelatin zymography and Western blot analyses showed that Dox down-regulated the enzyme activity of RANKL-induced MMP-9, but without affecting its protein expression. Furthermore, MMP-9 enzyme inhibitor also attenuated both RANKL-induced osteoclastogenesis and up-regulation of TRAP and cathepsin K mRNA expression, indicating that MMP-9 enzyme action is engaged in the promotion of RANKL-induced osteoclastogenesis. Finally, Dox treatment abrogated RANKL-induced osteoclastogenesis and TRAP activity in mouse calvaria along with the suppression of MMP9 enzyme activity, again without affecting the expression of MMP9 protein. These findings suggested that Dox inhibits RANKL-induced osteoclastogenesis by its inhibitory effect on MMP-9 enzyme activity independent of the MAPK-NFATc1 signaling cascade.

Inhibition of matrix metalloproteinase-9 activity by doxycycline ameliorates RANK ligand-induced osteoclast differentiation in vitro and in vivo

Energy Technology Data Exchange (ETDEWEB)

Franco, Gilson C.N. [Department of Immunology, Forsyth Institute, Cambridge, MA (United States); Department of Pharmacology, FOP/UNICAMP, Piracicaba, SP (Brazil); Kajiya, Mikihito [Department of Immunology, Forsyth Institute, Cambridge, MA (United States); Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA (United States); Nakanishi, Tadashi [Department of Immunology, Forsyth Institute, Cambridge, MA (United States); Ohta, Kouji [Department of Immunology, Forsyth Institute, Cambridge, MA (United States); Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA (United States); Rosalen, Pedro L.; Groppo, Francisco C. [Department of Pharmacology, FOP/UNICAMP, Piracicaba, SP (Brazil); Ernst, Cory W.O.; Boyesen, Janie L. [Department of Immunology, Forsyth Institute, Cambridge, MA (United States); Bartlett, John D.; Stashenko, Philip [Department of Cytokine Biology, Forsyth Institute, Cambridge, MA (United States); Taubman, Martin A. [Department of Immunology, Forsyth Institute, Cambridge, MA (United States); Kawai, Toshihisa, E-mail: tkawai@forsyth.org [Department of Immunology, Forsyth Institute, Cambridge, MA (United States); Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA (United States)

2011-06-10

Tetracycline antibiotics, including doxycycli/e (DOX), have been used to treat bone resorptive diseases, partially because of their activity to suppress osteoclastogenesis induced by receptor activator of nuclear factor kappa B ligand (RANKL). However, their precise inhibitory mechanism remains unclear. Therefore, the present study examined the effect of Dox on osteoclastogenesis signaling induced by RANKL, both in vitro and in vivo. Although Dox inhibited RANKL-induced osteoclastogenesis and down-modulated the mRNA expression of functional osteoclast markers, including tartrate-resistant acid phosphatase (TRAP) and cathepsin K, Dox neither affected RANKL-induced MAPKs phosphorylation nor NFATc1 gene expression in RAW264.7 murine monocytic cells. Gelatin zymography and Western blot analyses showed that Dox down-regulated the enzyme activity of RANKL-induced MMP-9, but without affecting its protein expression. Furthermore, MMP-9 enzyme inhibitor also attenuated both RANKL-induced osteoclastogenesis and up-regulation of TRAP and cathepsin K mRNA expression, indicating that MMP-9 enzyme action is engaged in the promotion of RANKL-induced osteoclastogenesis. Finally, Dox treatment abrogated RANKL-induced osteoclastogenesis and TRAP activity in mouse calvaria along with the suppression of MMP9 enzyme activity, again without affecting the expression of MMP9 protein. These findings suggested that Dox inhibits RANKL-induced osteoclastogenesis by its inhibitory effect on MMP-9 enzyme activity independent of the MAPK-NFATc1 signaling cascade.

Melittin inhibits osteoclast formation through the downregulation of the RANKL-RANK signaling pathway and the inhibition of interleukin-1β in murine macrophages.

Science.gov (United States)

Choe, Jung-Yoon; Kim, Seong-Kyu

2017-03-01

Melittin is a major toxic component of bee venom (Apis mellifera). It is not known whether melittin is involved in bone metabolism and osteoclastogenesis. The aim of this study was to determine the role of melittin in the regulation of osteoclastogenesis. In vitro osteoclastogenesis assays were performed using mouse RAW 264.7 cells and bone marrow-derived macrophages (BMMs) treated with receptor activator of nuclear factor-κB ligand (RANKL) and macrophage colony-stimulating factor (M-CSF). Morphologic and functional analyses for osteoclast-like multinucleated cells (MNCs) were performed by tartrate-resistant acid phosphatase (TRAP) staining, F-actin staining and pit formation methods. The gene expression of TRAP, cathepsin K, matrix metalloproteinase-9 (MMP-9) and carbonic anhydrase II was measured by reverse transcription-quantitative PCR. The protein expression levels of mitogen-activated protein kinases (MAPKs), the p65 subunit of nuclear factor-κB (NF-κB), c-Fos, c-Jun, nuclear factor of activated T cells, cytoplasmic 1 (NFATc1), TNF receptor-associated factor-6 (TRAF6), and interleukin-1β (IL-1β) were assessed by western blot analysis. Melittin inhibited the mRNA expression of TRAP, cathepsin K, MMP-9 and carbonic anhydrase II in RANKL-stimulated RAW 264.7 cells. The increased protein expression of TRAF6, p-extracellular signal-regulated kinase (ERK), p-JNK, p-p65, p-c-Fos and NFATc1 induced by RANKL was significantly suppressed in the RAW 264.7 cells treated with melittin. A synergistic effect of IL-1β on the formation of RANKL-induced osteoclast-like MNCs was found in two experimental cells. The increased expression of IL-1β following the stimulation of RAW 264.7 cells with RANKL activated TRAF6, p-ERK, p-JNK, p-p65, p-c-Fos and NFATc1. These effects were attenuated by the downregulation of IL-1β using siRNA against IL-1β, and also by treatment with melittin. On the whole, the findings of this study demonstrate that melittin

(-)-Epigallocatechin gallate inhibition of osteoclastic differentiation via NF-κB

International Nuclear Information System (INIS)

Lin, R.-W.; Chen, C.-H.; Wang, Y.-H.; Ho, M.-L.; Hung, S.-H.; Chen, I.-S.; Wang, G.-J.

2009-01-01

People who regularly drink tea have been found to have a higher bone mineral density (BMD) and to be at less risk of hip fractures than those who do not drink it. Green tea catechins such as (-)-epigallocatechin gallate (EGCG) have been reported to increase osteogenic functioning in mesenchymal stem cells. However, its effect on osteoclastogenesis remains unclear. In this study, we investigated the effect of EGCG on RANKL-activation osteoclastogenesis and NF-κB in RAW 264.7, a murine preosteoclast cell line. EGCG (10-100 μM) significantly suppressed the RANKL-induced differentiation of osteoclasts and the formation of pits in murine RAW 264.7 cells and bone marrow macrophages (BMMs). EGCG appeared to target osteoclastic differentiation at an early stage but had no cytotoxic effect on osteoclast precursors. In addition, it significantly inhibited RANKL-induced NF-κB transcriptional activity and nuclear translocation. We conclude that EGCG inhibits osteoclastogenesis through its activation of NF-κB.

Glechoma hederacea Suppresses RANKL-mediated Osteoclastogenesis.

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Hwang, J K; Erkhembaatar, M; Gu, D R; Lee, S H; Lee, C H; Shin, D M; Lee, Y R; Kim, M S

2014-07-01

Glechoma hederacea (GH), commonly known as ground-ivy or gill-over-the-ground, has been extensively used in folk remedies for relieving symptoms of inflammatory disorders. However, the molecular mechanisms underlying the therapeutic action of GH are poorly understood. Here, we demonstrate that GH constituents inhibit osteoclastogenesis by abrogating receptor activator of nuclear κ-B ligand (RANKL)-induced free cytosolic Ca(2+) ([Ca(2+)]i) oscillations. To evaluate the effect of GH on osteoclastogenesis, we assessed the formation of multi-nucleated cells (MNCs), enzymatic activity of tartrate-resistant acidic phosphatase (TRAP), expression of nuclear factor of activated T-cells cytoplasmic 1 (NFATc1), and [Ca(2+)]i alterations in response to treatment with GH ethanol extract (GHE) in primarily cultured bone marrow-derived macrophages (BMMs). Treatment of RANKL-stimulated or non-stimulated BMMs with GHE markedly suppressed MNC formation, TRAP activity, and NFATc1 expression in a dose-dependent manner. Additionally, GHE treatment induced a large transient elevation in [Ca(2+)]i while suppressing RANKL-induced [Ca(2+)]i oscillations, which are essential for NFATc1 activation. GHE-evoked increase in [Ca(2+)]i was dependent on extracellular Ca(2+) and was inhibited by 1,4-dihydropyridine (DHP), inhibitor of voltage-gated Ca(2+) channels (VGCCs), but was independent of store-operated Ca(2+) channels. Notably, after transient [Ca(2+)] elevation, treatment with GHE desensitized the VGCCs, resulting in an abrogation of RANKL-induced [Ca(2+)]i oscillations and MNC formation. These findings demonstrate that treatment of BMMs with GHE suppresses RANKL-mediated osteoclastogenesis by activating and then desensitizing DHP-sensitive VGCCs, suggesting potential applications of GH in the treatment of bone disorders, such as periodontitis, osteoporosis, and rheumatoid arthritis. © International & American Associations for Dental Research.

A specific subtype of osteoclasts secretes factors inducing nodule formation by osteoblasts

DEFF Research Database (Denmark)

Henriksen, Kim; Andreassen, Kim V; Thudium, Christian S

2012-01-01

Osteoclasts are known to be important for the coupling process between bone resorption and formation. The aim of this study was to address when osteoclasts are anabolically active. Human monocytes were differentiated into mature osteoclasts by treatment with M-CSF and RANKL. Conditioned medium wa...... dependent and independent of their resorptive activity, secrete factors stimulating osteoblastic bone formation.......Osteoclasts are known to be important for the coupling process between bone resorption and formation. The aim of this study was to address when osteoclasts are anabolically active. Human monocytes were differentiated into mature osteoclasts by treatment with M-CSF and RANKL. Conditioned medium...... release. The osteoblastic cell line 2T3 was treated with 50% of CM or non-CM for 12days. Bone formation was assessed by Alizarin Red extraction. CM from mature osteoclasts induced bone formation, while CM from macrophages did not. Non-resorbing osteoclasts generated from osteopetrosis patients showed...

Isoproterenol Increases RANKL Expression in a ATF4/NFATc1-Dependent Manner in Mouse Osteoblastic Cells

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Kyunghwa Baek

2017-10-01

Full Text Available Sympathetic nervous system stimulation-induced β-adrenergic signal transduction is known to induce bone loss and increase of osteoclast activity. Although isoproterenol, a nonspecific β-adrenergic receptor agonist, has been shown to increase receptor activator of NF-κB ligand (RANKL, the details of the regulatory mechanisms remain unclear. In the present study, we investigated the role of the nuclear factor of activated T-cells (NFAT in isoproterenol-induced RANKL expression in C2C12 and in primary cultured mouse calvarial cells. Isoproterenol increased nuclear factor of activated T-cells cytoplasmic 1 (NFATc1 and RANKL expressions at both mRNA and protein levels and increased NFAT reporter activity. NFATc1 knockdown blocked isoproterenol-mediated RANKL expression. Isoproterenol also promoted cAMP response element-binding protein 1 (CREB1 and activating transcription factor 4 (ATF4 phosphorylation. Isoproterenol-mediated transcriptional activation of NFAT was blocked by protein kinase A (PKA inhibitor H89. Isoproterenol-induced CREB1, ATF4, NFATc1, and RANKL expressions were suppressed by H89. Mutations in cAMP response element-like or NFAT-binding element suppressed isoproterenol-induced RANKL promoter activity. Chromatin immunoprecipitation analysis demonstrated that isoproterenol increased NFAT-binding and ATF4-binding activities on the mouse RANKL promoter, but did not increase CREB1-binding activity. Association of NFATc1 and ATF4 was not observed in a co-immunoprecipitation study. ATF4 knockdown suppressed isoproterenol-induced NFAT binding to the RANKL promoter, whereas NFATc1 knockdown did not suppress isoproterenol-induced ATF4 binding to the RANKL promoter. ATF4 knockdown suppressed isoproterenol-induced expressions of NFATc1 and RANKL. These results suggest that isoproterenol increases RANKL expression in an ATF4/NFATc1-dependent manner.

The polymethoxy flavonoid sudachitin suppresses inflammatory bone destruction by directly inhibiting osteoclastogenesis due to reduced ROS production and MAPK activation in osteoclast precursors.

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Yoko Ohyama

Full Text Available Inflammatory bone diseases, including rheumatoid arthritis, periodontitis and peri-implantitis, are associated not only with the production of inflammatory cytokines but also with local oxidative status, which is defined by intracellular reactive oxygen species (ROS. Osteoclast differentiation has been reported to be related to increased intracellular ROS levels in osteoclast lineage cells. Sudachitin, which is a polymethoxyflavone derived from Citrus sudachi, possesses antioxidant properties and regulates various functions in mammalian cells. However, the effects of sudachitin on inflammatory bone destruction and osteoclastogenesis remain unknown. In calvaria inflamed by a local lipopolysaccharide (LPS injection, inflammation-induced bone destruction and the accompanying elevated expression of osteoclastogenesis-related genes were reduced by the co-administration of sudachitin and LPS. Moreover, sudachitin inhibited osteoclast formation in cultures of isolated osteoblasts and osteoclast precursors. However, sudachitin rather increased the expression of receptor activator of NF-κB ligand (RANKL, which is an important molecule triggering osteoclast differentiation, and the mRNA ratio of RANKL/osteoprotegerin that is a decoy receptor for RANKL, in the isolated osteoblasts, suggesting the presence of additional target cells. When osteoclast formation was induced from osteoclast precursors derived from bone marrow cells in the presence of soluble RANKL and macrophage colony-stimulating factor, sudachitin inhibited osteoclastogenesis without influencing cell viability. Consistently, the expression of osteoclast differentiation-related molecules including c-fos, NFATc1, cathepsin K and osteoclast fusion proteins such as DC-STAMP and Atp6v0d2 was reduced by sudachitin. In addition, sudachitin decreased activation of MAPKs such as Erk and JNK and the ROS production evoked by RANKL in osteoclast lineage cells. Our findings suggest that sudachitin is a

Dasatinib inhibits both osteoclast activation and prostate cancer PC-3-cell-induced osteoclast formation.

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Araujo, John C; Poblenz, Ann; Corn, Paul; Parikh, Nila U; Starbuck, Michael W; Thompson, Jerry T; Lee, Francis; Logothetis, Christopher J; Darnay, Bryant G

2009-11-01

Therapies to target prostate cancer bone metastases have only limited effects. New treatments are focused on the interaction between cancer cells, bone marrow cells and the bone matrix. Osteoclasts play an important role in the development of bone tumors caused by prostate cancer. Since Src kinase has been shown to be necessary for osteoclast function, we hypothesized that dasatinib, a Src family kinase inhibitor, would reduce osteoclast activity and prostate cancer (PC-3) cell-induced osteoclast formation. Dasatinib inhibited RANKL-induced osteoclast differentiation of bone marrow-derived monocytes with an EC(50) of 7.5 nM. PC-3 cells, a human prostate cancer cell line, were able to differentiate RAW 264.7 cells, a murine monocytic cell line, into osteoclasts, and dasatinib inhibited this differentiation. In addition, conditioned medium from PC-3 cell cultures was able to differentiate RAW 264.7 cells into osteoclasts and this too, was inhibited by dasatinib. Even the lowest concentration of dasatinib, 1.25 nmol, inhibited osteoclast differentiation by 29%. Moreover, dasatinib inhibited osteoclast activity by 58% as measured by collagen 1 release. We performed in vitro experiments utilizing the Src family kinase inhibitor dasatinib to target osteoclast activation as a means of inhibiting prostate cancer bone metastases. Dasatinib inhibits osteoclast differentiation of mouse primary bone marrow-derived monocytes and PC-3 cell-induced osteoclast differentiation. Dasatinib also inhibits osteoclast degradation activity. Inhibiting osteoclast differentiation and activity may be an effective targeted therapy in patients with prostate cancer bone metastases.

Effects of Cinnamoyloxy-mammeisin from Geopropolis on Osteoclast Differentiation and Porphyromonas gingivalis-Induced Periodontitis.

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da Cunha, Marcos Guilherme; Ramos-Junior, Erivan Schnaider; Franchin, Marcelo; Taira, Thaise Mayumi; Beutler, John A; Franco, Gilson Cesar Nobre; Ikegaki, Masaharu; de Alencar, Severino Matias; Fukada, Sandra Yasuyo; Rosalen, Pedro Luiz

2017-06-23

Bone-loss-related diseases such as rheumatoid arthritis, osteomyelitis, osteoporosis, and periodontitis are associated with high rates of morbidity worldwide. These disorders are characterized by an imbalance between the formation and activity of osteoblasts and osteoclasts, leading to bone loss. In this context, we evaluated the effect of cinnamoyloxy-mammeisin (CNM), an anti-inflammatory coumarin found in Melipona scutellaris geopropolis, on key targets related to bone remodeling. In the present study we investigated the in vitro effects of CNM on osteoclast differentiation and M-CSF+RANKL-induced osteoclastogenic marker expression. Additionally, the interference of CNM treatment on osteoclast activity was evaluated by zymography and resorption area. Finally, we assessed the capacity of the compound to mitigate alveolar bone loss in vivo in experimental murine periodontitis induced by Porphyromonas gingivalis. We observed that treatment with CNM impaired osteoclast differentiation, as evidenced by a reduced number of tartrate-resistant acid-phosphatase-positive multinucleated cells (TRAP+) as well as the expression of osteoclastogenic markers upon M-CSF+RANKL-induced stimulation. Similarly, we observed reduced gelatinolytic and resorption capacity in M-CSF+RANKL-induced cells in vitro. Lastly, CNM attenuated alveolar bone loss in an experimental murine periodontitis model. These findings indicate that CNM may be considered a promising treatment for bone loss diseases.

Bacterial lipopolysaccharide induces osteoclast formation in RAW 264.7 macrophage cells

International Nuclear Information System (INIS)

Islam, Shamima; Hassan, Ferdaus; Tumurkhuu, Gantsetseg; Dagvadorj, Jargalsaikhan; Koide, Naoki; Naiki, Yoshikazu; Mori, Isamu; Yoshida, Tomoaki; Yokochi, Takashi

2007-01-01

Lipopolysaccharide (LPS) is a potent bone resorbing factor. The effect of LPS on osteoclast formation was examined by using murine RAW 264.7 macrophage cells. LPS-induced the formation of multinucleated giant cells (MGC) in RAW 264.7 cells 3 days after the exposure. MGCs were positive for tartrate-resistant acid phosphatase (TRAP) activity. Further, MGC formed resorption pits on calcium-phosphate thin film that is a substrate for osteoclasts. Therefore, LPS was suggested to induce osteoclast formation in RAW 264.7 cells. LPS-induced osteoclast formation was abolished by anti-tumor necrosis factor (TNF)-α antibody, but not antibodies to macrophage-colony stimulating factor (M-CSF) and receptor activator of nuclear factor (NF)-κB ligand (RANKL). TNF-α might play a critical role in LPS-induced osteoclast formation in RAW 264.7 cells. Inhibitors of NF-κB and stress activated protein kinase (SAPK/JNK) prevented the LPS-induced osteoclast formation. The detailed mechanism of LPS-induced osteoclast formation is discussed

Dasatinib inhibits both osteoclast activation and prostate cancer PC-3 cell-induced osteoclast formation

Science.gov (United States)

Araujo, John C.; Poblenz, Ann; Corn, Paul G.; Parikh, Nila U.; Starbuck, Michael W.; Thompson, Jerry T.; Lee, Francis; Logothetis, Christopher J.; Darnay, Bryant G.

2013-01-01

Purpose Therapies to target prostate cancer bone metastases have only limited effects. New treatments are focused on the interaction between cancer cells, bone marrow cells and the bone matrix. Osteoclasts play an important role in the development of bone tumors caused by prostate cancer. Since Src kinase has been shown to be necessary for osteoclast function, we hypothesized that dasatinib, a Src family kinase inhibitor, would reduce osteoclast activity and prostate cancer (PC-3) cell-induced osteoclast formation. Results Dasatinib inhibited RANKL-induced osteoclast differentiation of bone marrow-derived monocytes with an EC50 of 7.5 nM. PC-3 cells, a human prostate cancer cell line, were able to differentiate RAW 264.7 cells, a murine monocytic cell line, into osteoclasts and dasatinib inhibited this differentiation. In addition, conditioned medium from PC-3 cell cultures was able to differentiate RAW 264.7 cells into osteoclasts and this too, was inhibited by dasatinib. Even the lowest concentration of dasatinib, 1.25 nmol, inhibited osteoclast differentiation by 29%. Moreover, dasatinib inhibited osteoclast activity by 58% as measured by collagen 1 release. Experimental design We performed in vitro experiments utilizing the Src family kinase inhibitor dasatinib to target osteoclast activation as a means of inhibiting prostate cancer bone metastases. Conclusion Dasatinib inhibits osteoclast differentiation of mouse primary bone marrow-derived monocytes and PC-3 cell-induced osteoclast differentiation. Dasatinib also inhibits osteoclast degradation activity. Inhibiting osteoclast differentiation and activity may be an effective targeted therapy in patients with prostate cancer bone metastases. PMID:19855158

Modified salicylanilide and 3-phenyl-2H-benzo[e][1,3]oxazine-2,4(3H)-dione derivatives as novel inhibitors of osteoclast differentiation and bone resorption.

Science.gov (United States)

Chen, Chun-Liang; Liu, Fei-Lan; Lee, Chia-Chung; Chen, Tsung-Chih; Ahmed Ali, Ahmed Atef; Sytwu, Huey-Kang; Chang, Deh-Ming; Huang, Hsu-Shan

2014-10-09

Inhibition of osteoclast formation is a potential strategy to prevent inflammatory bone resorption and to treat bone diseases. In the present work, the purpose was to discover modified salicylanilides and 3-phenyl-2H-benzo[e][1,3]oxazine-2,4(3H)-dione derivatives as potential antiosteoclastogenic agents. Their inhibitory effects on RANKL-induced osteoclastogenesis from RAW264.7 cells were evaluated by TRAP stain assay. The most potent compounds, 1d and 5d, suppressed RANKL-induced osteoclast formation and TRAP activity dose-dependently. The cytotoxicity assay on RAW264.7 cells suggested that the inhibition of osteoclastic bone resorption by these compounds did not result from their cytotoxicity. Moreover, both compounds downregulated RANKL-induced NF-κB and NFATc1 in the nucleus, suppressed the expression of osteoclastogenesis-related marker genes during osteoclastogenesis, and prevented osteoclastic bone resorption but did not impair osteoblast differentiation in MC3T3-E1. Therefore, these modified salicylanilides and 3-phenyl-2H-benzo[e][1,3]oxazine-2,4(3H)-diones could be potential lead compounds for the development of a new class of antiresorptive agents.

Macrolactin F inhibits RANKL-mediated osteoclastogenesis by suppressing Akt, MAPK and NFATc1 pathways and promotes osteoblastogenesis through a BMP-2/smad/Akt/Runx2 signaling pathway.

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Li, Liang; Sapkota, Mahesh; Gao, Ming; Choi, Hyukjae; Soh, Yunjo

2017-11-15

The balance between bone formation and bone resorption is maintained by osteoblasts and osteoclasts. In the current study, macrolactin F (MF) was investigated for novel biological activity on the receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL)-induced osteoclastogenesis in primary bone marrow-derived macrophages (BMMs). We found that RANKL-induced osteoclast formation and differentiation from BMMs was significantly inhibited by MF in a dose-dependent manner without cytotoxicity. RANKL-induced F-actin ring formation and bone resorption activity in BMMs which was attenuated by MF. In addition, MF suppressed the expression of osteoclast-related genes, including c-myc, RANK, tartrate-resistant acid phosphatase (TRAP), nuclear factor of activated T cells c1 (NFATc1), cathepsin K and matrix metalloproteinase 9 (MMP9). Furthermore, the protein expression NFATc1, c-Fos, MMP9, cathepsin K and phosphorylation of Jun N-terminal kinase (JNK), p38 and Akt were also down-regulated by MF treatment. Interestingly, MF promoted pre-osteoblast cell differentiation on Alizarin Red-mineralization activity, alkaline phosphatase (ALP) activity, and the expression of osteoblastogenic markers including Runx2, Osterix, Smad4, ALP, type I collagen alpha 1 (Col1α), osteopontin (OPN), and osteocalcin (OCN) via activation of the BMP-2/smad/Akt/Runx2 pathway on MC3T3-E1. Taken together, these results indicate that MF may be useful as a therapeutic agent to enhance bone health and treat osteoporosis. Copyright © 2017 Elsevier B.V. All rights reserved.

Intercellular Communication between Keratinocytes and Fibroblasts Induces Local Osteoclast Differentiation: a Mechanism Underlying Cholesteatoma-Induced Bone Destruction.

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Iwamoto, Yoriko; Nishikawa, Keizo; Imai, Ryusuke; Furuya, Masayuki; Uenaka, Maki; Ohta, Yumi; Morihana, Tetsuo; Itoi-Ochi, Saori; Penninger, Josef M; Katayama, Ichiro; Inohara, Hidenori; Ishii, Masaru

2016-06-01

Bone homeostasis is maintained by a balance in activity between bone-resorbing osteoclasts and bone-forming osteoblasts. Shifting the balance toward bone resorption causes osteolytic bone diseases such as rheumatoid arthritis and periodontitis. Osteoclast differentiation is regulated by receptor activator of nuclear factor κB ligand (RANKL), which, under some pathological conditions, is produced by T and B lymphocytes and synoviocytes. However, the mechanism underlying bone destruction in other diseases is little understood. Bone destruction caused by cholesteatoma, an epidermal cyst in the middle ear resulting from hyperproliferation of keratinizing squamous epithelium, can lead to lethal complications. In this study, we succeeded in generating a model for cholesteatoma, epidermal cyst-like tissue, which has the potential for inducing osteoclastogenesis in mice. Furthermore, an in vitro coculture system composed of keratinocytes, fibroblasts, and osteoclast precursors was used to demonstrate that keratinocytes stimulate osteoclast differentiation through the induction of RANKL in fibroblasts. Thus, this study demonstrates that intercellular communication between keratinocytes and fibroblasts is involved in the differentiation and function of osteoclasts, which may provide the molecular basis of a new therapeutic strategy for cholesteatoma-induced bone destruction. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Recombinant Human Endostatin Suppresses Mouse Osteoclast Formation by Inhibiting the NF-κB and MAPKs Signaling Pathways

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Non eChen

2016-06-01

Full Text Available Rheumatoid arthritis is an autoimmune disease characterized by synovial hyperplasia and progressive joint destruction. As reported previously, recombinant human endostatin (rhEndostatin is associated with inhibition of joint bone destruction present in rat adjuvant-induced arthritis; however, the effect of rhEndostatin on bone destruction is not known. This study was designed to assess the inhibitory effect and mechanisms of rhEndostatin on formation and function of osteoclasts in vitro, and to gain insight into the mechanism underlying the inhibitory effect of bone destruction. Bone marrow-derived macrophages isolated from BALB/c mice were stimulated with receptor activator of NF-κB ligand (RANKL and macrophage colony-stimulating factor to establish osteoclast formation. Osteoclast formation was determined by TRAP staining. Cell viability of BMMs affected by rhEndostatin was determined using a MTT assay. Bone resorption was examined with a bone resorption pits assay. The expression of osteoclast-specific markers was analyzed using quantitative real-time PCR. The related signaling pathways were examined using a Luciferase reporter assay and western blot analysis. Indeed, rhEndostatin showed a significant reduction in the number of osteoclast-like cells and early-stage bone resorption. Moreover, molecular analysis demonstrated that rhEndostatin attenuated RANKL-induced NF-κB signaling by inhibiting the phosphorylation of IκBα and NF-κB p65 nuclear translocation. Furthermore, rhEndostatin significantly inhibited the activation of RANKL-dependent mitogen-activated protein kinases (MAPKs, such as ERK1/2, JNK, and p38. Hence, we demonstrated for the first time that preventing the formation and function of osteoclasts is an important anti-bone destruction mechanism of rhEndostatin, which might be useful in the prevention and treatment of bone destruction in RA.

RANKL release from self-assembling nanofiber hydrogels for inducing osteoclastogenesis in vitro.

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Xing, James Z; Lu, Lei; Unsworth, Larry D; Major, Paul W; Doschak, Michael R; Kaipatur, Neelambar R

2017-02-01

To develop a nanofiber hydrogel (NF-hydrogel) for sustained and controlled release of the recombinant receptor activator of NF-kB ligand; (RANKL) and to characterize the release kinetics and bioactivity of the released RANKL. Various concentrations of fluorescently-labelled RANKL protein were added to NF-hydrogels, composed of Acetyl-(Arg-Ala-Asp-Ala) 4 -CONH 2 [(RADA) 4 ] of different concentrations, to investigate the resulting in vitro release rates. The nano-structures of NF-hydrogel, with and without RANKL, were determined using atomic force microscopy (AFM). Released RANKL was further analyzed for changes in secondary and tertiary structure using CD spectroscopy and fluorescent emission spectroscopy, respectively. Bioactivity of released RANKL protein was determined using NFATc1 gene expression and tartrate resistant acid phosphatase (TRAP) activity of osteoclast cells as biomarkers. NF-hydrogel concentration dependent sustained release of RANKL protein was measured at concentrations between 0.5 and 2%(w/v). NF-hydrogel at 2%(w/v) concentration exhibited a sustained and slow-release of RANKL protein up to 48h. Secondary and tertiary structure analyses confirmed no changes to the RANKL protein released from NF-hydrogel in comparison to native RANKL. The results of NFATc1 gene mRNA expression and TRAP activities of osteoclast, showed that the release process did not affect the bioactivity of released RANKL. This novel study is the first of its kind to attempt in vitro characterization of NF-hydrogel based delivery of RANKL protein to induce osteoclastogenesis. We have shown the self-assembling NF-hydrogel peptide system is amenable to the sustained and controlled release of RANKL locally; that could in turn increase local concentration of RANKL to induce osteoclastogenesis, for application to the controlled mobilization of tooth movement in orthodontic procedures. Orthodontic tooth movement (OTM) occurs through controlled application of light forces to teeth

Interleukin-4 inhibits RANKL-induced expression of NFATc1 and c-Fos: A possible mechanism for downregulation of osteoclastogenesis

International Nuclear Information System (INIS)

Kamel Mohamed, Saad Gad; Sugiyama, Eiji; Shinoda, Kouichiro; Hounoki, Hiroyuki; Taki, Hirofumi; Maruyama, Muneharu; Miyahara, Tatsuro; Kobayashi, Masashi

2005-01-01

Interleukin-4 (IL-4), an anti-inflammatory cytokine, has been shown to inhibit osteoclast differentiation. Therefore, this cytokine is considered to be a promising therapeutic applicant for bone-resorbing diseases such as rheumatoid arthritis (RA). Recently NFATc1, a transcription factor, has been shown to play critical roles in osteoclastogenesis. The aim of this study was to clarify the role of IL-4 on the intracellular signaling of NFATc1. A RAW264.7 monocyte/macrophage cell line and murine bone marrow precursors were differentiated into osteoclasts in the presence of receptor activator of nuclear factor κB ligand (RANKL) and/or macrophage colony-stimulating factor. Tartrate-resistant acid phosphatase (TRAP) staining and a pit assay using dentine were used for the identification of activated osteoclasts. The protein expression of IL-4 receptor, NFATc1, and c-Fos was determined by Western blot analysis. In addition, the gene expression of NFATc1 and c-Fos was determined by reverse transcription and polymerase chain reaction. The IL-4 receptor was constitutively expressed in RAW264.7 cells. RANKL induced osteoclast generation, as determined by TRAP staining and pit assay. IL-4 inhibited RANKL-induced osteoclastogenesis at low concentrations of 10 ng/ml and more. Interestingly, IL-4 potently inhibited RANKL-induced expression of NFATc1 at mRNA level. Furthermore, IL-4 inhibited c-Fos expression, which is shown to be responsible for NFATc1 expression, in time- and dose-dependent manners. In addition, IL-4 inhibited the RANKL-induced expression of NFATc1 and c-Fos in murine bone marrow cells. Thus, we suggest that IL-4 may downregulate osteoclastogenesis in part through inhibition of the expression of transcription factors, NFATc1 and c-Fos. These findings provide new insight into development of new medication for osteoporosis and RA

Characterization of two types of osteoclasts from human peripheral blood monocytes

International Nuclear Information System (INIS)

Yuasa, Kimitaka; Mori, Kouki; Ishikawa, Hitoshi; Sudo, Akihiro; Uchida, Atsumasa; Ito, Yasuhiko

2007-01-01

The two osteoclastogenesis pathways, receptor activator nuclear factor (NF)-κB ligand (RANKL)-mediated and fusion regulatory protein-1 (FRP-1)-mediated osteoclastogenesis, have recently been reported. There were significant differences in differentiation and activation mechanisms between the two pathways. When monocytes were cultured with FRP-1 without adding M-CSF, essential for the RANKL system, TRAP-positive polykaryocyte formation occurred. FRP-1-mediated osteoclasts formed larger pits on mineralized calcium phosphate plates than RANKL+M-CSF-mediated osteoclasts did. Lacunae on dentin surfaces induced by FRP-1-mediated osteoclasts were inclined to be single and isolated. However, osteoclasts induced by RANKL+M-CSF made many connected pits on dentin surfaces as if they crawled on there. Interestingly, FRP-1 osteoclastogenesis was enhanced by M-CSF/IL-1α, while chemotactic behavior to the dentin slices was not effected. There were differences in pH and concentration of HCO3- at culture endpoint and in adherent feature to dentin surfaces. Our findings indicate there are two types of osteoclasts with distinct properties

Conditional deletion of CD98hc inhibits osteoclast development

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Hideki Tsumura

2016-03-01

Full Text Available The CD98 heavy chain (CD98hc regulates virus-induced cell fusion and monocyte fusion, and is involved in amino acid transportation. Here, we examined the role that CD98hc plays in the formation of osteoclasts using CD98hcflox/floxLysM-cre peritoneal macrophages (CD98hc-defect macrophages. Peritoneal macrophages were stimulated with co-cultured with osteoblasts in the presence of 1,25(OH2 vitamin D3, and thereafter stained with tartrate-resistant acid phosphatase staining solution. The multinucleated osteoclast formation was severely impaired in the peritoneal macrophages isolated from the CD98hc-defect mice compared with those from wild-type mice. CD98hc mediates integrin signaling and amino acid transport through the CD98 light chain (CD98lc. In integrin signaling, suppression of the M-CSF-RANKL-induced phosphorylation of ERK, Akt, JNK and p130Cas were observed at the triggering phase in the CD98h-defect peritoneal macrophages. Moreover, we showed that the general control non-derepressible (GCN pathway, which was activated by amino acid starvation, was induced by the CD98hc-defect peritoneal macrophages stimulated with RANKL. These results indicate that CD98 plays two important roles in osteoclast formation through integrin signaling and amino acid transport.

Imbalanced expression of RANKL and osteoprotegerin mRNA in pannus tissue of rheumatoid arthritis.

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Ainola, M; Mandelin, J; Liljeström, M; Konttinen, Y T; Salo, J

2008-01-01

To test if the pannus tissue is characterized by a high receptor activator of nuclear factor kappaB ligand to osteoprotegerin (RANKL:OPG) ratio, which could explain local osteoclastogenesis and formation of bony erosions. Messenger RNA and protein expressions of RANKL and OPG in rheumatoid and osteoarthritic tissue samples were measured using quantitative real-time RT-PCR and Western blot/densitometry. Pannus and synovitis fibroblasts explanted from tissue samples were cultured in vitro without and with TNF-alpha, IL-1Beta or IL-17 and analyzed quantitatively for RANKL expression. The ability of pannus fibroblasts to induce formation of multinuclear osteoclast-like cells from human monocytes, with macrophage-colony stimulating factor (M-CSF) but without RANKL added, was tested. Histochemical staining was used to assess the eventual presence of RANKL and tartrate resistant acid phosphatase positive osteoclast-like cells at the pannus-bone interface. RANKL:OPG ratios of messenger RNA (ppannus (2.06+/-0.73 and 2.2+/-0.65) compared to rheumatoid (0.62+/-0.13 and 1.31+/-0.69) and osteoarthritis (0.62+/-0.32 and 0.52+/-0.16) synovial membranes. Resting and stimulated (p dependent on the cytokine used) pannus fibroblasts produced RANKL in excess (p=0.0005) and unstimulated pannus fibroblasts also effectively induced osteoclast-like cell formation from monocytes in vitro without any exogenous RANKL added. Compatible with these findings, multinuclear osteoclasts-like cells were frequent in the fibroblast- and macrophage-rich pannus tissue at the soft tissue-to-bone interface. The high RANKL:OPG ratio, together with close fibroblast-to-monocyte contacts in pannus tissue, probably favor local generation of bone resorbing osteoclasts at the site of erosion in rheumatoid arthritis.

Irreversible inhibition of RANK expression as a possible mechanism for IL-3 inhibition of RANKL-induced osteoclastogenesis

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Khapli, Shruti M.; Tomar, Geetanjali B.; Barhanpurkar, Amruta P.; Gupta, Navita; Yogesha, S.D.; Pote, Satish T. [National Center for Cell Science, University of Pune Campus, Pune 411 007 (India); Wani, Mohan R., E-mail: mohanwani@nccs.res.in [National Center for Cell Science, University of Pune Campus, Pune 411 007 (India)

2010-09-03

Research highlights: {yields} IL-3 inhibits receptor activator of NF-{kappa}B ligand (RANKL)-induced osteoclastogenesis. {yields} IL-3 inhibits RANKL-induced JNK activation. {yields} IL-3 down-regulates expression of c-Fos and NFATc1 transcription factors. {yields} IL-3 down-regulates RANK expression posttranscriptionally and irreversibly. {yields} IL-3 inhibits in vivo RANK expression. -- Abstract: IL-3, a cytokine secreted by activated T lymphocytes, stimulates the proliferation, differentiation and survival of pluripotent hematopoietic stem cells. In this study, we investigated the mechanism of inhibitory action of IL-3 on osteoclast differentiation. We show here that IL-3 significantly inhibits receptor activator of NF-{kappa}B (RANK) ligand (RANKL)-induced activation of c-Jun N-terminal kinase (JNK). IL-3 down-regulates expression of c-Fos and nuclear factor of activated T cells (NFATc1) transcription factors. In addition, IL-3 down-regulates RANK expression posttranscriptionally in both purified osteoclast precursors and whole bone marrow cells. Furthermore, the inhibitory effect of IL-3 on RANK expression was irreversible. Interestingly, IL-3 inhibits in vivo RANK expression in mice. Thus, we provide the first evidence that IL-3 irreversibly inhibits RANK expression that results in inhibition of important signaling molecules induced by RANKL.

Irreversible inhibition of RANK expression as a possible mechanism for IL-3 inhibition of RANKL-induced osteoclastogenesis

International Nuclear Information System (INIS)

Khapli, Shruti M.; Tomar, Geetanjali B.; Barhanpurkar, Amruta P.; Gupta, Navita; Yogesha, S.D.; Pote, Satish T.; Wani, Mohan R.

2010-01-01

Research highlights: → IL-3 inhibits receptor activator of NF-κB ligand (RANKL)-induced osteoclastogenesis. → IL-3 inhibits RANKL-induced JNK activation. → IL-3 down-regulates expression of c-Fos and NFATc1 transcription factors. → IL-3 down-regulates RANK expression posttranscriptionally and irreversibly. → IL-3 inhibits in vivo RANK expression. -- Abstract: IL-3, a cytokine secreted by activated T lymphocytes, stimulates the proliferation, differentiation and survival of pluripotent hematopoietic stem cells. In this study, we investigated the mechanism of inhibitory action of IL-3 on osteoclast differentiation. We show here that IL-3 significantly inhibits receptor activator of NF-κB (RANK) ligand (RANKL)-induced activation of c-Jun N-terminal kinase (JNK). IL-3 down-regulates expression of c-Fos and nuclear factor of activated T cells (NFATc1) transcription factors. In addition, IL-3 down-regulates RANK expression posttranscriptionally in both purified osteoclast precursors and whole bone marrow cells. Furthermore, the inhibitory effect of IL-3 on RANK expression was irreversible. Interestingly, IL-3 inhibits in vivo RANK expression in mice. Thus, we provide the first evidence that IL-3 irreversibly inhibits RANK expression that results in inhibition of important signaling molecules induced by RANKL.

Immunological Reaction in TNF-α-Mediated Osteoclast Formation and Bone Resorption In Vitro and In Vivo

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Hideki Kitaura

2013-01-01

Full Text Available Tumor necrosis factor-α (TNF-α is a cytokine produced by monocytes, macrophages, and T cells and is induced by pathogens, endotoxins, or related substances. TNF-α may play a key role in bone metabolism and is important in inflammatory bone diseases such as rheumatoid arthritis. Cells directly involved in osteoclastogenesis include macrophages, which are osteoclast precursor cells, osteoblasts, or stromal cells. These cells express receptor activator of NF-κB ligand (RANKL to induce osteoclastogenesis, and T cells, which secrete RANKL, promote osteoclastogenesis during inflammation. Elucidating the detailed effects of TNF-α on bone metabolism may enable the identification of therapeutic targets that can efficiently suppress bone destruction in inflammatory bone diseases. TNF-α is considered to act by directly increasing RANK expression in macrophages and by increasing RANKL in stromal cells. Inflammatory cytokines such as interleukin- (IL- 12, IL-18, and interferon-γ (IFN-γ strongly inhibit osteoclast formation. IL-12, IL-18, and IFN-γ induce apoptosis in bone marrow cells treated with TNF-α  in vitro, and osteoclastogenesis is inhibited by the interactions of TNF-α-induced Fas and Fas ligand induced by IL-12, IL-18, and IFN-γ. This review describes and discusses the role of cells concerned with osteoclast formation and immunological reactions in TNF-α-mediated osteoclastogenesis in vitro and in vivo.

Mitochondria related peptide MOTS-c suppresses ovariectomy-induced bone loss via AMPK activation

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Ming, Wei, E-mail: weiming@xiyi.edu.cn [State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, Fourth Military Medical University, Xi’an 710032 (China); Department of Pharmacology, Xi’an Medical University, Xi’an 710021 (China); Lu, Gan, E-mail: leonming99@163.com [Department of Gynecology of Shaanxi Provincial People’s Hospital, Xi’an, 710068 (China); Xin, Sha, E-mail: 248967979@qq.com [Institute of Orthopedic Surgery, Xijing Hospital, Fourth Military Medical University, Xi’an 710032 (China); Huanyu, Lu, E-mail: 2366927258@qq.com [Department of Occupational and Environmental Health and the Ministry of Education Key Lab of Hazard Assessment and Control in Special Operational Environment, School of Public Health, Fourth Military Medical University, Xi’an 710032 (China); Yinghao, Jiang, E-mail: jiangyh@fmmu.edu.cn [State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, Fourth Military Medical University, Xi’an 710032 (China); Xiaoying, Lei, E-mail: leixiaoy@fmmu.edu.cn [State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, Fourth Military Medical University, Xi’an 710032 (China); Chengming, Xu, E-mail: chengmingxu@yeah.net [State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, Fourth Military Medical University, Xi’an 710032 (China); Banjun, Ruan, E-mail: running@163.com [State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, Fourth Military Medical University, Xi’an 710032 (China); Li, Wang, E-mail: wanglifw@fmmu.edu.cn [State Key Laboratory of Cancer Biology, Department of Pharmacogenomics, Fourth Military Medical University, Xi’an 710032 (China); and others

2016-08-05

Therapeutic targeting bone loss has been the focus of the study in osteoporosis. The present study is intended to evaluate whether MOTS-c, a novel mitochondria related 16 aa peptide, can protect mice from ovariectomy-induced osteoporosis. After ovary removal, the mice were injected with MOTS-c at a dose of 5 mg/kg once a day for 12 weeks. Our results showed that MOTS-c treatment significantly alleviated bone loss, as determined by micro-CT examination. Mechanistically, we found that the receptor activator of nuclear factor-κB ligand (RANKL) induced osteoclast differentiation was remarkably inhibited by MOTS-c. Moreover, MOTS-c increased phosphorylated AMPK levels, and compound C, an AMPK inhibitor, could partially abrogate the effects of the MOTS-c on osteoclastogenesis. Thus, our findings provide evidence that MOTS-c may exert as an inhibitor of osteoporosis via AMPK dependent inhibition of osteoclastogenesis. -- Highlights: •MOTS-c decreases OVX-induced bone loss in vivo. •MOTS-c inhibits RANKL-induced osteoclast formation. •MOTS-c inhibits RANKL-induced osteoclast-specific gene expression. •MOTS-c represses osteoclast differentiation via the activation of AMPK.

Mitochondria related peptide MOTS-c suppresses ovariectomy-induced bone loss via AMPK activation

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Ming, Wei; Lu, Gan; Xin, Sha; Huanyu, Lu; Yinghao, Jiang; Xiaoying, Lei; Chengming, Xu; Banjun, Ruan; Li, Wang

2016-01-01

Therapeutic targeting bone loss has been the focus of the study in osteoporosis. The present study is intended to evaluate whether MOTS-c, a novel mitochondria related 16 aa peptide, can protect mice from ovariectomy-induced osteoporosis. After ovary removal, the mice were injected with MOTS-c at a dose of 5 mg/kg once a day for 12 weeks. Our results showed that MOTS-c treatment significantly alleviated bone loss, as determined by micro-CT examination. Mechanistically, we found that the receptor activator of nuclear factor-κB ligand (RANKL) induced osteoclast differentiation was remarkably inhibited by MOTS-c. Moreover, MOTS-c increased phosphorylated AMPK levels, and compound C, an AMPK inhibitor, could partially abrogate the effects of the MOTS-c on osteoclastogenesis. Thus, our findings provide evidence that MOTS-c may exert as an inhibitor of osteoporosis via AMPK dependent inhibition of osteoclastogenesis. -- Highlights: •MOTS-c decreases OVX-induced bone loss in vivo. •MOTS-c inhibits RANKL-induced osteoclast formation. •MOTS-c inhibits RANKL-induced osteoclast-specific gene expression. •MOTS-c represses osteoclast differentiation via the activation of AMPK.

Development of 1-Amino-4-(phenylamino)anthraquinone-2-sulfonate Sodium Derivatives as a New Class of Inhibitors of RANKL-Induced Osteoclastogenesis.

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Lee, Chia-Chung; Chen, Chun-Liang; Liu, Fei-Lan; Chiou, Chung-Yu; Chen, Tsung-Chih; Wu, Cheng-Chi; Sun, Wei-Hsin; Chang, Deh-Ming; Huang, Hsu-Shan

2016-05-01

A series of 1-amino-4-(phenylamino)anthraquinone-2-sulfonate sodium derivatives was synthesized and evaluated for osteoclast inhibition using a TRAP-staining assay. Among them, two compounds, LCCY-13 and LCCY-15, dose-dependently suppressed receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast formation. Moreover, the cytotoxicity assay on RAW264.7 cells suggested that the inhibition of osteoclastic bone resorption by these compounds was not a result of their cytotoxicity. Further, the inhibitory activities of compounds LCCY-13 and LCCY-15 were further confirmed by including specific inhibition of NFATc1 expression levels in nuclei using an immunofluorescent analysis. In addition, LCCY-13 and LCCY-15 also significantly attenuated the bone resorption activity of osteoclasts according to a pit formation assay. Thus, a new class of 1-amino-4-(phenylamino)anthraquinone-2-sulfonate sodium compounds might be considered as an essential lead structure for the further development of anti-resorptive agents. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dietary emu oil supplementation suppresses 5-fluorouracil chemotherapy-induced inflammation, osteoclast formation, and bone loss.

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Raghu Nadhanan, Rethi; Abimosleh, Suzanne M; Su, Yu-Wen; Scherer, Michaela A; Howarth, Gordon S; Xian, Cory J

2012-06-01

Cancer chemotherapy can cause osteopenia or osteoporosis, and yet the underlying mechanisms remain unclear, and currently, no preventative treatments are available. This study investigated damaging effects of 5-fluorouracil (5-FU) on histological, cellular, and molecular changes in the tibial metaphysis and potential protective benefits of emu oil (EO), which is known to possess a potent anti-inflammatory property. Female dark agouti rats were gavaged orally with EO or water (1 ml·day(-1)·rat(-1)) for 1 wk before a single ip injection of 5-FU (150 mg/kg) or saline (Sal) was given. The treatment groups were H(2)O + Sal, H(2)O + 5-FU, EO + 5-FU, and EO + Sal. Oral gavage was given throughout the whole period up to 1 day before euthanasia (days 3, 4, and 5 post-5-FU). Histological analysis showed that H(2)O + 5-FU significantly reduced heights of primary spongiosa on days 3 and 5 and trabecular bone volume of secondary spongiosa on days 3 and 4. It reduced density of osteoblasts slightly and caused an increase in the density of osteoclasts on trabecular bone surface on day 4. EO supplementation prevented reduction of osteoblasts and induction of osteoclasts and bone loss caused by 5-FU. Gene expression studies confirmed an inhibitory effect of EO on osteoclasts since it suppressed 5-FU-induced expression of proinflammatory and osteoclastogenic cytokine TNFα, osteoclast marker receptor activator of nuclear factor-κB, and osteoclast-associated receptor. Therefore, this study demonstrated that EO can counter 5-FU chemotherapy-induced inflammation in bone, preserve osteoblasts, suppress osteoclast formation, and potentially be useful in preventing 5-FU chemotherapy-induced bone loss.

Cell adhesion signaling regulates RANK expression in osteoclast precursors.

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Ayako Mochizuki

Full Text Available Cells with monocyte/macrophage lineage expressing receptor activator of NF-κB (RANK differentiate into osteoclasts following stimulation with the RANK ligand (RANKL. Cell adhesion signaling is also required for osteoclast differentiation from precursors. However, details of the mechanism by which cell adhesion signals induce osteoclast differentiation have not been fully elucidated. To investigate the participation of cell adhesion signaling in osteoclast differentiation, mouse bone marrow-derived macrophages (BMMs were used as osteoclast precursors, and cultured on either plastic cell culture dishes (adherent condition or the top surface of semisolid methylcellulose gel loaded in culture tubes (non-adherent condition. BMMs cultured under the adherent condition differentiated into osteoclasts in response to RANKL stimulation. However, under the non-adherent condition, the efficiency of osteoclast differentiation was markedly reduced even in the presence of RANKL. These BMMs retained macrophage characteristics including phagocytic function and gene expression profile. Lipopolysaccharide (LPS and tumor necrosis factor -αTNF-α activated the NF-κB-mediated signaling pathways under both the adherent and non-adherent conditions, while RANKL activated the pathways only under the adherent condition. BMMs highly expressed RANK mRNA and protein under the adherent condition as compared to the non-adherent condition. Also, BMMs transferred from the adherent to non-adherent condition showed downregulated RANK expression within 24 hours. In contrast, transferring those from the non-adherent to adherent condition significantly increased the level of RANK expression. Moreover, interruption of cell adhesion signaling by echistatin, an RGD-containing disintegrin, decreased RANK expression in BMMs, while forced expression of either RANK or TNFR-associated factor 6 (TRAF6 in BMMs induced their differentiation into osteoclasts even under the non

CD147 promotes the formation of functional osteoclasts through NFATc1 signalling

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Nishioku, Tsuyoshi; Terasawa, Mariko; Baba, Misaki; Yamauchi, Atsushi; Kataoka, Yasufumi

2016-01-01

CD147, a membrane glycoprotein of the immunoglobulin superfamily, is highly upregulated during dynamic cellular events including tissue remodelling. Elevated CD147 expression is present in the joint of rheumatoid arthritis patients. However, the role of CD147 in bone destruction remains unclear. To determine whether CD147 is involved in osteoclastogenesis, we studied its expression in mouse osteoclasts and its role in osteoclast differentiation and function. CD147 expression was markedly upregulated during osteoclast differentiation. To investigate the role of CD147 in receptor activator of nuclear factor-kappa B ligand (RANKL)-induced osteoclastogenesis and bone resorption activity, osteoclast precursor cells were transfected with CD147 siRNA. Decreased CD147 expression inhibited osteoclast formation and bone resorption, inhibited RANKL-induced nuclear translocation of the nuclear factor of activated T cells (NFAT) c1 and decreased the expression of the d2 isoform of vacuolar ATPase Vo domain and cathepsin K. Therefore, CD147 plays a critical role in the differentiation and function of osteoclasts by upregulating NFATc1 through the autoamplification of its expression in osteoclastogenesis. - Highlights: • CD147 expression was markedly upregulated during osteoclast differentiation. • Downregulation of CD147 expression inhibited osteoclastgenesis and bone resorption. • Decreased CD147 expression inhibited RANKL-induced nuclear translocation of NFATc1.

CD147 promotes the formation of functional osteoclasts through NFATc1 signalling

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Nishioku, Tsuyoshi, E-mail: nishiokut@niu.ac.jp [Department of Clinical Pharmacology, Faculty of Pharmaceutical Sciences, Nagasaki International University, 2825-7 Huis Ten Bosch, Sasebo, Nagasaki 859-3298 (Japan); Department of Pharmaceutical Care and Health Sciences, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180 (Japan); Terasawa, Mariko; Baba, Misaki; Yamauchi, Atsushi; Kataoka, Yasufumi [Department of Pharmaceutical Care and Health Sciences, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka 814-0180 (Japan)

2016-04-29

CD147, a membrane glycoprotein of the immunoglobulin superfamily, is highly upregulated during dynamic cellular events including tissue remodelling. Elevated CD147 expression is present in the joint of rheumatoid arthritis patients. However, the role of CD147 in bone destruction remains unclear. To determine whether CD147 is involved in osteoclastogenesis, we studied its expression in mouse osteoclasts and its role in osteoclast differentiation and function. CD147 expression was markedly upregulated during osteoclast differentiation. To investigate the role of CD147 in receptor activator of nuclear factor-kappa B ligand (RANKL)-induced osteoclastogenesis and bone resorption activity, osteoclast precursor cells were transfected with CD147 siRNA. Decreased CD147 expression inhibited osteoclast formation and bone resorption, inhibited RANKL-induced nuclear translocation of the nuclear factor of activated T cells (NFAT) c1 and decreased the expression of the d2 isoform of vacuolar ATPase Vo domain and cathepsin K. Therefore, CD147 plays a critical role in the differentiation and function of osteoclasts by upregulating NFATc1 through the autoamplification of its expression in osteoclastogenesis. - Highlights: • CD147 expression was markedly upregulated during osteoclast differentiation. • Downregulation of CD147 expression inhibited osteoclastgenesis and bone resorption. • Decreased CD147 expression inhibited RANKL-induced nuclear translocation of NFATc1.

Oxidized lipids enhance RANKL production by T lymphocytes: implications for lipid-induced bone loss.

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Graham, Lucia S; Parhami, Farhad; Tintut, Yin; Kitchen, Christina M R; Demer, Linda L; Effros, Rita B

2009-11-01

Osteoporosis is a systemic disease that is associated with increased morbidity, mortality and health care costs. Whereas osteoclasts and osteoblasts are the main regulators of bone homeostasis, recent studies underscore a key role for the immune system, particularly via activation-induced T lymphocyte production of receptor activator of NFkappaB ligand (RANKL). Well-documented as a mediator of T lymphocyte/dendritic cell interactions, RANKL also stimulates the maturation and activation of bone-resorbing osteoclasts. Given that lipid oxidation products mediate inflammatory and metabolic disorders such as osteoporosis and atherosclerosis, and since oxidized lipids affect several T lymphocyte functions, we hypothesized that RANKL production might also be subject to modulation by oxidized lipids. Here, we show that short term exposure of both unstimulated and activated human T lymphocytes to minimally oxidized low density lipoprotein (LDL), but not native LDL, significantly enhances RANKL production and promotes expression of the lectin-like oxidized LDL receptor-1 (LOX-1). The effect, which is also observed with 8-iso-Prostaglandin E2, an inflammatory isoprostane produced by lipid peroxidation, is mediated via the NFkappaB pathway, and involves increased RANKL mRNA expression. The link between oxidized lipids and T lymphocytes is further reinforced by analysis of hyperlipidemic mice, in which bone loss is associated with increased RANKL mRNA in T lymphocytes and elevated RANKL serum levels. Our results suggest a novel pathway by which T lymphocytes contribute to bone changes, namely, via oxidized lipid enhancement of RANKL production. These findings may help elucidate clinical associations between cardiovascular disease and decreased bone mass, and may also lead to new immune-based approaches to osteoporosis.

Osteocytes, not Osteoblasts or Lining Cells, are the Main Source of the RANKL Required for Osteoclast Formation in Remodeling Bone.

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Jinhu Xiong

Full Text Available The cytokine receptor activator of nuclear factor kappa B ligand (RANKL, encoded by the Tnfsf11 gene, is essential for osteoclastogenesis and previous studies have shown that deletion of the Tnfsf11 gene using a Dmp1-Cre transgene reduces osteoclast formation in cancellous bone by more than 70%. However, the Dmp1-Cre transgene used in those studies leads to recombination in osteocytes, osteoblasts, and lining cells making it unclear whether one or more of these cell types produce the RANKL required for osteoclast formation in cancellous bone. Because osteoblasts, osteocytes, and lining cells have distinct locations and functions, distinguishing which of these cell types are sources of RANKL is essential for understanding the orchestration of bone remodeling. To distinguish between these possibilities, we have now created transgenic mice expressing the Cre recombinase under the control of regulatory elements of the Sost gene, which is expressed in osteocytes but not osteoblasts or lining cells in murine bone. Activity of the Sost-Cre transgene in osteocytes, but not osteoblast or lining cells, was confirmed by crossing Sost-Cre transgenic mice with tdTomato and R26R Cre-reporter mice, which express tdTomato fluorescent protein or LacZ, respectively, only in cells expressing the Cre recombinase or their descendants. Deletion of the Tnfsf11 gene in Sost-Cre mice led to a threefold decrease in osteoclast number in cancellous bone and increased cancellous bone mass, mimicking the skeletal phenotype of mice in which the Tnfsf11 gene was deleted using the Dmp1-Cre transgene. These results demonstrate that osteocytes, not osteoblasts or lining cells, are the main source of the RANKL required for osteoclast formation in remodeling cancellous bone.

A-Type Cranberry Proanthocyanidins Inhibit the RANKL-Dependent Differentiation and Function of Human Osteoclasts

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Amy B. Howell

2011-03-01

Full Text Available This study investigated the effect of A-type cranberry proanthocyanidins (AC-PACs on osteoclast formation and bone resorption activity. The differentiation of human pre-osteoclastic cells was assessed by tartrate-resistant acid phosphatase (TRAP staining, while the secretion of interleukin-8 (IL-8 and matrix metalloproteinases (MMPs was measured by ELISA. Bone resorption activity was investigated by using a human bone plate coupled with an immunoassay that detected the release of collagen helical peptides. AC-PACs up to 100 µg/mL were atoxic for osteoclastic cells. TRAP staining evidenced a dose-dependent inhibition of osteoclastogenesis. More specifically, AC-PACs at 50 µg/mL caused a 95% inhibition of RANKL-dependent osteoclast differentiation. This concentration of AC-PACs also significantly increased the secretion of IL-8 (6-fold and inhibited the secretion of both MMP-2 and MMP-9. Lastly, AC-PACs (10, 25, 50 and 100 µg/ml affected bone degradation mediated by mature osteoclasts by significantly decreasing the release of collagen helical peptides. This study suggests that AC-PACs can interfere with osteoclastic cell maturation and physiology as well as prevent bone resorption. These compounds may be considered as therapeutic agents for the prevention and treatment of periodontitis.

Toll-Like Receptor 2 Stimulation of Osteoblasts Mediates Staphylococcus Aureus Induced Bone Resorption and Osteoclastogenesis through Enhanced RANKL

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Kassem, Ali; Lindholm, Catharina; Lerner, Ulf H

2016-01-01

Severe Staphylococcus aureus (S. aureus) infections pose an immense threat to population health and constitute a great burden for the health care worldwide. Inter alia, S. aureus septic arthritis is a disease with high mortality and morbidity caused by destruction of the infected joints and systemic bone loss, osteoporosis. Toll-Like receptors (TLRs) are innate immune cell receptors recognizing a variety of microbial molecules and structures. S. aureus recognition via TLR2 initiates a signaling cascade resulting in production of various cytokines, but the mechanisms by which S. aureus causes rapid and excessive bone loss are still unclear. We, therefore, investigated how S. aureus regulates periosteal/endosteal osteoclast formation and bone resorption. S. aureus stimulation of neonatal mouse parietal bone induced ex vivo bone resorption and osteoclastic gene expression. This effect was associated with increased mRNA and protein expression of receptor activator of NF-kB ligand (RANKL) without significant change in osteoprotegerin (OPG) expression. Bone resorption induced by S. aureus was abolished by OPG. S. aureus increased the expression of osteoclastogenic cytokines and prostaglandins in the parietal bones but the stimulatory effect of S. aureus on bone resorption and Tnfsf11 mRNA expression was independent of these cytokines and prostaglandins. Stimulation of isolated periosteal osteoblasts with S. aureus also resulted in increased expression of Tnfsf11 mRNA, an effect lost in osteoblasts from Tlr2 knockout mice. S. aureus stimulated osteoclastogenesis in isolated periosteal cells without affecting RANKL-stimulated resorption. In contrast, S. aureus inhibited RANKL-induced osteoclast formation in bone marrow macrophages. These data show that S. aureus enhances bone resorption and periosteal osteoclast formation by increasing osteoblast RANKL production through TLR2. Our study indicates the importance of using different in vitro approaches for studies of how S

Ethanol Extract of Atractylodes macrocephala Protects Bone Loss by Inhibiting Osteoclast Differentiation

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Youn-Hwan Hwang

2013-06-01

Full Text Available The rhizome of Atractylodes macrocephala has been used mainly in Traditional Chinese Medicine for invigorating the functions of the stomach and spleen. In the present study, we investigated the inhibitory effect of the 70% ethanol extract of the rhizome of Atractylodes macrocephala (AMEE on osteoclast differentiation. We found that AMEE inhibits osteoclast differentiation from its precursors induced by receptor activator of nuclear factor-κB ligand (RANKL, an essential cytokine required for osteoclast differentiation. AMEE attenuated RANKL-induced activation of NF-κB signaling pathway, subsequently inhibiting the induction of osteoclastogenic transcription factors, c-Fos and nuclear factor of activated T cells cytoplasmic 1. Consistent with the in vitro results, administration of AMEE protected RANKL-induced bone loss in mice. We also identified atractylenolide I and II as active constituents contributing to the anti-osteoclastogenic effect of AMEE. Taken together, our results demonstrate that AMEE has a protective effect on bone loss via inhibiting osteoclast differentiation and suggest that AMEE may be useful in preventing and treating various bone diseases associated with excessive bone resorption.

RANK, RANKL and osteoprotegerin in arthritic bone loss

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M.C. Bezerra

2005-02-01

Full Text Available Rheumatoid arthritis is characterized by the presence of inflammatory synovitis and destruction of joint cartilage and bone. Tissue proteinases released by synovia, chondrocytes and pannus can cause cartilage destruction and cytokine-activated osteoclasts have been implicated in bone erosions. Rheumatoid arthritis synovial tissues produce a variety of cytokines and growth factors that induce monocyte differentiation to osteoclasts and their proliferation, activation and longer survival in tissues. More recently, a major role in bone erosion has been attributed to the receptor activator of nuclear factor kappa B ligand (RANKL released by activated lymphocytes and osteoblasts. In fact, osteoclasts are markedly activated after RANKL binding to the cognate RANK expressed on the surface of these cells. RANKL expression can be upregulated by bone-resorbing factors such as glucocorticoids, vitamin D3, interleukin 1 (IL-1, IL-6, IL-11, IL-17, tumor necrosis factor-alpha, prostaglandin E2, or parathyroid hormone-related peptide. Supporting this idea, inhibition of RANKL by osteoprotegerin, a natural soluble RANKL receptor, prevents bone loss in experimental models. Tumor growth factor-ß released from bone during active bone resorption has been suggested as one feedback mechanism for upregulating osteoprotegerin and estrogen can increase its production on osteoblasts. Modulation of these systems provides the opportunity to inhibit bone loss and deformity in chronic arthritis.

Cytosolic malate dehydrogenase regulates RANKL-mediated osteoclastogenesis via AMPK/c-Fos/NFATc1 signaling

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Oh, Se Jeong [Department of Oral Microbiology and Immunology, College of Dentistry, Wonkwang University, Iksan, Jeonbuk 54538 (Korea, Republic of); Gu, Dong Ryun [Department of Oral Microbiology and Immunology, College of Dentistry, Wonkwang University, Iksan, Jeonbuk 54538 (Korea, Republic of); Center for Metabolic Function Regulation (CMFR), School of Medicine, Wonkwang University, Iksan, Jeonbuk 54538 (Korea, Republic of); Jin, Su Hyun [Center for Metabolic Function Regulation (CMFR), School of Medicine, Wonkwang University, Iksan, Jeonbuk 54538 (Korea, Republic of); Park, Keun Ha [Department of Oral Microbiology and Immunology, College of Dentistry, Wonkwang University, Iksan, Jeonbuk 54538 (Korea, Republic of); Center for Metabolic Function Regulation (CMFR), School of Medicine, Wonkwang University, Iksan, Jeonbuk 54538 (Korea, Republic of); Lee, Seoung Hoon, E-mail: leesh2@wku.ac.kr [Department of Oral Microbiology and Immunology, College of Dentistry, Wonkwang University, Iksan, Jeonbuk 54538 (Korea, Republic of); Center for Metabolic Function Regulation (CMFR), School of Medicine, Wonkwang University, Iksan, Jeonbuk 54538 (Korea, Republic of); Wonkwang Institute of Biomaterials and Implant, Wonkwang University, Iksan, Jeonbuk 54538 (Korea, Republic of)

2016-06-17

Cytosolic malate dehydrogenase (malate dehydrogenase 1, MDH1) plays pivotal roles in the malate/aspartate shuttle that might modulate metabolism between the cytosol and mitochondria. In this study, we investigated the role of MDH1 in osteoclast differentiation and formation. MDH1 expression was induced by receptor activator of nuclear factor kappa-B ligand (RANKL) treatment. Knockdown of MDH1 by infection with retrovirus containing MDH1-specific shRNA (shMDH1) reduced mature osteoclast formation and bone resorption activity. Moreover, the expression of marker genes associated with osteoclast differentiation was downregulated by shMDH1 treatment, suggesting a role of MDH1 in osteoclast differentiation. In addition, intracellular ATP production was reduced following the activation of adenosine 5′ monophosphate-activated protein kinase (AMPK), a cellular energy sensor and negative regulator of RANKL-induced osteoclast differentiation, in shMDH1-infected osteoclasts compared to control cells. In addition, the expression of c-Fos and nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), a critical transcription factor of osteoclastogenesis, was decreased with MDH1 knockdown during RANKL-mediated osteoclast differentiation. These findings provide strong evidence that MDH1 plays a critical role in osteoclast differentiation and function via modulation of the intracellular energy status, which might affect AMPK activity and NFATc1 expression.

Cytosolic malate dehydrogenase regulates RANKL-mediated osteoclastogenesis via AMPK/c-Fos/NFATc1 signaling

International Nuclear Information System (INIS)

Oh, Se Jeong; Gu, Dong Ryun; Jin, Su Hyun; Park, Keun Ha; Lee, Seoung Hoon

2016-01-01

Cytosolic malate dehydrogenase (malate dehydrogenase 1, MDH1) plays pivotal roles in the malate/aspartate shuttle that might modulate metabolism between the cytosol and mitochondria. In this study, we investigated the role of MDH1 in osteoclast differentiation and formation. MDH1 expression was induced by receptor activator of nuclear factor kappa-B ligand (RANKL) treatment. Knockdown of MDH1 by infection with retrovirus containing MDH1-specific shRNA (shMDH1) reduced mature osteoclast formation and bone resorption activity. Moreover, the expression of marker genes associated with osteoclast differentiation was downregulated by shMDH1 treatment, suggesting a role of MDH1 in osteoclast differentiation. In addition, intracellular ATP production was reduced following the activation of adenosine 5′ monophosphate-activated protein kinase (AMPK), a cellular energy sensor and negative regulator of RANKL-induced osteoclast differentiation, in shMDH1-infected osteoclasts compared to control cells. In addition, the expression of c-Fos and nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), a critical transcription factor of osteoclastogenesis, was decreased with MDH1 knockdown during RANKL-mediated osteoclast differentiation. These findings provide strong evidence that MDH1 plays a critical role in osteoclast differentiation and function via modulation of the intracellular energy status, which might affect AMPK activity and NFATc1 expression.

Combined treatment with Dendrobium candidum and black tea extract promotes osteoprotective activity in ovariectomized estrogen deficient rats and osteoclast formation.

Science.gov (United States)

Wang, Ming-Yue; Shen, Chang; An, Meng-Fei; Xie, Chuan-Qi; Wu, Xin; Zhu, Qiang-Qiang; Sun, Bin; Huang, Yan-Ping; Zhao, Yun-Li; Wang, Xuan-Jun; Sheng, Jun

2018-05-01

Dendrobium candidum (DC) and black tea, are traditional chinese drinks, which contain multiple active ingredients. However, whether or not the combination of these two ingredients can improve osteoporosis remains unknown. This study therefore aimed to examine the effects of the combination of DC and black tea extract (BTE) on osteoporosis. Ovariectomy (OVX)-induced osteoporosis in vivo as well as receptor activator of NF-κB ligand (RANKL)-induced osteoclastogenesis in vitro was selected. Results showed that OVX rats that were treated orally with a DC and BTE combination for 12 weeks maintained their calcium (Ca) and phosphorus (P) homeostasis and exhibited significantly enhanced estradiol (E 2 ) and OPG levels. This combination treatment also simultaneously reduced levels of interleukin (IL)-1β, IL-6 and improved the organ coefficients of the uterus and femur as well as BMD and BMC in OVX rats. In addition, this DC and BTE combination suppressed osteoclast differentiation in the RANKL-stimulated osteoclastogenesis of RAW 264.7 cells and effectively inhibited the expression of osteoclast-associated genes and proteins. The results of this study further highlight the fact that a combination of DC and BTE improved ovariectomy-induced osteoporosis in rats and suppressed RANKL-stimulated osteoclastogenesis in RAW 264.7 cells. This combination also significantly alleviated osteoporosis when compared to the alternative sole treatments above, due to synergistic effects among components. One partial mechanism of this combination might be the inhibition of osteoclast proliferation and the regulation of NFATC1/c-Fos expression. Copyright © 2018 Elsevier Inc. All rights reserved.

Normalizing the bone marrow microenvironment with p38 inhibitor reduces multiple myeloma cell proliferation and adhesion and suppresses osteoclast formation

International Nuclear Information System (INIS)

Nguyen, Aaron N.; Stebbins, Elizabeth G.; Henson, Margaret; O'Young, Gilbert; Choi, Sun J.; Quon, Diana; Damm, Debby; Reddy, Mamatha; Ma, Jing Y.; Haghnazari, Edwin; Kapoun, Ann M.; Medicherla, Satyanarayana; Protter, Andy; Schreiner, George F.; Kurihara, Noriyoshi; Anderson, Judy; Roodman, G. David; Navas, Tony A.; Higgins, Linda S.

2006-01-01

The multiple myeloma (MM) bone marrow (BM) microenvironment plays a critical role in supporting tumor growth and survival as well as in promoting formation of osteolytic lesions. Recent results suggest that the p38 mitogen-activated protein kinase (MAPK) is an important factor in maintaining this activated environment. In this report, we demonstrate that the p38α MAPK inhibitor, SCIO-469, suppresses secretion of the tumor-supportive factors IL-6 and VEGF from BM stromal cells (BMSCs) as well as cocultures of BMSCs with MM cells, resulting in reduction in MM cell proliferation. Additionally, we show that SCIO-469 prevents TNFα-induced adhesion of MM cells to BMSCs through an ICAM-1- and VCAM-1-independent mechanism. Microarray analysis revealed a novel set of TNFα-induced chemokines in BMSCs that is strongly inhibited by SCIO-469. Furthermore, reintroduction of chemokines CXCL10 and CCL8 to BMSCs overcomes the inhibitory effect of SCIO-469 on TNFα-induced MM adhesion. Lastly, we show that SCIO-469 inhibits secretion and expression of the osteoclast-activating factors IL-11, RANKL, and MIP-1α as well as prevents human osteoclast formation in vitro. Collectively, these results suggest that SCIO-469 treatment can suppress factors in the bone marrow microenvironment to inhibit MM cell proliferation and adhesion and also to alleviate osteolytic activation in MM

Characterization of osteoclasts derived from CD14+ monocytes isolated from peripheral blood

DEFF Research Database (Denmark)

Sørensen, Mette Grøndahl; Henriksen, Kim; Schaller, Sophie

2007-01-01

Bone resorption is solely mediated by osteoclasts. Therefore, a pure osteoclast population is of high interest for the investigation of biological aspects of the osteoclasts, such as the direct effect of growth factors and hormones, as well as for testing and characterizing inhibitors of bone...... resorption. We have established a pure, stable, and reproducible system for purification of human osteoclasts from peripheral blood. We isolated CD14-positive (CD14+) monocytes using anti-CD14-coated beads. After isolation, the monocytes are differentiated into mature osteoclasts by stimulation...... of osteoclast precursors. No expression of osteoclast markers was observed in the absence of RANKL, whereas RANKL dose-dependently induced the expression of cathepsin K, tartrate-resistant acid phosphatase (TRACP), and matrix metallo proteinase (MMP)-9. Furthermore, morphological characterization of the cells...

RANK ligand signaling modulates the matrix metalloproteinase-9 gene expression during osteoclast differentiation

International Nuclear Information System (INIS)

Sundaram, Kumaran; Nishimura, Riko; Senn, Joseph; Youssef, Rimon F.; London, Steven D.; Reddy, Sakamuri V.

2007-01-01

Osteoclast differentiation is tightly regulated by receptor activator of NF-κB ligand (RANKL) signaling. Matrix metalloproteinase-9 (MMP-9), a type IV collagenase is highly expressed in osteoclast cells and plays an important role in degradation of extracellular matrix; however, the molecular mechanisms that regulate MMP-9 gene expression are unknown. In this study, we demonstrate that RANKL signaling induces MMP-9 gene expression in osteoclast precursor cells. We further show that RANKL regulates MMP-9 gene expression through TRAF6 but not TRAF2. Interestingly, blockade of p38 MAPK activity by pharmacological inhibitor, SB203580 increases MMP-9 activity whereas ERK1/2 inhibitor, PD98059 decreases RANKL induced MMP-9 activity in RAW264.7 cells. These data suggest that RANKL differentially regulates MMP-9 expression through p38 and ERK signaling pathways during osteoclast differentiation. Transient expression of MMP-9 gene (+ 1 to - 1174 bp relative to ATG start codon) promoter-luciferase reporter plasmids in RAW264.7 cells and RANKL stimulation showed significant increase (20-fold) of MMP-9 gene promoter activity; however, there is no significant change with respect to + 1 bp to - 446 bp promoter region and empty vector transfected cells. These results indicated that MMP-9 promoter sequence from - 446 bp to - 1174 bp relative to start codon is responsive to RANKL stimulation. Sequence analysis of the mouse MMP-9 gene promoter region further identified the presence of binding motif (- 1123 bp to - 1153 bp) for the nuclear factor of activated T cells 1 (NFATc1) transcription factor. Inhibition of NFATc1 using siRNA and VIVIT peptide inhibitor significantly decreased RANKL stimulation of MMP-9 activity. We further confirm by oligonucleotide pull-down assay that RANKL stimuli enhanced NFATc1 binding to MMP-9 gene promoter element. In addition, over-expression of constitutively active NFAT in RAW264.7 cells markedly increased (5-fold) MMP-9 gene promoter activity in

MECHANICAL VIBRATION INHIBITS OSTEOCLAST FORMATION BY REDUCING DC-STAMP RECEPTOR EXPRESSION IN OSTEOCLAST PRECURSOR CELLS

Science.gov (United States)

Kulkarni, R.N.; Voglewede, P.A.; Liu, D.

2014-01-01

It is well known that physical inactivity leads to loss of muscle mass, but it also causes bone loss. Mechanistically, osteoclastogenesis and bone resorption have recently been shown to be regulated by vibration. However, the underlying mechanism behind the inhibition of osteoclast formation is yet unknown. Therefore, we investigated whether mechanical vibration of osteoclast precursor cells affects osteoclast formation by the involvement of fusion-related molecules such as dendritic cell-specific transmembrane protein (DC-STAMP), and P2X7 receptor (P2X7R). RAW264.7 (a murine osteoclastic-like cell line) cells were treated with 20 ng/ml receptor activator of NF-κB ligand (RANKL). For 3 consecutive days, the cells were subjected to 1 hour of mechanical vibration with 20 µm displacement at a frequency of 4 Hz and compared to the control cells that were treated under the same condition but without the vibration. After 5 days of culture, osteoclast formation was determined. Gene expression of DC-STAMP and P2X7R by RAW264.7 cells were determined after 1 hour mechanical vibration, while protein production of the DC-STAMP was determined after 6 hours of post incubation after vibration. As a result, mechanical vibration of RAW264.7 cells inhibited the formation of osteoclasts. Vibration down-regulated DC-STAMP gene expression by 1.6-fold in the presence of RANKL and by 1.4-fold in the absence of RANKL. Additionally, DC-STAMP protein production was also down-regulated by 1.4-fold in the presence of RANKL and by 1.2-fold in the absence of RANKL in RAW264.7 cells in response to mechanical vibration. However, vibration did not affect P2X7R gene expression. Mouse anti-DC-STAMP antibody inhibited osteoclast formation in the absence of vibration. Our results suggest that mechanical vibration of osteoclast precursor cells reduce DC-STAMP expression in osteoclast precursor cells leading to the inhibition of osteoclast formation. PMID:23994170

Mechanical vibration inhibits osteoclast formation by reducing DC-STAMP receptor expression in osteoclast precursor cells.

Science.gov (United States)

Kulkarni, Rishikesh N; Voglewede, Philip A; Liu, Dawei

2013-12-01

It is well known that physical inactivity leads to loss of muscle mass, but it also causes bone loss. Mechanistically, osteoclastogenesis and bone resorption have recently been shown to be regulated by vibration. However, the underlying mechanism behind the inhibition of osteoclast formation is yet unknown. Therefore, we investigated whether mechanical vibration of osteoclast precursor cells affects osteoclast formation by the involvement of fusion-related molecules such as dendritic cell-specific transmembrane protein (DC-STAMP) and P2X7 receptor (P2X7R). RAW264.7 (a murine osteoclastic-like cell line) cells were treated with 20ng/ml receptor activator of NF-κB ligand (RANKL). For 3 consecutive days, the cells were subjected to 1h of mechanical vibration with 20μm displacement at a frequency of 4Hz and compared to the control cells that were treated under the same condition but without the vibration. After 5days of culture, osteoclast formation was determined. Gene expression of DC-STAMP and P2X7R by RAW264.7 cells was determined after 1h of mechanical vibration, while protein production of the DC-STAMP was determined after 6h of postincubation after vibration. As a result, mechanical vibration of RAW264.7 cells inhibited the formation of osteoclasts. Vibration down-regulated DC-STAMP gene expression by 1.6-fold in the presence of RANKL and by 1.4-fold in the absence of RANKL. Additionally, DC-STAMP protein production was also down-regulated by 1.4-fold in the presence of RANKL and by 1.2-fold in the absence of RANKL in RAW264.7 cells in response to mechanical vibration. However, vibration did not affect P2X7R gene expression. Mouse anti-DC-STAMP antibody inhibited osteoclast formation in the absence of vibration. Our results suggest that mechanical vibration of osteoclast precursor cells reduces DC-STAMP expression in osteoclast precursor cells leading to the inhibition of osteoclast formation. © 2013 Elsevier Inc. All rights reserved.

IL-1β Suppresses the Formation of Osteoclasts by Increasing OPG Production via an Autocrine Mechanism Involving Celecoxib-Related Prostaglandins in Chondrocytes

Directory of Open Access Journals (Sweden)

Yusuke Watanabe

2009-01-01

Full Text Available Elevated interleukin (IL-1 concentrations in synovial fluid have been implicated in joint bone and cartilage destruction. Previously, we showed that IL-1β stimulated the expression of prostaglandin (PG receptor EP4 via increased PGE2 production. However, the effect of IL-1β on osteoclast formation via chondrocytes is unclear. Therefore, we examined the effect of IL-1β and/or celecoxib on the expression of macrophage colony-stimulating factor (M-CSF, receptor activator of NF-κB ligand (RANKL, and osteoprotegerin (OPG in human chondrocytes, and the indirect effect of IL-1β on osteoclast-like cell formation using RAW264.7 cells. OPG and RANKL expression increased with IL-1β; whereas M-CSF expression decreased. Celecoxib blocked the stimulatory effect of IL-1β. Conditioned medium from IL-1β-treated chondrocytes decreased TRAP staining in RAW264.7 cells. These results suggest that IL-1β suppresses the formation of osteoclast-like cells via increased OPG production and decreased M-CSF production in chondrocytes, and OPG production may increase through an autocrine mechanism involving celecoxib-related PGs.

Tributyltin and triphenyltin inhibit osteoclast differentiation through a retinoic acid receptor-dependent signaling pathway

International Nuclear Information System (INIS)

Yonezawa, Takayuki; Hasegawa, Shin-ichi; Ahn, Jae-Yong; Cha, Byung-Yoon; Teruya, Toshiaki; Hagiwara, Hiromi; Nagai, Kazuo; Woo, Je-Tae

2007-01-01

Organotin compounds, such as tributyltin (TBT) and triphenyltin (TPT), have been widely used in agriculture and industry. Although these compounds are known to have many toxic effects, including endocrine-disrupting effects, their effects on bone resorption are unknown. In this study, we investigated the effects of organotin compounds, such as monobutyltin (MBT), dibutyltin (DBT), TBT, and TPT, on osteoclast differentiation using mouse monocytic RAW264.7 cells. MBT and DBT had no effects, whereas TBT and TPT dose-dependently inhibited osteoclast differentiation at concentrations of 3-30 nM. Treatment with a retinoic acid receptor (RAR)-specific antagonist, Ro41-5253, restored the inhibition of osteoclastogenesis by TBT and TPT. TBT and TPT reduced receptor activator of nuclear factor-κB ligand (RANKL) induced nuclear factor of activated T cells (NFAT) c1 expression, and the reduction in NFATc1 expression was recovered by Ro41-5253. Our results suggest that TBT and TPT suppress osteoclastogenesis by inhibiting RANKL-induced NFATc1 expression via an RAR-dependent signaling pathway

Esculetin attenuates receptor activator of nuclear factor kappa-B ligand-mediated osteoclast differentiation through c-Fos/nuclear factor of activated T-cells c1 signaling pathway

Energy Technology Data Exchange (ETDEWEB)

Baek, Jong Min; Park, Sun-Hyang; Cheon, Yoon-Hee; Ahn, Sung-Jun [Department of Anatomy, School of Medicine, Wonkwang University, Iksan, Jeonbuk 570-749 (Korea, Republic of); Lee, Myeung Su [Division of Rheumatology, Department of Internal Medicine, Wonkwang University, Iksan, Jeonbuk 570-749 (Korea, Republic of); Imaging Science-based Lung and Bone Diseases Research Center, Wonkwang University, Iksan, Jeonbuk 570-749 (Korea, Republic of); Institute for Skeletal Disease, Wonkwang University, Iksan, Jeonbuk 570-749 (Korea, Republic of); Oh, Jaemin, E-mail: jmoh@wku.ac.kr [Department of Anatomy, School of Medicine, Wonkwang University, Iksan, Jeonbuk 570-749 (Korea, Republic of); Imaging Science-based Lung and Bone Diseases Research Center, Wonkwang University, Iksan, Jeonbuk 570-749 (Korea, Republic of); Institute for Skeletal Disease, Wonkwang University, Iksan, Jeonbuk 570-749 (Korea, Republic of); Kim, Ju-Young, E-mail: kimjy1014@gmail.com [Imaging Science-based Lung and Bone Diseases Research Center, Wonkwang University, Iksan, Jeonbuk 570-749 (Korea, Republic of)

2015-05-29

Esculetin exerts various biological effects on anti-oxidation, anti-tumors, and anti-inflammation. However, the involvement of esculetin in the bone metabolism process, particularly osteoclast differentiation has not yet been investigated. In the present study, we first confirmed the inhibitory effect of esculetin on receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast formation. We then revealed the relationship between esculetin and the expression of osteoclast-specific molecules to elucidate its underlying mechanisms. Esculetin interfered with the expression of c-Fos and nuclear factor of activated T cell c1 (NFATc1) both at the mRNA and protein level with no involvement in osteoclast-associated early signaling pathways, suppressing the expression of various transcription factors exclusively expressed in osteoclasts such as tartrate-resistant acid phosphatase (Trap), osteoclast-associated receptor (Oscar), dendritic cell-specific transmembrane protein (Dcstamp), osteoclast stimulatory transmembrane protein (Ocstamp), cathepsin K, αvβ3 integrin, and calcitonin receptor (Ctr). Additionally, esculetin inhibited the formation of filamentous actin (F-actin) ring-positive osteoclasts during osteoclast differentiation. However, the development of F-actin structures and subsequent bone resorbing activity of mature osteoclasts, which are observed in osteoclast/osteoblast co-culture systems were not affected by esculetin. Taken together, our results indicate for the first time that esculetin inhibits RANKL-mediated osteoclastogenesis via direct suppression of c-Fos and NFATc1 expression and exerts an inhibitory effect on actin ring formation during osteoclastogenesis. - Highlights: • We first investigated the effects of esculetin on osteoclast differentiation and function. • Our data demonstrate for the first time that esculetin can suppress osteoclastogenesis in vitro. • Esculetin acts as an inhibitor of c-Fos and NFATc1 activation. �

Live imaging of osteoclast inhibition by bisphosphonates in a medaka osteoporosis model

Directory of Open Access Journals (Sweden)

Tingsheng Yu

2016-02-01

Full Text Available Osteoclasts are bone-resorbing cells derived from the monocyte/macrophage lineage. Excess osteoclast activity leads to reduced bone mineral density, a hallmark of diseases such as osteoporosis. Processes that regulate osteoclast activity are therefore targeted in current osteoporosis therapies. To identify and characterize drugs for treatment of bone diseases, suitable in vivo models are needed to complement cell-culture assays. We have previously reported transgenic medaka lines expressing the osteoclast-inducing factor receptor activator of nuclear factor κB ligand (Rankl under control of a heat shock-inducible promoter. Forced Rankl expression resulted in ectopic osteoclast formation, as visualized by live imaging in fluorescent reporter lines. This led to increased bone resorption and a dramatic reduction of mineralized matrix similar to the situation in humans with osteoporosis. In an attempt to establish the medaka as an in vivo model for osteoporosis drug screening, we treated Rankl-expressing larvae with etidronate and alendronate, two bisphosphonates commonly used in human osteoporosis therapy. Using live imaging, we observed an efficient, dose-dependent inhibition of osteoclast activity, which resulted in the maintenance of bone integrity despite an excess of osteoclast formation. Strikingly, we also found that bone recovery was efficiently promoted after inhibition of osteoclast activity and that osteoblast distribution was altered, suggesting effects on osteoblast-osteoclast coupling. Our data show that transgenic medaka lines are suitable in vivo models for the characterization of antiresorptive or bone-anabolic compounds by live imaging and for screening of novel osteoporosis drugs.

The orally available Btk inhibitor ibrutinib (PCI-32765) protects against osteoclast-mediated bone loss.

Science.gov (United States)

Shinohara, Masahiro; Chang, Betty Y; Buggy, Joseph J; Nagai, Yusuke; Kodama, Tatsuhiko; Asahara, Hiroshi; Takayanagi, Hiroshi

2014-03-01

Bone-resorbing osteoclasts play an essential role in normal bone homeostasis, as well as in various bone disorders such as osteoporosis and rheumatoid arthritis. Previously we showed that the Tec family of tyrosine kinases is essential for the differentiation of osteoclasts and the inhibition of Btk is a promising strategy for the prevention of the bone loss in osteoclast-associated bone disorders. Here we demonstrate that an orally available Btk inhibitor, ibrutinib (PCI-32765), suppresses osteoclastic bone resorption by inhibiting both osteoclast differentiation and function. Ibrutinib downregulated the expression of NFATc1, the key transcription factor for osteoclastogenesis, and disrupted the formation of the actin ring in mature osteoclasts. In addition, genome-wide screening revealed that Btk regulates the expression of the genes involved in osteoclast differentiation and function in both an NFATc1-dependent and -independent manner. Finally, we showed that ibrutinib administration ameliorated the bone loss that developed in a RANKL-induced osteoporosis mouse model. Thus, this study suggests ibrutinib to be a promising therapeutic agent for osteoclast-associated bone diseases. Copyright © 2013 Elsevier Inc. All rights reserved.

Tumor Necrosis Factor α Stimulates Osteoclast Differentiation by a Mechanism Independent of the Odf/Rankl–Rank Interaction

Science.gov (United States)

Kobayashi, Kanichiro; Takahashi, Naoyuki; Jimi, Eijiro; Udagawa, Nobuyuki; Takami, Masamichi; Kotake, Shigeru; Nakagawa, Nobuaki; Kinosaki, Masahiko; Yamaguchi, Kyoji; Shima, Nobuyuki; Yasuda, Hisataka; Morinaga, Tomonori; Higashio, Kanji; Martin, T. John; Suda, Tatsuo

2000-01-01

Osteoclast differentiation factor (ODF, also called RANKL/TRANCE/OPGL) stimulates the differentiation of osteoclast progenitors of the monocyte/macrophage lineage into osteoclasts in the presence of macrophage colony-stimulating factor (M-CSF, also called CSF-1). When mouse bone marrow cells were cultured with M-CSF, M-CSF–dependent bone marrow macrophages (M-BMMφ) appeared within 3 d. Tartrate-resistant acid phosphatase–positive osteoclasts were also formed when M-BMMφ were further cultured for 3 d with mouse tumor necrosis factor α (TNF-α) in the presence of M-CSF. Osteoclast formation induced by TNF-α was inhibited by the addition of respective antibodies against TNF receptor 1 (TNFR1) or TNFR2, but not by osteoclastogenesis inhibitory factor (OCIF, also called OPG, a decoy receptor of ODF/RANKL), nor the Fab fragment of anti–RANK (ODF/RANKL receptor) antibody. Experiments using M-BMMφ prepared from TNFR1- or TNFR2-deficient mice showed that both TNFR1- and TNFR2-induced signals were important for osteoclast formation induced by TNF-α. Osteoclasts induced by TNF-α formed resorption pits on dentine slices only in the presence of IL-1α. These results demonstrate that TNF-α stimulates osteoclast differentiation in the presence of M-CSF through a mechanism independent of the ODF/RANKL–RANK system. TNF-α together with IL-1α may play an important role in bone resorption of inflammatory bone diseases. PMID:10637272

TRAF Family Member-Associated NF-κB Activator (TANK) Induced by RANKL Negatively Regulates Osteoclasts Survival and Function

OpenAIRE

Mengrui Wu, Yiping Wang, Lianfu Deng, Wei Chen, Yi-Ping Li

2012-01-01

Osteoclasts are the principle bone-resorbing cells. Precise control of balanced osteoclast activity is indispensable for bone homeostasis. Osteoclast activation mediated by RANK-TRAF6 axis has been clearly identified. However, a negative regulation-machinery in osteoclast remains unclear. TRAF family member-associated NF-κB activator (TANK) is induced by about 10 folds during osteoclastogenesis, according to a genome-wide analysis of gene expression before and after osteoclast maturation...

TRAF Family Member-Associated NF-κB Activator (TANK) Induced by RANKL Negatively Regulates Osteoclasts Survival and Function

OpenAIRE

Wu, Mengrui; Wang, Yiping; Deng, Lianfu; Chen, Wei; Li, Yi-Ping

2012-01-01

Osteoclasts are the principle bone-resorbing cells. Precise control of balanced osteoclast activity is indispensable for bone homeostasis. Osteoclast activation mediated by RANK-TRAF6 axis has been clearly identified. However, a negative regulation-machinery in osteoclast remains unclear. TRAF family member-associated NF-κB activator (TANK) is induced by about 10 folds during osteoclastogenesis, according to a genome-wide analysis of gene expression before and after osteoclast maturation, and...

Allium cepa L. and Quercetin Inhibit RANKL/Porphyromonas gingivalis LPS-Induced Osteoclastogenesis by Downregulating NF-κB Signaling Pathway

Directory of Open Access Journals (Sweden)

Tatiane Oliveira

2015-01-01

Full Text Available Objectives. We evaluated the in vitro modulatory effects of Allium cepa L. extract (AcE and quercetin (Qt on osteoclastogenesis under inflammatory conditions (LPS-induced. Methods. RAW 264.7 cells were differentiated with 30 ng/mL of RANKL, costimulated with PgLPS (1 µg/mL, and treated with AcE (50–1000 µg/mL or Qt (1.25, 2.5, or 5 µM. Cell viability was determined by alamarBlue and protein assays. Nuclei morphology was analysed by DAPI staining. TRAP assays were performed as follows: p-nitrophenyl phosphate was used to determine the acid phosphatase activity of the osteoclasts and TRAP staining was used to evaluate the number and size of TRAP-positive multinucleated osteoclast cells. Von Kossa staining was used to measure osteoclast resorptive activity. Cytokine levels were measured on osteoclast precursor cell culture supernatants. Using western blot analysis, p-IκBα and IκBα degradation, inhibitor of NF-kappaB, were evaluated. Results. Both AcE and Qt did not affect cell viability and significantly reduced osteoclastogenesis compared to control. We observed lower production of IL-6 and IL-1α and an increased production of IL-3 and IL-4. AcE and Qt downregulated NF-κB pathway. Conclusion. AcE and Qt may be inhibitors of osteoclastogenesis under inflammatory conditions (LPS-induced via attenuation of RANKL/PgLPS-induced NF-κB activation.

Nitrogen-containing bisphosphonate, YM529/ONO-5920 (a novel minodronic acid), inhibits RANKL expression in a cultured bone marrow stromal cell line ST2

International Nuclear Information System (INIS)

Nishida, Shozo; Tsubaki, Masanobu; Hoshino, Mayumi; Namimatsu, Ayumi; Uji, Hiromi; Yoshioka, Shohei; Tanimori, Yoshihiro; Yanae, Masashi; Iwaki, Masahiro; Irimajiri, Kiyohiro

2005-01-01

Increase in bone resorption by osteoclasts can cause metabolic bone diseases, such as osteoporosis. Recent attention has been paid to the receptor activator of the NF-κB ligand (RANKL), an accelerator of osteoclast differentiation. RANKL is expressed on the bone marrow-derived stromal cell membrane and induces the differentiation of osteoclasts by binding to RANK expressed on the osteoclast precursor cell membrane. Since the inhibition of RANKL expression can lead to the inhibition of osteoclastic bone resorption, the clinical application of RANKL inhibition could be expected to have a major effect on metabolic bone disease therapy. In this study, we investigated whether or not YM529/ONO-5920, a nitrogen-containing bisphosphonate (a novel minodronic acid), inhibits RANKL expression in a bone marrow-derived stromal cell line (ST2 cells). Reverse transcription-polymerase chain reaction revealed that the administration of YM529/ONO-5920 to ST2 cells inhibited RANKL mRNA expression and reduced RANKL proteins as assessed by Western blot analysis. The inhibition of RANKL mRNA expression was reversed when geranylgeranyl pyrophosphate (GGPP), an intermediate in the mevalonate pathway, was used in combination. Furthermore, YM529/ONO-5920 reduced phosphorylated extracellular signal-regulated kinase 1/2 (ERK1/2), and similarly, U0126, a mitogen-activated protein kinase kinase 1/2 inhibitor, inhibited RANKL expression. Pretreatment with GGPP reversed the YM529/ONO-5920-induced decrease in phosphorylation of ERK. Furthermore, YM529/ONO-5920 decreased TRAP-positive cells in co-culture of ST2 cells and an osteoclast cell line, C7 cells, and this decrease was inhibited by pretreatment with GGPP. This indicates that YM529/ONO-5920 inhibits GGPP biosynthesis in the mevalonate pathway and then signal transduction in the Ras-mitogen-activated protein kinase pathway, thereby inhibiting RANKL expression on ST2 cells. These results suggest a newly elucidated action of bisphosphonates in

Generation mechanism of RANKL(+) effector memory B cells: relevance to the pathogenesis of rheumatoid arthritis.

Science.gov (United States)

Ota, Yuri; Niiro, Hiroaki; Ota, Shun-Ichiro; Ueki, Naoko; Tsuzuki, Hirofumi; Nakayama, Tsuyoshi; Mishima, Koji; Higashioka, Kazuhiko; Jabbarzadeh-Tabrizi, Siamak; Mitoma, Hiroki; Akahoshi, Mitsuteru; Arinobu, Yojiro; Kukita, Akiko; Yamada, Hisakata; Tsukamoto, Hiroshi; Akashi, Koichi

2016-03-16

The efficacy of B cell-depleting therapies for rheumatoid arthritis underscores antibody-independent functions of effector B cells such as cognate T-B interactions and production of pro-inflammatory cytokines. Receptor activator of nuclear factor κB ligand (RANKL) is a key cytokine involved in bone destruction and is highly expressed in synovial fluid B cells in patients with rheumatoid arthritis. In this study we sought to clarify the generation mechanism of RANKL(+) effector B cells and their impacts on osteoclast differentiation. Peripheral blood and synovial fluid B cells from healthy controls and patients with rheumatoid arthritis were isolated using cell sorter. mRNA expression of RANKL, osteoprotegerin, tumor necrosis factor (TNF)-α, and Blimp-1 was analyzed by quantitative real-time polymerase chain reaction. Levels of RANKL, CD80, CD86, and CXCR3 were analyzed using flow cytometry. Functional analysis of osteoclastogenesis was carried out in the co-culture system using macrophage RAW264 reporter cells. RANKL expression was accentuated in CD80(+)CD86(+) B cells, a highly activated B-cell subset more abundantly observed in patients with rheumatoid arthritis. Upon activation via B-cell receptor and CD40, switched-memory B cells predominantly expressed RANKL, which was further augmented by interferon-γ (IFN-γ) but suppressed by interleukin-21. Strikingly, IFN-γ also enhanced TNF-α expression, while it strongly suppressed osteoprotegerin expression in B cells. IFN-γ increased the generation of CXCR3(+)RANKL(+) effector B cells, mimicking the synovial B cell phenotype in patients with rheumatoid arthritis. Finally, RANKL(+) effector B cells in concert with TNF-α facilitated osteoclast differentiation in vitro. Our current findings have shed light on the generation mechanism of pathogenic RANKL(+) effector B cells that would be an ideal therapeutic target for rheumatoid arthritis in the future.

Mechanisms involved in regulation of osteoclastic differentiation by mechanical stress-loaded osteoblasts

International Nuclear Information System (INIS)

Kaneuji, Takeshi; Ariyoshi, Wataru; Okinaga, Toshinori; Toshinaga, Akihiro; Takahashi, Tetsu; Nishihara, Tatsuji

2011-01-01

Highlights: → Effect of compressive force on osteoblasts were examined. → Compressive force induced OPG expression and suppressed osteoclastogenesis. → This enhancement of OPG is dependent on Wnt/Ca2+ signal pathway. -- Abstract: Mechanical stress is known to be important for regulation of bone turnover, though the detailed mechanisms are not fully understood. In the present study, we examined the effect of mechanical stress on osteoblasts using a novel compression model. Mouse osteoblastic MC3T3-E1 cells were embedded in three-dimensional (3D) gels and cultured with continuous compressive force (0-10.0 g/cm 2 ) for 48 h, and the conditioned medium were collected. RAW264.7 cells were then incubated with the conditioned medium for various times in the presence of receptor activator of nuclear factor-κB ligand (RANKL). Conditioned medium was found to inhibit the differentiation of RAW264.7 cells into osteoclasts induced by RANKL via down-regulation of the expression of tumor necrosis factor receptor-associated factor 6 (TRAF6), phosphorylation of IκBα, and nuclear translocation of p50 and p65. Interestingly, the conditioned medium also had a high level of binding activity to RANKL and blocked the binding of RANK to RANKL. Furthermore, the binding activity of conditioned medium to RANKL was reduced when the 3D gel was supplemented with KN-93, an inhibitor of non-canonical Wnt/Ca 2+ pathway. In addition, expression level of osteoprotegerin (OPG) mRNA was increased in time- and force-dependent manners, and remarkably suppressed by KN-93. These results indicate that osteoblastic cells subjected to mechanical stress produce OPG, which binds to RANKL. Furthermore, this binding activity strongly inhibited osteoclastogenesis through suppression of TRAF6 and the nuclear factor-kappa B (NF-κB) signaling pathway, suggesting that enhancement of OPG expression induced by mechanical stress is dependent on non-canonical Wnt/Ca 2+ pathway.

Mechanisms involved in regulation of osteoclastic differentiation by mechanical stress-loaded osteoblasts

Energy Technology Data Exchange (ETDEWEB)

Kaneuji, Takeshi [Division of Oral and Maxillofacial Reconstructive Surgery, Department of Oral and Maxillofacial Surgery, Kyushu Dental College, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu 803-8580 (Japan); Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental College, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu 803-8580 (Japan); Ariyoshi, Wataru; Okinaga, Toshinori; Toshinaga, Akihiro [Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental College, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu 803-8580 (Japan); Takahashi, Tetsu [Division of Oral and Maxillofacial Reconstructive Surgery, Department of Oral and Maxillofacial Surgery, Kyushu Dental College, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu 803-8580 (Japan); Oral Bioresearch Center, Kyushu Dental College, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu 803-8580 (Japan); Nishihara, Tatsuji, E-mail: tatsujin@kyu-dent.ac.jp [Division of Infections and Molecular Biology, Department of Health Promotion, Kyushu Dental College, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu 803-8580 (Japan); Oral Bioresearch Center, Kyushu Dental College, 2-6-1 Manazuru, Kokurakita-ku, Kitakyushu 803-8580 (Japan)

2011-04-29

Highlights: {yields} Effect of compressive force on osteoblasts were examined. {yields} Compressive force induced OPG expression and suppressed osteoclastogenesis. {yields} This enhancement of OPG is dependent on Wnt/Ca2+ signal pathway. -- Abstract: Mechanical stress is known to be important for regulation of bone turnover, though the detailed mechanisms are not fully understood. In the present study, we examined the effect of mechanical stress on osteoblasts using a novel compression model. Mouse osteoblastic MC3T3-E1 cells were embedded in three-dimensional (3D) gels and cultured with continuous compressive force (0-10.0 g/cm{sup 2}) for 48 h, and the conditioned medium were collected. RAW264.7 cells were then incubated with the conditioned medium for various times in the presence of receptor activator of nuclear factor-{kappa}B ligand (RANKL). Conditioned medium was found to inhibit the differentiation of RAW264.7 cells into osteoclasts induced by RANKL via down-regulation of the expression of tumor necrosis factor receptor-associated factor 6 (TRAF6), phosphorylation of I{kappa}B{alpha}, and nuclear translocation of p50 and p65. Interestingly, the conditioned medium also had a high level of binding activity to RANKL and blocked the binding of RANK to RANKL. Furthermore, the binding activity of conditioned medium to RANKL was reduced when the 3D gel was supplemented with KN-93, an inhibitor of non-canonical Wnt/Ca{sup 2+} pathway. In addition, expression level of osteoprotegerin (OPG) mRNA was increased in time- and force-dependent manners, and remarkably suppressed by KN-93. These results indicate that osteoblastic cells subjected to mechanical stress produce OPG, which binds to RANKL. Furthermore, this binding activity strongly inhibited osteoclastogenesis through suppression of TRAF6 and the nuclear factor-kappa B (NF-{kappa}B) signaling pathway, suggesting that enhancement of OPG expression induced by mechanical stress is dependent on non-canonical Wnt

Etanercept Promotes Bone Formation via Suppression of Dickkopf-1 Expression in Rats with Collagen-Induced Arthritis

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Tanida, Atsushi; Kishimoto, Yuji; Okano, Toru; Hagino, Hiroshi

2013-01-01

Background Various clinical reports suggest etanercept (ETN) has some efficacy in bone formation in rheumatoid arthritis (RA). To examine this effect, we investigated the gene expression of cytokines relevant to osteoblast/osteoclast differentiation, and evaluated histomorphometric findings in mature rats with collagen-induced arthritis (CIA). Methods Total RNA was extracted from knee joints with CIA after ETN or placebo administration. Subsequently, realtime-PCR was carried out to quantify the mRNAs encoding Wnt-1, Dickkopf-1 (DKK-1), receptor activator of nuclear factor kappa-B ligand (RANKL), osteoprotegelin (OPG) and TNF (tumor necrosis factor)-alpha. In histomorphometric analysis, the infiltrating pannus volume and pannus surface, and the following items in contact with pannus surface were measured: osteoclast number, osteoid surface, osteoid volume and labeling surface. These were evaluated in the distal femur with CIA with or without ETN administration. Results TNF-alpha, RANKL and OPG mRNA expressions, linked to osteoclastogenesis, were not significantly different with or without ETN administration. ETN administration significantly increased Wnt-1 mRNA expression, the osteoblast promoter, and decreased DKK-1 mRNA expression, the Wnt signal inhibitor. In histomorphometric analysis, pannus volume, pannus surface and osteoclast number, parameters of bone destruction, were not significantly different among groups. Osteoid volume, osteoid surface and labeling surface, parameters of bone formation, increased significantly with ETN administration. Conclusion Our results suggest that ETN suppresses DDK-1 expression, and, as a result, Wnt expression is promoted and osteoblastogenesis becomes more active, independent of the regulation of osteoclast activity. Marked bone formation is attributed to the fact that ETN directly promotes osteoblastogenesis, not as a result of suppressing osteoclastogenesis. PMID:24031147

Aconitum pseudo-laeve var. erectum Inhibits Receptor Activator of Nuclear Factor Kappa-B Ligand-Induced Osteoclastogenesis via the c-Fos/nuclear Factor of Activated T-Cells, Cytoplasmic 1 Signaling Pathway and Prevents Lipopolysaccharide-Induced Bone Loss in Mice

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Jong Min Baek

2014-08-01

Full Text Available Aconitum pseudo-laeve var. erectum (APE has been widely shown in herbal medicine to have a therapeutic effect on inflammatory conditions. However, there has been no evidence on whether the extract of APE is involved in the biological bone metabolism process, particularly osteoclast-mediated bone resorption. In this study, we confirmed that the administration of APE could restore normal skeletal conditions in a murine model of lipopolysaccharide (LPS-induced bone loss via a decrease in the receptor activator of nuclear factor kappa-B ligand (RANKL/osteoprotegerin (OPG ratio and osteoclast number. We then investigated the effect of APE on the RANKL-induced formation and function of osteoclasts to elucidate its underlying molecular mechanisms. APE suppressed the formation of tartrate-resistant acid phosphatase (TRAP-positive cells, as well as the bone-resorbing activity of mature osteoclasts. Furthermore, APE attenuated nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1 and c-Fos without affecting any early signal pathway of osteoclastogenesis. Subsequently, APE significantly downregulated the expression of various genes exclusively expressed in osteoclasts. These results demonstrate that APE restores LPS-induced bone loss through a decrease of the serum RANKL/OPG ratio, and inhibits osteoclast differentiation and function, suggesting the promise of APE as a potential cure for various osteoclast-associated bone diseases.

Biotechnological approach for systemic delivery of membrane Receptor Activator of NF-κB Ligand (RANKL) active domain into the circulation

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Cappariello, Alfredo; Paone, Riccardo; Maurizi, Antonio; Capulli, Mattia; Rucci, Nadia; Muraca, Maurizio; Teti, Anna

2015-01-01

Deficiency of Receptor Activator of NF-κB Ligand (RANKL) prevents osteoclast formation causing osteopetrosis. RANKL is a membrane-bound protein cleaved into active soluble (s)RANKL by metalloproteinase 14 (MMP14). We created a bio-device that harbors primary osteoblasts, cultured on 3D hydroxyapatite scaffolds carrying immobilized MMP14 catalytic domain. Scaffolds were sealed in diffusion chambers and implanted in RANKL-deficient mice. Mice received 1 or 2 diffusion chambers, once or twice and were sacrificed after 1 or 2 months from implants. A progressive increase of body weight was observed in the implanted groups. Histological sections of tibias of non-implanted mice were negative for the osteoclast marker Tartrate-Resistant Acid Phosphatase (TRAcP), consistent with the lack of osteoclasts. In contrast, tibias excised from implanted mice showed TRAcP-positive cells in the bone marrow and on the bone surface, these latter morphologically similar to mature osteoclasts. In mice implanted with 4 diffusion chambers total, we noted the highest number and size of TRAcP-positive cells, with quantifiable eroded bone surface and significant reduction of trabecular bone volume. These data demonstrate that our bio-device delivers effective sRANKL, inducing osteoclastogenesis in RANKL-deficient mice, supporting the feasibility of an innovative experimental strategy to treat systemic cytokine deficiencies. PMID:25678116

CD147 promotes the formation of functional osteoclasts through NFATc1 signalling.

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Nishioku, Tsuyoshi; Terasawa, Mariko; Baba, Misaki; Yamauchi, Atsushi; Kataoka, Yasufumi

2016-04-29

CD147, a membrane glycoprotein of the immunoglobulin superfamily, is highly upregulated during dynamic cellular events including tissue remodelling. Elevated CD147 expression is present in the joint of rheumatoid arthritis patients. However, the role of CD147 in bone destruction remains unclear. To determine whether CD147 is involved in osteoclastogenesis, we studied its expression in mouse osteoclasts and its role in osteoclast differentiation and function. CD147 expression was markedly upregulated during osteoclast differentiation. To investigate the role of CD147 in receptor activator of nuclear factor-kappa B ligand (RANKL)-induced osteoclastogenesis and bone resorption activity, osteoclast precursor cells were transfected with CD147 siRNA. Decreased CD147 expression inhibited osteoclast formation and bone resorption, inhibited RANKL-induced nuclear translocation of the nuclear factor of activated T cells (NFAT) c1 and decreased the expression of the d2 isoform of vacuolar ATPase Vo domain and cathepsin K. Therefore, CD147 plays a critical role in the differentiation and function of osteoclasts by upregulating NFATc1 through the autoamplification of its expression in osteoclastogenesis. Copyright © 2016 Elsevier Inc. All rights reserved.

Prevention of wear particle-induced osteolysis by a novel V-ATPase inhibitor saliphenylhalamide through inhibition of osteoclast bone resorption.

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An Qin

Full Text Available Wear particle-induced peri-implant loosening (Aseptic prosthetic loosening is one of the most common causes of total joint arthroplasty. It is well established that extensive bone destruction (osteolysis by osteoclasts is responsible for wear particle-induced peri-implant loosening. Thus, inhibition of osteoclastic bone resorption should prevent wear particle induced osteolysis and may serve as a potential therapeutic avenue for prosthetic loosening. Here, we demonstrate for the first time that saliphenylhalamide, a new V-ATPase inhibitor attenuates wear particle-induced osteolysis in a mouse calvarial model. In vitro biochemical and morphological assays revealed that the inhibition of osteolysis is partially attributed to a disruption in osteoclast acidification and polarization, both a prerequisite for osteoclast bone resorption. Interestingly, the V-ATPase inhibitor also impaired osteoclast differentiation via the inhibition of RANKL-induced NF-κB and ERK signaling pathways. In conclusion, we showed that saliphenylhalamide affected multiple physiological processes including osteoclast differentiation, acidification and polarization, leading to inhibition of osteoclast bone resorption in vitro and wear particle-induced osteolysis in vivo. The results of the study provide proof that the new generation V-ATPase inhibitors, such as saliphenylhalamide, are potential anti-resorptive agents for treatment of peri-implant osteolysis.

Role of periodontal pathogenic bacteria in RANKL-mediated bone destruction in periodontal disease.

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Kajiya, Mikihito; Giro, Gabriela; Taubman, Martin A; Han, Xiaozhe; Mayer, Marcia P A; Kawai, Toshihisa

2010-11-08

Accumulated lines of evidence suggest that hyperimmune responses to periodontal bacteria result in the destruction of periodontal connective tissue and alveolar bone. The etiological roles of periodontal bacteria in the onset and progression of periodontal disease (PD) are well documented. However, the mechanism underlying the engagement of periodontal bacteria in RANKL-mediated alveolar bone resorption remains unclear. Therefore, this review article addresses three critical subjects. First, we discuss earlier studies of immune intervention, ultimately leading to the identification of bacteria-reactive lymphocytes as the cellular source of osteoclast-induction factor lymphokine (now called RANKL) in the context of periodontal bone resorption. Next, we consider (1) the effects of periodontal bacteria on RANKL production from a variety of adaptive immune effector cells, as well as fibroblasts, in inflamed periodontal tissue and (2) the bifunctional roles (upregulation vs. downregulation) of LPS produced from periodontal bacteria in a RANKL-induced osteoclast-signal pathway. Future studies in these two areas could lead to new therapeutic approaches for the management of PD by down-modulating RANKL production and/or RANKL-mediated osteoclastogenesis in the context of host immune responses against periodontal pathogenic bacteria.

Regulation of ITAM adaptor molecules and their receptors by inhibition of calcineurin-NFAT signalling during late stage osteoclast differentiation

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Zawawi, M.S.F. [Universiti Sains Malaysia (USM) (Malaysia); Discipline of Anatomy and Pathology, School of Medical Sciences, University of Adelaide, Adelaide, SA 5005 (Australia); Dharmapatni, A.A.S.S.K.; Cantley, M.D. [Discipline of Anatomy and Pathology, School of Medical Sciences, University of Adelaide, Adelaide, SA 5005 (Australia); McHugh, K.P. [University of Florida, College of Dentistry, Fl (United States); Haynes, D.R. [Discipline of Anatomy and Pathology, School of Medical Sciences, University of Adelaide, Adelaide, SA 5005 (Australia); Crotti, T.N., E-mail: tania.crotti@adelaide.edu.au [Discipline of Anatomy and Pathology, School of Medical Sciences, University of Adelaide, Adelaide, SA 5005 (Australia)

2012-10-19

Highlights: Black-Right-Pointing-Pointer Calcineurin/NFAT inhibitors FK506 and VIVIT treated human PBMC derived osteoclasts in vitro. Black-Right-Pointing-Pointer Differential regulation of ITAM receptors and adaptor molecules by calcineurin/NFAT inhibitors. Black-Right-Pointing-Pointer FK506 and VIVIT suppress ITAM factors during late phase osteoclast differentiation. -- Abstract: Osteoclasts are specialised bone resorptive cells responsible for both physiological and pathological bone loss. Osteoclast differentiation and activity is dependent upon receptor activator NF-kappa-B ligand (RANKL) interacting with its receptor RANK to induce the transcription factor, nuclear factor of activated T-cells, cytoplasmic, calcineurin-dependent 1 (NFATc1). The immunoreceptor tyrosine-based activation motif (ITAM)-dependent pathway has been identified as a co-stimulatory pathway in osteoclasts. Osteoclast-associated receptor (OSCAR) and triggering receptor expressed in myeloid cells (TREM2) are essential receptors that pair with adaptor molecules Fc receptor common gamma chain (FcR{gamma}) and DNAX-activating protein 12 kDa (DAP12) respectively to induce calcium signalling. Treatment with calcineurin-NFAT inhibitors, Tacrolimus (FK506) and the 11R-VIVIT (VIVIT) peptide, reduces NFATc1 expression consistent with a reduction in osteoclast differentiation and activity. This study aimed to investigate the effects of inhibiting calcineurin-NFAT signalling on the expression of ITAM factors and late stage osteoclast genes including cathepsin K (CathK), Beta 3 integrin ({beta}3) and Annexin VIII (AnnVIII). Human peripheral blood mononuclear cells (PBMCs) were differentiated with RANKL and macrophage-colony stimulating factor (M-CSF) over 10 days in the presence or absence of FK506 or VIVIT. Osteoclast formation (as assessed by tartrate resistant acid phosphatase (TRAP)) and activity (assessed by dentine pit resorption) were significantly reduced with treatment. Quantitative real

DC-STAMP Is an Osteoclast Fusogen Engaged in Periodontal Bone Resorption.

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Wisitrasameewong, W; Kajiya, M; Movila, A; Rittling, S; Ishii, T; Suzuki, M; Matsuda, S; Mazda, Y; Torruella, M R; Azuma, M M; Egashira, K; Freire, M O; Sasaki, H; Wang, C Y; Han, X; Taubman, M A; Kawai, T

2017-06-01

Dendritic cell-specific transmembrane protein (DC-STAMP) plays a key role in the induction of osteoclast (OC) cell fusion, as well as DC-mediated immune regulation. While DC-STAMP gene expression is upregulated in the gingival tissue with periodontitis, its pathophysiological roles in periodontitis remain unclear. To evaluate the effects of DC-STAMP in periodontitis, anti-DC-STAMP-monoclonal antibody (mAb) was tested in a mouse model of ligature-induced periodontitis ( n = 6-7/group) where Pasteurella pneumotropica ( Pp)-reactive immune response activated T cells to produce receptor activator of nuclear factor kappa-B ligand (RANKL), which, in turn, promotes the periodontal bone loss via upregulation of osteoclastogenesis. DC-STAMP was expressed on the cell surface of mature multinuclear OCs, as well as immature mononuclear OCs, in primary cultures of RANKL-stimulated bone marrow cells. Anti-DC-STAMP-mAb suppressed the emergence of large, but not small, multinuclear OCs, suggesting that DC-STAMP is engaged in the late stage of cell fusion. Anti-DC-STAMP-mAb also inhibited pit formation caused by RANKL-stimulated bone marrow cells. Attachment of ligature to a second maxillary molar induced DC-STAMP messenger RNA and protein, along with elevated tartrate-resistant acid phosphatase-positive (TRAP+) OCs and alveolar bone loss. As we expected, systemic administration of anti-DC-STAMP-mAb downregulated the ligature-induced alveolar bone loss. Importantly, local injection of anti-DC-STAMP-mAb also suppressed alveolar bone loss and reduced the total number of multinucleated TRAP+ cells in mice that received ligature attachment. Attachment of ligature induced significantly elevated tumor necrosis factor-α, interleukin-1β, and RANKL in the gingival tissue compared with the control site without ligature ( P < 0.05), which was unaffected by local injection with either anti-DC-STAMP-mAb or control-mAb. Neither in vivo anti- Pp IgG antibody nor in vitro anti- Pp T

RANKL downregulates cell surface CXCR6 expression through JAK2/STAT3 signaling pathway during osteoclastogenesis

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Li, Changhong; Zhao, Jinxia; Sun, Lin; Yao, Zhongqiang; Liu, Rui [Department of Rheumatology and Immunology, Peking University Third Hospital, Beijing 100191 (China); Huang, Jiansheng [Department of Pediatrics, Washington University School of Medicine, St. Louis, MO (United States); Liu, Xiangyuan, E-mail: liu-xiangyuan@263.net [Department of Rheumatology and Immunology, Peking University Third Hospital, Beijing 100191 (China)

2012-12-14

Highlights: Black-Right-Pointing-Pointer CXCR6 is down-regulated during RANKL-induced osteoclastogenesis in RAW264.7 cells. Black-Right-Pointing-Pointer CXCR6 reduction was nearly reversed by inhibition of JAK2/STAT3 signaling pathway. Black-Right-Pointing-Pointer CXCL16 alone does not positively regulate osteoclastogenesis. -- Abstract: The receptor activator of nuclear factor-{kappa}B ligand (RANKL), as a member of the tumor necrosis factor (TNF) family, plays an essential role in osteoclast differentiation and function. Chemokines and their receptors have recently been shown to play critical roles in osteoclastogenesis, however, whether CXCL16-CXCR6 plays role in RANKL-mediated osteoclastogenesis is unknown. In this study, we first reported that RANKL decreased CXCR6 in a dose-dependent manner, which may be through deactivation of Akt and STAT3 signaling induced by CXCL16. Interestingly, RANKL-mediated CXCR6 reduction may be associated to the activation of STAT3 by phosphorylation. When STAT3 activation was blocked by JAK2/STAT3 inhibitor AG490, RANKL failed to shut down CXCR6 expression during osteoclastogenesis. However, CXCL16 alone did not augment RANKL-mediated osteoclast differentiation and did not alter RANKL-receptor RANK mRNA expression. These results demonstrate that reduction of CXCL16-CXCR6 is critical in RANKL-mediated osteoclastogenesis, which is mainly through the activation of JAK2/STAT3 signaling. CXCL16-CXCR6 axis may become a novel target for the therapeutic intervention of bone resorbing diseases such as rheumatoid arthritis and osteoporosis.

Development of an in vitro culture method for stepwise differentiation of mouse embryonic stem cells and induced pluripotent stem cells into mature osteoclasts.

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Nishikawa, Keizo; Iwamoto, Yoriko; Ishii, Masaru

2014-05-01

The development of methods for differentiation of embryonic stem cells (ESCs) and induced pluripotent stem cell (iPSCs) into functional cells have helped to analyze the mechanism regulating cellular processes and to explore cell-based assays for drug discovery. Although several reports have demonstrated methods for differentiation of mouse ESCs into osteoclast-like cells, it remains unclear whether these methods are applicable for differentiation of iPSCs to osteoclasts. In this study, we developed a simple method for stepwise differentiation of mouse ESCs and iPSCs into bone-resorbing osteoclasts based upon a monoculture approach consisting of three steps. First, based on conventional hanging-drop methods, embryoid bodies (EBs) were produced from mouse ESCs or iPSCs. Second, EBs were cultured in medium supplemented with macrophage colony-stimulating factor (M-CSF), and differentiated to osteoclast precursors, which expressed CD11b. Finally, ESC- or iPSC-derived osteoclast precursors stimulated with receptor activator of nuclear factor-B ligand (RANKL) and M-CSF formed large multinucleated osteoclast-like cells that expressed tartrate-resistant acid phosphatase and were capable of bone resorption. Molecular analysis showed that the expression of osteoclast marker genes such as Nfatc1, Ctsk, and Acp5 are increased in a RANKL-dependent manner. Thus, our procedure is simple and easy and would be helpful for stem cell-based bone research.

Sulforaphane inhibits osteoclast differentiation by suppressing the cell-cell fusion molecules DC-STAMP and OC-STAMP

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Takagi, Tomohiro; Inoue, Hirofumi; Takahashi, Nobuyuki; Katsumata-Tsuboi, Rie; Uehara, Mariko

2017-01-01

Sulforaphane (SFN), a kind of isothiocyanate, is derived from broccoli sprouts. It has anti-tumor, anti-inflammatory, and anti-oxidation activity. The molecular function of SFN in the inhibition of osteoclast differentiation is not well-documented. In this study, we assessed the effect of SFN on osteoclast differentiation in vitro. SFN inhibited osteoclast differentiation in both bone marrow cells and RAW264.7 cells. Key molecules involved in the inhibitory effects of SFN on osteoclast differentiation were determined using a microarray analysis, which showed that SFN inhibits osteoclast-associated genes, such as osteoclast-associated receptor (OSCAR), nuclear factor of activated T cells cytoplasmic-1, tartrate-resistant acid phosphatase, and cathepsin K. Moreover, the mRNA expression levels of the cell-cell fusion molecules dendritic cell specific transmembrane protein (DC-STAMP) and osteoclast stimulatory transmembrane protein (OC-STAMP) were strongly suppressed in cells treated with SFN. Furthermore, SFN increased the phosphorylation of signal transducer and activator of transcription 1 (STAT1), a regulator of macrophage and osteoclast cell fusion. Thus, our data suggested that SFN significantly inhibits the cell-cell fusion molecules DC-STAMP and OC-STAMP by inducing the phosphorylation of STAT1 (Tyr701), which might be regulated by interactions with OSCAR. - Highlights: • Sulforaphane inhibited osteoclast differentiation and osteoclast cell-fusion. • Sulforaphane suppressed not only NFATc1, but also cell-cell fusion molecules, DC-STAMP and OC-STAMP. • Sulforaphane decreased multinucleated osteoclasts, whereas increased mono-nucleated osteoclasts. • Sulforaphane inhibits the cell-cell fusion by inducing the phosphorylation of STAT1 (Tyr701).

Bu-Shen-Ning-Xin decoction: inhibition of osteoclastogenesis by abrogation of the RANKL-induced NFATc1 and NF-κB signaling pathways via selective estrogen receptor α

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Wang L

2015-07-01

Full Text Available Ling Wang,1,2,* Xue-Min Qiu,1,2,* Yu-Yan Gui,1,2 Ying-Ping Xu,1,2 Hans-Jürgen Gober,3 Da-Jin Li11Laboratory for Reproductive Immunology, Hospital and Institute of Obstetrics and Gynecology, IBS, Fudan University Shanghai Medical College, 2Shanghai Key Laboratory of Female Reproductive Endocrine Related Diseases, Shanghai, People’s Republic of China; 3Department of Pharmacy, Wagner Jauregg Hospital and Children’s Hospital, Wagner Jauregg Weg, Linz, Austria*These authors contributed equally to this workIntroduction: Bu-Shen-Ning-Xin decoction (BSNXD is a traditional Chinese medicinal composition that has been used as a remedy for postmenopausal osteoporosis, but the mechanisms affecting bone metabolism are not fully understood.Purpose: We investigated the molecular mechanism and signaling pathway underlying the effect of BSNXD on osteoclastogenesis.Materials and methods: A postmenopausal osteoporosis animal model generated by ovariectomy was administered BSNXD and drug-derived serum was prepared. An enzyme immunoassay was conducted to measure the 17-β-estradiol (E2 concentration in the drug-derived serum. Bone marrow-derived monocyte/macrophage precursor cells were treated with drug-derived serum, and tartrate-resistance acid phosphatase staining was conducted to observe osteoclastogenesis. A bone resorption assay was performed to analyze the effect on osteoclastic resorptive function. Real-time PCR, flow cytometry, Western blotting, transfection, and luciferase assays were conducted to explore the related mechanism.Results: E2 was not elevated in BSNXD-derived serum. BSNXD-derived serum suppressed receptor activation of nuclear factor κB ligand (RANKL-activated osteoclastogenesis in a dose-dependent manner; this effect could be reversed by estrogen receptor α antagonist methyl-piperidino-pyrazole. The serum suppressed RANKL-induced NF-κB transcription and inhibited the accumulation of nuclear factor of activated T-cells, cytoplasmic 1

Dendrobium moniliforme Exerts Inhibitory Effects on Both Receptor Activator of Nuclear Factor Kappa-B Ligand-Mediated Osteoclast Differentiation in Vitro and Lipopolysaccharide-Induced Bone Erosion in Vivo.

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Baek, Jong Min; Kim, Ju-Young; Ahn, Sung-Jun; Cheon, Yoon-Hee; Yang, Miyoung; Oh, Jaemin; Choi, Min Kyu

2016-03-01

Dendrobium moniliforme (DM) is a well-known plant-derived extract that is widely used in Oriental medicine. DM and its chemical constituents have been reported to have a variety of pharmacological effects, including anti-oxidative, anti-inflammatory, and anti-tumor activities; however, no reports discuss the beneficial effects of DM on bone diseases such as osteoporosis. Thus, we investigated the relationship between DM and osteoclasts, cells that function in bone resorption. We found that DM significantly reduced receptor activator of nuclear factor kappa-B ligand (RANKL)-induced tartrate-resistant acid phosphatase (TRAP)-positive osteoclast formation; DM directly induced the down-regulation of c-Fos and nuclear factor of activated T cells c1 (NFATc1) without affecting other RANKL-dependent transduction pathways. In the later stages of osteoclast maturation, DM negatively regulated the organization of filamentous actin (F-actin), resulting in impaired bone-resorbing activity by the mature osteoclasts. In addition, micro-computed tomography (μ-CT) analysis of the murine model revealed that DM had a beneficial effect on lipopolysaccharide (LPS)-mediated bone erosion. Histological analysis showed that DM attenuated the degradation of trabecular bone matrix and formation of TRAP-positive osteoclasts in bone tissues. These results suggest that DM is a potential candidate for the treatment of metabolic bone disorders such as osteoporosis.

Key Triggers of Osteoclast-Related Diseases and Available Strategies for Targeted Therapies: A Review

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Haidi Bi

2017-12-01

Full Text Available Osteoclasts, the only cells with bone resorption functions in vivo, maintain the balance of bone metabolism by cooperating with osteoblasts, which are responsible for bone formation. Excessive activity of osteoclasts causes many diseases such as osteoporosis, periprosthetic osteolysis, bone tumors, and Paget’s disease. In contrast, osteopetrosis results from osteoclast deficiency. Available strategies for combating over-activated osteoclasts and the subsequently induced diseases can be categorized into three approaches: facilitating osteoclast apoptosis, inhibiting osteoclastogenesis, and impairing bone resorption. Bisphosphonates are representative molecules that function by triggering osteoclast apoptosis. New drugs, such as tumor necrosis factor and receptor activator of nuclear factor kappa-B ligand (RANKL inhibitors (e.g., denosumab have been developed for targeting the receptor activator of nuclear factor kappa-B /RANKL/osteoprotegerin system or CSF-1/CSF-1R axis, which play critical roles in osteoclast formation. Furthermore, vacuolar (H+-ATPase inhibitors, cathepsin K inhibitors, and glucagon-like peptide 2 impair different stages of the bone resorption process. Recently, significant achievements have been made in this field. The aim of this review is to provide an updated summary of the current progress in research involving osteoclast-related diseases and of the development of targeted inhibitors of osteoclast formation.

Ly49Q, an ITIM-bearing NK receptor, positively regulates osteoclast differentiation

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Hayashi, Mikihito; Nakashima, Tomoki; Kodama, Tatsuhiko; Makrigiannis, Andrew P.; Toyama-Sorimachi, Noriko; Takayanagi, Hiroshi

2010-01-01

Osteoclasts, multinucleated cells that resorb bone, play a key role in bone remodeling. Although immunoreceptor tyrosine-based activation motif (ITAM)-mediated signaling is critical for osteoclast differentiation, the significance of immunoreceptor tyrosine-based inhibitory motif (ITIM) has not been well understood. Here we report the function of Ly49Q, an Ly49 family member possessing an ITIM motif, in osteoclastogenesis. Ly49Q is selectively induced by receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL) stimulation in bone marrow-derived monocyte/macrophage precursor cells (BMMs) among the Ly49 family of NK receptors. The knockdown of Ly49Q resulted in a significant reduction in the RANKL-induced formation of tartrate-resistance acid phosphatase (TRAP)-positive multinucleated cells, accompanied by a decreased expression of osteoclast-specific genes such as Nfatc1, Tm7sf4, Oscar, Ctsk, and Acp5. Osteoclastogenesis was also significantly impaired in Ly49Q-deficient cells in vitro. The inhibitory effect of Ly49Q-deficiency may be explained by the finding that Ly49Q competed for the association of Src-homology domain-2 phosphatase-1 (SHP-1) with paired immunoglobulin-like receptor-B (PIR-B), an ITIM-bearing receptor which negatively regulates osteoclast differentiation. Unexpectedly, Ly49Q deficiency did not lead to impaired osteoclast formation in vivo, suggesting the existence of a compensatory mechanism. This study provides an example in which an ITIM-bearing receptor functions as a positive regulator of osteoclast differentiation.

Identification of a subpopulation of marrow MSC-derived medullary adipocytes that express osteoclast-regulating molecules: marrow adipocytes express osteoclast mediators.

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Vance Holt

Full Text Available Increased marrow medullary adipogenesis and an associated decrease in bone mineral density, usually observed in elderly individuals, is a common characteristic in senile osteoporosis. In this study we investigated whether cells of the medullary adipocyte lineage have the potential to directly support the formation of osteoclasts, whose activity in bone leads to bone degradation. An in vitro mesenchymal stem cell (MSC-derived medullary adipocyte lineage culture model was used to study the expression of the important osteoclast mediators RANKL, M-CSF, SDF-1, and OPG. We further assessed whether adipocytes at a specific developmental stage were capable of supporting osteoclast-like cell formation in culture. In vitro MSC-derived medullary adipocytes showed an mRNA and protein expression profile of M-CSF, RANKL, and OPG that was dependent on its developmental/metabolic stage. Furthermore, RANKL expression was observed in MSC-derived adipocytes that were at a distinct lineage stage and these cells were also capable of supporting osteoclast-like cell formation in co-cultures with peripheral blood mononuclear cells. These results suggest a connection between medullary adipocytes and osteoclast formation in vivo and may have major significance in regards to the mechanisms of decreased bone density in senile osteoporosis.

Feeding blueberry diets to young rats dose-dependently inhibits bone resorption through suppression of RANKL in stromal cells.

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Jian Zhang

Full Text Available Previous studies have demonstrated that weanling rats fed AIN-93G semi-purified diets supplemented with 10% whole blueberry (BB powder for two weeks beginning on postnatal day 21 (PND21 significantly increased bone formation at PND35. However, the minimal level of dietary BB needed to produce these effects is, as yet, unknown. The current study examined the effects of three different levels of BB diet supplementation (1, 3, and 5% for 35 days beginning on PND25 on bone quality, and osteoclastic bone resorption in female rats. Peripheral quantitative CT scan (pQCT of tibia, demonstrated that bone mineral density (BMD and content (BMC were dose-dependently increased in BB-fed rats compared to controls (P<0.05. Significantly increased bone mass after feeding 5% BB extracts was also observed in a TEN (total enteral nutrition rat model in which daily caloric and food intake was precisely controlled. Expression of RANKL (receptor activator of nuclear factor-κB ligand a protein essential for osteoclast formation was dose-dependently decreased in the femur of BB animals. In addition, expression of PPARγ (peroxisome proliferator-activated receptor γ which regulates bone marrow adipogenesis was suppressed in BB diet rats compared to non-BB diet controls. Finally, a set of in vitro cell cultures revealed that the inhibitory effect of BB diet rat serum on RANKL expression was more profound in mesenchymal stromal cells compared to its effect on mature osteoblasts, pre-adipocytes and osteocytes. These results suggest that inhibition of bone resorption may contribute to increased bone mass during early development after BB consumption.

Betulinic acid, a bioactive pentacyclic triterpenoid, inhibits skeletal-related events induced by breast cancer bone metastases and treatment

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Park, Se Young; Kim, Hyun-Jeong; Kim, Ki Rim; Lee, Sun Kyoung; Lee, Chang Ki; Park, Kwang-Kyun; Chung, Won-Yoon

2014-01-01

Many breast cancer patients experience bone metastases and suffer skeletal complications. The present study provides evidence on the protective and therapeutic potential of betulinic acid on cancer-associated bone diseases. Betulinic acid is a naturally occurring triterpenoid with the beneficial activity to limit the progression and severity of cancer, diabetes, cardiovascular diseases, atherosclerosis, and obesity. We first investigated its effect on breast cancer cells, osteoblastic cells, and osteoclasts in the vicious cycle of osteolytic bone metastasis. Betulinic acid reduced cell viability and the production of parathyroid hormone-related protein (PTHrP), a major osteolytic factor, in MDA-MB-231 human metastatic breast cancer cells stimulated with or without tumor growth factor-β. Betulinic acid blocked an increase in the receptor activator of nuclear factor-kappa B ligand (RANKL)/osteoprotegerin ratio by downregulating RANKL protein expression in PTHrP-treated human osteoblastic cells. In addition, betulinic acid inhibited RANKL-induced osteoclastogenesis in murine bone marrow macrophages and decreased the production of resorbed area in plates with a bone biomimetic synthetic surface by suppressing the secretion of matrix metalloproteinase (MMP)-2, MMP-9, and cathepsin K in RANKL-induced osteoclasts. Furthermore, oral administration of betulinic acid inhibited bone loss in mice intra-tibially inoculated with breast cancer cells and in ovariectomized mice causing estrogen deprivation, as supported by the restored bone morphometric parameters and serum bone turnover markers. Taken together, these findings suggest that betulinic acid may have the potential to prevent bone loss in patients with bone metastases and cancer treatment-induced estrogen deficiency. - Highlights: • Betulinic acid reduced PTHrP production in human metastatic breast cancer cells. • Betulinic acid blocked RANKL/OPG ratio in PTHrP-stimulated human osteoblastic cells. • Betulinic

Betulinic acid, a bioactive pentacyclic triterpenoid, inhibits skeletal-related events induced by breast cancer bone metastases and treatment

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Park, Se Young; Kim, Hyun-Jeong; Kim, Ki Rim; Lee, Sun Kyoung; Lee, Chang Ki; Park, Kwang-Kyun, E-mail: biochelab@yuhs.ac; Chung, Won-Yoon, E-mail: wychung@yuhs.ac

2014-03-01

Many breast cancer patients experience bone metastases and suffer skeletal complications. The present study provides evidence on the protective and therapeutic potential of betulinic acid on cancer-associated bone diseases. Betulinic acid is a naturally occurring triterpenoid with the beneficial activity to limit the progression and severity of cancer, diabetes, cardiovascular diseases, atherosclerosis, and obesity. We first investigated its effect on breast cancer cells, osteoblastic cells, and osteoclasts in the vicious cycle of osteolytic bone metastasis. Betulinic acid reduced cell viability and the production of parathyroid hormone-related protein (PTHrP), a major osteolytic factor, in MDA-MB-231 human metastatic breast cancer cells stimulated with or without tumor growth factor-β. Betulinic acid blocked an increase in the receptor activator of nuclear factor-kappa B ligand (RANKL)/osteoprotegerin ratio by downregulating RANKL protein expression in PTHrP-treated human osteoblastic cells. In addition, betulinic acid inhibited RANKL-induced osteoclastogenesis in murine bone marrow macrophages and decreased the production of resorbed area in plates with a bone biomimetic synthetic surface by suppressing the secretion of matrix metalloproteinase (MMP)-2, MMP-9, and cathepsin K in RANKL-induced osteoclasts. Furthermore, oral administration of betulinic acid inhibited bone loss in mice intra-tibially inoculated with breast cancer cells and in ovariectomized mice causing estrogen deprivation, as supported by the restored bone morphometric parameters and serum bone turnover markers. Taken together, these findings suggest that betulinic acid may have the potential to prevent bone loss in patients with bone metastases and cancer treatment-induced estrogen deficiency. - Highlights: • Betulinic acid reduced PTHrP production in human metastatic breast cancer cells. • Betulinic acid blocked RANKL/OPG ratio in PTHrP-stimulated human osteoblastic cells. • Betulinic

Lipoxin A4 suppresses osteoclastogenesis in RAW264.7 cells and prevents ovariectomy-induced bone loss

Energy Technology Data Exchange (ETDEWEB)

Liu, Changyu; Guan, Hanfeng; Cai, Cong; Li, Feng, E-mail: lifengmd@hust.edu.cn; Xiao, Jun, E-mail: jun_xiao@hust.edu.cn

2017-03-15

Lipoxin A4 (LXA4; 5S, 6R, 15Strihydroxy- 7,9,13-trans-11-eicosatetraenoic acid) is a metabolic product of arachidonic acid under the action of lipoxidase. This lipid molecule plays important roles in several biological functions, especially inflammatory processes. In vivo, LXA4 regulates the inflammatory response through several signaling pathways. Its mechanism suggests that it might have an effect on osteoclastogenesis and bone loss. Using both in vitro and in vivo studies, it was here observed that LXA4 could significantly inhibit the formation and function of osteoclasts and these effects could be blocked by Boc-2, the specific inhibitor of FPR2/ALX (the receptor of LXA4). Meanwhile, LXA4 reduce the amount of ovariectomy-induced bone loss. These protective effects was found to be associated with inhibition of nuclear factor-κB (NF-κB), activator protein-1 (AP-1), PI3K-AKT, and p-38, ERK, and JNK in MAPKs. The expression of the receptor activator of the NF-κB ligand RANKL:osteoprotegerin ratio and serum levels of TNF-α, IL-1β, and IL-6 were decreased by LXA4. Moreover, LXA4 prevented the production of reactive oxygen species (ROS), the expression of osteoclast-specific genes, including tartrate-resistant acid phosphatase (TRAP), cathepsin K (CK), matrix metalloproteinase (MMP)-9, RANK, and osteoclastic related transcription factors of c-Fos, NFATc1 could also be significantly inhibited by LXA4 in a dose-dependent manner. Studies have demonstrated that LXA4 can inhibit the formation and function of osteoclasts through modulation of several pathways both upstream and downstream of RANKL signaling and FPR2/ALX was involved in the procedures. This shows that LXA4 may be used as a new strategy for the treatment of osteoclast-related diseases. - Highlights: • Lipoxin A4 can significantly inhibit the formation and function of osteoclasts. • Several pathways both upstream and downstream of RANKL signaling can be inhibit by Lipoxin A4. • Lipoxin A4 can

Disulfiram attenuates osteoclast differentiation in vitro: a potential antiresorptive agent.

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Hua Ying

Full Text Available Disulfiram (DSF, a cysteine modifying compound, has long been clinically employed for the treatment of alcohol addiction. Mechanistically, DSF acts as a modulator of MAPK and NF-κB pathways signaling pathways. While these pathways are crucial for osteoclast (OC differentiation, the potential influence of DSF on OC formation and function has not been directly assessed. Here, we explore the pharmacological effects of DSF on OC differentiation, activity and the modulation of osteoclastogenic signaling cascades. We first analyzed cytotoxicity of DSF on bone marrow monocytes isolated from C57BL/6J mice. Upon the establishment of optimal dosage, we conducted osteoclastogenesis and bone resorption assays in the presence or absence of DSF treatment. Luciferase assays in RAW264.7 cells were used to examine the effects of DSF on major transcription factors activation. Western blot, reverse transcription polymerase chain reaction, intracellular acidification and proton influx assays were employed to further dissect the underlying mechanism. DSF treatment dose-dependently inhibited both mouse and human osteoclastogenesis, especially at early stages of differentiation. This inhibition correlated with a decrease in the expression of key osteoclastic marker genes including CtsK, TRAP, DC-STAMP and Atp6v0d2 as well as a reduction in bone resorption in vitro. Suppression of OC differentiation was found to be due, at least in part, to the blockade of several key receptor activators of nuclear factor kappa-B ligand (RANKL-signaling pathways including ERK, NF-κB and NFATc1. On the other hand, DSF failed to suppress intracellular acidification and proton influx in mouse and human osteoclasts using acridine orange quenching and microsome-based proton transport assays. Our findings indicate that DSF attenuates OC differentiation via the collective suppression of several key RANKL-mediated signaling cascades, thus making it an attractive agent for the treatment of OC

Involvement of the G-protein-coupled receptor 4 in RANKL expression by osteoblasts in an acidic environment

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Okito, Asuka [Department of Cellular Physiological Chemistry, Tokyo Medical and Dental University, Tokyo (Japan); Department of Orthodontic Science, Tokyo Medical and Dental University, Tokyo (Japan); Nakahama, Ken-ichi, E-mail: nakacell@tmd.ac.jp [Department of Cellular Physiological Chemistry, Tokyo Medical and Dental University, Tokyo (Japan); Akiyama, Masako [Department of Cellular Physiological Chemistry, Tokyo Medical and Dental University, Tokyo (Japan); Ono, Takashi [Department of Orthodontic Science, Tokyo Medical and Dental University, Tokyo (Japan); Morita, Ikuo [Department of Cellular Physiological Chemistry, Tokyo Medical and Dental University, Tokyo (Japan)

2015-03-06

Osteoclast activity is enhanced in acidic environments following systemic or local inflammation. However, the regulatory mechanism of receptor activator of NF-κB ligand (RANKL) expression in osteoblasts under acidic conditions is not fully understood. In the present paper, we detected the mRNA expression of the G-protein-coupled receptor (GPR) proton sensors GPR4 and GPR65 (T-cell death-associated gene 8, TDAG8), in osteoblasts. RANKL expression and the cyclic AMP (cAMP) level in osteoblasts were up-regulated under acidic culture conditions. Acidosis-induced up-regulation of RANKL was abolished by the protein kinase A inhibitor H89. To clarify the role of GPR4 in RANKL expression, GPR4 gain and loss of function experiments were performed. Gene knockdown and forced expression of GPR4 caused reduction and induction of RANKL expression, respectively. These results suggested that, at least in part, RANKL expression by osteoblasts in an acidic environment was mediated by cAMP/PKA signaling resulting from GPR4 activation. A comprehensive microarray analysis of gene expression of osteoblasts revealed that, under acidic conditions, the phenotype of osteoblasts was that of an osteoclast supporting cell rather than that of a mineralizing cell. These findings will contribute to a molecular understanding of bone disruption in an acidic environment. - Highlights: • RANKL expression was increased in osteoblasts under acidosis via cAMP/PKA pathway. • GRP4 knockdown resulted in decrease of RANKL expression. • GRP4 overexpression resulted in increase of RANKL expression. • Osteoblast mineralization was reduced under acidic condition.

G protein-coupled receptor 84 controls osteoclastogenesis through inhibition of NF-κB and MAPK signaling pathways.

Science.gov (United States)

Park, Ji-Wan; Yoon, Hye-Jin; Kang, Woo Youl; Cho, Seungil; Seong, Sook Jin; Lee, Hae Won; Yoon, Young-Ran; Kim, Hyun-Ju

2018-02-01

GPR84, a member of the G protein-coupled receptor family, is found predominantly in immune cells, such as macrophages, and functions as a pivotal modulator of inflammatory responses. In this study, we investigated the role of GPR84 in receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation. Our microarray data showed that GPR84 was significantly downregulated in osteoclasts compared to in their precursors, macrophages. The overexpression of GPR84 in bone marrow-derived macrophages suppressed the formation of multinucleated osteoclasts without affecting precursor proliferation. In addition, GPR84 overexpression attenuated the induction of c-Fos and nuclear factor of activated T cells, cytoplasmic 1 (NFATc1), which are transcription factors that are critical for osteoclastogenesis. Furthermore, knockdown of GPR84 using a small hairpin RNA promoted RANKL-mediated osteoclast differentiation and gene expression of osteoclastogenic markers. Mechanistically, GPR84 overexpression blocked RANKL-stimulated phosphorylation of IκBα and three MAPKs, JNK, ERK, and p38. GPR84 also suppressed NF-κB transcriptional activity mediated by RANKL. Conversely, GPR84 knockdown enhanced RANKL-induced activation of IκBα and the three MAPKs. Collectively, our results revealed that GPR84 functions as a negative regulator of osteoclastogenesis, suggesting that it may be a potential therapeutic target for osteoclast-mediated bone-destructive diseases. © 2017 Wiley Periodicals, Inc.

Down-regulation of Irf8 by Lyz2-cre/loxP accelerates osteoclast differentiation in vitro.

Science.gov (United States)

Saito, Emi; Suzuki, Dai; Kurotaki, Daisuke; Mochizuki, Ayako; Manome, Yoko; Suzawa, Tetsuo; Toyoshima, Yoichi; Ichikawa, Takahiro; Funatsu, Takahiro; Inoue, Tomio; Takami, Masamichi; Tamura, Tomohiko; Inagaki, Katsunori; Kamijo, Ryutaro

2017-06-01

Interferon regulatory factor 8 (Irf8) is a transcription factor that negatively regulates osteoclast differentiation and Irf8 global knockout (Irf8 -/- ) mice have been shown to have reduced bone volume resulting from increased osteoclast numbers. However, detailed analysis of the functions of Irf8 in osteoclast precursors with a monocyte/macrophage linage is difficult, because the population and properties of hematopoietic cells in Irf8 -/- mice are severely altered. Therefore, to clearly elucidate the functions of Irf8 during osteoclastogenesis, we established myeloid cell-specific Irf8 conditional knockout (Irf8 fl/fl ;Lyz2 cre/+ ) mice. We found that trabecular bone volume in the Irf8 fl/fl ;Lyz2 cre/+ mice was not significantly affected, while exposure to M-CSF and RANKL significantly increased TRAP activity in vitro in osteoclasts that underwent osteoclastogenesis from bone marrow-derived macrophages (BMMs) induced from bone marrow cells (BMCs) of those mice by addition of M-CSF. Our results also showed that expression of Irf8 mRNA and protein in BMMs obtained from Irf8 fl/fl ;Lyz2 cre/+ mice and cultured with M-CSF was reduced. These findings predicted that Lyz2/Lyz2-cre expression is induced when BMCs differentiate into BMMs in cultures with M-CSF. In osteoclast differentiation cultures, Lyz2 was gradually increased by M-CSF during the first 3 days of culture, then rapidly decreased by the addition of RANKL with M-CSF during the next 3 days. Furthermore, BMCs differentiated into osteoclasts while maintaining a low level of Lyz2 expression when cultured simultaneously with both M-CSF and RANKL from the initiation of culture. These findings suggest that Lyz2-cre expression is induced along with differentiation to BMMs by BMCs obtained from Irf8 fl/fl ;Lyz2 cre/+ mice and cultured with M-CSF. In addition, Irf8 was down-regulated by activation of the cre/loxP recombination system in BMMs and osteoclastogenesis was accelerated. Based on our results, we propose

Estrogen directly attenuates human osteoclastogenesis, but has no effect on resorption by mature osteoclasts

DEFF Research Database (Denmark)

Sørensen, M G; Henriksen, K; Dziegiel, Morten Hanefeld

2006-01-01

+ monocytes were cultured in the presence of M-CSF and RANKL to induce osteoclast differentiation. Addition of 0.1-10 nM 17beta-estradiol to differentiating osteoclasts resulted in a dose-dependent reduction in tartrate resistant acid phosphatase (TRACP) activity reaching 60% at 0.1 nM. In addition, 17beta-estradiol...... inhibited bone resorption, as measured by the release of the C-terminal crosslinked telopeptide (CTX), by 60% at 0.1 nM, but had no effect on the overall cell viability. In contrast to the results obtained with differentiating osteoclasts, addition of 17beta-estradiol (0.001-10 nM) to mature osteoclasts did...

Siglec-15, a member of the sialic acid-binding lectin, is a novel regulator for osteoclast differentiation

International Nuclear Information System (INIS)

Hiruma, Yoshiharu; Hirai, Takehiro; Tsuda, Eisuke

2011-01-01

Highlights: → Siglec-15 was identified as a gene overexpressed in giant cell tumor. → Siglec-15 mRNA expression increased in association with osteoclast differentiation. → Polyclonal antibody to Siglec-15 inhibited osteoclast differentiation in vitro. -- Abstract: Osteoclasts are tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells derived from monocyte/macrophage-lineage precursors and are critically responsible for bone resorption. In giant cell tumor of bone (GCT), numerous TRAP-positive multinucleated giant cells emerge and severe osteolytic bone destruction occurs, implying that the emerged giant cells are biologically similar to osteoclasts. To identify novel genes involved in osteoclastogenesis, we searched genes whose expression pattern was significantly different in GCT from normal and other bone tumor tissues. By screening a human gene expression database, we identified sialic acid-binding immunoglobulin-like lectin 15 (Siglec-15) as one of the genes markedly overexpressed in GCT. The mRNA expression level of Siglec-15 increased in association with osteoclast differentiation in cultures of mouse primary unfractionated bone marrow cells (UBMC), RAW264.7 cells of the mouse macrophage cell line and human osteoclast precursors (OCP). Treatment with polyclonal antibody to mouse Siglec-15 markedly inhibited osteoclast differentiation in primary mouse bone marrow monocyte/macrophage (BMM) cells stimulated with receptor activator of nuclear factor κB ligand (RANKL) or tumor necrosis factor (TNF)-α. The antibody also inhibited osteoclast differentiation in cultures of mouse UBMC and RAW264.7 cells stimulated with active vitamin D 3 and RANKL, respectively. Finally, treatment with polyclonal antibody to human Siglec-15 inhibited RANKL-induced TRAP-positive multinuclear cell formation in a human OCP culture. These results suggest that Siglec-15 plays an important role in osteoclast differentiation.

Siglec-15, a member of the sialic acid-binding lectin, is a novel regulator for osteoclast differentiation

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Hiruma, Yoshiharu, E-mail: hiruma.yoshiharu.hy@daiichisankyo.co.jp [Biological Research Laboratories, Daiichi Sankyo Co. Ltd., Tokyo 134-8630 (Japan); Hirai, Takehiro [Translational Medicine and Clinical Pharmacology Department, Daiichi Sankyo Co. Ltd., Tokyo 134-8630 (Japan); Tsuda, Eisuke [Biological Research Laboratories, Daiichi Sankyo Co. Ltd., Tokyo 134-8630 (Japan)

2011-06-10

Highlights: {yields} Siglec-15 was identified as a gene overexpressed in giant cell tumor. {yields} Siglec-15 mRNA expression increased in association with osteoclast differentiation. {yields} Polyclonal antibody to Siglec-15 inhibited osteoclast differentiation in vitro. -- Abstract: Osteoclasts are tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells derived from monocyte/macrophage-lineage precursors and are critically responsible for bone resorption. In giant cell tumor of bone (GCT), numerous TRAP-positive multinucleated giant cells emerge and severe osteolytic bone destruction occurs, implying that the emerged giant cells are biologically similar to osteoclasts. To identify novel genes involved in osteoclastogenesis, we searched genes whose expression pattern was significantly different in GCT from normal and other bone tumor tissues. By screening a human gene expression database, we identified sialic acid-binding immunoglobulin-like lectin 15 (Siglec-15) as one of the genes markedly overexpressed in GCT. The mRNA expression level of Siglec-15 increased in association with osteoclast differentiation in cultures of mouse primary unfractionated bone marrow cells (UBMC), RAW264.7 cells of the mouse macrophage cell line and human osteoclast precursors (OCP). Treatment with polyclonal antibody to mouse Siglec-15 markedly inhibited osteoclast differentiation in primary mouse bone marrow monocyte/macrophage (BMM) cells stimulated with receptor activator of nuclear factor {kappa}B ligand (RANKL) or tumor necrosis factor (TNF)-{alpha}. The antibody also inhibited osteoclast differentiation in cultures of mouse UBMC and RAW264.7 cells stimulated with active vitamin D{sub 3} and RANKL, respectively. Finally, treatment with polyclonal antibody to human Siglec-15 inhibited RANKL-induced TRAP-positive multinuclear cell formation in a human OCP culture. These results suggest that Siglec-15 plays an important role in osteoclast differentiation.

Interleukin-3 plays dual roles in osteoclastogenesis by promoting the development of osteoclast progenitors but inhibiting the osteoclastogenic process

Energy Technology Data Exchange (ETDEWEB)

Hong, Huixian [Department of Hematology, Guangzhou First People’s Hospital, Guangzhou Medical University, Guangzhou, Guangdong 510180 (China); Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294 (United States); Shi, Zhenqi [Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294 (United States); Qiao, Ping [Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294 (United States); Department of Pharmacology, Norman Bethune Medical College, Jilin University, Changchun, Jilin 130021 (China); Li, Hui [Department of Dermatology, University of Alabama at Birmingham, Birmingham, AL 35294 (United States); McCoy, Erin M. [Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294 (United States); Mao, Ping [Department of Hematology, Guangzhou First People’s Hospital, Guangzhou Medical University, Guangzhou, Guangdong 510180 (China); Xu, Hui [Department of Dermatology, University of Alabama at Birmingham, Birmingham, AL 35294 (United States); Feng, Xu [Department of Pathology, University of Alabama at Birmingham, Birmingham, AL 35294 (United States); Wang, Shunqing, E-mail: shqwang_cn@yahoo.com [Department of Hematology, Guangzhou First People’s Hospital, Guangzhou Medical University, Guangzhou, Guangdong 510180 (China)

2013-11-01

Highlights: •IL-3 treatment of bone marrow cells generates a population of hematopoietic cells. •IL-3-dependent hematopoietic cells are capable of differentiating into osteoclasts. •Osteoclasts derived from IL-3-dependent hematopoietic cells are functional. •IL-3 promotes the development of osteoclast progenitors. •IL-3 inhibits the osteoclastogenic process. -- Abstract: Interleukin (IL)-3, a multilineage hematopoietic growth factor, is implicated in the regulation of osteoclastogenesis. However, the role of IL-3 in osteoclastogenesis remains controversial; whereas early studies showed that IL-3 stimulates osteoclastogenesis, recent investigations demonstrated that IL-3 inhibits osteoclast formation. The objective of this work is to further address the role of IL-3 in osteoclastogenesis. We found that IL-3 treatment of bone marrow cells generated a population of cells capable of differentiating into osteoclasts in tissue culture dishes in response to the stimulation of the monocyte/macrophage-colony stimulating factor (M-CSF) and the receptor activator of nuclear factor kappa B ligand (RANKL). The IL-3-dependent hematopoietic cells were able to further proliferate and differentiate in response to M-CSF stimulation and the resulting cells were also capable of forming osteoclasts with M-CSF and RANKL treatment. Interestingly, IL-3 inhibits M-CSF-/RANKL-induced differentiation of the IL-3-dependent hematopoietic cells into osteoclasts. The flow cytometry analysis indicates that while IL-3 treatment of bone marrow cells slightly affected the percentage of osteoclast precursors in the surviving populations, it considerably increased the percentage of osteoclast precursors in the populations after subsequent M-CSF treatment. Moreover, osteoclasts derived from IL-3-dependent hematopoietic cells were fully functional. Thus, we conclude that IL-3 plays dual roles in osteoclastogenesis by promoting the development of osteoclast progenitors but inhibiting the

Osteoclast formation is strongly reduced both in vivo and in vitro in the absence of CD47/SIRPα-interaction

International Nuclear Information System (INIS)

Lundberg, Pernilla; Koskinen, Cecilia; Baldock, Paul A.; Loethgren, Hanna; Stenberg, Asa; Lerner, Ulf H.; Oldenborg, Per-Arne

2007-01-01

Physical interaction between the cell surface receptors CD47 and signal regulatory protein alpha (SIRPα) was reported to regulate cell migration, phagocytosis, cytokine production, and macrophage fusion. However, it is unclear if the CD47/SIRPα-interaction can also regulate macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor (NF)-κB ligand (RANKL)-stimulated formation of osteoclasts. Here, we show that functional blocking antibodies to either CD47 or SIRPα strongly reduced formation of multinucleated tartrate-resistant acid phosphatase (TRAP) + osteoclasts in cultures of murine hematopoietic cells, stimulated in vitro by M-CSF and RANKL. In addition, the numbers of osteoclasts formed in M-CSF/RANKL-stimulated bone marrow macrophage cultures from CD47 -/- mice were strongly reduced, and bones of CD47 -/- mice exhibited significantly reduced osteoclast numbers, as compared with wild-type controls. We conclude that the CD47/SIRPα interaction is important for M-CSF/RANKL-stimulated osteoclast formation both in vivo and in vitro, and that absence of CD47 results in decreased numbers of osteoclasts in CD47 -/- mice

The vitamin D analogue ED71 but Not 1,25(OH2D3 targets HIF1α protein in osteoclasts.

Directory of Open Access Journals (Sweden)

Yuiko Sato

Full Text Available Although both an active form of the vitamin D metabolite, 1,25(OH2D3, and the vitamin D analogue, ED71 have been used to treat osteoporosis, anti-bone resorbing activity is reportedly seen only in ED71- but not in 1,25(OH2D3 -treated patients. In addition, how ED71 inhibits osteoclast activity in patients has not been fully characterized. Recently, HIF1α expression in osteoclasts was demonstrated to be required for development of post-menopausal osteoporosis. Here we show that ED71 but not 1,25(OH2D3, suppress HIF1α protein expression in osteoclasts in vitro. We found that 1,25(OH2D3 or ED71 function in osteoclasts requires the vitamin D receptor (VDR. ED71 was significantly less effective in inhibiting M-CSF and RANKL-stimulated osteoclastogenesis than was 1,25(OH2D3 in vitro. Downregulation of c-Fos protein and induction of Ifnβ mRNA in osteoclasts, both of which reportedly block osteoclastogenesis induced by 1,25(OH2D3 in vitro, were both significantly higher following treatment with 1,25(OH2D3 than with ED71. Thus, suppression of HIF1α protein activity in osteoclasts in vitro, which is more efficiently achieved by ED71 rather than by 1,25(OH2D3, could be a reliable read-out in either developing or screening reagents targeting osteoporosis.

RANKL/RANK: from bone loss to the prevention of breast cancer.

Science.gov (United States)

Sigl, Verena; Jones, Laundette P; Penninger, Josef M

2016-11-01

RANK and RANKL, a receptor ligand pair belonging to the tumour necrosis factor family, are the critical regulators of osteoclast development and bone metabolism. Besides their essential function in bone, RANK and RANKL have also been identified as the key factors for the formation of a lactating mammary gland in pregnancy. Mechanistically, RANK and RANKL link the sex hormone progesterone with stem cell expansion and proliferation of mammary epithelial cells. Based on their normal physiology, RANKL/RANK control the onset of hormone-induced breast cancer through the expansion of mammary progenitor cells. Recently, we and others were able to show that RANK and RANKL are also critical regulators of BRCA1-mutation-driven breast cancer. Currently, the preventive strategy for BRCA1-mutation carriers includes preventive mastectomy, associated with wide-ranging risks and psychosocial effects. The search for an alternative non-invasive prevention strategy is therefore of paramount importance. As our work strongly implicates RANK and RANKL as key molecules involved in the initiation of BRCA1-associated breast cancer, we propose that anti-RANKL therapy could be a feasible preventive strategy for women carrying BRCA1 mutations, and by extension to other women with high risk of breast cancer. © 2016 The Authors.

Paracrine-mediated osteoclastogenesis by the osteosarcoma MG63 cell line: is RANKL/RANK signalling really important?

Science.gov (United States)

Costa-Rodrigues, J; Teixeira, C A; Fernandes, M H

2011-08-01

Although in the past little attention has been paid to the influence of osteosarcoma cells in osteoclast function, recent studies suggest a close relationship between osteosarcoma aggressiveness and osteoclastic activity. The present study addresses the paracrine effects of MG63 cells, a human osteosarcoma-derived cell line, on the differentiation of peripheral blood osteoclast precursor cells (PBMC). PBMC were cultured for 21 days in the presence of conditioned media from MG63 cell cultures (CM) collected at 48 h (CM_MG1), 7 days (CM_MG2) and 14 days (CM_MG3). MG63 cell cultures displayed the expression of ALP and BMP-2 and, also, the osteoclastogenic genes M-CSF and RANKL, although with a low expression of RANKL. PBMC cultures supplemented with CM presented an evident osteoclastogenic behavior, which was dependent on the culture period of the MG63 cells. The inductive effect appeared to be more relevant for the differentiation and activation genes, c-myc and c-src, and lower for genes associated with osteoclast function. In addition, PBMC cultures displayed increased functional parameters, including calcium phosphate resorbing activity. Assessment of the PBMC cultures in the presence of U0126, PDTC, and indomethacin suggested that in addition to MEK and NFkB pathways, other signaling mechanisms, probably not involving RANKL/RANK interaction, might be activated in the presence of conditioned medium from MG63. In conclusion, MG63 cell line appears to induce a significant paracrine-mediated osteoclastogenic response. Understanding the mechanisms underlying the interaction of osteosarcoma cells and osteoclasts may contribute to the development of new potential approaches in the treatment of such bone metabolic diseases.

Follicle-Stimulating Hormone Increases the Risk of Postmenopausal Osteoporosis by Stimulating Osteoclast Differentiation.

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Jie Wang

Full Text Available The objectives of this study were to observe the changes in follicle-stimulating hormone (FSH and bone mineral density (BMD in postmenopausal women, to research the relationship between FSH and postmenopausal osteoporosis, and to observe the effects of FSH on osteoclast differentiation in RAW264.7 cells.We analyzed 248 postmenopausal women with normal bone metabolism. A radioimmunoassay (RIA was used to detect serum FSH, luteinizing hormone (LH, and estradiol (E2. Dual-energy X-ray absorptiometry was used to measure forearm BMD. Then, we analyzed the age-related changes in serum FSH, LH and E2. Additionally, FSH serum concentrations were compared between a group of postmenopausal women with osteoporosis and a control group. Osteoclasts were induced from RAW264.7 cells in vitro by receptor activator of nuclear factor kappa B ligand (RANKL, and these cells were treated with 0, 5, 10, and 20 ng/ml FSH. After the osteoclasts matured, tartrate-resistant acid phosphatase (TRAP staining was used to identify osteoclasts, and the mRNA expression levels of genes involved in osteoclastic phenotypes and function, such as receptor activator of NF-κB (Rank, Trap, matrix metalloproteinase-9 (Mmp-9 and Cathepsin K, were detected in different groups using real-time PCR (polymerase chain reaction.1. FSH serum concentrations in postmenopausal women with osteoporosis increased notably compared with the control group. 2. RANKL induced RAW264.7 cell differentiation into mature osteoclasts in vitro. 3. FSH increased mRNA expression of genes involved in osteoclastic phenotypes and function, such as Rank, Trap, Mmp-9 and Cathepsin K, in a dose-dependent manner.The circulating concentration of FSH may play an important role in the acceleration of bone loss in postmenopausal women. FSH increases osteoclastogenesis in vitro.

MCP-1 expressed by osteoclasts stimulates osteoclastogenesis in an autocrine/paracrine manner

International Nuclear Information System (INIS)

Miyamoto, Kana; Ninomiya, Ken; Sonoda, Koh-Hei; Miyauchi, Yoshiteru; Hoshi, Hiroko; Iwasaki, Ryotaro; Miyamoto, Hiroya

2009-01-01

Monocyte chemoattractant protein-1 (MCP-1) is a chemokine that plays a critical role in the recruitment and activation of leukocytes. Here, we describe that multinuclear osteoclast formation was significantly inhibited in cells derived from MCP-1-deficient mice. MCP-1 has been implicated in the regulation of osteoclast cell-cell fusion; however defects of multinuclear osteoclast formation in the cells from mice deficient in DC-STAMP, a seven transmembrane receptor essential for osteoclast cell-cell fusion, was not rescued by recombinant MCP-1. The lack of MCP-1 in osteoclasts resulted in a down-regulation of DC-STAMP, NFATc1, and cathepsin K, all of which were highly expressed in normal osteoclasts, suggesting that osteoclast differentiation was inhibited in MCP-1-deficient cells. MCP-1 alone did not induce osteoclastogenesis, however, the inhibition of osteoclastogenesis in MCP-1-deficient cells was restored by addition of recombinant MCP-1, indicating that osteoclastogenesis was regulated in an autocrine/paracrine manner by MCP-1 under the stimulation of RANKL in osteoclasts.

Tetraspanin CD9 regulates osteoclastogenesis via regulation of p44/42 MAPK activity

International Nuclear Information System (INIS)

Yi, TacGhee; Kim, Hye-Jin; Cho, Je-Yoel; Woo, Kyung Mi; Ryoo, Hyun-Mo; Kim, Gwan-Shik; Baek, Jeong-Hwa

2006-01-01

Tetraspanin CD9 has been shown to regulate cell-cell fusion in sperm-egg fusion and myotube formation. However, the role of CD9 in osteoclast, another multinucleated cell type, is not still clear. Therefore, we investigated the role of CD9 in osteoclast differentiation. CD9 was expressed in osteoclast lineage cells and its expression level increased during the progression of RANKL-induced osteoclastogenesis. KMC8, a neutralizing antibody specific to CD9, significantly suppressed RANKL-induced multinucleated osteoclast formation and the mRNA expression of osteoclast differentiation marker genes. To define CD9-regulated osteoclastogenic signaling pathway, MAPK pathways were examined. KMC8 induced long-term phosphorylation of p44/42 MAPK, but not of p38 MAPK. Constitutive activation of p44/42 MAPK by overexpressing constitutive-active mutant of MEK1 almost completely blocked osteoclast differentiation. Taken together, these results suggest that CD9 expressed on osteoclast lineage cells might positively regulate osteoclastogenesis via the regulation of p44/42 MAPK activity

Avenanthramides Prevent Osteoblast and Osteocyte Apoptosis and Induce Osteoclast Apoptosis in Vitro in an Nrf2-Independent Manner

Directory of Open Access Journals (Sweden)

Gretel G. Pellegrini

2016-07-01

Full Text Available Oats contain unique bioactive compounds known as avenanthramides (AVAs with antioxidant properties. AVAs might enhance the endogenous antioxidant cellular response by activation of the transcription factor Nrf2. Accumulation of reactive oxygen species plays a critical role in many chronic and degenerative diseases, including osteoporosis. In this disease, there is an imbalance between bone formation by osteoblasts and bone resorption by osteoclasts, which is accompanied by increased osteoblast/osteocyte apoptosis and decreased osteoclast apoptosis. We investigated the ability of the synthethic AVAs 2c, 2f and 2p, to 1-regulate gene expression in bone cells, 2-affect the viability of osteoblasts, osteocytes and osteoclasts, and the generation of osteoclasts from their precursors, and 3-examine the potential involvement of the transcription factor Nrf2 in these actions. All doses of AVA 2c and 1 and 5 µM dose of 2p up-regulated collagen 1A expression. Lower doses of AVAs up-regulated OPG (osteoprotegerin in OB-6 osteoblastic cells, whereas 100 μM dose of 2f and all concentrations of 2c down-regulated RANKL gene expression in MLO-Y4 osteocytic cells. AVAs did not affect apoptosis of OB-6 osteoblastic cells or MLO-Y4 osteocytic cells; however, they prevented apoptosis induced by the DNA topoisomerase inhibitor etoposide, the glucocorticoid dexamethasone, and hydrogen peroxide. AVAs prevented apoptosis of both wild type (WT and Nrf2 Knockout (KO osteoblasts, demonstrating that AVAs-induced survival does not require Nrf2 expression. Further, KO osteoclast precursors produced more mature osteoclasts than WT; and KO cultures exhibited less apoptotic osteoclasts than WT cultures. Although AVAs did not affect WT osteoclasts, AVA 2p reversed the low apoptosis of KO osteoclasts. These in vitro results demonstrate that AVAs regulate, in part, the function of osteoblasts and osteocytes and prevent osteoblast/osteocyte apoptosis and increase osteoclast

Norisoboldine suppresses osteoclast differentiation through preventing the accumulation of TRAF6-TAK1 complexes and activation of MAPKs/NF-κB/c-Fos/NFATc1 Pathways.

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Zhi-Feng Wei

Full Text Available Norisoboldine (NOR is the main alkaloid constituent in the dry root of Lindera aggregata (Sims Kosterm. (L. strychnifolia Vill.. As reported previously, orally administered NOR displayed a robust inhibition of joint bone destruction present in both mouse collagen-induced arthritis and rat adjuvant-induced arthritis with lower efficacious doses than that required for ameliorating systemic inflammation. This attracted us to assess the effects of NOR on differentiation and function of osteoclasts, primary effector cells for inflammatory bone destruction, to get insight into its anti-rheumatoid arthritis mechanisms. Both RAW264.7 cells and mouse bone marrow-derived macrophages (BMMs were stimulated with RANKL (100 ng/mL to establish osteoclast differentiation models. ELISA, RT-PCR, gelatin zymography, western blotting, immunoprecipitation and EMSA were used to reveal related signalling pathways. NOR (10 and 30 µM, without significant cytotoxicity, showed significant reduction of the number of osteoclasts and the resorption pit areas, and it targeted osteoclast differentiation at the early stage. In conjunction with the anti-resorption effect of NOR, mRNA levels of cathepsin K and MMP-9 were decreased, and the activity of MMP-9 was attenuated. Furthermore, our mechanistic studies indicated that NOR obviously suppressed the ubiquitination of TRAF6, the accumulation of TRAF6-TAK1 complexes and the activation of ERK and p38 MAPK, and reduced the nuclear translocation of NF-κB-p65 and DNA-binding activity of NF-κB. However, NOR had little effect on expressions of TRAF6 or the phosphorylation and degradation of IκBα. Moreover, NOR markedly inhibited expressions of transcription factor NFATc1, but not c-Fos. Intriguingly, the subsequent nuclear translocations of c-Fos and NFATc1 were substantially down-regulated. Hence, we demonstrated for the first time that preventing the differentiation and function of osteoclasts at the early stage was an

Effects of high glucose and advanced glycation end products on the expressions of sclerostin and RANKL as well as apoptosis in osteocyte-like MLO-Y4-A2 cells

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Tanaka, Ken-ichiro, E-mail: ken1nai@med.shimane-u.ac.jp; Yamaguchi, Toru, E-mail: yamaguch@med.shimane-u.ac.jp; Kanazawa, Ippei, E-mail: ippei.k@med.shimane-u.ac.jp; Sugimoto, Toshitsugu, E-mail: sugimoto@med.shimane-u.ac.jp

2015-05-29

In diabetes mellitus (DM), high glucose (HG) and advanced glycation end products (AGEs) are involved in bone quality deterioration. Osteocytes produce sclerostin and receptor activator of nuclear factor-kB ligand (RANKL) and regulate osteoblast and osteoclast function. However, whether HG or AGEs directly affect osteocytes and regulate sclerostin and RANKL production is unknown. Here, we examined the effects of HG, AGE2, and AGE3 on the expression of sclerostin and RANKL and on apoptosis in osteocyte-like MLO-Y4-A2 cells. Treatment of the cells with 22 mM glucose, 100 μg/mL either AGE2 or AGE3 significantly increased the expression of sclerostin protein and mRNA; however, both AGEs, but not glucose, significantly decreased the expression of RANKL protein and mRNA. Moreover, treatment of the cells with HG, AGE2, or AGE3 for 72 h induced significant apoptosis. These detrimental effects of HG, AGE2, and AGE3 on sclerostin and RANKL expressions and on apoptosis were antagonized by pretreatment of the cells with 10{sup −8} M human parathyroid hormone (PTH)-(1–34). Thus, HG and AGEs likely suppress bone formation by increasing sclerostin expression in osteocytes, whereas AGEs suppress bone resorption by decreasing RANKL expression. Together, these processes may cause low bone turnover in DM. In addition, HG and AGEs may cause cortical bone deterioration by inducing osteocyte apoptosis. PTH may effectively treat these pathological processes and improve osteocyte function. - Highlights: • AGEs are involved in bone quality deterioration in diabetes mellitus (DM). • AGEs increased sclerostin as well as apoptosis, and decreased RANKL in osteocytes. • The effects of AGEs on osteocyte function were antagonized by human PTH-(1–34). • AGEs may cause low bone turnover and cortical porosity in DM. • PTH may be effective in bone quality deterioration by improving osteocyte function.

Massive elimination of multinucleated osteoclasts by eupatilin is due to dual inhibition of transcription and cytoskeletal rearrangement

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Ju-Young Kim

2015-12-01

Full Text Available Osteoporosis is an aging-associated disease requiring better therapeutic modality. Eupatilin is a major flavonoid from Artemisia plants such as Artemisia princeps and Artemisia argyi which has been reported to possess various beneficial biological effects including anti-inflammation, anti-tumor, anti-cancer, anti-allergy, and anti-oxidation activity. Complete blockade of RANK-dependent osteoclastogenesis was accomplished upon stimulation prior to the receptor activator of nuclear factor κB (RANK-ligand (RANKL treatment or post-stimulation of bone marrow macrophages (BMCs in the presence of RANKL with eupatilin. This blockade was accompanied by inhibition of rapid phosphorylation of Akt, GSK3β, ERK and IκB as well as downregulation of c-Fos and NFATc1 at protein, suggesting that transcriptional suppression is a key mechanism for anti-osteoclastogenesis. Transient reporter assays or gain of function assays confirmed that eupatilin was a potent transcriptional inhibitor in osteoclasts (OC. Surprisingly, when mature osteoclasts were cultured on bone scaffolds in the presence of eupatilin, bone resorption activity was also completely blocked by dismantling the actin rings, suggesting that another major acting site of eupatilin is cytoskeletal rearrangement. The eupatilin-treated mature osteoclasts revealed a shrunken cytoplasm and accumulation of multi-nuclei, eventually becoming fibroblast-like cells. No apoptosis occurred. Inhibition of phosphorylation of cofilin by eupatilin suggests that actin may play an important role in the morphological change of multinucleated cells (MNCs. Human OC similarly responded to eupatilin. However, eupatilin has no effects on osteoblast differentiation and shows cytotoxicity on osteoblast in the concentration of 50 μM. When eupatilin was administered to LPS-induced osteoporotic mice after manifestation of osteoporosis, it prevented bone loss. Ovariectomized (OVX mice remarkably exhibited bone protection effects

Technetium-99 conjugated with methylene diphosphonate inhibits receptor activator of nuclear factor-κB ligand-induced osteoclastogenesis.

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Gong, Wei; Dou, Huan; Liu, Xianqin; Sun, Lingyun; Hou, Yayi

2012-10-01

1. In the present study, we investigated the effects of technetium-99 conjugated with methylene diphosphonate ((99)Tc-MDP), an agent used in radionuclide therapy, on receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclastogenesis and explored the underlying mechanisms. 2. The murine macrophage cell line RAW264.7 and bone marrow-derived-macrophages from C57BL/6 mice (BMM) were used as models for osteoclastogenesis in vitro. The expression of some key factors in RANKL (50 ng/mL)-induced osteoclastogenesis in RAW264.7 cells was investigated by flow cytometry and real-time reverse transcription-polymerase chain reaction (RT-PCR). To detect multinucleated osteoclast formation, RAW264.7 cells were induced with RANKL for 4 days, whereas BMM were induced by 50 ng/mL RANKL and 20 ng/mL macrophage colony-stimulating factor for 7 days, before being stained with tartrate-resistant acid phosphatase. 3. Osteoclastogenesis was evaluated using the osteoclast markers CD51, matrix metalloproteinase (MMP)-9 and cathepsin K. At 0.01 μg/mL, (99)Tc-MDP significantly inhibited RANKL-induced osteoclastogenesis without any cytotoxicity. In addition, (99)Tc-MDP abolished the appearance of multinucleated osteoclasts. 4. Real-time RT-PCR analysis of transcription factor expression revealed that (99)Tc-MDP inhibited the expression of c-Fos and nuclear factor of activated T cells. In addition, (99)Tc-MDP inhibited the expression of the inflammatory factors interleukin (IL)-6, tumour necrosis factor-α and IL-1β. Finally, (99)Tc-MDP inhibited the activation of mitogen-activated protein kinases in RAW264.7 cells following RANKL stimulation. 5. In conclusion, (99)Tc-MDP possesses anti-osteoclastogenic activity against RANKL-induced osteoclast formation. © 2012 The Authors Clinical and Experimental Pharmacology and Physiology © 2012 Wiley Publishing Asia Pty Ltd.

Tributyltin induces distinct effects on cortical and trabecular bone in female C57Bl/6J mice.

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Watt, James; Baker, Amelia H; Meeks, Brett; Pajevic, Paola D; Morgan, Elise F; Gerstenfeld, Louis C; Schlezinger, Jennifer J

2018-09-01

The retinoid X receptors (RXR), peroxisome proliferator activated receptor gamma (PPARγ), and liver X receptors (LXR) all have been shown to regulate bone homeostasis. Tributyltin (TBT) is an environmental contaminant that is a dual RXRα/β and PPARγ agonist. TBT induces RXR, PPARγ, and LXR-mediated gene transcription and suppresses osteoblast differentiation in vitro. Bone marrow multipotent mesenchymal stromal cells derived from female C57BL/6J mice were more sensitive to suppression of osteogenesis by TBT than those derived from male mice. In vivo, oral gavage of 12 week old female, C57Bl/6J mice with 10 mg/kg TBT for 10 weeks resulted in femurs with a smaller cross-sectional area and thinner cortex. Surprisingly, TBT induced significant increases in trabecular thickness, number, and bone volume fraction. TBT treatment did not change the Rankl:Opg RNA ratio in whole bone, and histological analyses showed that osteoclasts in the trabecular space were minimally reduced. In contrast, expression of cardiotrophin-1, an osteoblastogenic cytokine secreted by osteoclasts, increased. In primary bone marrow macrophage cultures, TBT marginally inhibited the number of osteoclasts that differentiated, in spite of significantly suppressing expression of osteoclast markers Nfatc1, Acp5, and Ctsk and resorptive activity. TBT induced expression of RXR- and LXR-dependent genes in whole bone and in vitro osteoclast cultures. However, only an RXR antagonist, but not an LXR antagonist, significantly inhibited TBTs ability to suppress osteoclast differentiation. These results suggest that TBT has distinct effects on cortical versus trabecular bone, likely resulting from independent effects on osteoblast and osteoclast differentiation that are mediated through RXR. © 2018 Wiley Periodicals, Inc.

The Study of Mechanisms of Protective Effect of Rg1 against Arthritis by Inhibiting Osteoclast Differentiation and Maturation in CIA Mice

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Yanqing Gu

2014-01-01

Full Text Available Ginsenoside Rg1 is a natural product extracted from Panax ginseng C.A. Although Rg1 protects tissue structure and functions by inhibiting local inflammatory reaction, the mechanism remains poorly understood. In vitro, Rg1 dose-dependently inhibited TRAP activity in receptor activator of nuclear factor-κB ligand- (RANKL- induced osteoclasts and decreased the number of osteoclasts and osteoclast resorption area. Rg1 also significantly inhibited the RANK signaling pathway, including suppressing the expression of Trap, cathepsin K, matrix metalloproteinase 9 (MMP9, and calcitonin receptor (CTR. In vivo, Rg1 dramatically decreased arthritis scores in CIA mice and effectively controlled symptoms of inflammatory arthritis. Pathologic analysis demonstrated that Rg1 significantly attenuated pathological changes in CIA mice. Pronounced reduction in synovial hyperplasia and inflammatory cell invasion were observed in CIA mice after Rg1 therapy. Alcian blue staining results illustrated that mice treated with Rg1 had significantly reduced destruction in the articular cartilage. TRAP and cathepsin K staining results demonstrated a significant reduction of numbers of OCs in the articular cartilage in proximal interphalangeal joints and ankle joints in Rg1-treated mice. In summary, this study revealed that Rg1 reduced the inflammatory destruction of periarticular bone by inhibiting differentiation and maturation of osteoclasts in CIA mice.

F4/80 inhibits osteoclast differentiation via downregulation of nuclear factor of activated T cells, cytoplasmic 1.

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Kang, Ju-Hee; Sim, Jung-Sun; Zheng, Ting; Yim, Mijung

2017-04-01

Osteoclastogenesis is an essential process in bone metabolism, which can be induced by RANKL stimulation. The F4/80 glycoprotein is a member of the EGF-transmembrane 7 (TM7) family and has been established as a specific cell-surface marker for murine macrophages. This study aimed to identify the role of F4/80 in osteoclastogenesis. Using mouse bone marrow-derived macrophages (BMMs), we observed that the mRNA level of F4/80 was dramatically reduced as these cells differentiated into osteoclasts. Furthermore, osteoclastogenesis was decreased in F4/80 high BMMs compared to F4/80 -/low BMMs. The inhibitory effect of F4/80 was associated with decreased expression of nuclear factor of activated T cells, cytoplasmic 1 (NFATc1). Ectopic overexpression of a constitutively active form of NFATc1 rescued the anti-osteoclastogenic effect of F4/80 completely, suggesting that the anti-osteoclastogenic effect of F4/80 was mainly due to reduction in NFATc1 expression. As an underlying mechanism, we demonstrated that the presence of F4/80 abrogated the effect of RANKL on the phosphorylation of CREB and activated the expression of IFN-β, which are restored by cyclic AMP. Collectively, our results demonstrate that the presence of F4/80 suppresses RANKL-induced osteoclastogenesis by impairing the expression of NFATc1 via CREB and IFN-β. Therefore, F4/80 may hold therapeutic potential for bone destructive diseases.

Rare sugar D-allose strongly induces thioredoxin-interacting protein and inhibits osteoclast differentiation in Raw264 cells.

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Yamada, Kana; Noguchi, Chisato; Kamitori, Kazuyo; Dong, Youyi; Hirata, Yuko; Hossain, Mohammad A; Tsukamoto, Ikuko; Tokuda, Masaaki; Yamaguchi, Fuminori

2012-02-01

Oxidative stress modulates the osteoclast differentiation via redox systems, and thioredoxin 1 (Trx) promotes the osteoclast formation by regulating the activity of transcription factors. The function of Trx is known to be regulated by its binding partner, thioredoxin-interacting protein (TXNIP). We previously reported that the expression of TXNIP gene is strongly induced by a rare sugar D-allose. In this study, we tested the hypothesis that D-allose could inhibit the osteoclast differentiation by regulating the Trx function. We used a murine Raw264 cell line that differentiates to the osteoclast by the receptor activator of nuclear factor-κB ligand (RANKL) treatment. The effect of sugars was evaluated by tartrate-resistant acid phosphatase staining. The expression and localization of TXNIP and Trx protein were examined by Western blotting and immunohistochemisty. The activity of the nuclear factor-κB, nuclear factor of activated T cells, and activator protein 1 transcription factors was measured by the luciferase reporter assay. The addition of D-allose (25 mmol/L) inhibited the osteoclast differentiation down to 9.53% ± 1.27% of a receptor activator of nuclear factor-κB ligand-only treatment. During the osteoclast differentiation, a significant increase of TNXIP was observed by D-allose treatment. The immunohistochemical analysis showed that both Trx and TXNIP existed in the nucleus in preosteoclasts and osteoclasts. Overexpression of TXNIP by plasmid transfection also inhibited the osteoclast formation, indicating the functional importance of TXNIP for the osteoclast differentiation. Transcriptional activity of the activator protein 1, nuclear factor-κB, and nuclear factor of activated T cells, known to be modulated by Trx, were inhibited by D-allose. In conclusion, our data indicate that D-allose is a strong inhibitor of the osteoclast differentiation, and this effect could be caused by TXNIP induction and a resulting inhibition of the Trx function

Inhibition of osteoclastogenesis by RNA interference targeting RANK

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Ma Ruofan

2012-08-01

Full Text Available Abstract Background Osteoclasts and osteoblasts regulate bone resorption and formation to allow bone remodeling and homeostasis. The balance between bone resorption and formation is disturbed by abnormal recruitment of osteoclasts. Osteoclast differentiation is dependent on the receptor activator of nuclear factor NF-kappa B (RANK ligand (RANKL as well as the macrophage colony-stimulating factor (M-CSF. The RANKL/RANK system and RANK signaling induce osteoclast formation mediated by various cytokines. The RANK/RANKL pathway has been primarily implicated in metabolic, degenerative and neoplastic bone disorders or osteolysis. The central role of RANK/RANKL interaction in osteoclastogenesis makes RANK an attractive target for potential therapies in treatment of osteolysis. The purpose of this study was to assess the effect of inhibition of RANK expression in mouse bone marrow macrophages on osteoclast differentiation and bone resorption. Methods Three pairs of short hairpin RNAs (shRNA targeting RANK were designed and synthesized. The optimal shRNA was selected among three pairs of shRNAs by RANK expression analyzed by Western blot and Real-time PCR. We investigated suppression of osteoclastogenesis of mouse bone marrow macrophages (BMMs using the optimal shRNA by targeting RANK. Results Among the three shRANKs examined, shRANK-3 significantly suppressed [88.3%] the RANK expression (p Conclusions These findings suggest that retrovirus-mediated shRNA targeting RANK inhibits osteoclast differentiation and osteolysis. It may appear an attractive target for preventing osteolysis in humans with a potential clinical application.

Molecular Signaling Pathways Mediating Osteoclastogenesis Induced by Prostate Cancer Cells

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Rafiei, Shahrzad; Komarova, Svetlana V

2013-01-01

Advanced prostate cancer commonly metastasizes to bone leading to osteoblastic and osteolytic lesions. Although an osteolytic component governed by activation of bone resorbing osteoclasts is prominent in prostate cancer metastasis, the molecular mechanisms of prostate cancer-induced osteoclastogenesis are not well-understood. We studied the effect of soluble mediators released from human prostate carcinoma cells on osteoclast formation from mouse bone marrow and RAW 264.7 monocytes. Soluble factors released from human prostate carcinoma cells significantly increased viability of naïve bone marrow monocytes, as well as osteoclastogenesis from precursors primed with receptor activator of nuclear factor κ-B ligand (RANKL). The prostate cancer-induced osteoclastogenesis was not mediated by RANKL as it was not inhibited by osteoprotegerin (OPG). However inhibition of TGFβ receptor I (TβRI), or macrophage-colony stimulating factor (MCSF) resulted in attenuation of prostate cancer-induced osteoclastogenesis. We characterized the signaling pathways induced in osteoclast precursors by soluble mediators released from human prostate carcinoma cells. Prostate cancer factors increased basal calcium levels and calcium fluctuations, induced nuclear localization of nuclear factor of activated t-cells (NFAT)c1, and activated prolonged phosphorylation of ERK1/2 in RANKL-primed osteoclast precursors. Inhibition of calcium signaling, NFATc1 activation, and ERK1/2 phosphorylation significantly reduced the ability of prostate cancer mediators to stimulate osteoclastogenesis. This study reveals the molecular mechanisms underlying the direct osteoclastogenic effect of prostate cancer derived factors, which may be beneficial in developing novel osteoclast-targeting therapeutic approaches

Clinical prognostic significance and pro-metastatic activity of RANK/RANKL via the AKT pathway in endometrial cancer.

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Wang, Jing; Liu, Yao; Wang, Lihua; Sun, Xiao; Wang, Yudong

2016-02-02

RANK/RANKL plays a key role in metastasis of certain malignant tumors, which makes it a promising target for developing novel therapeutic strategies for cancer. However, the prognostic value and pro-metastatic activity of RANK in endometrial cancer (EC) remain to be determined. Thus, the present study investigated the effect of RANK on the prognosis of EC patients, as well as the pro-metastatic activity of EC cells. The results indicated that those with high expression of RANK showed decreased overall survival and progression-free survival. Statistical analysis revealed the positive correlations between RANK/RANKL expression and metastasis-related factors. Additionally, RANK/RANKL significantly promoted cell migration/invasion via activating AKT/β-catenin/Snail pathway in vitro. However, RANK/RANKL-induced AKT activation could be suppressed after osteoprotegerin (OPG) treatment. Furthermore, the combination of medroxyprogesterone acetate (MPA) and RANKL could in turn attenuate the effect of RANKL alone. Similarly, MPA could partially inhibit the RANK-induced metastasis in an orthotopic mouse model via suppressing AKT/β-catenin/Snail pathway. Therefore, therapeutic inhibition of MPA in RANK/RANKL-induced metastasis was mediated by AKT/β-catenin/Snail pathway both in vitro and in vivo, suggesting a potential target of RANK for gene-based therapy for EC.

The proliferative human monocyte subpopulation contains osteoclast precursors

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Lari, Roya; Kitchener, Peter D; Hamilton, John A

2009-01-01

Introduction Immediate precursors of bone-resorbing osteoclasts are cells of the monocyte/macrophage lineage. Particularly during clinical conditions showing bone loss, it would appear that osteoclast precursors are mobilized from bone marrow into the circulation prior to entering tissues undergoing such loss. The observed heterogeneity of peripheral blood monocytes has led to the notion that different monocyte subpopulations may have special or restricted functions, including as osteoclast precursors. Methods Human peripheral blood monocytes were sorted based upon their degree of proliferation and cultured in macrophage colony-stimulating factor (M-CSF or CSF-1) and receptor activator of nuclear factor-kappa-B ligand (RANKL). Results The monocyte subpopulation that is capable of proliferation gave rise to significantly more multinucleated, bone-resorbing osteoclasts than the bulk of the monocytes. Conclusions Human peripheral blood osteoclast precursors reside in the proliferative monocyte subpopulation. PMID:19222861

Expression profile of osteoprotegerin, RANK and RANKL genes in the femoral head of patients with avascular necrosis.

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Samara, Stavroula; Dailiana, Zoe; Chassanidis, Christos; Koromila, Theodora; Papatheodorou, Loukia; Malizos, Konstantinos N; Kollia, Panagoula

2014-02-01

Femoral head avascular necrosis (AVN) is a recalcitrant disease of the hip that leads to joint destruction. Osteoprotegerin (OPG), Receptor Activator of Nuclear Factor kappa-B (RANK) and RANK ligand (RANKL) regulate the balance between osteoclasts-osteoblasts. The expression of these genes affects the maturation and function of osteoblasts-osteoclasts and bone remodeling. In this study, we investigated the molecular pathways leading to AVN by studying the expression profile of OPG, RANK and RANKL genes. Quantitative Real Time-PCR was performed for evaluation of OPG, RANK and RANKL expression. Analysis was based on parallel evaluation of mRNA and protein levels in normal/necrotic sites of 42 osteonecrotic femoral heads (FHs). OPG and RANKL protein levels were estimated by western blotting. The OPG mRNA levels were higher (insignificantly) in the necrotic than the normal site (p > 0.05). Although the expression of RANK and RANKL was significantly lower than OPG in both sites, RANK and RANKL mRNA levels were higher in the necrotic part than the normal (p < 0.05). Protein levels of OPG and RANKL showed no remarkable divergence. Our results indicate that differential expression mechanisms for OPG, RANK and RANKL that could play an important role in the progress of bone remodeling in the necrotic area, disturbing bone homeostasis. This finding may have an effect on the resulting bone destruction and the subsequent collapse of the hip joint. Copyright © 2013. Published by Elsevier Inc.

Age-related effects on osteoclastic activities after orthodontic tooth movement.

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Li, X; Li, M; Lu, J; Hu, Y; Cui, L; Zhang, D; Yang, Y

2016-10-01

To elucidate the effects of age on the expression levels of the receptor activator of the nuclear factor-κB ligand (RANKL) and osteoclasts in the periodontal ligament during orthodontic mechanical loading and post-orthodontic retention. The study included 20 male Sprague-Dawley rats, ten in the young group (aged four to five weeks) and ten in the adult group (aged 18 to 20 weeks). In each rat, the upper-left first molar was subjected to a seven-day orthodontic force loading followed by a seven-day retention period. The upper-right first molar served as a control. The amount of orthodontic tooth movement was measured after seven-day force application and seven-day post-orthodontic retention. The expression levels of RANKL and the tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts were evaluated on day 7 (end of mechanical force loading) and day 14 (after seven days of post-orthodontic retention). Statistical analysis was performed using the t-test, and significance was set at p 0.05) after the seven-day force application. On the compression side, the expression of RANKL and TRAP-positive osteoclasts in both the young and the adult groups increased after the application of force for seven days, and then decreased at the end of the seven-day retention period. However, by the end of the period, the expression of RANKL on the compression side dropped to the control level in the young group (p > 0.05), while it was still higher than that on the control side in the adult group (p 0.05), but it was significantly higher in the adult group than that in the young group after seven-day post-orthodontic retention (p Cite this article: X. Li, M. Li, J. Lu, Y. Hu, L. Cui, D. Zhang, Y. Yang. Age-related effects on osteoclastic activities after orthodontic tooth movement. Bone Joint Res 2016;5:492-499. DOI: 10.1302/2046-3758.510.BJR-2016-0004.R2. © 2016 Li et al.

Genetic ablation of CD68 results in mice with increased bone and dysfunctional osteoclasts.

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Jason W Ashley

Full Text Available CD68 is a member of the lysosome associated membrane protein (LAMP family that is restricted in its expression to cells of the monocyte/macrophage lineage. This lineage restriction includes osteoclasts, and, while previous studies of CD68 in macrophages and dendritic cells have proposed roles in lipid metabolism, phagocytosis, and antigen presentation, the expression and function of CD68 in osteoclasts have not been explored. In this study, we investigated the expression and localization of CD68 in macrophages and osteoclasts in response to the monocyte/macrophage-colony stimulating factor (M-CSF and the receptor activator of NF-κB ligand (RANKL. We found that M-CSF stimulates CD68 expression and RANKL alters the apparent molecular weight of CD68 as measured by Western immunoblotting. In addition, we explored the significance of CD68 expression in osteoclasts by generating mice that lack expression of CD68. These mice have increased trabecular bone, and in vitro assessment of CD68(-/- osteoclasts revealed that, in the absence of CD68, osteoclasts demonstrate an accumulation of intracellular vesicle-like structures, and do not efficiently resorb bone. These findings demonstrate a role for CD68 in the function of osteoclasts, and future studies will determine the mechanistic nature of the defects seen in CD68(-/- osteoclasts.

Fisetin Inhibits Osteoclast Differentiation via Downregulation of p38 and c-Fos-NFATc1 Signaling Pathways

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Sik-Won Choi

2012-01-01

Full Text Available The prevention or therapeutic treatment of loss of bone mass is an important means of improving the quality of life for patients with disorders related to osteoclast-mediated bone loss. Fisetin, a flavonoid dietary ingredient found in the smoke tree (Continus coggygria, exhibits various biological activities, but its effect on osteoclast differentiation is unknown. In this study, fisetin dose-dependently inhibited the RANKL-induced osteoclast differentiation with downregulation of the activity or expression of p38, c-Fos, and NFATc1 signaling molecules. The p38/c-Fos/NFATc1-regulated expression of genes required for cell fusion and bone resorption, such as DC-STAMP and cathepsin K, was also inhibited by fisetin. Considering the rescue of fisetin's inhibitory action by NFATc1 over-expression, the cascade of p38-c-Fos-NFATc1 could be strongly involved in the inhibitory effect of fisetin on osteoclast differentiation. Furthermore, fisetin inhibited the bone-resorbing activity of mature osteoclasts. In conclusion, fisetin may be of use in the treatment of osteoclast-related disorders, including osteoporosis.

Exogenous IFN-beta regulates the RANKL-c-Fos-IFN-beta signaling pathway in the collagen antibody-induced arthritis model.

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Zhao, Rong; Chen, Ni-Nan; Zhou, Xiao-Wei; Miao, Ping; Hu, Chao-Ying; Qian, Liu; Yu, Qi-Wen; Zhang, Ji-Ying; Nie, Hong; Chen, Xue-hua; Li, Pu; Xu, Rong; Xiao, Lian-Bo; Zhang, Xin; Liu, Jian-Ren; Zhang, Dong-Qing

2014-12-10

Although a variety of drugs have been used to treat the symptoms of rheumatoid arthritis (RA), none of them are able to cure the disease. Interferon β (IFN-β) has pleiotropic effects on RA, but whether it can be used to treat RA remains globally controversial. Thus, in this study we tested the effects of IFN-β on RA patients and on collagen antibody-induced arthritis (CAIA) model mice. The cytokine and auto-antibody expression profiles in the serum and synovial fluid (SF) from RA patients were assessed using enzyme-linked immunosorbent assay (ELISA) and compared with the results from osteoarthritis (OA) patients. Exogenous IFN-β was administered to RA patients and CAIA model mice, and the therapeutic effects were evaluated. Endogenous IFN-β expression in the joint bones of CAIA model mice was evaluated by quantitative real-time PCR (qRT-PCR). The effects of exogenous IFN-β on CAIA model mice were assessed using a clinical scoring system, hematoxylin eosin and safranin-O with fast green counterstain histology, molybdenum target X-ray, and tartrate-resistant acid phosphatase (TRAP) staining. The RANKL-RANK signaling pathway was analyzed using qRT-PCR. The RAW 264.7 cell line was differentiated into osteoclasts with RANKL stimulation and then treated with exogenous IFN-β. The expression of inflammatory cytokines (IFN-γ, IL-17, MMP-3, and RANKL) and auto-antibodies (CII antibodies, RF-IgM, and anti-CCP/GPI) were significantly higher in RA compared with OA patients. After IFN-β intervention, some clinical symptoms in RA patients were partially alleviated, and the expression of IFN-γ, IL-17, MMP-3, and OPG) returned to normal levels. In the CAIA model, the expression of endogenous IFN-β in the joint bones was decreased. After IFN-β administration, the arthritis scores were decreased; synovial inflammation, cartilage, and bone destruction were clearly attenuated; and the expression of c-Fos and NFATc1 were reduced, while RANKL and TRAF6 expression was

Expression of Msx-1 is suppressed in bisphosphonate associated osteonecrosis related jaw tissue-etiopathology considerations respecting jaw developmental biology-related unique features

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Schlegel Karl A

2010-10-01

Full Text Available Abstract Background Bone-destructive disease treatments include bisphosphonates and antibodies against the osteoclast differentiator, RANKL (aRANKL; however, osteonecrosis of the jaw (ONJ is a frequent side-effect. Current models fail to explain the restriction of bisphosphonate (BP-related and denosumab (anti-RANKL antibody-related ONJ to jaws. Msx-1 is exclusively expressed in craniofacial structures and pivotal to cranial neural crest (CNC-derived periodontal tissue remodeling. We hypothesised that Msx-1 expression might be impaired in bisphosphonate-related ONJ. The study aim was to elucidate Msx-1 and RANKL-associated signal transduction (BMP-2/4, RANKL in ONJ-altered and healthy periodontal tissue. Methods Twenty ONJ and twenty non-BP exposed periodontal samples were processed for RT-PCR and immunohistochemistry. An automated staining-based alkaline phosphatase-anti-alkaline phosphatase method was used to measure the stained cells:total cell-number ratio (labelling index, Bonferroni adjustment. Real-time RT-PCR was performed on ONJ-affected and healthy jaw periodontal samples (n = 20 each to quantitatively compare Msx-1, BMP-2, RANKL, and GAPDH mRNA levels. Results Semi-quantitative assessment of the ratio of stained cells showed decreased Msx-1 and RANKL and increased BMP-2/4 (all p Conclusions These results explain the sclerotic and osteopetrotic changes of periodontal tissue following BP application and substantiate clinical findings of BP-related impaired remodeling specific to periodontal tissue. RANKL suppression substantiated the clinical finding of impaired bone remodelling in BP- and aRANKL-induced ONJ-affected bone structures. Msx-1 suppression in ONJ-adjacent periodontal tissue suggested a bisphosphonate-related impairment in cellular differentiation that occurred exclusively jaw remodelling. Further research on developmental biology-related unique features of jaw bone structures will help to elucidate pathologies restricted to

Gambogic acid inhibits multiple myeloma mediated osteoclastogenesis through suppression of chemokine receptor CXCR4 signaling pathways.

Science.gov (United States)

Pandey, Manoj K; Kale, Vijay P; Song, Chunhua; Sung, Shen-shu; Sharma, Arun K; Talamo, Giampaolo; Dovat, Sinisa; Amin, Shantu G

2014-10-01

Bone disease, characterized by the presence of lytic lesions and osteoporosis is the hallmark of multiple myeloma (MM). Stromal cell-derived factor 1α (SDF-1α) and its receptor, CXC chemokine receptor 4 (CXCR4), has been implicated as a regulator of bone resorption, suggesting that agents that can suppress SDF1α/CXCR4 signaling might inhibit osteoclastogenesis, a process closely linked to bone resorption. We, therefore, investigated whether gambogic acid (GA), a xanthone, could inhibit CXCR4 signaling and suppress osteoclastogenesis induced by MM cells. Through docking studies we predicted that GA directly interacts with CXCR4. This xanthone down-regulates the expression of CXCR4 on MM cells in a dose- and time-dependent manner. The down-regulation of CXCR4 was not due to proteolytic degradation, but rather GA suppresses CXCR4 mRNA expression by inhibiting nuclear factor-kappa B (NF-κB) DNA binding. This was further confirmed by quantitative chromatin immunoprecipitation assay, as GA inhibits p65 binding at the CXCR4 promoter. GA suppressed SDF-1α-induced chemotaxis of MM cells and downstream signaling of CXCR4 by inhibiting phosphorylation of Akt, p38, and Erk1/2 in MM cells. GA abrogated the RANKL-induced differentiation of macrophages to osteoclasts in a dose- and time-dependent manner. In addition, we found that MM cells induced differentiation of macrophages to osteoclasts, and that GA suppressed this process. Importantly, suppression of osteoclastogenesis by GA was mediated through IL-6 inhibition. Overall, our results show that GA is a novel inhibitor of CXCR4 expression and has a strong potential to suppress osteoclastogenesis mediated by MM cells. Published by Elsevier Inc.

Expression of osteoblast and osteoclast regulatory genes in the bone marrow microenvironment in multiple myeloma

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Kristensen, Ida B; Christensen, Jacob Haaber; Lyng, Maria Bibi

2014-01-01

Multiple myeloma (MM) lytic bone disease (LBD) is caused by osteoclast activation and osteoblast inhibition. RANK/RANKL/OPG play central roles in osteoclast activation and Wnt inhibitor DKK1 in osteoblast inhibition. The role of other Wnt inhibitors is less clear. We evaluated gene expression...... of osteoclast regulators (RANK, RANKL, OPG, TRAIL, MIP1A), Wnt inhibitors (DKK1, SFRP2, SFRP3, sclerostin, WIF1) and osteoblast transcription factors (RUNX2, osterix) by quantitative reverse transcriptase polymerase chain reaction (RT-PCR) in the bone marrow (BM) microenvironment using snap-frozen BM biopsies...... radiographs and the bone resorption marker CTX-1. Protein levels were evaluated by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry. Among Wnt inhibitors, only SFRP3 and DKK1 were significantly overexpressed in advanced LBD, correlating with protein levels. SFRP3 correlated with CTX-1. Our...

Inhibition of osteoclast differentiation by overexpression of NDRG2 in monocytes

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Kang, Kyeongah; Nam, Sorim; Kim, Bomi; Lim, Ji Hyun; Yang, Young; Lee, Myeong-Sok; Lim, Jong-Seok, E-mail: jslim@sookmyung.ac.kr

2015-12-25

N-Myc downstream-regulated gene 2 (NDRG2), a member of the NDRG family of differentiation-related genes, has been characterized as a regulator of dendritic cell differentiation from monocytes, CD34{sup +} progenitor cells, and myelomonocytic leukemic cells. In this study, we show that NDRG2 overexpression inhibits the differentiation of U937 cells into osteoclasts in response to stimulation with a combination of macrophage colony-stimulating factor (M-CSF) and soluble receptor activator of NF-κB ligand (RANKL). U937 cells stably expressing NDRG2 are unable to differentiate into multinucleated osteoclast-like cells and display reduced tartrate-resistant acid phosphatase (TRAP) activity and resorption pit formation. Furthermore, NDRG2 expression significantly suppresses the expression of genes that are crucial for the proliferation, survival, differentiation, and function of osteoclasts, including c-Fos, Atp6v0d2, RANK, and OSCAR. The activation of ERK1/2 and p38 is also inhibited by NDRG2 expression during osteoclastogenesis, and the inhibition of osteoclastogenesis by NDRG2 correlates with the down-regulation of the expression of the transcription factor PU.1. Taken together, our results suggest that the expression of NDRG2 potentially inhibits osteoclast differentiation and plays a role in modulating the signal transduction pathway responsible for osteoclastogenesis. - Highlights: • The expression of NDRG2 significantly impairs osteoclast differentiation. • PU.1 and p38 MAPK inhibitions by NDRG2 are critical for the inhibition of osteoclastogenesis. • Knockdown of NDRG2 rescues the ability of monocytes to differentiate into osteoclasts. • NDRG2 expression in BM and primary macrophages also impairs osteoclast differentiation. • This study implies the potential of NDRG2 expression in the inhibition of osteoclastogenesis.

Biglycan deficiency increases osteoclast differentiation and activity due to defective osteoblasts

DEFF Research Database (Denmark)

Bi, Yanming; Nielsen, Karina L; Kilts, Tina M

2006-01-01

to be independent of the differential production of soluble RANKL and OPG and, instead, due to a decrease in osteoblast maturation accompanied by increase in osteoblastic proliferation. In addition to the imbalance between differentiation and proliferation, there was a differential decrease in secretory leukocyte......Bone mass is maintained by a fine balance between bone formation by osteoblasts and bone resorption by osteoclasts. Although osteoblasts and osteoclasts have different developmental origins, it is generally believed that the differentiation, function, and survival of osteoclasts are regulated...... by osteogenic cells. We have previously shown that the extracellular matrix protein, biglycan (Bgn), plays an important role in the differentiation of osteoblast precursors. In this paper, we showed that Bgn is involved in regulating osteoclast differentiation through its effect on osteoblasts...

Donepezil prevents RANK-induced bone loss via inhibition of osteoclast differentiation by downregulating acetylcholinesterase

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Tsuyoshi Sato

2015-09-01

Conclusions: AChE promotes osteoclast differentiation in vitro. Donepezil inhibits osteoclast function in vitro and prevents bone loss by suppressing bone resorption in vivo, suggesting the possibility that donepezil reduces fracture risk in patients with Alzheimer's disease.

Discovery of novel benzopyranyl tetracycles that act as inhibitors of osteoclastogenesis induced by receptor activator of NF-κB ligand.

Science.gov (United States)

Zhu, Mingyan; Kim, Myung Hee; Lee, Sanghee; Bae, Su Jung; Kim, Seong Hwan; Park, Seung Bum

2010-12-23

A novel benzopyran-fused molecular framework 7ai was discovered as a specific inhibitor of RANKL-induced osteoclastogenesis using a cell-based TRAP activity assay from drug-like small-molecule libraries constructed by diversity-oriented synthesis. Its inhibitory activity was confirmed by in vitro evaluations including specific inhibition of RANKL-induced ERK phosphorylation and NF-κB transcriptional activation. 7ai can serve as a specific small-molecule modulator for mechanistic studies of RANKL-induced osteoclast differentiation as well as a potential lead for the development of antiresorptive drugs.

Regulation of vacuolar H+-ATPase in microglia by RANKL

International Nuclear Information System (INIS)

Serrano, Eric M.; Ricofort, Ryan D.; Zuo, Jian; Ochotny, Noelle; Manolson, Morris F.; Holliday, L. Shannon

2009-01-01

Vacuolar H + -ATPases (V-ATPases) are large electrogenic proton pumps composed of numerous subunits that play vital housekeeping roles in the acidification of compartments of the endocytic pathway. Additionally, V-ATPases play specialized roles in certain cell types, a capacity that is linked to cell type selective expression of isoforms of some of the subunits. We detected low levels of the a3 isoform of the a-subunit in mouse brain extracts. Examination of various brain-derived cell types by immunoblotting showed a3 was expressed in the N9 microglia cell line and in primary microglia, but not in other cell types. The expression of a3 in osteoclasts requires stimulation by Receptor Activator of Nuclear Factor κB-ligand (RANKL). We found that Receptor Activator of Nuclear Factor κB (RANK) was expressed by microglia. Stimulation of microglia with RANKL triggered increased expression of a3. V-ATPases in microglia were shown to bind microfilaments, and stimulation with RANKL increased the proportion of V-ATPase associated with the detergent-insoluble cytoskeletal fraction and with actin. In summary, microglia express the a3-subunit of V-ATPase. The expression of a3 and the interaction between V-ATPases and microfilaments was modulated by RANKL. These data suggest a novel molecular pathway for regulating microglia.

Neuropeptide substance P stimulates the formation of osteoclasts via synovial fibroblastic cells

International Nuclear Information System (INIS)

Matayoshi, Takaaki; Goto, Tetsuya; Fukuhara, Eiji; Takano, Hiroshi; Kobayashi, Shigeru; Takahashi, Tetsu

2005-01-01

The present study was designed to evaluate the effects of neuropeptide substance P (Sp) on the formation of osteoclasts via synovial fibroblastic cells. Synovial fibroblastic cells derived from rat knee joint expressed the Sp receptor, neurokinin-1 receptor (NK 1 -R). The addition of Sp stimulated the proliferation of synovial fibroblastic cells and this effect was inhibited by Sp or NK 1 -R antagonists. Increased expression of the receptor activator of nuclear factor κB ligand (Rankle) in synovial fibroblastic cells after the addition of Sp was demonstrated by reverse transcriptase-polymerase chain reaction and immunofluorescence staining. Osteoprotegerin expression in synovial fibroblastic cells was decreased after incubation with SP. In co-cultures of synovial fibroblastic cells and rat peripheral blood monocytes, SP stimulated osteoclastogenesis. These results suggest that SP in the joint cavity may cause both hypertrophy of the synovium and induction of increased osteoclast formation through the increased expression of RANKL in the synovium

MicroRNA-124 inhibits the progression of adjuvant-induced arthritis in rats.

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Nakamachi, Yuji; Ohnuma, Kenichiro; Uto, Kenichi; Noguchi, Yoriko; Saegusa, Jun; Kawano, Seiji

2016-03-01

MicroRNAs (miRNAs) are small endogenous, non-coding RNAs that act as post-transcriptional regulators. We analysed the in vivo effect of miRNA-124 (miR-124, the rat analogue of human miR-124a) on adjuvant-induced arthritis (AIA) in rats. AIA was induced in Lewis rats by injecting incomplete Freund's adjuvant with heat-killed Mycobacterium tuberculosis. Precursor (pre)-miR-124 was injected into the right hind ankle on day 9. Morphological changes in the ankle joint were assessed by micro-CT and histopathology. Cytokine expression was examined by western blotting and real-time RT-PCR. The effect of miR-124 on predicted target messenger RNAs (mRNAs) was examined by luciferase reporter assays. The effect of pre-miR-124 or pre-miR-124a on the differentiation of human osteoclasts was examined by tartrate-resistant acid phosphatase staining. We found that miR-124 suppressed AIA in rats, as demonstrated by decreased synoviocyte proliferation, leucocyte infiltration and cartilage or bone destruction. Osteoclast counts and expression level of receptor activator of the nuclear factor κB ligand (RANKL), integrin β1 (ITGB1) and nuclear factor of activated T cells cytoplasmic 1 (NFATc1) were reduced in AIA rats treated with pre-miR-124. Luciferase analysis showed that miR-124 directly targeted the 3'UTR of the rat NFATc1, ITGB1, specificity protein 1 and CCAAT/enhancer-binding protein α mRNAs. Pre-miR-124 also suppressed NFATc1 expression in RAW264.7 cells. Both miR-124 and miR-124a directly targeted the 3'-UTR of human NFATc1 mRNA, and both pre-miR-124 and pre-miR-124a suppressed the differentiation of human osteoclasts. We found that miR-124 ameliorated AIA by suppressing critical prerequisites for arthritis development, such as RANKL and NFATc1. Thus, miR-124a is a candidate for therapeutic use for human rheumatoid arthritis. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Diclofenac sodium inhibits NFkappaB transcription in osteoclasts.

Science.gov (United States)

Karakawa, A; Fukawa, Y; Okazaki, M; Takahashi, K; Sano, T; Amano, H; Yamamoto, M; Yamada, S

2009-11-01

A non-steroidal anti-inflammatory drug, diclofenac, acts efficiently against inflammation; however, down-regulation of diclofenac on bone remodeling has raised concerns. The inhibitory mechanisms of diclofenac are poorly understood. We hypothesized that diclofenac down-regulates osteoclast differentiation and activation via inhibition of the translocation of phosphorylated nuclear factor kappa B (NFkappaB). When osteoclasts prepared from mouse hematopoietic stem cells were treated with diclofenac, tartrateresistant acid phosphatase-positive multinucleated cells decreased in a concentration-dependent manner. Pit formation assay revealed the abolition of osteoclastic bone resorption; levels of cathepsin K transcripts, an osteoclastic resorption marker, were down-regulated time-dependently. Diclofenac induced the accumulation of the inhibitor of kappa B in cytosol, which led to suppression of the nuclear translocation of NFkappaB and phosphorylated NFkappaB. These results suggest that the novel mechanism of diclofenac for bone remodeling is associated with phosphorylated NFkappaB reduction, which regulates osteoclast differentiation and activation.

cAMP/PKA regulates osteogenesis, adipogenesis and ratio of RANKL/OPG mRNA expression in mesenchymal stem cells by suppressing leptin.

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Der-Chih Yang

Full Text Available BACKGROUND: Mesenchymal stem cells (MSCs are a pluripotent cell type that can differentiate into adipocytes, osteoblasts and other cells. The reciprocal relationship between adipogenesis and osteogenesis was previously demonstrated; however, the mechanisms remain largely unknown. METHODS AND FINDINGS: We report that activation of PKA by 3-isobutyl-1 methyl xanthine (IBMX and forskolin enhances adipogenesis, the gene expression of PPARgamma2 and LPL, and downregulates the gene expression of Runx2 and osteopontin, markers of osteogenesis. PKA activation also decreases the ratio of Receptor Activator of the NF-kappaB Ligand to Osteoprotegerin (RANKL/OPG gene expression - the key factors of osteoclastogenesis. All these effects are mediated by the cAMP/PKA/CREB pathway by suppressing leptin, and may contribute to PKA stimulators-induced in vivo bone loss in developing zebrafish. CONCLUSIONS: Using MSCs, the center of a newly proposed bone metabolic unit, we identified cAMP/PKA signaling, one of the many signaling pathways that regulate bone homeostasis via controlling cyto-differentiation of MSCs and altering RANKL/OPG gene expression.

Topical Treatment with Xiaozheng Zhitong Paste (XZP Alleviates Bone Destruction and Bone Cancer Pain in a Rat Model of Prostate Cancer-Induced Bone Pain by Modulating the RANKL/RANK/OPG Signaling

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Yanju Bao

2015-01-01

Full Text Available To explore the effects and mechanisms of Xiaozheng Zhitong Paste (XZP on bone cancer pain, Wistar rats were inoculated with vehicle or prostate cancer PC-3 into the tibia bone and treated topically with inert paste, XZP at 15.75, 31.5, or 63 g/kg twice per day for 21 days. Their bone structural damage, nociceptive behaviors, bone osteoclast and osteoblast activity, and the levels of OPG, RANL, RNAK, PTHrP, IGF-1, M-CSF, IL-8, and TNF-α were examined. In comparison with that in the placebo group, significantly reduced numbers of invaded cancer cells, decreased levels of bone damage and mechanical threshold and paw withdrawal latency, lower levels of serum TRACP5b, ICTP, PINP, and BAP, and less levels of bone osteoblast and osteoclast activity were detected in the XZP-treated rats (P<0.05. Moreover, significantly increased levels of bone OPG but significantly decreased levels of RANL, RNAK, PTHrP, IGF-1, M-CSF, IL-8, and TNF-α were detected in the XZP-treated rats (P<0.05 for all. Together, XZP treatment significantly mitigated the cancer-induced bone damage and bone osteoclast and osteoblast activity and alleviated prostate cancer-induced bone pain by modulating the RANKL/RANK/OPG pathway and bone cancer-related inflammation in rats.

Urokinase plasminogen activator receptor affects bone homeostasis by regulating osteoblast and osteoclast function

DEFF Research Database (Denmark)

Furlan, Federico; Galbiati, Clara; Jørgensen, Niklas R

2007-01-01

of macrophage-colony stimulating factor (M-CSF) and RANKL. Phalloidin staining in osteoclasts served to study actin ring and podosome formation. RESULTS: pQCT revealed increased bone mass in uPAR-null mice. Mechanical tests showed reduced load-sustaining capability in uPAR KO tibias. uPAR KO osteoblasts showed...... a proliferative advantage with no difference in apoptosis, higher matrix mineralization, and earlier appearance of alkaline phosphatase (ALP). Surface RANKL expression at different stages of differentiation was not altered. AP-1 components, such as JunB and Fra-1, were upregulated in uPAR KO osteoblasts, along...

Tumor associated osteoclast-like giant cells promote tumor growth and lymphangiogenesis by secreting vascular endothelial growth factor-C

International Nuclear Information System (INIS)

Hatano, Yu; Nakahama, Ken-ichi; Isobe, Mitsuaki; Morita, Ikuo

2014-01-01

Highlights: • M-CSF and RANKL expressing HeLa cells induced osteoclastogenesis in vitro. • We established OGC-containing tumor model in vivo. • OGC-containing tumor became larger independent of M-CSF or RANKL effect. • VEGF-C secreted from OGCs was a one of candidates for OGC-containing tumor growth. - Abstract: Tumors with osteoclast-like giant cells (OGCs) have been reported in a variety of organs and exert an invasive and prometastatic phenotype, but the functional role of OGCs in the tumor environment has not been fully clarified. We established tumors containing OGCs to clarify the role of OGCs in tumor phenotype. A mixture of HeLa cells expressing macrophage colony-stimulating factor (M-CSF, HeLa-M) and receptor activator of nuclear factor-κB ligand (RANKL, HeLa-R) effectively supported the differentiation of osteoclast-like cells from bone marrow macrophages in vitro. Moreover, a xenograft study showed OGC formation in a tumor composed of HeLa-M and HeLa-R. Surprisingly, the tumors containing OGCs were significantly larger than the tumors without OGCs, although the growth rates were not different in vitro. Histological analysis showed that lymphangiogenesis and macrophage infiltration in the tumor containing OGCs, but not in other tumors were accelerated. According to quantitative PCR analysis, vascular endothelial growth factor (VEGF)-C mRNA expression increased with differentiation of osteoclast-like cells. To investigate whether VEGF-C expression is responsible for tumor growth and macrophage infiltration, HeLa cells overexpressing VEGF-C (HeLa-VC) were established and transplanted into mice. Tumors composed of HeLa-VC mimicked the phenotype of the tumors containing OGCs. Furthermore, the vascular permeability of tumor microvessels also increased in tumors containing OGCs and to some extent in VEGF-C-expressing tumors. These results suggest that macrophage infiltration and vascular permeability are possible mediators in these tumors. These

Osteoclasts secrete non-bone derived signals that induce bone formation

DEFF Research Database (Denmark)

Karsdal, Morten A; Neutzsky-Wulff, Anita V; Dziegiel, Morten Hanefeld

2008-01-01

Bone turnover is a highly regulated process, where bone resorption in the normal healthy individual always is followed by bone formation in a manner referred to as coupling. Patients with osteopetrosis caused by defective acidification of the resorption lacuna have severely decreased resorption......) from human osteoclasts cultured on either bone or plastic, and tested their effects on bone nodule formation by osteoblasts. Both types of CM were shown to dose-dependently induce bone nodule formation, whereas non-conditioned osteoclast culture medium had no effects. These data show that osteoclasts...

Regulation of vacuolar H{sup +}-ATPase in microglia by RANKL

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Serrano, Eric M.; Ricofort, Ryan D.; Zuo, Jian [Department of Orthodontics, University of Florida College of Dentistry, Gainesville, FL 32610 (United States); Ochotny, Noelle [Department of Pharmacology, University of Toronto, Toronto, Ont., Canada M5G 1G6 (Canada); Manolson, Morris F. [Faculty of Dentistry, University of Toronto, Toronto, Ont., Canada M5G 1G6 (Canada); Holliday, L. Shannon, E-mail: sholliday@dental.ufl.edu [Department of Orthodontics, University of Florida College of Dentistry, Gainesville, FL 32610 (United States); Department of Anatomy and Cell Biology, University of Florida College of Medicine, Gainesville, FL 32610 (United States)

2009-11-06

Vacuolar H{sup +}-ATPases (V-ATPases) are large electrogenic proton pumps composed of numerous subunits that play vital housekeeping roles in the acidification of compartments of the endocytic pathway. Additionally, V-ATPases play specialized roles in certain cell types, a capacity that is linked to cell type selective expression of isoforms of some of the subunits. We detected low levels of the a3 isoform of the a-subunit in mouse brain extracts. Examination of various brain-derived cell types by immunoblotting showed a3 was expressed in the N9 microglia cell line and in primary microglia, but not in other cell types. The expression of a3 in osteoclasts requires stimulation by Receptor Activator of Nuclear Factor {kappa}B-ligand (RANKL). We found that Receptor Activator of Nuclear Factor {kappa}B (RANK) was expressed by microglia. Stimulation of microglia with RANKL triggered increased expression of a3. V-ATPases in microglia were shown to bind microfilaments, and stimulation with RANKL increased the proportion of V-ATPase associated with the detergent-insoluble cytoskeletal fraction and with actin. In summary, microglia express the a3-subunit of V-ATPase. The expression of a3 and the interaction between V-ATPases and microfilaments was modulated by RANKL. These data suggest a novel molecular pathway for regulating microglia.

Use of ethanol extracts of Terminalia chebula to prevent periodontal disease induced by dental plaque bacteria.

Science.gov (United States)

Lee, Jongsung; Nho, Youn Hwa; Yun, Seok Kyun; Hwang, Young Sun

2017-02-16

The fruit of the Terminalia chebula tree has been widely used for the treatment of various disorders. Its anti-diabetic, anti-mutagenic, anti-oxidant, anti-bacterial, anti-fungal, and anti-viral effects have been studied. Dental plaque bacteria (DPB) are intimately associated with gingivitis and periodontitis. In the quest for materials that will prove useful in the treatment and prevention of periodontal disease, we investigated the preventive effects of an ethanol extract of Terminalia chebula (EETC) on DPB-induced inflammation and bone resorption. The anti-bacterial effect of EETC was analyzed using the disc diffusion method. The anti-inflammatory effect of EETC was determined by molecular biological analysis of the DPB-mediated culture cells. Prevention of osteoclastic bone resorption by EETC was explored using osteoclast formation and pit formation assays. EETC suppressed the growth of oral bacteria and reduced the induction of inflammatory cytokines and proteases, abolishing the expression of PGE2 and COX-2 and inhibiting matrix damage. By stimulating the DPB-derived lipopolysaccharides, EETC inhibited both osteoclast formation in osteoclast precursors and RANKL expression in osteoblasts, thereby contributing to the prevention of bone resorption. EETC may be a beneficial supplement to help prevent DPB-mediated periodontal disease.

A Modified Glycosaminoglycan, GM-0111, Inhibits Molecular Signaling Involved in Periodontitis.

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Justin R Savage

Full Text Available Periodontitis is characterized by microbial infection, inflammation, tissue breakdown, and accelerated loss of alveolar bone matrix. Treatment targeting these multiple stages of the disease provides ways to treat or prevent periodontitis. Certain glycosaminoglycans (GAGs block multiple inflammatory mediators as well as suppress bacterial growth, suggesting that these GAGs may be exploited as a therapeutic for periodontitis.We investigated the effects of a synthetic GAG, GM-0111, on various molecular events associated with periodontitis: growth of Porphyromonas gingivalis (P. gingivalis and Aggregatibacter actinomycetemcomitans (A. actinomycetemcomitans pathogenic bacteria associated with periodontitis; activation of pro-inflammatory signaling through TLR2 and TLR4 in mouse macrophage RAW 264.7 cells and heterologously expressed HEK 293 cells; osteoclast formation and bone matrix resorption in cultured mouse pre-osteoclasts.(1 GM-0111 suppressed the growth of P. gingivalis and A. actinomycetemcomitans even at 1% (w/v solution. The antibacterial effects of GM-0111 were stronger than hyaluronic acid (HA or xylitol in P. gingivalis at all concentrations and comparable to xylitol in A. actinomycetemcomitans at ≥2% (w/v solution. We also observed that GM-0111 suppressed biofilm formation of P. gingivalis and these effects were much stronger than HA. (2 GM-0111 inhibited TLR-mediated pro-inflammatory cellular signaling both in macrophage and HEK 293 cells with higher selectivity for TLR2 than TLR4 (IC50 of 1-10 ng/mL vs. > 100 μg/mL, respectively. (3 GM-0111 blocked RANKL-induced osteoclast formation (as low as 300 ng/mL and bone matrix resorption. While GM-0111 showed high affinity binding to RANKL, it did not interfere with RANKL/RANK/NF-κB signaling, suggesting that GM-0111 inhibits osteoclast formation by a RANKL-RANK-independent mechanism.We report that GM-0111 inhibits multiple molecular events involved in periodontitis, spanning from the

Wedelolactone enhances osteoblastogenesis by regulating Wnt/β-catenin signaling pathway but suppresses osteoclastogenesis by NF-κB/c-fos/NFATc1 pathway.

Science.gov (United States)

Liu, Yan-Qiu; Hong, Zhi-Lai; Zhan, Li-Bin; Chu, Hui-Ying; Zhang, Xiao-Zhe; Li, Guo-Hui

2016-08-25

Bone homeostasis is maintained by formation and destruction of bone, which are two processes tightly coupled and controlled. Targeting both stimulation on bone formation and suppression on bone resorption becomes a promising strategy for treating osteoporosis. In this study, we examined the effect of wedelolactone, a natural product from Ecliptae herba, on osteoblastogenesis as well as osteoclastogenesis. In mouse bone marrow mesenchymal stem cells (BMSC), wedelolactone stimulated osteoblast differentiation and bone mineralization. At the molecular level, wedelolactone directly inhibited GSK3β activity and enhanced the phosphorylation of GSK3β, thereafter stimulated the nuclear translocation of β-catenin and runx2. The expression of osteoblastogenesis-related marker gene including osteorix, osteocalcin and runx2 increased. At the same concentration range, wedelolactone inhibited RANKL-induced preosteoclastic RAW264.7 actin-ring formation and bone resorption pits. Further, wedelolactone blocked NF-kB/p65 phosphorylation and abrogated the NFATc1 nuclear translocation. As a result, osteoclastogenesis-related marker gene expression decreased, including c-src, c-fos, and cathepsin K. In ovariectomized mice, administration of wedelolactone prevented ovariectomy-induced bone loss by enhancing osteoblast activity and inhibiting osteoclast activity. Together, these data demonstrated that wedelolactone facilitated osteoblastogenesis through Wnt/GSK3β/β-catenin signaling pathway and suppressed RANKL-induced osteoclastogenesis through NF-κB/c-fos/NFATc1 pathway. These results suggested that wedelolacone could be a novel dual functional therapeutic agent for osteoporosis.

Expression of osteoprotegerin, RNAK and RANKL genes in femoral head avascular necrosis and related signaling pathway.

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Miao, Qingtang; Hao, Sibin; Li, Hongmei; Sun, Fang; Wang, Xueling

2015-01-01

Femoral head avascular necrosis (AVN) causes the damage of hip joint and related dysfunctions, thus consisting of a clinical challenge. Osteoprotegerin (OPG), receptor activator of nuclear factor κB (RANK) and its ligand (RANKL) all regulate the formation of bones via gene transcriptional regulation for the balance between osteoblasts and osteoclasts. This study thus investigated the expressional profiles of OPG, RANK and RANKL genes in AVN patients, and explored related molecular mediating pathways. Real-time qPCR was used to measure the gene expression of OPG, RANK and RANKL genes in AVN femoral head tissue samples from 42 patients, along with normal tissues. Western blotting analysis was performed to quantify protein levels of OPG and RANKL. There was a trend but not statistically significant elevation of mRNA levels of OPG in femoral head AVN tissues compared to normal tissues (P>0.05). The expression of RNAK and RNAKL, however, was significantly elevated in necrotic tissues (P<0.05). No significant difference in protein levels of OPG or RANKL between groups. The expression of OPG, RANK and RANKL genes exert a crucial role in the progression of AVN, suggesting their roles in mediating bone homeostasis and potential effects on bone destruction.

Caffeic acid phenethyl ester protects against glucocorticoid-induced osteoporosis in vivo: Impact on oxidative stress and RANKL/OPG signals

International Nuclear Information System (INIS)

Tolba, Mai F.; El-Serafi, Ahmed T.; Omar, Hany A.

2017-01-01

Glucocorticoid-induced osteoporosis (GIO) is one of the most common causes of secondary osteoporosis. Given that glucocorticoids are considered as a main component of the treatment protocols for a variety of inflammation and immune-mediated diseases besides its use as adjuvant to several chemotherapeutic agents, it is crucial to find ways to overcome this critical adverse effect. Caffeic acid phenethyl ester (CAPE), which is a natural compound derived from honeybee propolis displayed promising antiosteoporotic effects against mechanical bone injury in various studies. The current work aimed at investigating the potential protective effect of CAPE against GIO in vivo with emphasis on the modulation of oxidative status and receptor activator of NF-kB ligand (RANKL)/osteoprotegrin (OPG) signaling. The results showed that CAPE opposed dexamethasone (DEX)-mediated alterations in bone histology and tartarate-resistant acid phosphatase (TRAP) activity. In addition, CAPE restored oxidative balance, Runt-related transcription factor 2 (RunX2) expression and reduced caspase-3 activity in femur tissues. Co-administration of CAPE with DEX normalized RANKL/OPG ratio and Akt activation indicating a reduction in DEX-osteoclastogenesis. In conclusion, concurrent treatment of CAPE with DEX exhibited promising effects in the protection against DEX-induced osteoporosis through opposing osteoclastogenesis and protecting osteoblasts. The potent antioxidant activity of CAPE is, at least in part, involved in its anti-apoptotic effects and modulation of RunX2 and RANKL/OPG signals. The use of CAPE-enriched propolis formulas is strongly recommended for patients on chronic glucocorticoid therapy to help in the attenuation of GIO. - Highlights: • Caffeic acid phenethyl ester (CAPE) counteracts DEX-induced osteoporosis. • CAPE hinders DEX-induced alterations in oxidation parameters as GSH, SOD and MDA. • CAPE opposes osteoclastogenesis via suppressing RANL/OPG ratio and Akt signals. �

Caffeic acid phenethyl ester protects against glucocorticoid-induced osteoporosis in vivo: Impact on oxidative stress and RANKL/OPG signals

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Tolba, Mai F. [Department of Pharmacology and Toxicology, Faculty of Pharmacy, Ain Shams University, Cairo 11566 (Egypt); Chapman University, Irvine 92618, CA (United States); El-Serafi, Ahmed T. [Sharjah Institute for Medical Research, University of Sharjah, Sharjah 27272 (United Arab Emirates); Department of Medical Biochemistry, Faculty of Medicine, Suez Canal University, Ismailia (Egypt); Omar, Hany A., E-mail: hanyomar@sharjah.ac.ae [Sharjah Institute for Medical Research, University of Sharjah, Sharjah 27272 (United Arab Emirates); Department of Pharmacology, Faculty of Pharmacy, Beni-Suef University, Beni-Suef 62514 (Egypt)

2017-06-01

Glucocorticoid-induced osteoporosis (GIO) is one of the most common causes of secondary osteoporosis. Given that glucocorticoids are considered as a main component of the treatment protocols for a variety of inflammation and immune-mediated diseases besides its use as adjuvant to several chemotherapeutic agents, it is crucial to find ways to overcome this critical adverse effect. Caffeic acid phenethyl ester (CAPE), which is a natural compound derived from honeybee propolis displayed promising antiosteoporotic effects against mechanical bone injury in various studies. The current work aimed at investigating the potential protective effect of CAPE against GIO in vivo with emphasis on the modulation of oxidative status and receptor activator of NF-kB ligand (RANKL)/osteoprotegrin (OPG) signaling. The results showed that CAPE opposed dexamethasone (DEX)-mediated alterations in bone histology and tartarate-resistant acid phosphatase (TRAP) activity. In addition, CAPE restored oxidative balance, Runt-related transcription factor 2 (RunX2) expression and reduced caspase-3 activity in femur tissues. Co-administration of CAPE with DEX normalized RANKL/OPG ratio and Akt activation indicating a reduction in DEX-osteoclastogenesis. In conclusion, concurrent treatment of CAPE with DEX exhibited promising effects in the protection against DEX-induced osteoporosis through opposing osteoclastogenesis and protecting osteoblasts. The potent antioxidant activity of CAPE is, at least in part, involved in its anti-apoptotic effects and modulation of RunX2 and RANKL/OPG signals. The use of CAPE-enriched propolis formulas is strongly recommended for patients on chronic glucocorticoid therapy to help in the attenuation of GIO. - Highlights: • Caffeic acid phenethyl ester (CAPE) counteracts DEX-induced osteoporosis. • CAPE hinders DEX-induced alterations in oxidation parameters as GSH, SOD and MDA. • CAPE opposes osteoclastogenesis via suppressing RANL/OPG ratio and Akt signals. �

Methyl Gallate Inhibits Osteoclast Formation and Function by Suppressing Akt and Btk-PLCγ2-Ca2+ Signaling and Prevents Lipopolysaccharide-Induced Bone Loss.

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Baek, Jong Min; Kim, Ju-Young; Lee, Chang Hoon; Yoon, Kwon-Ha; Lee, Myeung Su

2017-03-07

In the field of bone research, various natural derivatives have emerged as candidates for osteoporosis treatment by targeting abnormally elevated osteoclastic activity. Methyl gallate, a plant-derived phenolic compound, is known to have numerous pharmacological effects against inflammation, oxidation, and cancer. Our purpose was to explore the relation between methyl gallate and bone metabolism. Herein, we performed screening using methyl gallate by tartrate resistant acid phosphatase (TRAP) staining and revealed intracellular mechanisms responsible for methyl gallate-mediated regulation of osteoclastogenesis by Western blotting and quantitative reverse transcription polymerase chain reaction (RT-PCR). Furthermore, we assessed the effects of methyl gallate on the characteristics of mature osteoclasts. We found that methyl gallate significantly suppressed osteoclast formation through Akt and Btk-PLCγ2-Ca 2+ signaling. The blockade of these pathways was confirmed through transduction of cells with a CA-Akt retrovirus and evaluation of Ca 2+ influx intensity (staining with Fluo-3/AM). Indeed, methyl gallate downregulated the formation of actin ring-positive osteoclasts and resorption pit areas. In agreement with in vitro results, we found that administration of methyl gallate restored osteoporotic phenotype stimulated by acute systemic injection of lipopolysaccharide in vivo according to micro-computed tomography and histological analysis. Our data strongly indicate that methyl gallate may be useful for the development of a plant-based antiosteoporotic agent.

Methyl Gallate Inhibits Osteoclast Formation and Function by Suppressing Akt and Btk-PLCγ2-Ca2+ Signaling and Prevents Lipopolysaccharide-Induced Bone Loss

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Jong Min Baek

2017-03-01

Full Text Available In the field of bone research, various natural derivatives have emerged as candidates for osteoporosis treatment by targeting abnormally elevated osteoclastic activity. Methyl gallate, a plant-derived phenolic compound, is known to have numerous pharmacological effects against inflammation, oxidation, and cancer. Our purpose was to explore the relation between methyl gallate and bone metabolism. Herein, we performed screening using methyl gallate by tartrate resistant acid phosphatase (TRAP staining and revealed intracellular mechanisms responsible for methyl gallate-mediated regulation of osteoclastogenesis by Western blotting and quantitative reverse transcription polymerase chain reaction (RT-PCR. Furthermore, we assessed the effects of methyl gallate on the characteristics of mature osteoclasts. We found that methyl gallate significantly suppressed osteoclast formation through Akt and Btk-PLCγ2-Ca2+ signaling. The blockade of these pathways was confirmed through transduction of cells with a CA-Akt retrovirus and evaluation of Ca2+ influx intensity (staining with Fluo-3/AM. Indeed, methyl gallate downregulated the formation of actin ring-positive osteoclasts and resorption pit areas. In agreement with in vitro results, we found that administration of methyl gallate restored osteoporotic phenotype stimulated by acute systemic injection of lipopolysaccharide in vivo according to micro-computed tomography and histological analysis. Our data strongly indicate that methyl gallate may be useful for the development of a plant-based antiosteoporotic agent.

Rhus javanica Gall Extract Inhibits the Differentiation of Bone Marrow-Derived Osteoclasts and Ovariectomy-Induced Bone Loss

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Tae-Ho Kim

2016-01-01

Full Text Available Inhibition of osteoclast differentiation and bone resorption is a therapeutic strategy for the management of postmenopausal bone loss. This study investigated the effects of Rhus javanica (R. javanica extracts on bone marrow cultures to develop agents from natural sources that may prevent osteoclastogenesis. Extracts of R. javanica (eGr cocoons spun by Rhus javanica (Bell. Baker inhibited the osteoclast differentiation and bone resorption. The effects of aqueous extract (aeGr or 100% ethanolic extract (eeGr on ovariectomy- (OVX- induced bone loss were investigated by various biochemical assays. Furthermore, microcomputed tomography (µCT was performed to study bone remodeling. Oral administration of eGr (30 mg or 100 mg/kg/day for 6 weeks augmented the inhibition of femoral bone mineral density (BMD, bone mineral content (BMC, and other factors involved in bone remodeling when compared to OVX controls. Additionally, eGr slightly decreased bone turnover markers that were increased by OVX. Therefore, it may be suggested that the protective effects of eGr could have originated from the suppression of OVX-induced increase in bone turnover. Collectively, the findings of this study indicate that eGr has potential to activate bone remodeling by inhibiting osteoclast differentiation and bone loss.

Role of Muramyl Dipeptide in Lipopolysaccharide-Mediated Biological Activity and Osteoclast Activity

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Hideki Kitaura

2018-01-01

Full Text Available Lipopolysaccharide (LPS is an endotoxin and bacterial cell wall component that is capable of inducing inflammation and immunological activity. Muramyl dipeptide (MDP, the minimal essential structural unit responsible for the immunological activity of peptidoglycans, is another inflammation-inducing molecule that is ubiquitously expressed by bacteria. Several studies have shown that inflammation-related biological activities were synergistically induced by interactions between LPS and MDP. MDP synergistically enhances production of proinflammatory cytokines that are induced by LPS exposure. Injection of MDP induces lethal shock in mice challenged with LPS. LPS also induces osteoclast formation and pathological bone resorption; MDP enhances LPS induction of both processes. Furthermore, MDP enhances the LPS-induced receptor activator of NF-κB ligand (RANKL expression and toll-like receptor 4 (TLR4 expression both in vivo and in vitro. Additionally, MDP enhances LPS-induced mitogen-activated protein kinase (MAPK signaling in stromal cells. Taken together, these findings suggest that MDP plays an important role in LPS-induced biological activities. This review discusses the role of MDP in LPS-mediated biological activities, primarily in relation to osteoclastogenesis.

Protective effect of zinc supplementation against cadmium-induced oxidative stress and the RANK/RANKL/OPG system imbalance in the bone tissue of rats

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Brzóska, Malgorzata M.; Rogalska, Joanna

2013-01-01

It was investigated whether protective influence of zinc (Zn) against cadmium (Cd)-induced disorders in bone metabolism may be related to its antioxidative properties and impact on the receptor activator of nuclear factor (NF)-κΒ (RANK)/RANK ligand (RANKL)/osteoprotegerin (OPG) system. Numerous indices of oxidative/antioxidative status, and Cd and Zn were determined in the distal femur of the rats administered Zn (30 and 60 mg/l) or/and Cd (5 and 50 mg/l) for 6 months. Soluble RANKL (sRANKL) and OPG were measured in the bone and serum. Zn supplementation importantly protected from Cd-induced oxidative stress preventing protein, DNA, and lipid oxidation in the bone. Moreover, Zn protected from the Cd-induced increase in sRANKL concentration and the sRANKL/OPG ratio, and decrease in OPG concentration in the bone and serum. Numerous correlations were noted between indices of the oxidative/antioxidative bone status, concentrations of sRANKL and OPG in the bone and serum, as well as the bone concentrations of Zn and Cd, and previously reported by us in these animals (Brzóska et al., 2007) indices of bone turnover and bone mineral density. The results allow us to conclude that the ability of Zn to prevent from oxidative stress and the RANK/RANKL/OPG system imbalance may be implicated in the mechanisms of its protective impact against Cd-induced bone damage. This paper is the first report from an in vivo study providing evidence that beneficial Zn impact on the skeleton under exposure to Cd is related to the improvement of the bone tissue oxidative/antioxidative status and mediating the RANK/RANKL/OPG system. - Highlights: • Cd induces oxidative stress in the bone tissue. • Cd disturbs bone metabolism via disorder of the RANK/RANKL/OPG system balance. • Zn supplementation protects from Cd-induced oxidative stress in the bone tissue. • Zn protects from the RANK/RANKL/OPG system imbalance caused by Cd in the bone tissue. • Enhanced Zn intake protects from Cd-induced

Protective effect of zinc supplementation against cadmium-induced oxidative stress and the RANK/RANKL/OPG system imbalance in the bone tissue of rats

Energy Technology Data Exchange (ETDEWEB)

Brzóska, Malgorzata M., E-mail: Malgorzata.Brzoska@umb.edu.pl; Rogalska, Joanna

2013-10-01

It was investigated whether protective influence of zinc (Zn) against cadmium (Cd)-induced disorders in bone metabolism may be related to its antioxidative properties and impact on the receptor activator of nuclear factor (NF)-κΒ (RANK)/RANK ligand (RANKL)/osteoprotegerin (OPG) system. Numerous indices of oxidative/antioxidative status, and Cd and Zn were determined in the distal femur of the rats administered Zn (30 and 60 mg/l) or/and Cd (5 and 50 mg/l) for 6 months. Soluble RANKL (sRANKL) and OPG were measured in the bone and serum. Zn supplementation importantly protected from Cd-induced oxidative stress preventing protein, DNA, and lipid oxidation in the bone. Moreover, Zn protected from the Cd-induced increase in sRANKL concentration and the sRANKL/OPG ratio, and decrease in OPG concentration in the bone and serum. Numerous correlations were noted between indices of the oxidative/antioxidative bone status, concentrations of sRANKL and OPG in the bone and serum, as well as the bone concentrations of Zn and Cd, and previously reported by us in these animals (Brzóska et al., 2007) indices of bone turnover and bone mineral density. The results allow us to conclude that the ability of Zn to prevent from oxidative stress and the RANK/RANKL/OPG system imbalance may be implicated in the mechanisms of its protective impact against Cd-induced bone damage. This paper is the first report from an in vivo study providing evidence that beneficial Zn impact on the skeleton under exposure to Cd is related to the improvement of the bone tissue oxidative/antioxidative status and mediating the RANK/RANKL/OPG system. - Highlights: • Cd induces oxidative stress in the bone tissue. • Cd disturbs bone metabolism via disorder of the RANK/RANKL/OPG system balance. • Zn supplementation protects from Cd-induced oxidative stress in the bone tissue. • Zn protects from the RANK/RANKL/OPG system imbalance caused by Cd in the bone tissue. • Enhanced Zn intake protects from Cd-induced

 Dehydroepiandrosterone sulfate, osteoprotegerin and its soluble ligand sRANKL and bone metabolism in girls with anorexia nervosa

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Zofia Ostrowska

2012-09-01

Full Text Available  Background:Only scarce data exist concerning the relationship between dehydroepiandrosterone (DHEA and/or its sulfate form DHEAS and bone status in adolescents with anorexia nervosa (AN.Aim:We investigated whether a relationship existed between DHEAS and bone metabolism (as assessed based on serum osteocalcin [OC], and collagen type I cross-linked carboxy-terminal telopeptide [CTx]. We also aimed to establish whether the above mentioned relationship might be affected by osteoprotegerin (OPG and its soluble ligand sRANKL.Material/Methods:Fifty-six female patients with AN and 21 healthy female subjects aged 13 to 16 years participated in the study. Serum DHEAS, OC, CTx, OPG and sRANKL were measured by ELISA.Results:Our female patients with AN demonstrated significant suppression of DHEAS and bone markers, an increase in OPG and sRANKL levels, and a reduction of the OPG/sRANKL ratio. DHEAS, CTx and the OPG/sRANKL ratio correlated positively with BMI. A significant positive correlation was also observed between DHEAS and the OPG/sRANKL ratio, OC and the OPG/sRANKL ratio, and CTx and sRANKL. The correlation was negative in the case of DHEAS and CTx, DHEAS and sRANKL, CTx and the OPG/sRANKL ratio, and sRANKL and the OPG/sRANKL ratio.Discussion/DHEAS suppression in girls with anorexia nervosa was associated with a decrease in the levels of bone markers, an increase in OPG and sRANKL concentrations and a significant decrease in the OPG/sRANKL ratio. DHEAS suppression in girls with anorexia nervosa might have a harmful effect on their bone tissue, probably via a shift in the OPG/RANKL ratio toward a functional excess of sRANKL.

Effect of Bisphosphonates on the Levels of Rankl and Opg in Gingival Crevicular Fluid of Patients With Periodontal Disease and Post-menopausal Osteoporosis.

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Verde, María E; Bermejo, Daniela; Gruppi, Adriana; Grenón, Miriam

2015-12-01

The Receptor activator of nuclear factor-kappa B ligand (RANKL)/RANK/Osteoprotegerine (OPG) system has been proposed as essential for osteoclast biology and identified as key part in regulating the physiology and pathology of the skeletal system. The study of the RANKL/RANK/OPG system has increased the understanding of the mechanisms involved in the bone remodeling process, especially in postmenopausal osteoporosis and periodontal disease. Bisphosphonates have become the mainstay of the treatment and prevention of post-menopausal osteoporosis. They inhibit the formation and dissolution of calcium phosphate crystals in bone and also osteoclasts, thus reducing bone turnover.Current investigations relate osteoporosis with the appearance and progression of periodontal disease. Although the etiology of both is different, the bone loss present in both shares several characteristics. Thus, therapy used for osteoporosis can be considered of value in the treatment of periodontal disease. The aim of this study was to evaluate the levels of RANKL, OPG and their relationship in gingival crevicular fluid (GCF) in patients with periodontal disease and postmenopausal osteoporosis/ osteopenia in relation to consumption of bisphosphonates. We studied 66 periodontal active sites obtained from 17 post- menopausal women patients aged between 45-70 years old with osteoporosis/osteopenia and periodontal disease. GCF samples were collected using sterile filter paper strips. To determine the concentration of RANKL and OPG, a commercial ELISA assay was used. The values of RANKL, OPG and their ratio (RANKL/ OPG) were compared with Mann-Whitney U Test. The values of RANKL, OPG and their ratio obtained in patients with osteoporosis/osteopenia and periodontal disease with or without bisphosphonates treatment showed no differences. Bisphosphonates do not alter the concentration of RANKL and OPG and their ratio in the GCF of patients with osteoporosis/ osteopenia and periodontal disease

Distribution of Inositol 1,4,5-Trisphosphate Receptors in Rat Osteoclasts

International Nuclear Information System (INIS)

Morikawa, Kazumasa; Goto, Tetsuya; Tanimura, Akihiko; Kobayashi, Shigeru; Maki, Kenshi

2008-01-01

Inositol 1,4,5-trisphosphate (IP 3 ) receptors (IP 3 Rs) are Ca 2+ channels that localize to intracellular Ca 2+ stores such as the endoplasmic reticulum (ER). Recently, IP 3 Rs were found to participate in the formation of the cytoskeleton and cellular adhesions. In this study, we examined the cellular localization of type I, II, and III IP 3 Rs to assess their role in cellular adhesion in rat osteoclasts. Rat bone marrow cells were cultured in α-MEM with 10% fetal bovine serum, M-CSF, RANKL, and 1,25(OH) 2 D 3 for 1 week to promote osteoclast formation. Type I, II, and III IP 3 R expression in the osteoclasts was then examined by RT-PCR. Double-staining was performed using antibodies against type I, II, and III IP 3 Rs and DiOC 6 , an ER marker, or TRITC-phalloidin, an actin filament marker. Expression of all three IP 3 Rs was detected in the newly formed osteoclasts; however, the localization of the type I and II IP 3 Rs was predominantly close to nuclear, and possibly colocalized with the ER, while the type III IP 3 Rs were localized to the ER and podosomes, actin-rich adhesion structures in osteoclasts. These findings suggest that type III IP 3 Rs are associated with osteoclast adhesion

Approach to novel functional foods for stress control 4. Regulation of serotonin transporter by food factors.

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Ito, Mikiko; Haito, Sakiko; Furumoto, Mari; Kawai, Yoshichika; Terao, Junji; Miyamoto, Ken-ichi

2005-11-01

Serotonin transporters (SERTs) are pre-synaptic proteins specialized for the clearance of serotonin following vesicular release at central nervous system (CNS) and enteric nervous system synapses. SERTs are high affinity targets in vivo for antidepressants such as serotonin selective reuptake inhibitors (SSRIs). These include 'medical' psychopharmacological agents such as analgesics and antihistamines, a plant extract called St John's Wort (Hypericum). Osteoclasts are the primary cells responsible for bone resorption. They arise by the differentiation of osteoclast precursors of the monocyte/macrophage lineage. The expression of SERTs was increased in RANKL-induced osteoclast-like cells. Using RANKL stimulation of RAW264.7 cells as a model system for osteoclast differentiation, we studied the direct effects of food factor on serotonin uptake. The SSRIs (fluoxetine and fluvoxamine) inhibited markedly (approximately 95%) in serotonin transport in differentiated osteoclast cells. The major components of St. John's Wort, hyperforin and hypericine were significantly decreased in serotonin transport activity. Thus, a new in vitro model using RANKL-induced osteoclast-like cells may be useful to analyze the regulation of SERT by food factors and SSRIs.

Evaluation of the osteoclastogenic process associated with RANK / RANK-L / OPG in odontogenic myxomas

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González-Galván, María del Carmen; Mosqueda-Taylor, Adalberto; Bologna-Molina, Ronell; Setien-Olarra, Amaia; Marichalar-Mendia, Xabier; Aguirre-Urizar, José-Manuel

2018-01-01

Background Odontogenic myxoma (OM) is a benign intraosseous neoplasm that exhibits local aggressiveness and high recurrence rates. Osteoclastogenesis is an important phenomenon in the tumor growth of maxillary neoplasms. RANK (Receptor Activator of Nuclear Factor κappa B) is the signaling receptor of RANK-L (Receptor activator of nuclear factor kappa-Β ligand) that activates the osteoclasts. OPG (osteoprotegerin) is a decoy receptor for RANK-L that inhibits pro-osteoclastogenesis. The RANK / RANKL / OPG system participates in the regulation of osteolytic activity under normal conditions, and its alteration has been associated with greater bone destruction, and also with tumor growth. Objectives To analyze the immunohistochemical expression of OPG, RANK and RANK-L proteins in odontogenic myxomas (OMs) and their relationship with the tumor size. Material and Methods Eighteen OMs, 4 small ( 3cm) and 18 dental follicles (DF) that were included as control were studied by means of standard immunohistochemical procedure with RANK, RANKL and OPG antibodies. For the evaluation, 5 fields (40x) of representative areas of OM and DF were selected where the expression of each antibody was determined. Descriptive and comparative statistical analyses were performed with the obtained data. Results There are significant differences in the expression of RANK in OM samples as compared to DF (p = 0.022) and among the OMSs and OMLs (p = 0.032). Also a strong association is recognized in the expression of RANK-L and OPG in OM samples. Conclusions Activation of the RANK / RANK-L / OPG triad seems to be involved in the mechanisms of bone balance and destruction, as well as associated with tumor growth in odontogenic myxomas. Key words:Odontogenic myxoma, dental follicle, RANK, RANK-L, OPG, osteoclastogenesis. PMID:29680857

The Modulatory Effects of Mesenchymal Stem Cells on Osteoclastogenesis

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Wessam E. Sharaf-Eldin

2016-01-01

Full Text Available The effect of mesenchymal stem cells (MSCs on bone formation has been extensively demonstrated through several in vitro and in vivo studies. However, few studies addressed the effect of MSCs on osteoclastogenesis and bone resorption. Under physiological conditions, MSCs support osteoclastogenesis through producing the main osteoclastogenic cytokines, RANKL and M-CSF. However, during inflammation, MSCs suppress osteoclast formation and activity, partly via secretion of the key anti-osteoclastogenic factor, osteoprotegerin (OPG. In vitro, co-culture of MSCs with osteoclasts in the presence of high concentrations of osteoclast-inducing factors might reflect the in vivo inflammatory pathology and prompt MSCs to exert an osteoclastogenic suppressive effect. MSCs thus seem to have a dual effect, by stimulating or inhibiting osteoclastogenesis, depending on the inflammatory milieu. This effect of MSCs on osteoclast formation seems to mirror the effect of MSCs on other immune cells, and may be exploited for the therapeutic potential of MSCs in bone loss associated inflammatory diseases.

Genetic deletion of muscle RANK or selective inhibition of RANKL is not as effective as full-length OPG-fc in mitigating muscular dystrophy.

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Dufresne, Sébastien S; Boulanger-Piette, Antoine; Bossé, Sabrina; Argaw, Anteneh; Hamoudi, Dounia; Marcadet, Laetitia; Gamu, Daniel; Fajardo, Val A; Yagita, Hideo; Penninger, Josef M; Russell Tupling, A; Frenette, Jérôme

2018-04-24

Although there is a strong association between osteoporosis and skeletal muscle atrophy/dysfunction, the functional relevance of a particular biological pathway that regulates synchronously bone and skeletal muscle physiopathology is still elusive. Receptor-activator of nuclear factor κB (RANK), its ligand RANKL and the soluble decoy receptor osteoprotegerin (OPG) are the key regulators of osteoclast differentiation and bone remodelling. We thus hypothesized that RANK/RANKL/OPG, which is a key pathway for bone regulation, is involved in Duchenne muscular dystrophy (DMD) physiopathology. Our results show that muscle-specific RANK deletion (mdx-RANK mko ) in dystrophin deficient mdx mice improves significantly specific force [54% gain in force] of EDL muscles with no protective effect against eccentric contraction-induced muscle dysfunction. In contrast, full-length OPG-Fc injections restore the force of dystrophic EDL muscles [162% gain in force], protect against eccentric contraction-induced muscle dysfunction ex vivo and significantly improve functional performance on downhill treadmill and post-exercise physical activity. Since OPG serves a soluble receptor for RANKL and as a decoy receptor for TRAIL, mdx mice were injected with anti-RANKL and anti-TRAIL antibodies to decipher the dual function of OPG. Injections of anti-RANKL and/or anti-TRAIL increase significantly the force of dystrophic EDL muscle [45% and 17% gains in force, respectively]. In agreement, truncated OPG-Fc that contains only RANKL domains produces similar gains, in terms of force production, than anti-RANKL treatments. To corroborate that full-length OPG-Fc also acts independently of RANK/RANKL pathway, dystrophin/RANK double-deficient mice were treated with full-length OPG-Fc for 10 days. Dystrophic EDL muscles exhibited a significant gain in force relative to untreated dystrophin/RANK double-deficient mice, indicating that the effect of full-length OPG-Fc is in part independent of the RANKL

Sympathetic Neurotransmitters Modulate Osteoclastogenesis and Osteoclast Activity in the Context of Collagen-Induced Arthritis

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Muschter, Dominique; Schäfer, Nicole; Stangl, Hubert; Straub, Rainer H.; Grässel, Susanne

2015-01-01

Excessive synovial osteoclastogenesis is a hallmark of rheumatoid arthritis (RA). Concomitantly, local synovial changes comprise neuronal components of the peripheral sympathetic nervous system. Here, we wanted to analyze if collagen-induced arthritis (CIA) alters bone marrow-derived macrophage (BMM) osteoclastogenesis and osteoclast activity, and how sympathetic neurotransmitters participate in this process. Therefore, BMMs from Dark Agouti rats at different CIA stages were differentiated into osteoclasts in vitro and osteoclast number, cathepsin K activity, matrix resorption and apoptosis were analyzed in the presence of acetylcholine (ACh), noradrenaline (NA) vasoactive intestinal peptide (VIP) and assay-dependent, adenylyl cyclase activator NKH477. We observed modulation of neurotransmitter receptor mRNA expression in CIA osteoclasts without affecting protein level. CIA stage-dependently altered marker gene expression associated with osteoclast differentiation and activity without affecting osteoclast number or activity. Neurotransmitter stimulation modulated osteoclast differentiation, apoptosis and activity. VIP, NA and adenylyl cyclase activator NKH477 inhibited cathepsin K activity and osteoclastogenesis (NKH477, 10-6M NA) whereas ACh mostly acted pro-osteoclastogenic. We conclude that CIA alone does not affect metabolism of in vitro generated osteoclasts whereas stimulation with NA, VIP plus specific activation of adenylyl cyclase induced anti-resorptive effects probably mediated via cAMP signaling. Contrary, we suggest pro-osteoclastogenic and pro-resorptive properties of ACh mediated via muscarinic receptors. PMID:26431344

Similar healthy osteoclast and osteoblast activity on nanocrystalline hydroxyapatite and nanoparticles of tri-calcium phosphate compared to natural bone

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MacMillan AK

2014-12-01

Full Text Available Adam K MacMillan,1 Francis V Lamberti,1 Julia N Moulton,2 Benjamin M Geilich,2 Thomas J Webster2,3 1RTI Surgical, Alachua, FL, USA; 2Department of Chemical Engineering, Northeastern University, Boston, MA, USA; 3Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah, Saudi Arabia Abstract: While there have been numerous studies to determine osteoblast (bone forming cell functions on nanocrystalline compared to micron crystalline ceramics, there have been few studies which have examined osteoclast activity (including tartrate-resistant acid phosphatase, formation of resorption pits, size of resorption pits, and receptor activator of nuclear factor κB [RANK]. This is despite the fact that osteoclasts are an important part of maintaining healthy bone since they resorb bone during the bone remodeling process. Moreover, while it is now well documented that bone formation is enhanced on nanoceramics compared to micron ceramics, some have pondered whether osteoblast functions (such as osteoprotegerin and RANK ligand [RANKL] are normal (ie, non-diseased on such materials compared to natural bone. For these reasons, the objective of the present in vitro study was to determine various functions of osteoclasts and osteoblasts on nanocrystalline and micron crystalline hydroxyapatite as well as tri-calcium phosphate materials and compare such results to cortical and cancellous bone. Results showed for the first time similar osteoclast activity (including tartrate-resistant acid phosphatase, formation of resorption pits, size of resorption pits, and RANK and osteoblast activity (osteoprotegerin and RANKL on nanocrystalline hydroxyapatite compared to natural bone, whereas osteoclast and osteoblast functions on micron crystalline versions of these ceramics were much different than natural bone. In this manner, this study provides additional evidence that nanocrystalline calcium phosphates can serve as suitable synthetic

Expression of Msx-1 is suppressed in bisphosphonate associated osteonecrosis related jaw tissue-etiopathology considerations respecting jaw developmental biology-related unique features.

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Wehrhan, Falk; Hyckel, Peter; Ries, Jutta; Stockmann, Phillip; Nkenke, Emeka; Schlegel, Karl A; Neukam, Friedrich W; Amann, Kerstin

2010-10-13

Bone-destructive disease treatments include bisphosphonates and antibodies against the osteoclast differentiator, RANKL (aRANKL); however, osteonecrosis of the jaw (ONJ) is a frequent side-effect. Current models fail to explain the restriction of bisphosphonate (BP)-related and denosumab (anti-RANKL antibody)-related ONJ to jaws. Msx-1 is exclusively expressed in craniofacial structures and pivotal to cranial neural crest (CNC)-derived periodontal tissue remodeling. We hypothesised that Msx-1 expression might be impaired in bisphosphonate-related ONJ. The study aim was to elucidate Msx-1 and RANKL-associated signal transduction (BMP-2/4, RANKL) in ONJ-altered and healthy periodontal tissue. Twenty ONJ and twenty non-BP exposed periodontal samples were processed for RT-PCR and immunohistochemistry. An automated staining-based alkaline phosphatase-anti-alkaline phosphatase method was used to measure the stained cells:total cell-number ratio (labelling index, Bonferroni adjustment). Real-time RT-PCR was performed on ONJ-affected and healthy jaw periodontal samples (n = 20 each) to quantitatively compare Msx-1, BMP-2, RANKL, and GAPDH mRNA levels. Semi-quantitative assessment of the ratio of stained cells showed decreased Msx-1 and RANKL and increased BMP-2/4 (all p Msx-1 (p Msx-1 suppression in ONJ-adjacent periodontal tissue suggested a bisphosphonate-related impairment in cellular differentiation that occurred exclusively jaw remodelling. Further research on developmental biology-related unique features of jaw bone structures will help to elucidate pathologies restricted to maxillofacial tissue.

Urokinase plasminogen activator receptor affects bone homeostasis by regulating osteoblast and osteoclast function

DEFF Research Database (Denmark)

Furlan, Federico; Galbiati, Clara; Jørgensen, Niklas R

2007-01-01

PAR and produce urokinase (uPA). The purpose of this study was to investigate the role of uPAR in bone remodeling. MATERIALS AND METHODS: In vivo studies were performed in uPAR knockout (KO) and wildtype (WT) mice on a C57Bl6/SV129 (75:25) background. Bone mass was analyzed by pQCT. Excised tibias were subjected......The uPAR and its ligand uPA are expressed by both osteoblasts and osteoclasts. Their function in bone remodeling is unknown. We report that uPAR-lacking mice display increased BMD, increased osteogenic potential of osteoblasts, decreased osteoclasts formation, and altered cytoskeletal...... of macrophage-colony stimulating factor (M-CSF) and RANKL. Phalloidin staining in osteoclasts served to study actin ring and podosome formation. RESULTS: pQCT revealed increased bone mass in uPAR-null mice. Mechanical tests showed reduced load-sustaining capability in uPAR KO tibias. uPAR KO osteoblasts showed...

Osteoprotegerin in bone metastases: mathematical solution to the puzzle.

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Marc D Ryser

Full Text Available Bone is a common site for cancer metastasis. To create space for their growth, cancer cells stimulate bone resorbing osteoclasts. Cytokine RANKL is a key osteoclast activator, while osteoprotegerin (OPG is a RANKL decoy receptor and an inhibitor of osteoclastogenesis. Consistently, systemic application of OPG decreases metastatic tumor burden in bone. However, OPG produced locally by cancer cells was shown to enhance osteolysis and tumor growth. We propose that OPG produced by cancer cells causes a local reduction in RANKL levels, inducing a steeper RANKL gradient away from the tumor and towards the bone tissue, resulting in faster resorption and tumor expansion. We tested this hypothesis using a mathematical model of nonlinear partial differential equations describing the spatial dynamics of OPG, RANKL, PTHrP, osteoclasts, tumor and bone mass. We demonstrate that at lower expression rates, tumor-derived OPG enhances the chemotactic RANKL gradient and osteolysis, whereas at higher expression rates OPG broadly inhibits RANKL and decreases osteolysis and tumor burden. Moreover, tumor expression of a soluble mediator inducing RANKL in the host tissue, such as PTHrP, is important for correct orientation of the RANKL gradient. A meta-analysis of OPG, RANKL and PTHrP expression in normal prostate, carcinoma and metastatic tissues demonstrated an increase in expression of OPG, but not RANKL, in metastatic prostate cancer, and positive correlation between OPG and PTHrP in metastatic prostate cancer. The proposed mechanism highlights the importance of the spatial distribution of receptors, decoys and ligands, and can be applied to other systems involving regulation of spatially anisotropic processes.

Targeting Integrin-β1 Impedes Cytokine-Induced Osteoclast ...

African Journals Online (AJOL)

but not in RANKL pathway. Given that, inflammatory cytokine secretions such as TNF-α are progressively implicated in pathological osteolysis, targeting this pathway may .... RANKL or TNF-alpha treated culture systems ... universal PCR Master Mix (Life Technologies,. USA). ... and developed using Super Signal West Dura.

Osteoclast TGF-β Receptor Signaling Induces Wnt1 Secretion and Couples Bone Resorption to Bone Formation

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Weivoda, Megan M; Ruan, Ming; Pederson, Larry; Hachfeld, Christine; Davey, Rachel A; Zajac, Jeffrey D; Westendorf, Jennifer J; Khosla, Sundeep; Oursler, Merry Jo

2016-01-01

Osteoblast-mediated bone formation is coupled to osteoclast-mediated bone resorption. These processes become uncoupled with age, leading to increased risk for debilitating fractures. Therefore, understanding how osteoblasts are recruited to sites of resorption is vital to treating age-related bone loss. Osteoclasts release and activate TGF-β from the bone matrix. Here we show that osteoclastspecific inhibition of TGF-β receptor signaling in mice results in osteopenia due to reduced osteoblast numbers with no significant impact on osteoclast numbers or activity. TGF-β induced osteoclast expression of Wnt1, a protein crucial to normal bone formation, and this response was blocked by impaired TGF-β receptor signaling. Osteoclasts in aged murine bones had lower TGF-β signaling and Wnt1 expression in vivo. Ex vivo stimulation of osteoclasts derived from young or old mouse bone marrow macrophages showed no difference in TGF-β–induced Wnt1 expression. However, young osteoclasts expressed reduced Wnt1 when cultured on aged mouse bone chips compared to young mouse bone chips, consistent with decreased skeletal TGF-β availability with age. Therefore, osteoclast responses to TGF-β are essential for coupling bone resorption to bone formation, and modulating this pathway may provide opportunities to treat age-related bone loss. PMID:26108893

Transgenic mice for a tamoxifen-induced, conditional expression of the Cre recombinase in osteoclasts.

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Maria Arantzazu Sanchez-Fernandez

Full Text Available BACKGROUND: Studies on osteoclasts, the bone resorbing cells, have remained limited due to the lack of transgenic mice allowing the conditional knockout of genes in osteoclasts at any time during development or adulthood. METHODOLOGY/PRINCIPAL FINDING: We report here on the generation of transgenic mice which specifically express a tamoxifen-inducible Cre recombinase in osteoclasts. These mice, generated on C57BL/6 and FVB background, express a fusion Cre recombinase-ERT2 protein whose expression is driven by the promoter of cathepsin K (CtsK, a gene highly expressed in osteoclasts. We tested the cellular specificity of Cre activity in CtsKCreERT2 strains by breeding with Rosa26LacZ reporter mice. PCR and histological analyses of the CtsKCreERT2LacZ positive adult mice and E17.5 embryos show that Cre activity is restricted largely to bone tissue. In vitro, primary osteoclasts derived from the bone marrow of CtsKCreERT2+/-LacZ+/- adult mice show a Cre-dependent β-galactosidase activity after tamoxifen stimulation. CONCLUSIONS/SIGNIFICANCE: We have generated transgenic lines that enable the tamoxifen-induced, conditional deletion of loxP-flanked genes in osteoclasts, thus circumventing embryonic and postnatal gene lethality and avoiding gene deletion in other cell types. Such CtsKCreERT2 mice provide a convenient tool to study in vivo the different facets of osteoclast function in bone physiology during different developmental stages and adulthood of mice.

Acute effects of dietary fatty acids on osteclastogenesis via RANKL/RANK/OPG system.

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Naranjo, M Carmen; Garcia, Indara; Bermudez, Beatriz; Lopez, Sergio; Cardelo, Magdalena P; Abia, Rocio; Muriana, Francisco J G; Montserrat-de la Paz, Sergio

2016-11-01

Postprandial state is directly linked with chronic diseases. We hypothesized that dietary fats may have acute effects on health status by modulating osteoclast differentiation and activation in a fatty acid-dependent manner. In healthy subjects, a fat-enriched meal increased plasma levels of the RANKL (receptor activator of nuclear factor κB ligand)/OPG (osteoprotegerin) ratio (SFAs > MUFAs = PUFAs) in the postprandial state. Postprandial TRL-SFAs enhanced tartrate-resistant acid phosphatase (TRAP) activity and the expression of osteoclast marker genes (TRAP, OSCAR, RANK, and CATHK) while downregulated the expression of OPG gene in human monocyte-derived osteoclasts. These effects were not observed with monounsaturated fatty acid (MUFA)-enriched postprandial triglyceride-rich lipoproteins (TRLs). Moreover, postprandial TRL-SFAs increased the release of osteoclastogenic cytokines (TNF-α, IL-1β, and IL-6) meanwhile TRL-MUFAs and TRL-PUFAs increased the release of anti-osteoclastogenic cytokines (IL-4 and IL-10) in the medium of human monocyte-derived osteoclasts. For the first time, we show that postprandial TRLs are metabolic entities with osteoclastogenic activity and that this property is related to the type of dietary fatty acid in the meal. The osteoclastogenic potency was as follows: SFAs > MUFAs = PUFAs. These exciting findings open opportunities for developing nutritional strategies with olive oil as the principal dietary source of MUFAs, notably oleic acid, to prevent development and progression of osteoclast-related diseases. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Constitutive expression of TNF-related activation-induced cytokine (TRANCE/receptor activating NF-κB ligand (RANK-L by rat plasmacytoid dendritic cells.

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Thomas Anjubault

Full Text Available Plasmacytoid dendritic cells (pDCs are a subset of DCs whose major function relies on their capacity to produce large amount of type I IFN upon stimulation via TLR 7 and 9. This function is evolutionary conserved and place pDC in critical position in the innate immune response to virus. Here we show that rat pDC constitutively express TNF-related activation-induced cytokine (TRANCE also known as Receptor-activating NF-κB ligand (RANKL. TRANCE/RANKL is a member of the TNF superfamily which plays a central role in osteoclastogenesis through its interaction with its receptor RANK. TRANCE/RANK interaction are also involved in lymphoid organogenesis as well as T cell/DC cross talk. Unlike conventional DC, rat CD4(high pDC were shown to constitutively express TRANCE/RANKL both at the mRNA and the surface protein level. TRANCE/RANKL was also induced on the CD4(low subsets of pDC following activation by CpG. The secreted form of TRANCE/RANKL was also produced by rat pDC. Of note, levels of mRNA, surface and secreted TRANCE/RANKL expression were similar to that observed for activated T cells. TRANCE/RANKL expression was found on pDC in all lymphoid organs as well blood and BM with a maximum expression in mesenteric lymph nodes. Despite this TRANCE/RANKL expression, we were unable to demonstrate in vitro osteoclastogenesis activity for rat pDC. Taken together, these data identifies pDC as novel source of TRANCE/RANKL in the immune system.

Slight changes in the mechanical stimulation affects osteoblast- and osteoclast-like cells in co-culture.

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Kadow-Romacker, Anke; Duda, Georg N; Bormann, Nicole; Schmidmaier, Gerhard; Wildemann, Britt

2013-12-01

Osteoblast- and osteoclast-like cells are responsible for coordinated bone maintenance, illustrated by a balanced formation and resorption. Both parameters appear to be influenced by mechanical constrains acting on each of these cell types individually. We hypothesized that the interactions between both cell types are also influenced by mechanical stimulation. Co-cultures of osteoblast- and osteoclast-like cells were stimulated with 1,100 µstrain, 0.1 or 0.3 Hz for 1-5 min/day over 5 days. Two different setups depending on the differentiation of the osteoclast-like cells were used: i) differentiation assay for the fusion of pre-osteoclasts to osteoclasts, ii) resorption assay to determine the activity level of osteoclast-like cells. In the differentiation assay (co-culture of osteoblasts with unfused osteoclast precursor cells) the mechanical stimulation resulted in a significant decrease of collagen-1 and osteocalcin produced by osteoblast-like cells. Significantly more TRAP-iso5b was measured after stimulation for 3 min with 0.1 Hz, indicating enhanced osteoclastogenesis. In the resorption assay (co-culture of osteoblasts with fused osteoclasts) the stimulation for 3 min with 0.3 Hz significantly increased the resorption activity of osteoclasts measured by the pit formation and the collagen resorption. The same mechanical stimulation resulted in an increased collagen-1 production by the osteoblast-like cells. The ratio of RANKL/OPG was not different between the groups. These findings demonstrate that already small changes in duration or frequency of mechanical stimulation had significant consequences for the behavior of osteoblast- and osteoclast-like cells in co-culture, which partially depend on the differentiation status of the osteoclast-like cells.

Cepharanthine Prevents Estrogen Deficiency-Induced Bone Loss by Inhibiting Bone Resorption

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Chen-he Zhou

2018-03-01

Full Text Available Osteoporosis is a common health problem worldwide caused by an imbalance of bone formation vs. bone resorption. However, current therapeutic approaches aimed at enhancing bone formation or suppressing bone resorption still have some limitations. In this study, we demonstrated for the first time that cepharanthine (CEP, derived from Stephania cepharantha Hayata exerted a protective effect on estrogen deficiency-induced bone loss. This protective effect was confirmed to be achieved through inhibition of bone resorption in vivo, rather than through enhancement of bone formation in vivo. Furthermore, the in vitro study revealed that CEP attenuated receptor activator of nuclear factor κB ligand (RANKL-induced osteoclast formation, and suppressed bone resorption by impairing the c-Jun N-terminal kinase (JNK and phosphatidylinositol 3-kinase (PI3K-AKT signaling pathways. The inhibitory effect of CEP could be partly reversed by treatment with anisomycin (a JNK and p38 agonist and/or SC79 (an AKT agonist in vitro. Our results thus indicated that CEP could prevent estrogen deficiency-induced bone loss by inhibiting osteoclastogenesis. Hence, CEP might be a novel therapeutic agent for anti-osteoporosis therapy.

Requirement of the inducible nitric oxide synthase pathway for IL-1-induced osteoclastic bone resorption.

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van't Hof, R J; Armour, K J; Smith, L M; Armour, K E; Wei, X Q; Liew, F Y; Ralston, S H

2000-07-05

Nitric oxide has been suggested to be involved in the regulation of bone turnover, especially in pathological conditions characterized by release of bone-resorbing cytokines. The cytokine IL-1 is thought to act as a mediator of periarticular bone loss and tissue damage in inflammatory diseases such as rheumatoid arthritis. IL-1 is a potent stimulator of both osteoclastic bone resorption and expression of inducible nitric oxide synthase (iNOS) in bone cells and other cell types. In this study, we investigated the role that the iNOS pathway plays in mediating the bone-resorbing effects of IL-1 by studying mice with targeted disruption of the iNOS gene. Studies in vitro and in vivo showed that iNOS-deficient mice exhibited profound defects of IL-1-induced osteoclastic bone resorption but responded normally to calciotropic hormones such as 1,25 dihydroxyvitamin D3 and parathyroid hormone. Immunohistochemical studies and electrophoretic mobility shift assays performed on bone marrow cocultures from iNOS-deficient mice showed abnormalities in IL-1-induced nuclear translocation of the p65 component of NFkappaB and in NFkappaB-DNA binding, which were reversed by treatment with the NO donor S-nitroso-acetyl penicillamine. These results show that the iNOS pathway is essential for IL-1-induced bone resorption and suggest that the effects of NO may be mediated by modulating IL-1-induced nuclear activation of NFkappaB in osteoclast precursors.

Requirement of the inducible nitric oxide synthase pathway for IL-1-induced osteoclastic bone resorption

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van't Hof, R. J.; Armour, K. J.; Smith, L. M.; Armour, K. E.; Wei, X. Q.; Liew, F. Y.; Ralston, S. H.

2000-01-01

Nitric oxide has been suggested to be involved in the regulation of bone turnover, especially in pathological conditions characterized by release of bone-resorbing cytokines. The cytokine IL-1 is thought to act as a mediator of periarticular bone loss and tissue damage in inflammatory diseases such as rheumatoid arthritis. IL-1 is a potent stimulator of both osteoclastic bone resorption and expression of inducible nitric oxide synthase (iNOS) in bone cells and other cell types. In this study, we investigated the role that the iNOS pathway plays in mediating the bone-resorbing effects of IL-1 by studying mice with targeted disruption of the iNOS gene. Studies in vitro and in vivo showed that iNOS-deficient mice exhibited profound defects of IL-1-induced osteoclastic bone resorption but responded normally to calciotropic hormones such as 1,25 dihydroxyvitamin D3 and parathyroid hormone. Immunohistochemical studies and electrophoretic mobility shift assays performed on bone marrow cocultures from iNOS-deficient mice showed abnormalities in IL-1-induced nuclear translocation of the p65 component of NFκB and in NFκB-DNA binding, which were reversed by treatment with the NO donor S-nitroso-acetyl penicillamine. These results show that the iNOS pathway is essential for IL-1-induced bone resorption and suggest that the effects of NO may be mediated by modulating IL-1-induced nuclear activation of NFκB in osteoclast precursors. PMID:10869429

Vitamin K2 stimulates osteoblastogenesis and suppresses osteoclastogenesis by suppressing NF-κB activation.

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Yamaguchi, Masayoshi; Weitzmann, M Neale

2011-01-01

Several bone protective factors are reported to exhibit stimulatory activities on bone formation coupled with inhibitory effects on bone resorption; one such factor is vitamin K2. Vitamin K species [K1 (phylloquinone) and K2 (menaquinone)] have long been associated with bone protective activities and are receiving intense interest as nutritional supplements for the prevention or amelioration of bone disease in humans. However, the mechanisms of vitamin K action on the skeleton are poorly defined. Activation of the nuclear factor κB (NF-κB) signal transduction pathway is essential for osteoclast formation and resorption. By contrast, NF-κB signaling potently antagonizes osteoblast differentiation and function, prompting us to speculate that NF-κB antagonists may represent a novel class of dual anti-catabolic and pro-anabolic agents. We now show that vitamin K2 action on osteoblast and osteoclast formation and activity is accomplished by down-regulating basal and cytokine-induced NF-κB activation, by increasing IκB mRNA, in a γ-carboxylation-independent manner. Furthermore, vitamin K2 prevented repression by tumor necrosis factor α (TNFα) of SMAD signaling induced by either transforming growth factor ß (TGFß) or bone morphogenetic protein-2 (BMP-2). Vitamin K2 further antagonized receptor activator of NF-κB (RANK) ligand (RANKL)-induced NF-κB activation in osteoclast precursors. Our data provide a novel mechanism to explain the dual pro-anabolic and anti-catabolic activities of vitamin K2, and may further support the concept that pharmacological modulation of NF-κB signal transduction may constitute an effective mechanism for ameliorating pathological bone loss and for promoting bone health.

Molecular Stress-inducing Compounds Increase Osteoclast Formation in a Heat Shock Factor 1 Protein-dependent Manner*

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Chai, Ryan C.; Kouspou, Michelle M.; Lang, Benjamin J.; Nguyen, Chau H.; van der Kraan, A. Gabrielle J.; Vieusseux, Jessica L.; Lim, Reece C.; Gillespie, Matthew T.; Benjamin, Ivor J.; Quinn, Julian M. W.; Price, John T.

2014-01-01

Many anticancer therapeutic agents cause bone loss, which increases the risk of fractures that severely reduce quality of life. Thus, in drug development, it is critical to identify and understand such effects. Anticancer therapeutic and HSP90 inhibitor 17-(allylamino)-17-demethoxygeldanamycin (17-AAG) causes bone loss by increasing osteoclast formation, but the mechanism underlying this is not understood. 17-AAG activates heat shock factor 1 (Hsf1), the master transcriptional regulator of heat shock/cell stress responses, which may be involved in this negative action of 17-AAG upon bone. Using mouse bone marrow and RAW264.7 osteoclast differentiation models we found that HSP90 inhibitors that induced a heat shock response also enhanced osteoclast formation, whereas HSP90 inhibitors that did not (including coumermycin A1 and novobiocin) did not affect osteoclast formation. Pharmacological inhibition or shRNAmir knockdown of Hsf1 in RAW264.7 cells as well as the use of Hsf1 null mouse bone marrow cells demonstrated that 17-AAG-enhanced osteoclast formation was Hsf1-dependent. Moreover, ectopic overexpression of Hsf1 enhanced 17-AAG effects upon osteoclast formation. Consistent with these findings, protein levels of the essential osteoclast transcription factor microphthalmia-associated transcription factor were increased by 17-AAG in an Hsf1-dependent manner. In addition to HSP90 inhibitors, we also identified that other agents that induced cellular stress, such as ethanol, doxorubicin, and methotrexate, also directly increased osteoclast formation, potentially in an Hsf1-dependent manner. These results, therefore, indicate that cellular stress can enhance osteoclast differentiation via Hsf1-dependent mechanisms and may significantly contribute to pathological and therapeutic related bone loss. PMID:24692538

Molecular stress-inducing compounds increase osteoclast formation in a heat shock factor 1 protein-dependent manner.

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Chai, Ryan C; Kouspou, Michelle M; Lang, Benjamin J; Nguyen, Chau H; van der Kraan, A Gabrielle J; Vieusseux, Jessica L; Lim, Reece C; Gillespie, Matthew T; Benjamin, Ivor J; Quinn, Julian M W; Price, John T

2014-05-09

Many anticancer therapeutic agents cause bone loss, which increases the risk of fractures that severely reduce quality of life. Thus, in drug development, it is critical to identify and understand such effects. Anticancer therapeutic and HSP90 inhibitor 17-(allylamino)-17-demethoxygeldanamycin (17-AAG) causes bone loss by increasing osteoclast formation, but the mechanism underlying this is not understood. 17-AAG activates heat shock factor 1 (Hsf1), the master transcriptional regulator of heat shock/cell stress responses, which may be involved in this negative action of 17-AAG upon bone. Using mouse bone marrow and RAW264.7 osteoclast differentiation models we found that HSP90 inhibitors that induced a heat shock response also enhanced osteoclast formation, whereas HSP90 inhibitors that did not (including coumermycin A1 and novobiocin) did not affect osteoclast formation. Pharmacological inhibition or shRNAmir knockdown of Hsf1 in RAW264.7 cells as well as the use of Hsf1 null mouse bone marrow cells demonstrated that 17-AAG-enhanced osteoclast formation was Hsf1-dependent. Moreover, ectopic overexpression of Hsf1 enhanced 17-AAG effects upon osteoclast formation. Consistent with these findings, protein levels of the essential osteoclast transcription factor microphthalmia-associated transcription factor were increased by 17-AAG in an Hsf1-dependent manner. In addition to HSP90 inhibitors, we also identified that other agents that induced cellular stress, such as ethanol, doxorubicin, and methotrexate, also directly increased osteoclast formation, potentially in an Hsf1-dependent manner. These results, therefore, indicate that cellular stress can enhance osteoclast differentiation via Hsf1-dependent mechanisms and may significantly contribute to pathological and therapeutic related bone loss.

Conditional abrogation of Atm in osteoclasts extends osteoclast lifespan and results in reduced bone mass.

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Hirozane, Toru; Tohmonda, Takahide; Yoda, Masaki; Shimoda, Masayuki; Kanai, Yae; Matsumoto, Morio; Morioka, Hideo; Nakamura, Masaya; Horiuchi, Keisuke

2016-09-28

Ataxia-telangiectasia mutated (ATM) kinase is a central component involved in the signal transduction of the DNA damage response (DDR) and thus plays a critical role in the maintenance of genomic integrity. Although the primary functions of ATM are associated with the DDR, emerging data suggest that ATM has many additional roles that are not directly related to the DDR, including the regulation of oxidative stress signaling, insulin sensitivity, mitochondrial homeostasis, and lymphocyte development. Patients and mice lacking ATM exhibit growth retardation and lower bone mass; however, the mechanisms underlying the skeletal defects are not fully understood. In the present study, we generated mutant mice in which ATM is specifically inactivated in osteoclasts. The mutant mice did not exhibit apparent developmental defects but showed reduced bone mass due to increased osteoclastic bone resorption. Osteoclasts lacking ATM were more resistant to apoptosis and showed a prolonged lifespan compared to the controls. Notably, the inactivation of ATM in osteoclasts resulted in enhanced NF-κB signaling and an increase in the expression of NF-κB-targeted genes. The present study reveals a novel function for ATM in regulating bone metabolism by suppressing the lifespan of osteoclasts and osteoclast-mediated bone resorption.

STAT6 silencing induces hepatocellular carcinoma-derived cell apoptosis and growth inhibition by decreasing the RANKL expression.

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Qing, Tian; Yamin, Zhang; Guijie, Wang; Yan, Jin; Zhongyang, Shen

2017-08-01

Signal transducer and activator of transcription-6 (STAT6) is highly expressed in various human cancers and considered a regulator of multiple biological processes in cancers, including cell apoptosis. Evidence has indicated that STAT6 predicts a worse prognosis in hepatocellular carcinoma (HCC) patients. The objective of this study was to investigate the effects and mechanism of STAT6 in human HCC cells. We found that STAT6 silencing significantly inhibited HepG2 and Hep3B cell survival and proliferation. We observed that depletion of STAT6 increased HepG2 and Hep3B cell apoptosis by using a histone DNA ELISA detection kit. STAT6 silencing induced expression of apoptosis-associated genes Bax and caspase-3/7 and inhibited anti-apoptosis gene Bcl-2 levels. We also observed that STAT6 silencing downregulated the expression of receptor activator of NF-κB ligand (RANKL). Our results demonstrated that treatment with pcDNA3.1-RANKL abolished STAT6 depletion-induced HepG2 and Hep3B cell apoptosis and growth inhibition. Based on these findings, we believe that RANKL plays a major role in STAT6-induced HCC cell apoptosis. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Combined Inhibition of the BMP pathway and the RANK-RANKL axis in a Mixed Lytic/blastic Prostate Cancer Lesion

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Virk, Mandeep S.; Alaee, Farhang; Petrigliano, Frank A.; Sugiyama, Osamu; Chatziioannou, Arion F.; Stout, David; Dougall, William C.; Lieberman, Jay R.

2010-01-01

The purpose of this study was to investigate the influence of combined inhibition of RANKL (receptor activator of nuclear factor kappa-B ligand) and bone morphogenetic protein (BMP) activity in a mixed lytic/blastic prostate cancer lesion in bone. Human prostate cancer cells (C4 2b) were injected into immunocompromised mice using an intratibial injection model to create mixed lytic/blastic lesions. RANK-Fc, a recombinant RANKL antagonist, was injected subcutaneously three times a week (10mg/kg) to inhibit RANKL and subsequent formation, function and survival of osteoclasts. Inhibition of BMP activity was achieved by transducing prostate cancer cells ex vivo with a retroviral vector expressing noggin (retronoggin; RN). There were three treatment groups (RANK-Fc treatment, RN treatment and combined RN and RANK-Fc treatment) and two control groups (untreated control and empty vector control for the RN treatment group). The progression of bone lesion and tumor growth was evaluated using plain radiographs, hind limb tumor size, 18F-Fluorodeoxyglucose and 18F-fluoride micro PET-CT, histology and histomorphometry. Treatment with RANK-Fc alone inhibited osteolysis and transformed a mixed lytic/blastic lesion into an osteoblastic phenotype. Treatment with RN alone inhibited the osteoblastic component in a mixed lytic/blastic lesion and resulted in formation of smaller osteolytic bone lesion with smaller soft tissue size. The animals treated with both RN and RANK-Fc demonstrated delayed development of bone lesions, inhibition of osteolysis, small soft tissue tumors and preservation of bone architecture with less tumor induced new bone formation. This study suggests that combined inhibition of the RANKL and the BMP pathway may be an effective biologic therapy to inhibit the progression of established mixed lytic/blastic prostate cancer lesions in bone. PMID:21073986

Dual Effect of Chrysanthemum indicum Extract to Stimulate Osteoblast Differentiation and Inhibit Osteoclast Formation and Resorption In Vitro

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Jong Min Baek

2014-01-01

Full Text Available The risk of bone-related diseases increases due to the imbalance between bone resorption and bone formation by osteoclasts and osteoblasts, respectively. The goal in the development of antiosteoporotic treatments is an agent that will improve bone through simultaneous osteoblast stimulation and osteoclast inhibition without undesirable side effects. To achieve this goal, numerous studies have been performed to identify novel approaches using natural oriental herbs to treat bone metabolic diseases. In the present study, we investigated the effect of Chrysanthemum indicum extract (CIE on the differentiation of osteoclastic and osteoblastic cells. CIE inhibited the formation of TRAP-positive mature osteoclasts and of filamentous-actin rings and disrupted the bone-resorbing activity of mature osteoclasts in a dose-dependent manner. CIE strongly inhibited Akt, GSK3β, and IκB phosphorylation in RANKL-stimulated bone marrow macrophages and did not show any effects on MAP kinases, including p38, ERK, and JNK. Interestingly, CIE also enhanced primary osteoblast differentiation via upregulation of the expression of alkaline phosphatase and the level of extracellular calcium concentrations during the early and terminal stages of differentiation, respectively. Our results revealed that CIE could have a potential therapeutic role in bone-related disorders through its dual effects on osteoclast and osteoblast differentiation.

Porphyromonas endodontalis lipopolysaccharides induce RANKL by mouse osteoblast in a way different from that of Escherichia coli lipopolysaccharide.

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Tang, Yin; Sun, Feifei; Li, Xiaoting; Zhou, Yuan; Yin, Shihai; Zhou, Xuedong

2011-12-01

Porphyromonas endodontalis lipopolysaccharide (LPS) has been shown to have a high positive rate in infected root canals and symptomatic apical periodontitis. It may play an integral role as a potent stimulator of inflammatory cytokines involved in apical lesions. The receptor activator of nuclear factor-κB ligand (RANKL) has been proven to be the key regulator of bone remodeling. This study investigated P. endodontalis LPS-induced RANKL production and LPS signaling in mouse osteoblasts. LPS-induced RANKL production in mouse osteoblast MC3T3-E1 cells was measured by Western blot and real-time polymerase chain reaction, and the Toll-like receptors (TLRs) were determined by the blocking test using anti-TLRs antibodies. In addition, specific inhibitors were used to analyze the intracellular signaling pathways. Escherichia coli LPS was used as the control. Both of the anti-TLR2 and anti-TLR4 antibodies significantly (P endodontalis LPS; only anti-TLR2 antibody had a significant (P endodontalis LPS-infected osteoblasts (P endodontalis LPS has the ability to promote the expression of RANKL in mouse osteoblasts, and this induction was mainly through the TLR2/4-JNK signaling pathway, a situation quite different from that of typical bacterial endotoxin (E. coli LPS). Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Anti-osteoporotic activity of harpagide by regulation of bone formation in osteoblast cell culture and ovariectomy-induced bone loss mouse models.

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Chung, Hwa-Jin; Kyung Kim, Won; Joo Park, Hyen; Cho, Lan; Kim, Me-Riong; Kim, Min Jeong; Shin, Joon-Shik; Ho Lee, Jin; Ha, In-Hyuk; Kook Lee, Sang

2016-02-17

Harpagide, an iridoid glucoside, is a constituent of the root of Harpagophytum procumbens var. sublobatum (Engl.) Stapf, Devil's claw which has been used in patients with osteoarthritis (OA). In the present study, we investigated the anti-osteoporotic potential of harpagide and its underlying mechanism of action in in vitro cell culture and in vivo bone loss animal models. Harpagide was obtained from the alkalic hydrolysis of harpagoside, a major constituent of H. procumbens var. sublobatum Analysis of biomarkers for bone formation in osteoblastic MC3T3-E1 cells and bone resorption in osteoclast cells derived from mouse bone marrow cells was performed to evaluate the mechanism of action. The protective activity of harpagide against bone loss was also evaluated in ovariectomized (OVX) mouse model. Harpagide improved bone properties by stimulating the process of differentiation and maturation of osteoblast cells and suppressing the process of RANKL-induced differentiation of osteoclast cells. In OVX-induced bone loss mouse model, oral administration of harpagide significantly improved recovery of bone mineral density, trabecular bone volume, and trabecular number in the femur. Harpagide also prevented increase of trabecular separation and structure model index induced by OVX. Harpagide effectively inhibited the serum levels of biochemical markers of bone loss, including alkaline phosphatase, osteocalcin, C-terminal telopeptide, and tartrate-resistant acid phosphatase. Taken together, the present study demonstrates that harpagide has a potential for prevention of bone loss in OVX mice by regulating the stimulation of osteoblast differentiation and the suppression of osteoclast formation. Therefore, these findings suggest that harpagide might serve as a bioactive compound derived from H. procumbens var. sublobatum for improvement of age-dependent bone destruction disease. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

The polyphenol fisetin protects bone by repressing NF-κB and MKP-1-dependent signaling pathways in osteoclasts.

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Laurent Léotoing

Full Text Available Osteoporosis is a bone pathology leading to increase fractures risk and challenging quality of life. Since current treatments could exhibit deleterious side effects, the use of food compounds derived from plants represents a promising innovative alternative due to their potential therapeutic and preventive activities against human diseases. In this study, we investigated the ability of the polyphenol fisetin to counter osteoporosis and analyzed the cellular and molecular mechanisms involved. In vivo, fisetin consumption significantly prevented bone loss in estrogen deficiency and inflammation mice osteoporosis models. Indeed, bone mineral density, micro-architecture parameters and bone markers were positively modulated by fisetin. Consistent with in vivo results, we showed that fisetin represses RANKL-induced osteoclast differentiation and activity as demonstrated by an inhibition of multinucleated cells formation, TRAP activity and differentiation genes expression. The signaling pathways NF-κB, p38 MAPK, JNK and the key transcription factors c-Fos and NFATc1 expressions induced by RANKL, were negatively regulated by fisetin. We further showed that fisetin inhibits the constitutive proteasomal degradation of MKP-1, the phosphatase that deactivates p38 and JNK. Consistently, using shRNA stable cell lines, we demonstrated that impairment of MKP-1 decreases fisetin potency. Taken together, these results strongly support that fisetin should be further considered as a bone protective agent.

The Polyphenol Fisetin Protects Bone by Repressing NF-κB and MKP-1-Dependent Signaling Pathways in Osteoclasts

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Léotoing, Laurent; Wauquier, Fabien; Guicheux, Jérôme; Miot-Noirault, Elisabeth; Wittrant, Yohann; Coxam, Véronique

2013-01-01

Osteoporosis is a bone pathology leading to increase fractures risk and challenging quality of life. Since current treatments could exhibit deleterious side effects, the use of food compounds derived from plants represents a promising innovative alternative due to their potential therapeutic and preventive activities against human diseases. In this study, we investigated the ability of the polyphenol fisetin to counter osteoporosis and analyzed the cellular and molecular mechanisms involved. In vivo, fisetin consumption significantly prevented bone loss in estrogen deficiency and inflammation mice osteoporosis models. Indeed, bone mineral density, micro-architecture parameters and bone markers were positively modulated by fisetin. Consistent with in vivo results, we showed that fisetin represses RANKL-induced osteoclast differentiation and activity as demonstrated by an inhibition of multinucleated cells formation, TRAP activity and differentiation genes expression. The signaling pathways NF-κB, p38 MAPK, JNK and the key transcription factors c-Fos and NFATc1 expressions induced by RANKL, were negatively regulated by fisetin. We further showed that fisetin inhibits the constitutive proteasomal degradation of MKP-1, the phosphatase that deactivates p38 and JNK. Consistently, using shRNA stable cell lines, we demonstrated that impairment of MKP-1 decreases fisetin potency. Taken together, these results strongly support that fisetin should be further considered as a bone protective agent. PMID:23861901

Inhibition of osteoclastogenesis by osteoblast-like cells genetically engineered to produce interleukin-10.

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Fujioka, Kazuki; Kishida, Tsunao; Ejima, Akika; Yamamoto, Kenta; Fujii, Wataru; Murakami, Ken; Seno, Takahiro; Yamamoto, Aihiro; Kohno, Masataka; Oda, Ryo; Yamamoto, Toshiro; Fujiwara, Hiroyoshi; Kawahito, Yutaka; Mazda, Osam

2015-01-16

Bone destruction at inflamed joints is an important complication associated with rheumatoid arthritis (RA). Interleukin-10 (IL-10) may suppress not only inflammation but also induction of osteoclasts that play key roles in the bone destruction. If IL-10-producing osteoblast-like cells are induced from patient somatic cells and transplanted back into the destructive bone lesion, such therapy may promote bone remodeling by the cooperative effects of IL-10 and osteoblasts. We transduced mouse fibroblasts with genes for IL-10 and Runx2 that is a crucial transcription factor for osteoblast differentiation. The IL-10-producing induced osteoblast-like cells (IL-10-iOBs) strongly expressed osteoblast-specific genes and massively produced bone matrix that were mineralized by calcium phosphate in vitro and in vivo. Culture supernatant of IL-10-iOBs significantly suppressed induction of osteoclast from RANKL-stimulated Raw264.7 cells as well as LPS-induced production of inflammatory cytokine by macrophages. The IL-10-iOBs may be applicable to novel cell-based therapy against bone destruction associated with RA. Copyright © 2014 Elsevier Inc. All rights reserved.

Administration of RANKL boosts thymic regeneration upon bone marrow transplantation.

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Lopes, Noella; Vachon, Hortense; Marie, Julien; Irla, Magali

2017-06-01

Cytoablative treatments lead to severe damages on thymic epithelial cells (TECs), which result in delayed de novo thymopoiesis and a prolonged period of T-cell immunodeficiency. Understanding the mechanisms that govern thymic regeneration is of paramount interest for the recovery of a functional immune system notably after bone marrow transplantation (BMT). Here, we show that RANK ligand (RANKL) is upregulated in CD4 + thymocytes and lymphoid tissue inducer (LTi) cells during the early phase of thymic regeneration. Importantly, whereas RANKL neutralization alters TEC recovery after irradiation, ex vivo RANKL administration during BMT boosts the regeneration of TEC subsets including thymic epithelial progenitor-enriched cells, thymus homing of lymphoid progenitors, and de novo thymopoiesis. RANKL increases specifically in LTi cells, lymphotoxin α, which is critical for thymic regeneration. RANKL treatment, dependent on lymphotoxin α, is beneficial upon BMT in young and aged individuals. This study thus indicates that RANKL may be clinically useful to improve T-cell function recovery after BMT by controlling multiple facets of thymic regeneration. © 2017 The Authors. Published under the terms of the CC BY 4.0 license.

Influence of Simultaneous Targeting of the Bone Morphogenetic Protein Pathway and RANK-RANKL Axis in Osteolytic Prostate Cancer Lesion in Bone

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Virk, Mandeep S.; Petrigliano, Frank A.; Liu, Nancy Q.; Chatziioannou, Arion F.; Stout, David; Kang, Christine O.; Dougall, William C.; Lieberman, Jay R.

2009-01-01

Metastasis to bone is the leading cause of morbidity and mortality in advanced prostate cancer patients. Considering the complex reciprocal interactions between the tumor cells and the bone microenvironment, there is increasing interest in developing combination therapies targeting both the tumor growth and the bone microenvironment. In this study, we investigated the effect of simultaneous blockade of BMP pathway and RANK-RANKL axis in an osteolytic prostate cancer lesion in bone. We used a retroviral vector encoding noggin (Retronoggin) to antagonize the effect of BMPs and RANK: Fc, which is a recombinant RANKL antagonist was used to inhibit RANK-RANKL axis. The tumor growth and bone loss were evaluated using plain radiographs, hind limb tumor measurements, micro PET-CT (18F- fluorodeoxyglucose [FDG] and 18F-fluoride tracer), and histology. Tibias implanted with PC-3 cells developed pure osteolytic lesions at 2 weeks with progressive increase in cortical bone destruction at successive time points. Tibias implanted with PC-3 cells over expressing noggin (Retronoggin) resulted in reduced tumor size and decreased bone loss compared to the implanted tibias in untreated control animals. RANK: Fc administration inhibited the formation of osteoclasts, delayed the development of osteolytic lesions, decreased bone loss and reduced tumor size in tibias implanted with PC-3 cells. The combination therapy with RANK: Fc and noggin over expression effectively delayed the radiographic development of osteolytic lesions, and decreased the bone loss and tumor burden compared to implanted tibias treated with noggin over expression alone. Furthermore, the animals treated with the combination strategy exhibited decreased bone loss (micro CT) and lower tumor burden (FDG micro PET) compared to animals treated with RANK: Fc alone. Combined blockade of RANK-RANKL axis and BMP pathway resulted in reduced tumor burden and decreased bone loss compared to inhibition of either individual

A novel phthalimide derivative, TC11, has preclinical effects on high-risk myeloma cells and osteoclasts.

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Maiko Matsushita

Full Text Available Despite the recent advances in the treatment of multiple myeloma (MM, MM patients with high-risk cytogenetic changes such as t(4;14 translocation or deletion of chromosome 17 still have extremely poor prognoses. With the goal of helping these high-risk MM patients, we previously developed a novel phthalimide derivative, TC11. Here we report the further characterization of TC11 including anti-myeloma effects in vitro and in vivo, a pharmacokinetic study in mice, and anti-osteoclastogenic activity. Intraperitoneal injections of TC11 significantly delayed the growth of subcutaneous tumors in human myeloma-bearing SCID mice. Immunohistochemical analyses showed that TC11 induced apoptosis of MM cells in vivo. In the pharmacokinetic analyses, the Cmax was 2.1 μM at 1 h after the injection of TC11, with 1.2 h as the half-life. TC11 significantly inhibited the differentiation and function of tartrate-resistant acid phosphatase (TRAP-positive multinucleated osteoclasts in mouse osteoclast cultures using M-CSF and RANKL. We also revealed that TC11 induced the apoptosis of myeloma cells accompanied by α-tubulin fragmentation. In addition, TC11 and lenalidomide, another phthalimide derivative, directly bound to nucleophosmin 1 (NPM1, whose role in MM is unknown. Thus, through multiple molecular interactions, TC11 is a potentially effective drug for high-risk MM patients with bone lesions. The present results suggest the possibility of the further development of novel thalidomide derivatives by drug designing.

RANK and RANK ligand expression in primary human osteosarcoma

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Daniel Branstetter

2015-09-01

Our results demonstrate RANKL expression was observed in the tumor element in 68% of human OS using IHC. However, the staining intensity was relatively low and only 37% (29/79 of samples exhibited≥10% RANKL positive tumor cells. RANK expression was not observed in OS tumor cells. In contrast, RANK expression was clearly observed in other cells within OS samples, including the myeloid osteoclast precursor compartment, osteoclasts and in giant osteoclast cells. The intensity and frequency of RANKL and RANK staining in OS samples were substantially less than that observed in GCTB samples. The observation that RANKL is expressed in OS cells themselves suggests that these tumors may mediate an osteoclastic response, and anti-RANKL therapy may potentially be protective against bone pathologies in OS. However, the absence of RANK expression in primary human OS cells suggests that any autocrine RANKL/RANK signaling in human OS tumor cells is not operative, and anti-RANKL therapy would not directly affect the tumor.

25-hydroxycholesterol promotes RANKL-induced osteoclastogenesis through coordinating NFATc1 and Sp1 complex in the transcription of miR-139-5p

International Nuclear Information System (INIS)

Zhang, Lishan; Lv, Yinping; Xian, Guozhe; Lin, Yanliang

2017-01-01

25-hydroxycholesterol (25-HC) is implicated in many processes, including lipid metabolism and the immune response. However, the role of 25-HC in RANKL-induced osteoclastogenesis remains largely unknown. Our results showed that 25-HC inhibited miR-139-5p expression in mouse bone marrow macrophages (BMMs) cultured in receptor activator of NF-κB ligand (RANKL) and monocyte macrophage colony-stimulating factor (M-CSF). Further investigation suggested that 25-HC promoted the expression of nuclear factor of activated T cell cytoplasmic 1 (NFATc1) and Sp1, especially in the presence of RANKL and M-CSF. Meanwhile, 25-HC induced nuclear translocation of NFATc1, resulting in the interaction between NFATc1 and Sp1 that was confirmed by co-immunoprecipitation. Chromatin immunoprecipitation assay indicated that Sp1 could bind to miR-139-5p promoter, but NFATc1 had no binding capacity. Although forming NFATc1/Sp1 complex increased its binding to miR-139-5p promoter, the complex inhibited the transcriptional activity of Sp1. Inhibition of NFATc1 increase the expression of miR-139-5p, which might be due to the release of free Sp1 that could bind to the promoter of miR-139-5p. Enforced expression of miR-139-5p impaired osteoclastogenesis induced by co-treatment with 25-HC and RANKL. These results suggested that 25-HC induced the interaction between NFATc1 and Sp1, reducing the level of free Sp1 to inhibit miR-139-5p expression and promote osteoclastogenesis. - Highlights: • 25-hydroxycholesterol inhibited miR-139-5p expression in bone marrow macrophages. • 25-hydroxycholesterol promoted the expression of NFATc1 and Sp1. • 25-hydroxycholesterol induced the interaction between NFATc1 and Sp1. • NFATc1/Sp1 complex inhibited the transcription of miR-139-5p. • MiR-139-5p impaired osteoclastogenesis induced by 25-hydroxycholesterol and RANKL.

Anti-tumor effect in human breast cancer by TAE226, a dual inhibitor for FAK and IGF-IR in vitro and in vivo

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Kurio, Naito [Department of Oral and Maxillofacial Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, 700-8525 (Japan); Shimo, Tsuyoshi, E-mail: shimotsu@md.okayama-u.ac.jp [Department of Oral and Maxillofacial Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, 700-8525 (Japan); Fukazawa, Takuya; Takaoka, Munenori [Department of General Surgery, Kawasaki Medical School, Okayama, 700-0821 (Japan); Okui, Tatsuo; Hassan, Nur Mohammad Monsur; Honami, Tatsuki [Department of Oral and Maxillofacial Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, 700-8525 (Japan); Hatakeyama, Shinji [Novartis Institutes for BioMedical Research, Basel (Switzerland); Ikeda, Masahiko [Department of Surgery, Fukuyama City Hospital, Fukuyama, 720-8511 (Japan); Naomoto, Yoshio [Department of General Surgery, Kawasaki Medical School, Okayama, 700-0821 (Japan); Sasaki, Akira [Department of Oral and Maxillofacial Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, 700-8525 (Japan)

2011-05-01

Focal adhesion kinase (FAK) is a 125-kDa non-receptor type tyrosine kinase that localizes to focal adhesions. FAK overexpression is frequently found in invasive and metastatic cancers of the breast, colon, thyroid, and prostate, but its role in osteolytic metastasis is not well understood. In this study, we have analyzed anti-tumor effects of the novel FAK Tyr{sup 397} inhibitor TAE226 against bone metastasis in breast cancer by using TAE226. Oral administration of TAE226 in mice significantly decreased bone metastasis and osteoclasts involved which were induced by MDA-MB-231 breast cancer cells and increased the survival rate of the mouse models of bone metastasis. TAE226 also suppressed the growth of subcutaneous tumors in vivo and the proliferation and migration of MDA-MB-231 cells in vitro. Significantly, TAE226 inhibited the osteoclast formation in murine pre-osteoclastic RAW264.7 cells, and actin ring and pit formation in mature osteoclasts. Moreover, TAE226 inhibited the receptor activator for nuclear factor {kappa} B Ligand (RANKL) gene expression induced by parathyroid hormone-related protein (PTHrP) in bone stromal ST2 cells and blood free calcium concentration induced by PTHrP administration in vivo. These findings suggest that FAK was critically involved in osteolytic metastasis and activated in tumors, pre-osteoclasts, mature osteoclasts, and bone stromal cells and TAE226 can be effectively used for the treatment of cancer induced bone metastasis and other bone diseases.

RANK/RANKL/OPG Signalization Implication in Periodontitis: New Evidence from a RANK Transgenic Mouse Model

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Bouchra Sojod

2017-05-01

Full Text Available Periodontitis is based on a complex inflammatory over-response combined with possible genetic predisposition factors. The RANKL/RANK/OPG signaling pathway is implicated in bone resorption through its key function in osteoclast differentiation and activation, as well as in the inflammatory response. This central element of osteo-immunology has been suggested to be perturbed in several diseases, including periodontitis, as it is a predisposing factor for this disease. The aim of the present study was to validate this hypothesis using a transgenic mouse line, which over-expresses RANK (RTg and develops a periodontitis-like phenotype at 5 months of age. RTg mice exhibited severe alveolar bone loss, an increased number of TRAP positive cells, and disorganization of periodontal ligaments. This phenotype was more pronounced in females. We also observed dental root resorption lacunas. Hyperplasia of the gingival epithelium, including Malassez epithelial rests, was visible as early as 25 days, preceding any other symptoms. These results demonstrate that perturbations of the RANKL/RANK/OPG system constitute a core element of periodontitis, and more globally, osteo-immune diseases.

RANK/RANKL/OPG Signalization Implication in Periodontitis: New Evidence from a RANK Transgenic Mouse Model

Science.gov (United States)

Sojod, Bouchra; Chateau, Danielle; Mueller, Christopher G.; Babajko, Sylvie; Berdal, Ariane; Lézot, Frédéric; Castaneda, Beatriz

2017-01-01

Periodontitis is based on a complex inflammatory over-response combined with possible genetic predisposition factors. The RANKL/RANK/OPG signaling pathway is implicated in bone resorption through its key function in osteoclast differentiation and activation, as well as in the inflammatory response. This central element of osteo-immunology has been suggested to be perturbed in several diseases, including periodontitis, as it is a predisposing factor for this disease. The aim of the present study was to validate this hypothesis using a transgenic mouse line, which over-expresses RANK (RTg) and develops a periodontitis-like phenotype at 5 months of age. RTg mice exhibited severe alveolar bone loss, an increased number of TRAP positive cells, and disorganization of periodontal ligaments. This phenotype was more pronounced in females. We also observed dental root resorption lacunas. Hyperplasia of the gingival epithelium, including Malassez epithelial rests, was visible as early as 25 days, preceding any other symptoms. These results demonstrate that perturbations of the RANKL/RANK/OPG system constitute a core element of periodontitis, and more globally, osteo-immune diseases. PMID:28596739

The Effect of RANKL/OPG Balance on Reducing Implant Complications

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Elizabeth R. Kapasa

2017-09-01

Full Text Available Despite the phenomenal success of implants particularly in the realms of dentistry and orthopaedics, there are still challenges to overcome. The failure of implants resulting from infection, prosthetic loosening, and non-union continue to be the most notorious examples. The cascade of fracture healing and bone repair, especially with the presence of an implant, is complex because it involves a multifaceted immune response alongside the intricate process of bone formation and remodelling. Bone loss is a serious clinical problem that is frequently accompanied by chronic inflammation, illustrating that there is a convoluted relationship between inflammation and bone erosion. The effects of pro-inflammatory factors play a significant role in initiating and maintaining osteoclastogenesis that results in bone resorption by osteoclasts. This is because there is a disruption of the relative ratio between Receptor Activator of Nuclear Factor κB-Ligand (RANKL and osteoprotegerin (OPG, which is central to modulating bone repair and remodelling. This review aims to provide a background to the bone remodelling process, the bone repair cascade post-implantation, and the associated complications. Furthermore, current clinical solutions that can influence bone formation via either internal or extrinsic mechanisms will be described. These efficacious treatments for osteolysis via targeting the RANKL/OPG ratio may be crucial to reducing the incidence of related implant failures in the future.

Suppression Effect of Astaxanthin on Osteoclast Formation In Vitro and Bone Loss In Vivo

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Yun-Ho Hwang

2018-03-01

Full Text Available Osteoporosis is characterized by a reduction of the bone mineral density (BMD and microarchitectural deterioration of the bone, which lead to bone fragility and susceptibility to fracture. Astaxanthin (AST has a variety of biological activities, such as a protective effect against asthma or neuroinflammation, antioxidant effect, and decrease of the osteoclast number in the right mandibles in the periodontitis model. Although treatment with AST is known to have an effect on inflammation, no studies on the effect of AST exposure on bone loss have been performed. Thus, in the present study, we examined the antiosteoporotic effect of AST on bone mass in ovariectomized (OVX mice and its possible mechanism of action. The administration of AST (5, 10 mg/kg for 6 weeks suppressed the enhancement of serum calcium, inorganic phosphorus, alkaline phosphatase, total cholesterol, and tartrate-resistant acid phosphatase (TRAP activity. The bone mineral density (BMD and bone microarchitecture of the trabecular bone in the tibia and femur were recovered by AST exposure. Moreover, in the in vitro experiment, we demonstrated that AST inhibits osteoclast formation through the expression of the nuclear factor of activated T cells (NFAT c1, dendritic cell-specific transmembrane protein (DC-STAMP, TRAP, and cathepsin K without any cytotoxic effects on bone marrow-derived macrophages (BMMs. Therefore, we suggest that AST may have therapeutic potential for the treatment of postmenopausal osteoporosis.

Mechanism of Action of Bortezomib and the New Proteasome Inhibitors on Myeloma Cells and the Bone Microenvironment: Impact on Myeloma-Induced Alterations of Bone Remodeling

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Fabrizio Accardi

2015-01-01

Full Text Available Multiple myeloma (MM is characterized by a high capacity to induce alterations in the bone remodeling process. The increase in osteoclastogenesis and the suppression of osteoblast formation are both involved in the pathophysiology of the bone lesions in MM. The proteasome inhibitor (PI bortezomib is the first drug designed and approved for the treatment of MM patients by targeting the proteasome. However, recently novel PIs have been developed to overcome bortezomib resistance. Interestingly, several preclinical data indicate that the proteasome complex is involved in both osteoclast and osteoblast formation. It is also evident that bortezomib either inhibits osteoclast differentiation induced by the receptor activator of nuclear factor kappa B (NF-κB ligand (RANKL or stimulates the osteoblast differentiation. Similarly, the new PIs including carfilzomib and ixazomib can inhibit bone resorption and stimulate the osteoblast differentiation. In a clinical setting, PIs restore the abnormal bone remodeling by normalizing the levels of bone turnover markers. In addition, a bone anabolic effect was described in responding MM patients treated with PIs, as demonstrated by the increase in the osteoblast number. This review summarizes the preclinical and clinical evidence on the effects of bortezomib and other new PIs on myeloma bone disease.

15-deoxy-δ12,14-prostaglandin j2 inhibits osteolytic breast cancer bone metastasis and estrogen deficiency-induced bone loss.

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Ki Rim Kim

Full Text Available Breast cancer is the major cause of cancer death in women worldwide. The most common site of metastasis is bone. Bone metastases obstruct the normal bone remodeling process and aberrantly enhance osteoclast-mediated bone resorption, which results in osteolytic lesions. 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2 is an endogenous ligand of peroxisome proliferator-activated receptor gamma (PPARγ that has anti-inflammatory and antitumor activity at micromolar concentrations through PPARγ-dependent and/or PPARγ-independent pathways. We investigated the inhibitory activity of 15d-PGJ2 on the bone loss that is associated with breast cancer bone metastasis and estrogen deficiency caused by cancer treatment. 15d-PGJ2 dose-dependently inhibited viability, migration, invasion, and parathyroid hormone-related protein (PTHrP production in MDA-MB-231 breast cancer cells. 15d-PGJ2 suppressed receptor activator of nuclear factor kappa-B ligand (RANKL mRNA levels and normalized osteoprotegerin (OPG mRNA levels in hFOB1.19 osteoblastic cells treated with culture medium from MDA-MB-231 cells or PTHrP, which decreased the RANKL/OPG ratio. 15d-PGJ2 blocked RANKL-induced osteoclastogenesis and inhibited the formation of resorption pits by decreasing the activities of cathepsin K and matrix metalloproteinases, which are secreted by mature osteoclasts. 15d-PGJ2 exerted its effects on breast cancer and bone cells via PPARγ-independent pathways. In Balb/c nu/nu mice that received an intracardiac injection of MDA-MB-231 cells, subcutaneously injected 15d-PGJ2 substantially decreased metastatic progression, cancer cell-mediated bone destruction in femora, tibiae, and mandibles, and serum PTHrP levels. 15d-PGJ2 prevented the destruction of femoral trabecular structures in estrogen-deprived ICR mice as measured by bone morphometric parameters and serum biochemical data. Therefore, 15d-PGJ2 may be beneficial for the prevention and treatment of breast cancer

Suppressed osteoclast differentiation at the chondro-osseous junction mediates endochondral ossification retardation in long bones of Wistar fetal rats with prenatal ethanol exposure

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Pan, Zhengqi [Department of Orthopedic Surgery, Zhongnan Hospital of Wuhan University, Wuhan 430071 (China); Department of Pharmacology, Basic Medical School of Wuhan University, Wuhan 430071 (China); Zhang, Xianrong [Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan 430071 (China); Shangguan, Yangfan; Hu, Hang [Department of Orthopedic Surgery, Zhongnan Hospital of Wuhan University, Wuhan 430071 (China); Chen, Liaobin, E-mail: lbchen@whu.edu.cn [Department of Orthopedic Surgery, Zhongnan Hospital of Wuhan University, Wuhan 430071 (China); Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan 430071 (China); Wang, Hui, E-mail: wanghui19@whu.edu.cn [Department of Pharmacology, Basic Medical School of Wuhan University, Wuhan 430071 (China); Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan 430071 (China)

2016-08-15

Prenatal ethanol exposure (PEE) inhibits longitudinal growth of fetal bones, but the underlying mechanisms remain unknown. In this study, we aimed to investigate how PEE induces the retardation of long bone development in fetal rats. Pregnant Wistar rats were treated with ethanol or distilled water (control group) by gavage from gestational day (GD) 9 to 20. Fetuses were delivered by cesarean section on GD20. Fetal sera were collected for assessing corticosterone (CORT) level. Fetal long bones were harvested for histochemical, immunohistochemical and gene expression analysis. Primary chondrocytes were treated with ethanol or CORT for analyzing genes expression. PEE fetuses showed a significant reduction in birth weight and body length. The serum CORT concentration in PEE group was significantly increased, while the body weight, body length and femur length all were significantly decreased in the PEE group. The length of the epiphyseal hypertrophy zone was enlarged, whereas the length of the primary ossification center was significantly reduced in PEE fetuses. TUNEL assay showed reduced apoptosis in the PEE group. Further, the gene expression of osteoprotegerin (OPG) was markedly up-regulated. In vitro experiments showed that CORT (but not ethanol) treatment significantly activated the expression of OPG, while the application of glucocorticoid receptor inhibitor, mifepristone, attenuated these change induced by CORT. These results indicated that PEE-induced glucocorticoid over-exposure enhanced the expression of OPG in fetal epiphyseal cartilage and further lead to the suppressed osteoclast differentiation in the chondro-osseous junction and consequently inhibited the endochondral ossification in long bones of fetal rats. - Highlights: • Glucocorticoid but not ethanol enhanced the expression of OPG in chondrocytes. • PEE reduced osteoclast differentiation relative with over-expression of OPG. • PEE inhibited endochondral ossification in fetal long bones of

A time-dependent degeneration manner of condyle in rat CFA-induced inflamed TMJ.

Science.gov (United States)

Xu, Liqin; Guo, Huilin; Li, Cheng; Xu, Jie; Fang, Wei; Long, Xing

2016-01-01

Temporomandibular joint (TMJ) inflammation is a potential risk factor of osteoarthritis (OA) but the detailed degenerative changes in the inflamed TMJ remain unclear. In this study, we evaluated the changes of condylar cartilage and subchondral bone in rat inflamed TMJ induced by Freund's complete adjuvant (CFA). Articular cavity was injected with CFA and the TMJ samples were collected 1, 2, 3, and 4-week post-injection. Hematoxylin & Eosin (H&E) staining, toluidine blue (TB) staining, Safranin O (S.O) staining, Masson trichrome staining and micro-CT were used to assess TMJ degeneration during inflammation. Osteoclast and osteoblast activities were analyzed by tartrate-resistant acid phosphatase (TRAP) staining and osteocalcin (OCN) immunohistochemistry staining respectively. The expression of receptor activator of NF-kB ligand (RANKL) and osteoprotegerin (OPG) in condylar cartilage and subchondral bone was also evaluated through immunohistochemistry and RANKL/OPG ratio was evaluated. Reduced cartilage thickness, decreased number of chondrocytes, and down-regulated proteoglycan expression were observed in the condylar cartilage in the inflamed TMJ. Enhanced osteoclast activity, and expanded bone marrow cavity were reached the peak in the 2-week after CFA-injection. Meanwhile the RANKL/OPG ratio in the cartilage and subchondral bone also increased in the 2-week CFA-injection. Immature, unmineralized new bones with irregular trabecular bone structure, atypical condylar shape, up-regulated OCN expression, and decreased bone mineral density (BMD) were found in the inflamed TMJ. The time-dependent degeneration manner of TMJ cartilage and subchondral bone was found in CFA-induced arthritis rat model. The degeneration in the TMJ with inflammation might be a risk factor and should be concerned.

Naringin prevents ovariectomy-induced osteoporosis and promotes osteoclasts apoptosis through the mitochondria-mediated apoptosis pathway

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Li, Fengbo [Tianjin Institute of Orthopedics in Traditional Chinese and Western Medicine, No. 155, Munan Road, Tianjin TJ 300050 (China); Graduate School of Tianjin Medical University, No. 22, Qixiangtai Street, Heping District, Tianjin 300070 (China); Sun, Xiaolei; Ma, Jianxiong [Tianjin Institute of Orthopedics in Traditional Chinese and Western Medicine, No. 155, Munan Road, Tianjin TJ 300050 (China); Ma, Xinlong, E-mail: gengxiao502@163.com [Tianjin Institute of Orthopedics in Traditional Chinese and Western Medicine, No. 155, Munan Road, Tianjin TJ 300050 (China); Zhao, Bin; Zhang, Yang; Tian, Peng [Tianjin Institute of Orthopedics in Traditional Chinese and Western Medicine, No. 155, Munan Road, Tianjin TJ 300050 (China); Li, Yanjun [Graduate School of Tianjin Medical University, No. 22, Qixiangtai Street, Heping District, Tianjin 300070 (China); Han, Zhe [Tianjin Institute of Orthopedics in Traditional Chinese and Western Medicine, No. 155, Munan Road, Tianjin TJ 300050 (China)

2014-09-26

Highlights: • Naringin possesses many pharmacological activities, promotes the proliferation of osteoblast. • Undecalcified histological obtain dynamic parameters of callus formation and remodeling. • Naringin regulate osteoclast apoptosis by mitochondrial pathway. - Abstract: Naringin, the primary active compound of the traditional Chinese medicine Rhizoma drynariae, possesses many pharmacological activities. The present study is an effort to explore the anti-osteoporosis potential of naringin in vivo and in vitro. In vivo, we used ovariectomized rats to clarify the mechanisms by which naringin anti-osteoporosis. In vitro, we used osteoclasts to investigate naringin promotes osteoclasts apoptosis. Naringin was effective at enhancing BMD, trabecular thickness, bone mineralization, and mechanical strength in a dose-dependent manner. The result of RT-PCR analysis revealed that naringin down-regulated the mRNA expression levels of BCL-2 and up-regulated BAX, caspase-3 and cytochrome C. In addition, naringin significantly reduced the bone resorption area in vitro. These findings suggest that naringin promotes the apoptosis of osteoclasts by regulating the activity of the mitochondrial apoptosis pathway and prevents OVX-induced osteoporosis in rats.

Naringin prevents ovariectomy-induced osteoporosis and promotes osteoclasts apoptosis through the mitochondria-mediated apoptosis pathway

International Nuclear Information System (INIS)

Li, Fengbo; Sun, Xiaolei; Ma, Jianxiong; Ma, Xinlong; Zhao, Bin; Zhang, Yang; Tian, Peng; Li, Yanjun; Han, Zhe

2014-01-01

Highlights: • Naringin possesses many pharmacological activities, promotes the proliferation of osteoblast. • Undecalcified histological obtain dynamic parameters of callus formation and remodeling. • Naringin regulate osteoclast apoptosis by mitochondrial pathway. - Abstract: Naringin, the primary active compound of the traditional Chinese medicine Rhizoma drynariae, possesses many pharmacological activities. The present study is an effort to explore the anti-osteoporosis potential of naringin in vivo and in vitro. In vivo, we used ovariectomized rats to clarify the mechanisms by which naringin anti-osteoporosis. In vitro, we used osteoclasts to investigate naringin promotes osteoclasts apoptosis. Naringin was effective at enhancing BMD, trabecular thickness, bone mineralization, and mechanical strength in a dose-dependent manner. The result of RT-PCR analysis revealed that naringin down-regulated the mRNA expression levels of BCL-2 and up-regulated BAX, caspase-3 and cytochrome C. In addition, naringin significantly reduced the bone resorption area in vitro. These findings suggest that naringin promotes the apoptosis of osteoclasts by regulating the activity of the mitochondrial apoptosis pathway and prevents OVX-induced osteoporosis in rats

Msx-1 is suppressed in bisphosphonate-exposed jaw bone analysis of bone turnover-related cell signalling after bisphosphonate treatment.

Science.gov (United States)

Wehrhan, F; Hyckel, P; Amann, K; Ries, J; Stockmann, P; Schlegel, Ka; Neukam, Fw; Nkenke, E

2011-05-01

Bone-destructive disease treatments include bisphosphonates and antibodies against receptor activator for nuclear factor κB ligand (aRANKL). Osteonecrosis of the jaw (ONJ) is a side-effect. Aetiopathology models failed to explain their restriction to the jaw. The osteoproliferative transcription factor Msx-1 is expressed constitutively only in mature jaw bone. Msx-1 expression might be impaired in bisphosphonate-related ONJ. This study compared the expression of Msx-1, Bone Morphogenetic Protein (BMP)-2 and RANKL, in ONJ-affected and healthy jaw bone. An automated immunohistochemistry-based alkaline phosphatase-anti-alkaline phosphatase method was used on ONJ-affected and healthy jaw bone samples (n = 20 each): cell-number ratio (labelling index, Bonferroni adjustment). Real-time RT-PCR was performed to quantitatively compare Msx-1, BMP-2, RANKL and GAPDH mRNA levels. Labelling indices were significantly lower for Msx-1 (P Msx-1, 22-fold lower (P Msx-1, RANKL suppression and BMP-2 induction were consistent with the bisphosphonate-associated osteopetrosis and impaired bone remodelling in BP- and aRANKL-induced ONJ. Msx-1 suppression suggested a possible explanation of the exclusivity of ONJ in jaw bone. Functional analyses of Msx-1- RANKL interaction during bone remodelling should be performed in the future. © 2011 John Wiley & Sons A/S.

Oxidized low density lipoprotein increases RANKL level in human vascular cells. Involvement of oxidative stress

Energy Technology Data Exchange (ETDEWEB)

Mazière, Cécile, E-mail: maziere.cecile@chu-amiens.fr [Biochemistry Laboratory, South Hospital University, René Laennec Avenue, Amiens 80000 (France); Salle, Valéry [Internal Medicine, North Hospital University, Place Victor Pauchet, Amiens 80000 (France); INSERM U1088 (EA 4292), SFR CAP-Santé (FED 4231), University of Picardie – Jules Verne (France); Gomila, Cathy; Mazière, Jean-Claude [Biochemistry Laboratory, South Hospital University, René Laennec Avenue, Amiens 80000 (France)

2013-10-18

Highlights: •Oxidized LDL enhances RANKL level in human smooth muscle cells. •The effect of OxLDL is mediated by the transcription factor NFAT. •UVA, H{sub 2}O{sub 2} and buthionine sulfoximine also increase RANKL level. •All these effects are observed in human fibroblasts and endothelial cells. -- Abstract: Receptor Activator of NFκB Ligand (RANKL) and its decoy receptor osteoprotegerin (OPG) have been shown to play a role not only in bone remodeling but also in inflammation, arterial calcification and atherosclerotic plaque rupture. In human smooth muscle cells, Cu{sup 2+}-oxidized LDL (CuLDL) 10–50 μg/ml increased reactive oxygen species (ROS) and RANKL level in a dose-dependent manner, whereas OPG level was not affected. The lipid extract of CuLDL reproduced the effects of the whole particle. Vivit, an inhibitor of the transcription factor NFAT, reduced the CuLDL-induced increase in RANKL, whereas PKA and NFκB inhibitors were ineffective. LDL oxidized by myeloperoxidase (MPO-LDL), or other pro-oxidant conditions such as ultraviolet A (UVA) irradiation, incubation with H{sub 2}O{sub 2} or with buthionine sulfoximine (BSO), an inhibitor of glutathione synthesis{sub ,} also induced an oxidative stress and enhanced RANKL level. The increase in RANKL in pro-oxidant conditions was also observed in fibroblasts and endothelial cells. Since RANKL is involved in myocardial inflammation, vascular calcification and plaque rupture, this study highlights a new mechanism whereby OxLDL might, by generation of an oxidative stress, exert a deleterious effect on different cell types of the arterial wall.

Biochemical and morphological changes associated with macrophages and osteoclasts when challenged with infection - biomed 2011.

Science.gov (United States)

Wiggers, Erin Callie; Johnson, William; Tucci, Michelle; Benghuzzi, Hamed

2011-01-01

Osteomyelitis is a bacterial infection of the bone that occurs frequently as a complication of open fractures and various kinds of orthopedic surgery. This infection can often lead to more extensive surgeries and even death of the patient. In animal models of osteomyelitis, the site of infection by Staphylococcus aureus was observed to have high numbers of both macrophages and osteoclasts, both of which may contribute to large amounts of osteolysis and tissue damage. In order to evaluate the immune response in both types of cells, two cells lines, a macrophage cell line and a macrophage cell line stimulated to become osteoclasts by the addition of receptor activator of nuclear-factor B (RANKL), were exposed to lipopolysaccharides, opsonized S. aureus, and unopsonized S. aureus. The results showed that both cell types activated a biochemical cascade that included the release of cytokines and nitric oxide associated with cell damage and death in response to infection. However, macrophages and osteoclasts differed in response magnitude, most likely due to differences in cell-membrane receptors. This data supports the growing body of research that links the immune and skeletal systems. Further understanding of biochemical pathways shared by the two systems could lead to significant advances in the treatment of osteomyelitis and the success of prostheses.

Circulating RANKL and RANKL/OPG and Breast Cancer Risk by ER and PR Subtype: Results from the EPIC Cohort.

Science.gov (United States)

Sarink, Danja; Schock, Helena; Johnson, Theron; Overvad, Kim; Holm, Marianne; Tjønneland, Anne; Boutron-Ruault, Marie-Christine; His, Mathilde; Kvaskoff, Marina; Boeing, Heiner; Lagiou, Pagona; Papatesta, Eleni-Maria; Trichopoulou, Antonia; Palli, Domenico; Pala, Valeria; Mattiello, Amalia; Tumino, Rosario; Sacerdote, Carlotta; Bueno-de-Mesquita, H B As; van Gils, Carla H; Peeters, Petra H; Weiderpass, Elisabete; Agudo, Antonio; Sánchez, Maria-José; Chirlaque, Maria-Dolores; Ardanaz, Eva; Amiano, Pilar; Khaw, Kay Tee; Travis, Ruth; Dossus, Laure; Gunter, Mark; Rinaldi, Sabina; Merritt, Melissa; Riboli, Elio; Kaaks, Rudolf; Fortner, Renée T

2017-09-01

Receptor activator of nuclear factor-kappa B (RANK)-RANK ligand (RANKL) signaling promotes mammary tumor development in experimental models. Circulating concentrations of soluble RANKL (sRANKL) may influence breast cancer risk via activation of RANK signaling; this may be modulated by osteoprotegerin (OPG), the decoy receptor for RANKL. sRANKL and breast cancer risk by hormone receptor subtype has not previously been investigated. A case-control study was nested in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. This study included 1,976 incident invasive breast cancer cases [estrogen receptor positive (ER+), n = 1,598], matched 1:1 to controls. Women were pre- or postmenopausal at blood collection. Serum sRANKL was quantified using an ELISA, serum OPG using an electrochemiluminescent assay. Risk ratios (RR) and 95% confidence intervals (95% CI) were calculated using conditional logistic regression. Associations between sRANKL and breast cancer risk differed by tumor hormone receptor status ( P het = 0.05). Higher concentrations of sRANKL were positively associated with risk of ER+ breast cancer [5th vs. 1st quintile RR 1.28 (95% CI, 1.01-1.63); P trend = 0.20], but not ER- disease. For both ER+ and estrogen and progesterone receptor positive (ER+PR+) breast cancer, results considering the sRANKL/OPG ratio were similar to those for sRANKL; we observed a suggestive inverse association between the ratio and ER-PR- disease [5th vs. 1st quintile RR = 0.60 (0.31-1.14); P trend = 0.03]. This study provides the first large-scale prospective data on circulating sRANKL and breast cancer. We observed limited evidence for an association between sRANKL and breast cancer risk. Cancer Prev Res; 10(9); 525-34. ©2017 AACR . ©2017 American Association for Cancer Research.

Turmeric (Curcuma longa) inhibits inflammatory nuclear factor (NF)-κB and NF-κB-regulated gene products and induces death receptors leading to suppressed proliferation, induced chemosensitization, and suppressed osteoclastogenesis.

Science.gov (United States)

Kim, Ji H; Gupta, Subash C; Park, Byoungduck; Yadav, Vivek R; Aggarwal, Bharat B

2012-03-01

The incidence of cancer is significantly lower in regions where turmeric is heavily consumed. Whether lower cancer incidence is due to turmeric was investigated by examining its effects on tumor cell proliferation, on pro-inflammatory transcription factors NF-κB and STAT3, and on associated gene products. Cell proliferation and cell cytotoxicity were measured by the MTT method, NF-κB activity by EMSA, protein expression by Western blot analysis, ROS generation by FACS analysis, and osteoclastogenesis by TRAP assay. Turmeric inhibited NF-κB activation and down-regulated NF-κB-regulated gene products linked to survival (Bcl-2, cFLIP, XIAP, and cIAP1), proliferation (cyclin D1 and c-Myc), and metastasis (CXCR4) of cancer cells. The spice suppressed the activation of STAT3, and induced the death receptors (DR)4 and DR5. Turmeric enhanced the production of ROS, and suppressed the growth of tumor cell lines. Furthermore, turmeric sensitized the tumor cells to chemotherapeutic agents capecitabine and taxol. Turmeric was found to be more potent than pure curcumin for cell growth inhibition. Turmeric also inhibited NF-κB activation induced by RANKL that correlated with the suppression of osteoclastogenesis. Our results indicate that turmeric can effectively block the proliferation of tumor cells through the suppression of NF-κB and STAT3 pathways. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bone impairment in phenylketonuria is characterized by circulating osteoclast precursors and activated T cell increase.

Directory of Open Access Journals (Sweden)

Ilaria Roato

Full Text Available BACKGROUND: Phenylketonuria (PKU is a rare inborn error of metabolism often complicated by a progressive bone impairment of uncertain etiology, as documented by both ionizing and non- ionizing techniques. METHODOLOGY: Peripheral blood mononuclear cell (PBMC cultures were performed to study osteoclastogenesis, in the presence or absence of recombinant human monocyte-colony stimulating factor (M-CSF and receptor activator of NFκB ligand (RANKL. Flow cytometry was utilized to analyze osteoclast precursors (OCPs and T cell phenotype. Tumour necrosis factor α (TNF-α, RANKL and osteoprotegerin (OPG were quantified in cell culture supernatants by ELISA. The effects of RANKFc and anti-TNF-α antibodies were also investigated to determine their ability to inhibit osteoclastogenesis. In addition, bone conditions and phenylalanine levels in PKU patients were clinically evaluated. PRINCIPAL FINDINGS: Several in vitro studies in PKU patients' cells identified a potential mechanism of bone formation inhibition commonly associated with this disorder. First, PKU patients disclosed an increased osteoclastogenesis compared to healthy controls, both in unstimulated and M-CSF/RANKL stimulated PBMC cultures. OCPs and the measured RANKL/OPG ratio were higher in PKU patients compared to healthy controls. The addition of specific antagonist RANKFc caused osteoclastogenesis inhibition, whereas anti-TNF-α failed to have this effect. Among PBMCs isolated from PKU patients, activated T cells, expressing CD69, CD25 and RANKL were identified. Confirmatory in vivo studies support this proposed model. These in vivo studies included the analysis of osteoclastogenesis in PKU patients, which demonstrated an inverse relation to bone condition assessed by phalangeal Quantitative Ultrasound (QUS. This was also directly related to non-compliance to therapeutic diet reflected by hyperphenylalaninemia. CONCLUSIONS: Our results indicate that PKU spontaneous osteoclastogenesis

Novel anti-cancer strategy in bone tumors by targeting molecular and cellular modulators of bone resorption.

Science.gov (United States)

Brounais, Bénédicte; Ruiz, Carmen; Rousseau, Julie; Lamoureux, François; Blanchard, Frédéric; Heymann, Dominique; Redini, Françoise

2008-11-01

Tumor cells alter the balanced process of bone formation and bone resorption mediated respectively by osteoblasts and osteoclasts, leading to the disruption of the normal equilibrium and resulting in a spectrum of osteolytic to osteoblastic lesions. This review will summarize research on molecules that play direct and essential roles in the differentiation and activity of osteoclasts, and the role of these molecules in bone destruction caused by cancer. Results from experimental models suggest that the Receptor Activator of NF-kB Ligand (RANKL), a member of the TNF superfamily is a common effector of bony lesions in osteolysis caused by primary and secondary bone tumors. Therefore, osteoclast represents an attractive target across a broad range of tumors that develop in bone. Elucidation of the mechanisms of RANKL interactions with its activator (RANK) and decoy (osteoprotegerin: OPG) receptors has enable the development of pharmacological inhibitors of RANKL (and of its signalling pathway) which have been recently patented, with potential for the treatment of cancer-induced bone disease. Blocking bone resorption by specific other drugs such as bisphosphonates, inhibitors of cathepsin K (the main enzyme involved in bone resorption mechanisms) or signalling pathways regulating osteoclast differentiation and activation is also a promising target for the treatment of osteolysis associated to bone tumors.

Effects of transforming growth factor beta 1 on the regulation of osteoclastic development and function

International Nuclear Information System (INIS)

Hattersley, G.; Chambers, T.J.

1991-01-01

Transforming growth factor (TGF) beta 1 is a multifunctional cytokine with powerful effects on osteoblastic cells. Its role in the regulation of osteoclast generation and function, however, is unclear. It has been reported both to stimulate and to inhibit resorption in organ culture and to inhibit multinuclear cell formation in bone marrow cultures. We tested the effects of TGF-beta 1 on bone resorption by osteoclasts isolated from neonatal rat long bones. We found potent stimulation of osteoclastic bone resorption, mediated by osteoblastic cells, with an EC50 of 10 pg/ml, considerably lower than that of well-documented osteotropic hormones. Stimulation was not mediated by Swiss mouse 3T3 cells, a nonosteoblastic cell line. TGF-beta 1 strongly inhibited the generation of calcitonin receptor (CTR)-positive cells in mouse bone marrow cultures, but as for isolated osteoclasts, bone resorption per CTR-positive cell was increased. The inhibition of CTR-positive cell formation was associated with suppression of maturation of other bone marrow derivatives and may be related more to the known ability of TGF-beta 1 to suppress the proliferation of primitive hematopoietic cells than to a specific role of TGF-beta 1 in osteoclast generation

Myostatin is a direct regulator of osteoclast differentiation and its inhibition reduces inflammatory joint destruction in mice.

Science.gov (United States)

Dankbar, Berno; Fennen, Michelle; Brunert, Daniela; Hayer, Silvia; Frank, Svetlana; Wehmeyer, Corinna; Beckmann, Denise; Paruzel, Peter; Bertrand, Jessica; Redlich, Kurt; Koers-Wunrau, Christina; Stratis, Athanasios; Korb-Pap, Adelheid; Pap, Thomas

2015-09-01

Myostatin (also known as growth and differentiation factor 8) is a secreted member of the transforming growth factor-β (TGF-β) family that is mainly expressed in skeletal muscle, which is also its primary target tissue. Deletion of the myostatin gene (Mstn) in mice leads to muscle hypertrophy, and animal studies support the concept that myostatin is a negative regulator of muscle growth and regeneration. However, myostatin deficiency also increases bone formation, mainly through loading-associated effects on bone. Here we report a previously unknown direct role for myostatin in osteoclastogenesis and in the progressive loss of articular bone in rheumatoid arthritis (RA). We demonstrate that myostatin is highly expressed in the synovial tissues of RA subjects and of human tumor necrosis factor (TNF)-α transgenic (hTNFtg) mice, a model for human RA. Myostatin strongly accelerates receptor activator of nuclear factor κB ligand (RANKL)-mediated osteoclast formation in vitro through transcription factor SMAD2-dependent regulation of nuclear factor of activated T-cells (NFATC1). Myostatin deficiency or antibody-mediated inhibition leads to an amelioration of arthritis severity in hTNFtg mice, chiefly reflected by less bone destruction. Consistent with these effects in hTNFtg mice, the lack of myostatin leads to increased grip strength and less bone erosion in the K/BxN serum-induced arthritis model in mice. The results strongly suggest that myostatin is a potent therapeutic target for interfering with osteoclast formation and joint destruction in RA.

Leucine-rich repeat kinase-1 regulates osteoclast function by modulating RAC1/Cdc42 Small GTPase phosphorylation and activation.

Science.gov (United States)

Zeng, Canjun; Goodluck, Helen; Qin, Xuezhong; Liu, Bo; Mohan, Subburaman; Xing, Weirong

2016-10-01

Leucine-rich repeat kinase-1 (Lrrk1) consists of ankyrin repeats (ANK), leucine-rich repeats (LRR), a GTPase-like domain of Roc (ROC), a COR domain, a serine/threonine kinase domain (KD), and WD40 repeats (WD40). Previous studies have revealed that knockout (KO) of Lrrk1 in mice causes severe osteopetrosis, and a human mutation of Lrrk1 leads to osteosclerotic metaphysial dysplasia. The molecular mechanism by which Lrrk1 regulates osteoclast function is unknown. In this study, we generated a series of Lrrk1 mutants and evaluated their ability to rescue defective bone resorption in Lrrk1-deficient osteoclasts by use of pit formation assays. Overexpression of Lrrk1 or LRR-truncated Lrrk1, but not ANK-truncated Lrrk1, WD40-truncated Lrrk1, Lrrk1-KD, or K651A mutant Lrrk1, rescued bone resorption function of Lrrk1 KO osteoclasts. We next examined whether RAC1/Cdc42 small GTPases are direct substrates of Lrrk1 in osteoclasts. Western blot and pull-down assays revealed that Lrrk1 deficiency in osteoclasts resulted in reduced phosphorylation and activation of RAC1/Cdc42. In vitro kinase assays confirmed that recombinant Lrrk1 phosphorylated RAC1-GST protein, and immunoprecipitation showed that the interaction of Lrrk1 with RAC1 occurred within 10 min after RANKL treatment. Overexpression of constitutively active Q61L RAC1 partially rescued the resorptive function of Lrrk1-deficient osteoclasts. Furthermore, lack of Lrrk1 in osteoclasts led to reduced autophosphorylation of p21 protein-activated kinase-1 at Ser 144 , catalyzed by RAC1/Cdc42 binding and activation. Our data indicate that Lrrk1 regulates osteoclast function by directly modulating phosphorylation and activation of small GTPase RAC1/Cdc42 and that its function depends on ANK, ROC, WD40, and kinase domains. Copyright © 2016 the American Physiological Society.

Effects of Wenyangbushen formula on the expression of VEGF, OPG, RANK and RANKL in rabbits with steroid-induced femoral head avascular necrosis.

Science.gov (United States)

Song, Hong-Mei; Wei, Ying-Chen; Li, Nan; Wu, Bin; Xie, Na; Zhang, Kun-Mu; Wang, Shi-Zhong; Wang, He-Ming

2015-12-01

The present study aimed to investigate the effects of Wenyangbushen formula on the mRNA and protein expression levels of vascular endothelial growth factor (VEGF), osteoprotegerin (OPG), receptor activator of nuclear factor (NF)‑κβ ligand (RANK), and RANK ligand (RANKL) in a rabbit model of steroid‑induced avascular necrosis of the femoral head (SANFH). The present study also aimed to examine the potential mechanism underlying the effect of this formula on the treatment of SANFH. A total of 136 New Zealand rabbits were randomly divided into five groups: Normal group, model group, and three groups treated with the traditional Chinese medicine (TCM), Wenyangbushen decoction, at a low, moderate and high dose, respectively. The normal group and positive control group were intragastrically administered with saline. The TCM groups were treated with Wenyangbushen decoction at the indicated dosage. Following treatment for 8 weeks, the mRNA and protein expression levels of VEGF, OPG, RANK and RANKL in the femoral head tissues were determined using reverse transcription‑quantitative polymerase chain reaction and western blot analyses, respectively. The data revealed that Wenyangbushen decoction effectively promoted the growth of bone cells, osteoblasts and chondrocytes, and prevented cell apoptosis in the SANFH. The mRNA and protein expression levels of OPG and VEGF were increased, while the levels of RANK and RANKL were reduced in the necrotic tissue of the model group, compared with those in the normal rabbits. Wenyangbushen treatment prevented these changes, manifested by an upregulation in the expression levels of VEGF and OPG, and downregulation in the expression levels of RANK and RANKL in a dose‑dependent manner. It was concluded that treatment with Wenyangbushen formula alleviated necrosis of the femoral head induced by steroids. It was observed to promote bone cell, osteoblast and chondrocyte growth, as well as prevent cell apoptosis. In addition, it

Effect of heparin and alendronate coating on titanium surfaces on inhibition of osteoclast and enhancement of osteoblast function

Energy Technology Data Exchange (ETDEWEB)

Moon, Ho-Jin; Yun, Young-Pil [Department of Maxillofacial Biomedical Engineering, School of Dentistry, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Han, Choong-Wan; Kim, Min Sung [Department of Oral and Maxillofacial Radiology, School of Dentistry, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Institute of Oral Biology, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Kim, Sung Eun; Bae, Min Soo [Department of Maxillofacial Biomedical Engineering, School of Dentistry, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Kim, Gyu-Tae; Choi, Yong-Suk; Hwang, Eui-Hwan [Department of Oral and Maxillofacial Radiology, School of Dentistry, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Institute of Oral Biology, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Lee, Joon Woo [Department of Technology Commercialization Information, Korea Institute of Science and Technology Information (KISTI), 66, Hoegi-ro, Dongdaemun-gu, Seoul 130-741 (Korea, Republic of); Lee, Jin-Moo; Lee, Chang-Hoon [Department of Oriental Gynecology, College of Oriental Medicine, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Kim, Duck-Su [Department of Conservative Dentistry, School of Dentistry, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Kwon, Il Keun, E-mail: kwoni@khu.ac.kr [Department of Maxillofacial Biomedical Engineering, School of Dentistry, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Institute of Oral Biology, Kyung Hee University, Seoul 130-701 (Korea, Republic of)

2011-09-23

Highlights: {yields} We examine bone metabolism of engineered alendronate attached to Ti surfaces. {yields} Alendronate-immobilized Ti enhances activation of osteoblast differentiation. {yields} Alendronate-immobilized Ti inhibits osteoclast differentiation. {yields} Alendronate-immobilized Ti may be a bioactive implant with dual functions. -- Abstract: The failure of orthopedic and dental implants has been attributed mainly to loosening of the implant from host bone, which may be due to weak bonding of the implant material to bone tissue. Titanium (Ti) is used in the field of orthopedic and dental implants because of its excellent biocompatibility and outstanding mechanical properties. Therefore, in the field of materials science and tissue engineering, there has been extensive research to immobilize bioactive molecules on the surface of implant materials in order to provide the implants with improved adhesion to the host bone tissue. In this study, chemically active functional groups were introduced on the surface of Ti by a grafting reaction with heparin and then the Ti was functionalized by immobilizing alendronate onto the heparin-grafted surface. In the MC3T3-E1 cell osteogenic differentiation study, the alendronate-immobilized Ti substrates significantly enhanced alkaline phosphatase activity (ALP) and calcium content. Additionally, nuclear factor kappa B ligand (RANKL)-induced osteoclast differentiation of RAW264.7 cells was inhibited with the alendronate-immobilized Ti as confirmed by TRAP analysis. Real time PCR analysis showed that mRNA expressions of osteocalcin and osteopontin, which are markers for osteogenesis, were upregulated in MC3T3-E1 cells cultured on alendronate-immobilized Ti. The mRNA expressions of TRAP and Cathepsin K, markers for osteoclastogenesis, in RAW264.7 cells cultured on alendronate-immobilized Ti were down-regulated. Our study suggests that alendronate-immobilized Ti may be a bioactive implant with dual functions to enhance

Complex osteoclastogenic inductive effects of nicotine over hydroxyapatite.

Science.gov (United States)

Costa-Rodrigues, Joao; Rocha, Isabel; Fernandes, Maria H

2018-02-01

Cigarette smoke is associated to pathological weakening of bone tissue, being considered an important playmaker in conditions such as osteoporosis and periodontal bone loss. In addition, it is also associated with an increased risk of failure in bone regeneration strategies. The present work aimed to characterize the effects of nicotine on human osteoclastogenesis over a hydroxyapatite substrate. Osteoclast precursors were maintained in the absence or presence of the osteoclastogenesis enhancers M-CSF and RANKL, and were further treated with nicotine levels representative of the concentrations observed in the plasma and saliva of smokers. It was observed that nicotine at low concentrations elicit an increase in osteoclast differentiation, but only in the presence of M-CSF and RANKL it was also able to significantly increase the resorbing ability of osteoclasts. A slight downregulation of NFkB pathway and an increase in the production of TNF-α and, particularly PGE2, were involved in the observed effects of nicotine. At high concentrations, nicotine revealed cytotoxic effects, causing a decrease in cell density. In conclusion, nicotine at levels found in the plasma of the smokers, has the ability to act directly on osteoclast precursors, inducing its osteoclastogenic differentiation. The stimulatory behavior appears to be dependent on the stage of osteoclastic differentiation of the precursor cells, which means, in the absence of M-CSF and RANKL, it only favors the initial stages of osteoclast differentiation, while in the presence of the growth factors, a significant increase in their resorbing ability is also achieved. © 2017 Wiley Periodicals, Inc.

Requirement of the inducible nitric oxide synthase pathway for IL-1-induced osteoclastic bone resorption

OpenAIRE

van't Hof, R. J.; Armour, K. J.; Smith, L. M.; Armour, K. E.; Wei, X. Q.; Liew, F. Y.; Ralston, S. H.

2000-01-01

Nitric oxide has been suggested to be involved in the regulation of bone turnover, especially in pathological conditions characterized by release of bone-resorbing cytokines. The cytokine IL-1 is thought to act as a mediator of periarticular bone loss and tissue damage in inflammatory diseases such as rheumatoid arthritis. IL-1 is a potent stimulator of both osteoclastic bone resorption and expression of inducible nitric oxide synthase (iNOS) in bone cells and other cell types. In this study,...

Osteoclast Fusion

DEFF Research Database (Denmark)

Marie Julie Møller, Anaïs; Delaissé, Jean-Marie; Søe, Kent

2017-01-01

on the nuclearity of fusion partners. While CD47 promotes cell fusions involving mono-nucleated pre-osteoclasts, syncytin-1 promotes fusion of two multi-nucleated osteoclasts, but also reduces the number of fusions between mono-nucleated pre-osteoclasts. Furthermore, CD47 seems to mediate fusion mostly through...... individual fusion events using time-lapse and antagonists of CD47 and syncytin-1. All time-lapse recordings have been studied by two independent observers. A total of 1808 fusion events were analyzed. The present study shows that CD47 and syncytin-1 have different roles in osteoclast fusion depending...... broad contact surfaces between the partners' cell membrane while syncytin-1 mediate fusion through phagocytic-cup like structure. J. Cell. Physiol. 9999: 1-8, 2016. © 2016 Wiley Periodicals, Inc....

RANK und RANKL - Vom Knochen zum Mammakarzinom

Directory of Open Access Journals (Sweden)

Sigl V

2012-01-01

Full Text Available RANK („Receptor Activator of NF-κB“ und sein Ligand RANKL sind Schlüsselmoleküle im Knochenmetabolismus und spielen eine essenzielle Rolle in der Entstehung von pathologischen Knochenveränderungen. Die Deregulation des RANK/RANKL-Systems ist zum Beispiel ein Hauptgrund für das Auftreten von postmenopausaler Osteoporose bei Frauen. Eine weitere wesentliche Funktion von RANK und RANKL liegt in der Entwicklung von milchsekretierenden Drüsen während der Schwangerschaft. Dabei regulieren Sexualhormone, wie zum Beispiel Progesteron, die Expression von RANKL und induzieren dadurch die Proliferation von epithelialen Zellen der Brust. Seit Längerem war schon bekannt, dass RANK und RANKL in der Metastasenbildung von Brustkrebszellen im Knochengewebe beteiligt sind. Wir konnten nun das RANK/RANKLSystem auch als essenziellen Mechanismus in der Entstehung von hormonellem Brustkrebs identifizieren. In diesem Beitrag werden wir daher den neuesten Erkenntnissen besondere Aufmerksamkeit schenken und diese kritisch in Bezug auf Brustkrebsentwicklung betrachten.

OPG/RANKL/RANK cytokine system in renal osteodystrophy

Directory of Open Access Journals (Sweden)

Ivica Avberšek-Lužnik

2007-11-01

Full Text Available Background: Renal osteodystrophy is one of the most common complications affecting patients with endstage renal disease treated with hemodialysis (HD. The action of calciotropic hormones in renal osteodystrophy is regulated by the OPG/RANKL/RANK system. Its function is modulated by interleukines, calcitriol and parathyroid hormone (PTH.The aim of our study was to confirm that this system is involved in the pathogenesis of renal osteodystrophy and supports the mechanism of PTH action on bone.Methods: 106 HD patients (mean age 60 years and 50 healthy volunteers (mean age 64 years were enrolled in the study. In serum samples of patients and controls we determined concentrations of OPG, RANKL, tartarat resistant acid phosphatase 5b (TRAP 5b, serum Cterminal telopeptide cross-links of type I collagen (CTx, bone specific alkaline phosphatase (BALP, osteocalcin (OC and parathyroid hormone (PTH. We compared serum measurements of HD patients and controls and assessed the correlation of OPG and RANKL with bone markers. The most frequent OPG promotor gene polymorphisms were also determined. SPSS 12.1 for Windows was used for statistical analysis.Results: Median OPG concentrations were approximately three times higher in HD patients (0.804 µg/l than in healthy volunteers (0.272 µg/l. Mean serum RANKL concentrations were 1.66- fold higher in HD patients (1.36 pmol/l than in controls (0.82 pmol/l. Serum RANKL levels significantly differed between patients with and without calcitriol therapy (p = 0.001. After dividing HD patients into tertiles according to PTH, we observed significantly higher OPG values in the lower and RANKL in the upper tertile (p < 0.001. OPG did not correlate with bone resorption markers. Only weak correlation of bone formation markers with osteocalcin was noted. In contrast to OPG, RANKL correlated well with PTH, OC and CTX. OPG promoter gene polymorphisms (149 T → C, 163 A → G, 950 T → C do not influence OPG expression and

Impaired bone remodeling in children with osteogenesis imperfecta treated and untreated with bisphosphonates: the role of DKK1, RANKL, and TNF-α.

Science.gov (United States)

Brunetti, G; Papadia, F; Tummolo, A; Fischetto, R; Nicastro, F; Piacente, L; Ventura, A; Mori, G; Oranger, A; Gigante, I; Colucci, S; Ciccarelli, M; Grano, M; Cavallo, L; Delvecchio, M; Faienza, M F

2016-07-01

In this study, we investigated the bone cell activity in patients with osteogenesis imperfecta (OI) treated and untreated with neridronate. We demonstrated the key role of Dickkopf-1 (DKK1), receptor activator of nuclear factor-κB ligand (RANKL), and tumor necrosis factor alpha (TNF-α) in regulating bone cell of untreated and treated OI subjects. These cytokines could represent new pharmacological targets for OI. Bisphosphonates are widely used in the treatment of children with osteogenesis imperfecta (OI) with the objective of reducing the risk of fractures. Although bisphosphonates increase bone mineral density in OI subjects, the effects on fracture incidence are conflicting. The aim of this study was to investigate the mechanisms underlying bone cell activity in subjects with mild untreated forms of OI and in a group of subjects with severe OI treated with cycles of intravenous neridronate. Sclerostin, DKK1, TNF-α, RANKL, osteoprotegerin (OPG), and bone turnover markers were quantified in serum of 18 OI patients (12 females, mean age 8.86 ± 3.90), 8 of which were receiving cyclic intravenous neridronate, and 21 sex- and age-matched controls. The effects on osteoblastogenesis and OPG expression of media conditioned by the serum of OI patients and anti-DKK1 neutralizing antibody were evaluated. Osteoclastogenesis was assessed in cultures from patients and controls. DKK1 and RANKL levels were significantly increased both in untreated and in treated OI subjects with respect to controls. The serum from patients with high DKK1 levels inhibited both osteoblast differentiation and OPG expression in vitro. High RANKL and low OPG messenger RNA (mRNA) levels were found in lymphomonocytes from patients. High amounts of TNF-α were expressed by monocytes, and an elevated percentage of circulating CD11b-CD51/CD61+ osteoclast precursors was observed in patients. Our study demonstrated the key role of DKK1, RANKL, and TNF-α in regulating bone cell activity of subjects

Caffeine may enhance orthodontic tooth movement through increasing osteoclastogenesis induced by periodontal ligament cells under compression.

Science.gov (United States)

Yi, Jianru; Yan, Boxi; Li, Meile; Wang, Yu; Zheng, Wei; Li, Yu; Zhao, Zhihe

2016-04-01

Caffeine is the kernel component of coffee and has multiple effects on bone metabolism. Here we aimed to investigate the effects of caffeine intake on orthodontic tooth movement (OTM). (1) In the in vivo study, two groups comprising 15 randomly assigned rats each underwent orthodontic treatment. One group ingested caffeine at 25mg/kg body weight per day and the other, plain water. After 3 weeks, the degree of tooth movement and effect on the periodontium were assessed. (2) In the in vitro study, we established a model mimicking the essential bioprocess of OTM, which contained a periodontal ligament tissue model (PDLtm), and a co-culture system of osteoblasts (OBs) and osteoclast precursors (pre-OCs). After being subjected to static compressive force with or without caffeine administration, the conditioned media from the PDLtm were used for the OB/pre-OC co-cultures to induce osteoclastogenesis. (1) In vivo, the caffeine group displayed a significantly greater rate of tooth movement than the control. The alveolar bone mineral density and bone volume fraction were similar between the two groups; however, immunohistochemical staining showed that the caffeine group had significantly more TRAP(+) osteoclasts and higher RANKL expression in the compressed periodontium. (2) In vitro, caffeine at 0.01mM significantly enhanced the compression-induced expression of RANKL and COX-2, as well as prostaglandin E2 production in the PDLtm. Furthermore, the "caffeine+compression"-conditioned media induced significantly more TRAP(+) OC formation when compared with compression alone. Daily intake of caffeine, at least at some specific dosage, may enhance OTM through increasing osteoclastogenesis. Copyright © 2016 Elsevier Ltd. All rights reserved.

Noncanonical Wnt signaling promotes osteoclast differentiation and is facilitated by the human immunodeficiency virus protease inhibitor ritonavir

International Nuclear Information System (INIS)

Santiago, Francisco; Oguma, Junya; Brown, Anthony M.C.; Laurence, Jeffrey

2012-01-01

Highlights: ► First demonstration of direct role for noncanonical Wnt in osteoclast differentiation. ► Demonstration of Ryk as a Wnt5a/b receptor in inhibition of canonical Wnt signaling. ► Modulation of noncanonical Wnt signaling by a clinically important drug, ritonavir. ► Establishes a mechanism for an important clinical problem: HIV-associated bone loss. -- Abstract: Wnt proteins that signal via the canonical Wnt/β-catenin pathway directly regulate osteoblast differentiation. In contrast, most studies of Wnt-related effects on osteoclasts involve indirect changes. While investigating bone mineral density loss in the setting of human immunodeficiency virus (HIV) infection and its treatment with the protease inhibitor ritonavir (RTV), we observed that RTV decreased nuclear localization of β-catenin, critical to canonical Wnt signaling, in primary human and murine osteoclast precursors. This occurred in parallel with upregulation of Wnt5a and Wnt5b transcripts. These Wnts typically stimulate noncanonical Wnt signaling, and this can antagonize the canonical Wnt pathway in many cell types, dependent upon Wnt receptor usage. We now document RTV-mediated upregulation of Wnt5a/b protein in osteoclast precursors. Recombinant Wnt5b and retrovirus-mediated expression of Wnt5a enhanced osteoclast differentiation from human and murine monocytic precursors, processes facilitated by RTV. In contrast, canonical Wnt signaling mediated by Wnt3a suppressed osteoclastogenesis. Both RTV and Wnt5b inhibited canonical, β-catenin/T cell factor-based Wnt reporter activation in osteoclast precursors. RTV- and Wnt5-induced osteoclast differentiation were dependent upon the receptor-like tyrosine kinase Ryk, suggesting that Ryk may act as a Wnt5a/b receptor in this context. This is the first demonstration of a direct role for Wnt signaling pathways and Ryk in regulation of osteoclast differentiation, and its modulation by a clinically important drug, ritonavir. These studies

Expression of RANKL/OPG during bone remodeling in vivo

Energy Technology Data Exchange (ETDEWEB)

Tanaka, H., E-mail: tnk@ymghp.jp [Department of Orthopedic Surgery, Yamaguchi Grand Medical Center, 77 Ohsaki, Hofu, Yamaguchi 747-8511 (Japan); Gerontology Research Center, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224 (United States); Mine, T. [Department of Orthopedic Surgery, Yamaguchi University School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505 (Japan); Ogasa, H. [Gerontology Research Center, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224 (United States); Department of Orthopedic Surgery, Yamaguchi University School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505 (Japan); Taguchi, T. [Department of Orthopedic Surgery, Yamaguchi University School of Medicine, 1-1-1 Minamikogushi, Ube, Yamaguchi 755-8505 (Japan); Liang, C.T. [Gerontology Research Center, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224 (United States); National Health Research Institutes, Taipei 115, Taiwan (China)

2011-08-12

Highlights: {yields} This is the first study to determine the relationship between osteogenic differentiation and RANKL/OPG expression during bone remodeling in vivo. {yields} The OPG expression peak occurred during the bone formation phase, whereas the marked elevation of RANKL expression was observed during the bone resorption phase. {yields} Histological analysis showed that RANKL/OPG immunoreactivity was predominantly associated with bone marrow cells in the marrow cavity. {yields} The present study confirmed that RANKL/OPG are key factors linking bone formation to resorption during the bone remodeling process. -- Abstract: The interaction between receptor activator of nuclear factor {kappa}B ligand (RANKL) and osteoprotegerin (OPG) plays a dominant role in osteoclastogenesis. As both proteins are produced by osteoblast lineage cells, they are considered to represent a key link between bone formation and resorption. In this study, we investigated the expression of RANKL and OPG during bone remodeling in vivo to determine the relationship between osteoclastogenic stimulation and osteoblastic differentiation. Total RNA was prepared from rat femurs after marrow ablation on days 0, 3, 6, and 9. The temporal activation patterns of osteoblast-related genes (procollagen {alpha}1 (I), alkaline phosphatase, osteopontin, and osteocalcin) were examined by Northern blot analysis. An appreciable increase in the expression of these osteoblast markers was observed on day 3. The peak increase in gene expression was observed on day 6 followed by a slight reduction by day 9. Real-time PCR analysis showed that the OPG mRNA expression was markedly upregulated on day 6 and slightly decreased on day 9. In contrast, RANKL mRNA expression was increased by more than 20-fold on day 9. The RANKL/OPG ratio, an index of osteoclastogenic stimulation, peaked on day 9. Histological analysis showed that RANKL and OPG immunoreactivity were predominantly associated with bone marrow cells. The

Expression of RANKL/OPG during bone remodeling in vivo

International Nuclear Information System (INIS)

Tanaka, H.; Mine, T.; Ogasa, H.; Taguchi, T.; Liang, C.T.

2011-01-01

Highlights: → This is the first study to determine the relationship between osteogenic differentiation and RANKL/OPG expression during bone remodeling in vivo. → The OPG expression peak occurred during the bone formation phase, whereas the marked elevation of RANKL expression was observed during the bone resorption phase. → Histological analysis showed that RANKL/OPG immunoreactivity was predominantly associated with bone marrow cells in the marrow cavity. → The present study confirmed that RANKL/OPG are key factors linking bone formation to resorption during the bone remodeling process. -- Abstract: The interaction between receptor activator of nuclear factor κB ligand (RANKL) and osteoprotegerin (OPG) plays a dominant role in osteoclastogenesis. As both proteins are produced by osteoblast lineage cells, they are considered to represent a key link between bone formation and resorption. In this study, we investigated the expression of RANKL and OPG during bone remodeling in vivo to determine the relationship between osteoclastogenic stimulation and osteoblastic differentiation. Total RNA was prepared from rat femurs after marrow ablation on days 0, 3, 6, and 9. The temporal activation patterns of osteoblast-related genes (procollagen α1 (I), alkaline phosphatase, osteopontin, and osteocalcin) were examined by Northern blot analysis. An appreciable increase in the expression of these osteoblast markers was observed on day 3. The peak increase in gene expression was observed on day 6 followed by a slight reduction by day 9. Real-time PCR analysis showed that the OPG mRNA expression was markedly upregulated on day 6 and slightly decreased on day 9. In contrast, RANKL mRNA expression was increased by more than 20-fold on day 9. The RANKL/OPG ratio, an index of osteoclastogenic stimulation, peaked on day 9. Histological analysis showed that RANKL and OPG immunoreactivity were predominantly associated with bone marrow cells. The expression of bone formation

Stochastic differentiation into an osteoclast lineage from cloned macrophage-like cells

Energy Technology Data Exchange (ETDEWEB)

Hayashi, Shin-Ichi, E-mail: shayashi@med.tottori-u.ac.jp [Division of Immunology, Department of Molecular and Cellular Biology, School of Life Science, Faculty of Medicine, Tottori University, 86 Nishi-Cho, Yonago, Tottori 683-8503 (Japan); Murata, Akihiko; Okuyama, Kazuki; Shimoda, Yuhki; Hikosaka, Mari [Division of Immunology, Department of Molecular and Cellular Biology, School of Life Science, Faculty of Medicine, Tottori University, 86 Nishi-Cho, Yonago, Tottori 683-8503 (Japan); Yasuda, Hisataka [Planning and Development, Bioindustry Division, Oriental Yeast Co., Ltd, Itabashi-Ku, Tokyo 174-8505 (Japan); Yoshino, Miya [Division of Immunology, Department of Molecular and Cellular Biology, School of Life Science, Faculty of Medicine, Tottori University, 86 Nishi-Cho, Yonago, Tottori 683-8503 (Japan)

2012-11-16

Highlights: Black-Right-Pointing-Pointer The frequency of C7 differentiation into osteoclast was low and constant. Black-Right-Pointing-Pointer Only extended C7 cell cultures exponentially increased osteoclast+ cultures. Black-Right-Pointing-Pointer C7 cell differentiation into committed osteoclast precursors is on 'autopilot'. Black-Right-Pointing-Pointer The system may maintain the stem cell self-renewal and differentiation. -- Abstract: Differentiation into osteoclasts is induced by a macrophage colony-stimulating factor and receptor activator of nuclear-factor {kappa}B ligand. The macrophage-like cell line, C7 has the potential to differentiate into osteoclasts when it is cultured with both factors for 6 days. Although C7 is an established cell line, the frequency of differentiation into this lineage was less than 10%, and the ratio was maintained at a constant level, even after repeated cloning. In this study, to increase the differentiation of C7 cells to osteoclasts, C7 derivative treatments with several activators and/or inhibitors were performed for 3 days prior to setting osteoclast induction analysis; however, a reagent to significantly up-regulate the frequency of differentiation was not found. Only extended cultures for osteoclastogenesis exponentially increased the frequency of osteoclast precursors. It is likely that C7 cell differentiation into committed osteoclast precursors is on 'autopilot' rather than requiring specific signals to drive this process.

Stochastic differentiation into an osteoclast lineage from cloned macrophage-like cells

International Nuclear Information System (INIS)

Hayashi, Shin-Ichi; Murata, Akihiko; Okuyama, Kazuki; Shimoda, Yuhki; Hikosaka, Mari; Yasuda, Hisataka; Yoshino, Miya

2012-01-01

Highlights: ► The frequency of C7 differentiation into osteoclast was low and constant. ► Only extended C7 cell cultures exponentially increased osteoclast+ cultures. ► C7 cell differentiation into committed osteoclast precursors is on ‘autopilot’. ► The system may maintain the stem cell self-renewal and differentiation. -- Abstract: Differentiation into osteoclasts is induced by a macrophage colony-stimulating factor and receptor activator of nuclear-factor κB ligand. The macrophage-like cell line, C7 has the potential to differentiate into osteoclasts when it is cultured with both factors for 6 days. Although C7 is an established cell line, the frequency of differentiation into this lineage was less than 10%, and the ratio was maintained at a constant level, even after repeated cloning. In this study, to increase the differentiation of C7 cells to osteoclasts, C7 derivative treatments with several activators and/or inhibitors were performed for 3 days prior to setting osteoclast induction analysis; however, a reagent to significantly up-regulate the frequency of differentiation was not found. Only extended cultures for osteoclastogenesis exponentially increased the frequency of osteoclast precursors. It is likely that C7 cell differentiation into committed osteoclast precursors is on ‘autopilot’ rather than requiring specific signals to drive this process.

Transforming growth factor-β synthesized by stromal cells and cancer cells participates in bone resorption induced by oral squamous cell carcinoma

International Nuclear Information System (INIS)

Nakamura, Ryosuke; Kayamori, Kou; Oue, Erika; Sakamoto, Kei; Harada, Kiyoshi; Yamaguchi, Akira

2015-01-01

Transforming growth factor beta (TGF-β) plays a significant role in the regulation of the tumor microenvironment. To explore the role of TGF-β in oral cancer-induced bone destruction, we investigated the immunohistochemical localization of TGF-β and phosphorylated Smad2 (p-Smad2) in 12 surgical specimens of oral squamous cell carcinoma (OSCC). These studies revealed TGF-β and p-Smad2 expression in cancer cells in all tested cases. Several fibroblasts located between cancer nests and resorbing bone expressed TGF-β in 10 out of 12 cases and p-Smad2 in 11 out of 12 cases. Some osteoclasts also exhibited p ∼ Smad2 expression. The OSCC cell line, HSC3, and the bone marrow-derived fibroblastic cell line, ST2, synthesized substantial levels of TGF-β. Culture media derived from HSC3 cells could stimulate Tgf-β1 mRNA expression in ST2 cells. Recombinant TGF-β1 could stimulate osteoclast formation induced by receptor activator of nuclear factor kappa-B ligand (RANKL) in RAW264 cells. TGF-β1 could upregulate the expression of p-Smad2 in RAW264 cells, and this action was suppressed by the addition of a neutralizing antibody against TGF-β or by SB431542. Transplantation of HSC3 cells onto the calvarial region of athymic mice caused bone destruction, associated with the expression of TGF-β and p-Smad2 in both cancer cells and stromal cells. The bone destruction was substantially inhibited by the administration of SB431542. The present study demonstrated that TGF-β synthesized by both cancer cells and stromal cells participates in the OSCC-induced bone destruction. - Highlights: • Cancer cell, fibroblastic cells, and osteoclasts at bone resorbing area by oral cancer exhibited TGF-β and p-Smad2. • TGF-β1 stimulated osteoclastogenesis induced by RAKL in RAW264 cell. • Xenograft model of oral cancer-induced bone resorption was substantially inhibited by SB431542. • TGF-β synthesized by both cancer cells and stromal cells participates in the OSCC-induced

Transforming growth factor-β synthesized by stromal cells and cancer cells participates in bone resorption induced by oral squamous cell carcinoma

Energy Technology Data Exchange (ETDEWEB)

Nakamura, Ryosuke [Department of Oral Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo (Japan); Department of Maxillofacial Surgery, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo (Japan); Kayamori, Kou [Department of Oral Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo (Japan); Oue, Erika [Department of Oral Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo (Japan); Department of Maxillofacial Surgery, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo (Japan); Sakamoto, Kei [Department of Oral Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo (Japan); Harada, Kiyoshi [Department of Maxillofacial Surgery, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo (Japan); Yamaguchi, Akira, E-mail: akira.mpa@tmd.ac.jp [Department of Oral Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo (Japan)

2015-03-20

Transforming growth factor beta (TGF-β) plays a significant role in the regulation of the tumor microenvironment. To explore the role of TGF-β in oral cancer-induced bone destruction, we investigated the immunohistochemical localization of TGF-β and phosphorylated Smad2 (p-Smad2) in 12 surgical specimens of oral squamous cell carcinoma (OSCC). These studies revealed TGF-β and p-Smad2 expression in cancer cells in all tested cases. Several fibroblasts located between cancer nests and resorbing bone expressed TGF-β in 10 out of 12 cases and p-Smad2 in 11 out of 12 cases. Some osteoclasts also exhibited p ∼ Smad2 expression. The OSCC cell line, HSC3, and the bone marrow-derived fibroblastic cell line, ST2, synthesized substantial levels of TGF-β. Culture media derived from HSC3 cells could stimulate Tgf-β1 mRNA expression in ST2 cells. Recombinant TGF-β1 could stimulate osteoclast formation induced by receptor activator of nuclear factor kappa-B ligand (RANKL) in RAW264 cells. TGF-β1 could upregulate the expression of p-Smad2 in RAW264 cells, and this action was suppressed by the addition of a neutralizing antibody against TGF-β or by SB431542. Transplantation of HSC3 cells onto the calvarial region of athymic mice caused bone destruction, associated with the expression of TGF-β and p-Smad2 in both cancer cells and stromal cells. The bone destruction was substantially inhibited by the administration of SB431542. The present study demonstrated that TGF-β synthesized by both cancer cells and stromal cells participates in the OSCC-induced bone destruction. - Highlights: • Cancer cell, fibroblastic cells, and osteoclasts at bone resorbing area by oral cancer exhibited TGF-β and p-Smad2. • TGF-β1 stimulated osteoclastogenesis induced by RAKL in RAW264 cell. • Xenograft model of oral cancer-induced bone resorption was substantially inhibited by SB431542. • TGF-β synthesized by both cancer cells and stromal cells participates in the OSCC-induced

Negative feedback loop of bone resorption by NFATc1-dependent induction of Cadm1.

Directory of Open Access Journals (Sweden)

Shinya Nakamura

Full Text Available Trimethylation of histone H3 lysine 4 and lysine 27 (H3K4me3 and H3K27me3 at gene promoter regions critically regulates gene expression. Key developmental genes tend to exhibit changes in histone modification patterns from the H3K4me3/H3K27me3 bivalent pattern to the H3K4me3 monovalent pattern. Using comprehensive chromatin immunoprecipitation followed by sequencing in bone marrow-derived macrophages (BMMs and mature osteoclasts, we found that cell surface adhesion molecule 1 (Cadm1 is a direct target of nuclear factor of activated T cells 1 (NFATc1 and exhibits a bivalent histone pattern in BMMs and a monovalent pattern in osteoclasts. Cadm1 expression was upregulated in BMMs by receptor activator of nuclear factor kappa B ligand (RANKL, and blocked by a calcineurin/NFATc1 inhibitor, FK506. Cadm1-deficient mice exhibited significantly reduced bone mass compared with wild-type mice, which was due to the increased osteoclast differentiation, survival and bone-resorbing activity in Cadm1-deficient osteoclasts. These results suggest that Cadm1 is a direct target of NFATc1, which is induced by RANKL through epigenetic modification, and regulates osteoclastic bone resorption in a negative feedback manner.

Differences in responses to X-ray exposure between osteoclast and osteoblast cells

International Nuclear Information System (INIS)

Zhang, Jian; Wang, Ziyang; Wu, Anqing; Nie, Jing; Pei, Hailong; Hu, Wentao; Wang, Bing; Shang, Peng; Li, Bingyan; Zhou, Guangming

2017-01-01

Radiation-induced bone loss is a potential health concern for cancer patients undergoing radiotherapy. Enhanced bone resorption by osteoclasts and decreased bone formation by osteoblasts were thought to be the main reasons. In this study, we showed that both pre-differentiating and differentiating osteoclasts were relatively sensitive to X-rays compared with osteoblasts. X-rays decreased cell viability to a greater degree in RAW264.7 cells and in differentiating cells than than in osteoblastic MC3T3-E1 cells. X-rays at up to 8 Gy had little effects on osteoblast mineralization. In contrast, X-rays at 1 Gy induced enhanced osteoclastogenesis by enhanced cell fusion, but had no effects on bone resorption. A higher dose of X-rays at 8 Gy, however, had an inhibitory effect on bone resorption. In addition, actin ring formation was disrupted by 8 Gy of X-rays and reorganized into clusters. An increased activity of Caspase 3 was found after X-ray exposure. Actin disorganization and increased apoptosis may be the potential effects of X-rays at high doses, by inhibiting osteoclast differentiation. Taken together, our data indicate high radiosensitivity of osteoclasts. X-ray irradiation at relatively low doses can activate osteoclastogenesis, but not osteogenic differentiation. The radiosensitive osteoclasts are the potentially responsive cells for X-ray-induced bone loss.

miR-218 is involved in the negative regulation of osteoclastogenesis and bone resorption by partial suppression of p38MAPK-c-Fos-NFATc1 signaling: Potential role for osteopenic diseases.

Science.gov (United States)

Qu, Bo; Xia, Xun; Yan, Ming; Gong, Kai; Deng, Shaolin; Huang, Gang; Ma, Zehui; Pan, Xianming

2015-10-15

The increased osteoclastic activity accounts for pathological bone loss in diseases including osteoporosis. MicroRNAs are widely accepted to be involved in the regulation of osteopenic diseases. Recently, the low expression of miR-218 was demonstrated in CD14(+) peripheral blood mononuclear cells (PBMCs) from patients with postmenopausal osteoporosis. However, its role and the underlying mechanism in osteoporosis are still undefined. Here, an obvious decrease in miR-218 expression was observed during osteoclastogenesis under receptor activator of nuclear factor κB ligand (RANKL) stimulation, in both osteoclast precursors of bone marrow macrophages (BMMs) and RAW 264.7. Further analysis confirmed that overexpression of miR-218 obviously attenuated the formation of multinuclear mature osteoclasts, concomitant with the decrease in Trap and Cathepsin K levels, both the master regulators of osteoclastogenesis. Moreover, miR-218 up-regulation dramatically inhibited osteoclast precursor migration, actin ring formation and bone resorption. Mechanism assay demonstrated that miR-218 overexpression attenuated the expression of p38MAPK, c-Fos and NFATc1 signaling molecules. Following preconditioning with P79350, an agonist of p38MAPK, the inhibitor effect of miR-218 on osteoclastogenesis and bone-resorbing activity was strikingly ameliorated. Together, this study revealed a crucial role of miR-218 as a negative regulator for osteoclastogenesis and bone resorption by suppressing the p38MAPK-c-Fos-NFATc1 pathway. Accordingly, this research will provide a promising therapeutic agent against osteopenic diseases including osteoporosis. Copyright © 2015 Elsevier Inc. All rights reserved.

Anti-osteopontin monoclonal antibody prevents ovariectomy-induced osteoporosis in mice by promotion of osteoclast apoptosis

Energy Technology Data Exchange (ETDEWEB)

Zhang, Bo [International Joint Cancer Institute, The Second Military Medical University, 800 Xiang Yin Road, Shanghai 200433 (China); PLA General Hospital Cancer Center and PLA Cancer Research Institute, PLA Postgraduate School of Medicine, 28 Fuxing Road, Beijing (China); Dai, Jianxin [International Joint Cancer Institute, The Second Military Medical University, 800 Xiang Yin Road, Shanghai 200433 (China); PLA General Hospital Cancer Center and PLA Cancer Research Institute, PLA Postgraduate School of Medicine, 28 Fuxing Road, Beijing (China); National Engineering Research Center for Antibody Medicine and Shanghai Key Lab. of Cell Engineering and Antibody, 399 Libing Road, Shanghai 201203 (China); Wang, Huaqing [International Joint Cancer Institute, The Second Military Medical University, 800 Xiang Yin Road, Shanghai 200433 (China); Wei, Huafeng [International Joint Cancer Institute, The Second Military Medical University, 800 Xiang Yin Road, Shanghai 200433 (China); PLA General Hospital Cancer Center and PLA Cancer Research Institute, PLA Postgraduate School of Medicine, 28 Fuxing Road, Beijing (China); Zhao, Jian [International Joint Cancer Institute, The Second Military Medical University, 800 Xiang Yin Road, Shanghai 200433 (China); National Engineering Research Center for Antibody Medicine and Shanghai Key Lab. of Cell Engineering and Antibody, 399 Libing Road, Shanghai 201203 (China); Guo, Yajun, E-mail: yguo_smmu@163.com [International Joint Cancer Institute, The Second Military Medical University, 800 Xiang Yin Road, Shanghai 200433 (China); PLA General Hospital Cancer Center and PLA Cancer Research Institute, PLA Postgraduate School of Medicine, 28 Fuxing Road, Beijing (China); National Engineering Research Center for Antibody Medicine and Shanghai Key Lab. of Cell Engineering and Antibody, 399 Libing Road, Shanghai 201203 (China); and others

2014-09-26

Highlight: • We first report that anti-osteopontin mAb could protect osteoporosis in mice. • Anti-osteopontin mAb could promote the osteoclast apoptosis. • Targeting osteopontin might have therapeutic potentials for osteoporosis. - Abstract: Osteopontin (OPN) is abundant in mineralized tissues and has long been implicated in bone remodeling. However, the therapeutic effect of targeting OPN in bone loss diseases and the underlying molecular mechanism remain largely unknown. Here, we reported that anti-OPN mAb (23C3) could protect against ovariectomy-induced osteoporosis in mice, demonstrated by microcomputed tomography analysis and histopathology evaluation. In vitro assay showed that 23C3 mAb reduced osteoclasts (OCs)-mediated bone resorption through promotion of mature OC apoptosis. Thus, the study has important implications for understanding the role of OPN in OC bone resorption and survival, and OPN antagonists may have therapeutic potential for osteoporosis and other osteopenic diseases.

Anti-osteopontin monoclonal antibody prevents ovariectomy-induced osteoporosis in mice by promotion of osteoclast apoptosis

International Nuclear Information System (INIS)

Zhang, Bo; Dai, Jianxin; Wang, Huaqing; Wei, Huafeng; Zhao, Jian; Guo, Yajun

2014-01-01

Highlight: • We first report that anti-osteopontin mAb could protect osteoporosis in mice. • Anti-osteopontin mAb could promote the osteoclast apoptosis. • Targeting osteopontin might have therapeutic potentials for osteoporosis. - Abstract: Osteopontin (OPN) is abundant in mineralized tissues and has long been implicated in bone remodeling. However, the therapeutic effect of targeting OPN in bone loss diseases and the underlying molecular mechanism remain largely unknown. Here, we reported that anti-OPN mAb (23C3) could protect against ovariectomy-induced osteoporosis in mice, demonstrated by microcomputed tomography analysis and histopathology evaluation. In vitro assay showed that 23C3 mAb reduced osteoclasts (OCs)-mediated bone resorption through promotion of mature OC apoptosis. Thus, the study has important implications for understanding the role of OPN in OC bone resorption and survival, and OPN antagonists may have therapeutic potential for osteoporosis and other osteopenic diseases

A comparison of osteoclast-rich and osteoclast-poor osteopetrosis in adult mice sheds light on the role of the osteoclast in coupling bone resorption and bone formation

DEFF Research Database (Denmark)

Thudium, Christian S; Moscatelli, Ilana; Flores, Carmen

2014-01-01

that osteoclasts are important for regulating osteoblast activity. To illuminate the role of the osteoclast in controlling bone remodeling, we transplanted irradiated skeletally mature 3-month old wild-type mice with hematopoietic stem cells (HSCs) to generate either an osteoclast-rich or osteoclast-poor adult......Osteopetrosis due to lack of acid secretion by osteoclasts is characterized by abolished bone resorption, increased osteoclast numbers, but normal or even increased bone formation. In contrast, osteoclast-poor osteopetrosis appears to have less osteoblasts and reduced bone formation, indicating...... osteopetrosis model. We used fetal liver HSCs from (1) oc/oc mice, (2) RANK KO mice, and (3) compared these to wt control cells. TRAP5b activity, a marker of osteoclast number and size, was increased in the oc/oc recipients, while a significant reduction was seen in the RANK KO recipients. In contrast, the bone...

Ammonium tetrathiomolybdate enhances the antitumor effects of cetuximab via the suppression of osteoclastogenesis in head and neck squamous carcinoma.

Science.gov (United States)

Morisawa, Ayaka; Okui, Tatsuo; Shimo, Tsuyoshi; Ibaragi, Soichiro; Okusha, Yuka; Ono, Mitsuaki; Nguyen, Thi Thu Ha; Hassan, Nur Mohammad Monsur; Sasaki, Akira

2018-03-01

Head and neck squamous cell carcinoma (HNSCC) poses a significant challenge clinically where one of the mechanisms responsible for the invasion into facial bones occurs via the activation of osteoclasts. Copper has been demonstrated to play a key role in skeletal remodeling. However, the role of copper in cancer-associated bone destruction is thus far unknown. Lysyl oxidase (LOX) is a copper-dependent enzyme that promotes osteoclastogenesis. In the present study, we investigated the effects of copper on HNSCC with bone invasion by the copper chelator, ammonium tetrathiomolybdate (TM) in vitro and in vivo. We demonstrate that TM blocks the proliferation of HNSCC cells, inhibits LOX activation and decreases the expression of the receptor activator of nuclear factor-κB ligand (RANKL) in osteoblasts and osteocytes, subsequently suppressing bone destruction. These findings suggest that copper is a potential target for the treatment of HNSCCs associated with bone destruction.

Global epigenomic analysis indicates protocadherin-7 activates osteoclastogenesis by promoting cell–cell fusion

Energy Technology Data Exchange (ETDEWEB)

Nakamura, Haruhiko [Department of Orthopaedic Surgery, Faculty of Medicine, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan); Department of Cell Signaling, Graduate School of Medical and Dental Science, Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, Tokyo 113-8549 (Japan); Nakashima, Tomoki [Department of Cell Signaling, Graduate School of Medical and Dental Science, Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, Tokyo 113-8549 (Japan); Japan Science and Technology Agency, PRESTO, Yushima 1-5-45, Bunkyo-ku, Tokyo 113-8549 (Japan); Hayashi, Mikihito [Department of Cell Signaling, Graduate School of Medical and Dental Science, Tokyo Medical and Dental University, Yushima 1-5-45, Bunkyo-ku, Tokyo 113-8549 (Japan); Japan Science and Technology Agency, ERATO, Takayanagi Osteonetwork Project, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Izawa, Naohiro; Yasui, Tetsuro [Department of Orthopaedic Surgery, Faculty of Medicine, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan); Aburatani, Hiroyuki [Genome Science Division, Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1, Komaba, Meguro-ku, Tokyo 153-8904 (Japan); Tanaka, Sakae [Department of Orthopaedic Surgery, Faculty of Medicine, The University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo 113-0033 (Japan); Takayanagi, Hiroshi, E-mail: takayana@m.u-tokyo.ac.jp [Japan Science and Technology Agency, ERATO, Takayanagi Osteonetwork Project, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan); Department of Immunology, Graduate School of Medicine and Faculty of Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

2014-12-12

Highlights: • Identification of epigenetically regulated genes during osteoclastogenesis. • Pcdh7 is regulated by H3K4me3 and H3K27me3 during osteoclastogenesis. • Pcdh7 expression is increased by RANKL during osteoclastogenesis. • Establishment of novel cell fusion analysis for osteoclasts by imaging cytometer. • Pcdh7 regulates osteoclastogenesis by promoting cell fusion related gene expressions. - Abstract: Gene expression is dependent not only on genomic sequences, but also epigenetic control, in which the regulation of chromatin by histone modification plays a crucial role. Histone H3 lysine 4 trimethylation (H3K4me3) and histone H3 lysine 27 trimethylation (H3K27me3) are related to transcriptionally activated and silenced sequences, respectively. Osteoclasts, the multinucleated cells that resorb bone, are generated by the fusion of precursor cells of monocyte/macrophage lineage. To elucidate the molecular and epigenetic regulation of osteoclast differentiation, we performed a chromatin immunoprecipitation sequencing (ChIP-seq) analysis for H3K4me3 and H3K27me3 in combination with RNA sequencing. We focused on the histone modification change from H3K4me3(+)H3K27me3(+) to H3K4me3(+)H3K27me3(–) and identified the protocadherin-7 gene (Pcdh7) to be among the genes epigenetically regulated during osteoclastogenesis. Pcdh7 was induced by RANKL stimulation in an NFAT-dependent manner. The knockdown of Pcdh7 inhibited RANKL-induced osteoclast differentiation due to the impairment of cell–cell fusion, accompanied by a decreased expression of the fusion-related genes Dcstamp, Ocstamp and Atp6v0d2. This study demonstrates that Pcdh7 plays a key role in osteoclastogenesis by promoting cell–cell fusion.

Global epigenomic analysis indicates protocadherin-7 activates osteoclastogenesis by promoting cell–cell fusion

International Nuclear Information System (INIS)

Nakamura, Haruhiko; Nakashima, Tomoki; Hayashi, Mikihito; Izawa, Naohiro; Yasui, Tetsuro; Aburatani, Hiroyuki; Tanaka, Sakae; Takayanagi, Hiroshi

2014-01-01

Highlights: • Identification of epigenetically regulated genes during osteoclastogenesis. • Pcdh7 is regulated by H3K4me3 and H3K27me3 during osteoclastogenesis. • Pcdh7 expression is increased by RANKL during osteoclastogenesis. • Establishment of novel cell fusion analysis for osteoclasts by imaging cytometer. • Pcdh7 regulates osteoclastogenesis by promoting cell fusion related gene expressions. - Abstract: Gene expression is dependent not only on genomic sequences, but also epigenetic control, in which the regulation of chromatin by histone modification plays a crucial role. Histone H3 lysine 4 trimethylation (H3K4me3) and histone H3 lysine 27 trimethylation (H3K27me3) are related to transcriptionally activated and silenced sequences, respectively. Osteoclasts, the multinucleated cells that resorb bone, are generated by the fusion of precursor cells of monocyte/macrophage lineage. To elucidate the molecular and epigenetic regulation of osteoclast differentiation, we performed a chromatin immunoprecipitation sequencing (ChIP-seq) analysis for H3K4me3 and H3K27me3 in combination with RNA sequencing. We focused on the histone modification change from H3K4me3(+)H3K27me3(+) to H3K4me3(+)H3K27me3(–) and identified the protocadherin-7 gene (Pcdh7) to be among the genes epigenetically regulated during osteoclastogenesis. Pcdh7 was induced by RANKL stimulation in an NFAT-dependent manner. The knockdown of Pcdh7 inhibited RANKL-induced osteoclast differentiation due to the impairment of cell–cell fusion, accompanied by a decreased expression of the fusion-related genes Dcstamp, Ocstamp and Atp6v0d2. This study demonstrates that Pcdh7 plays a key role in osteoclastogenesis by promoting cell–cell fusion

Role of CXC chemokine ligand 13 in oral squamous cell carcinoma associated osteolysis in athymic mice.

Science.gov (United States)

Pandruvada, Subramanya N M; Yuvaraj, Sambandam; Liu, Xiang; Sundaram, Kumaran; Shanmugarajan, Srinivasan; Ries, William L; Norris, James S; London, Steven D; Reddy, Sakamuri V

2010-05-15

Oral squamous cell carcinomas (OSCC) are malignant tumors with a potent activity of local bone invasion; however, the molecular mechanisms of tumor osteolysis are unclear. In this study, we identified high level expression of chemokine ligand, CXCL13 and RANK ligand (RANKL) in OSCC cells (SCC1, SCC12 and SCC14a). OSCC cell-conditioned media (20%) induced osteoclast differentiation which was inhibited by OPG in peripheral blood monocyte cultures indicating that OSCC cells produce soluble RANKL. Recombinant hCXCL13 (10 ng/ml) significantly enhanced RANKL-stimulated osteoclast differentiation in these cultures. Trans-well migration assay identified that CXCL13 induces chemotaxis of peripheral blood monocytes in vitro which was inhibited by addition of anti-CXCR5 receptor antibody. Zymogram analysis of conditioned media from OSCC cells revealed matrix metalloproteinase-9 (MMP-9) activity. Interestingly, CXCL13 treatment to OSCC cells induced CXCR5 and MMP-9 expression suggesting an autocrine regulatory function in OSCC cells. To examine the OSCC tumor cell bone invasion/osteolysis, we established an in vivo model for OSCC by subcutaneous injection of OSCC cells onto the surface of calvaria in NCr-nu/nu athymic mice, which developed tumors in 4-5 weeks. muCT analysis revealed numerous osteolytic lesions in calvaria from OSCC tumor-bearing mice. Histochemical staining of calvarial sections from these mice revealed a significant increase in the numbers of TRAP-positive osteoclasts at the tumor-bone interface. Immunohistochemical analysis confirmed CXCL13 and MMP-9 expression in tumor cells. Thus, our data implicate a functional role for CXCL13 in bone invasion and may be a potential therapeutic target to prevent osteolysis associated with OSCC tumors in vivo.

Osteoclast inhibition impairs chondrosarcoma growth and bone destruction.

Science.gov (United States)

Otero, Jesse E; Stevens, Jeff W; Malandra, Allison E; Fredericks, Douglas C; Odgren, Paul R; Buckwalter, Joseph A; Morcuende, Jose

2014-12-01

Because Chondrosarcoma is resistant to available chemotherapy and radiation regimens, wide resection is the mainstay in treatment, which frequently results in high morbidity and which may not prevent local recurrence. There is a clear need for improved adjuvant treatment of this malignancy. We have observed the presence of osteoclasts in the microenvironment of chondrosarcoma in human pathological specimens. We utilized the Swarm rat chondrosarcoma (SRC) model to test the hypothesis that osteoclasts affect chondrosarcoma pathogenesis. We implanted SRC tumors in tibia of Sprague-Dawley rats and analyzed bone histologically and radiographically for bone destruction and tumor growth. At three weeks, tumors invaded local bone causing cortical disruption and trabecular resorption. Bone destruction was accompanied by increased osteoclast number and resorbed bone surface. Treatment of rats with the zoledronic acid prevented cortical destruction, inhibited trabecular resorption, and resulted in decreased tumor volume in bone. To confirm that inhibition of osteoclasts per se, and not off-target effects of drug, was responsible for the prevention of tumor growth and bone destruction, we implanted SRC into osteopetrotic rat tibia. SRC-induced bone destruction and tumor growth were impaired in osteopetrotic bone compared with control bone. The results from our animal model demonstrate that osteoclasts contribute to chondrosarcoma-mediated bone destruction and tumor growth and may represent a therapeutic target in particular chondrosarcoma patients. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Distinctive and selective route of PI3K/PKCα-PKCδ/RhoA-Rac1 signaling in osteoclastic cell migration.

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Kim, Jin-Man; Kim, Mi Yeong; Lee, Kyunghee; Jeong, Daewon

2016-12-05

Cell migration during specialized stages of osteoclast precursors, mononuclear preosteoclasts, and multinucleated mature osteoclasts remain uncertain. M-CSF- and osteopontin-induced osteoclastic cell migration was inhibited by function-blocking monoclonal antibodies specific to the integrin αv and β3 subunits, suggesting that integrin αvβ3 mediates migratory signaling induced by M-CSF and osteopontin. M-CSF and osteopontin stimulation was shown to regulate two branched signaling processes, PI3K/PKCα/RhoA axis and PI3K/PKCδ/Rac1 axis. Interestingly, inactivation of RhoA or Rac1 blocked preosteoclast and mature osteoclast migration but not osteoclast precursor migration in a transwell-based cell migration assay. Moreover, the inhibitory effect on preosteoclast and mature osteoclast migration induced by Rac1 inactivation was more effective than that by RhoA inactivation. Collectively, our findings suggest that osteoclast precursor migration depends on PI3K/PKCα-PKCδ signaling mediated via integrin αvβ3 bypassing RhoA and Rac1, whereas preosteoclast and mature osteoclast migration relies on PI3K/PKCα-PKCδ/RhoA-Rac1 axis signaling mediated via integrin αvβ3 with increased dependency on PKCδ/Rac1 signaling route as differentiation progresses. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Inhibition of bone resorption by Tanshinone VI isolated from Salvia miltiorrhiza Bunge

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V. Nicolin

2010-05-01

Full Text Available During the last decade, a more detailed knowledge of molecular mechanisms involved in osteoclastogenesis has driven research efforts in the development and screening of compound libraries of several small molecules that specifically inhibit the pathway involved in the commitment of the osteoclast precursor cells. Natural compounds that suppress osteoclast differentiation may have therapeutic value in treating osteoporosis and other bone erosive diseases such as rheumatoid arthritis or metastasis associated with bone loss. In ongoing investigation into anti-osteoporotic compounds from natural products we have analyzed the effect of Tanshinone VI on osteoclasts differentiation, using a physiologic three-dimensional osteoblast/bone marrow model of cell co-culture. Tanshinone VI is an abietane diterpene extracted from the root of Salvia miltiorrhiza Bunge (Labiatae, a Chinese traditional crude drug, ‘’Tan-Shen’’. Tashinone has been widely used in clinical practice for the prevention of cardiac diseases, arthritis and other inflammation-related disorders based on its pharmacological actions in multiple tissues. Although Tanshinone VI A has been used as a medicinal agent in the treatment of many diseases, its role in osteoclast-related bone diseases remains unknown. We showed previously that Tanshinone VI greatly inhibits osteoclast differentiation and suppresses bone resorption through disruption of the actin ring; subsequently, we intended to examine the precise inhibitory mechanism of Tanshinone VI on osteoclast differentiating factor. This study shows, for the first time, that Tanshinone VI prevents osteoclast differentiation by inhibiting RANKL expression and NFkB induction.

Stromal cells and osteoclasts are responsible for exacerbated collagen-induced arthritis in interferon-beta-deficient mice

DEFF Research Database (Denmark)

Treschow, Alexandra P; Teige, Ingrid; Nandakumar, Kutty S

2005-01-01

OBJECTIVE: Clinical trials using interferon-beta (IFNbeta) in the treatment of rheumatoid arthritis have shown conflicting results. We undertook this study to understand the mechanisms of IFNbeta in arthritis at a physiologic level. METHODS: Collagen-induced arthritis (CIA) was induced in IFNbeta....... Differences in osteoclast maturation were determined in situ by histology of arthritic and naive paws and by in vitro maturation studies of naive bone marrow cells. The importance of IFNbeta-producing fibroblasts was determined by transferring fibroblasts into mice at the time of CIA immunization. RESULTS...

Aryl hydrocarbon receptor suppresses the osteogenesis of mesenchymal stem cells in collagen-induced arthritic mice through the inhibition of β-catenin

Energy Technology Data Exchange (ETDEWEB)

Tong, Yulong [Department of Immunology, School of Basic Medical Sciences, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069 (China); Niu, Menglin [Department of Immunology, School of Basic Medical Sciences, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069 (China); Department of Blood Transfusion, Peking University Cancer Hospital & Institute, No. 52 Fucheng Rd., Beijing 100142 (China); Du, Yuxuan; Mei, Wentong; Cao, Wei; Dou, Yunpeng [Department of Immunology, School of Basic Medical Sciences, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069 (China); Yu, Haitao [Department of Clinical Laboratory, The First Hospital of Lanzhou University, Lanzhou, Gansu Province 730000 (China); Du, Xiaonan [Department of Immunology, School of Basic Medical Sciences, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069 (China); Yuan, Huihui, E-mail: huihui_yuan@163.com [Department of Immunology, School of Basic Medical Sciences, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069 (China); Zhao, Wenming, E-mail: zhao-wenming@163.com [Department of Immunology, School of Basic Medical Sciences, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069 (China)

2017-01-15

The contributions of aryl hydrocarbon receptor (Ahr) to the pathogenesis of rheumatoid arthritis (RA), particularly bone loss, have not been clearly explored. The imbalance between osteoblasts and osteoclasts is a major reason for bone loss. The dysfunction of osteoblasts, which are derived from mesenchymal stem cells (MSCs), induced bone erosion occurs earlier and is characterized as more insidious. Here, we showed that the nuclear expression and translocation of Ahr were both significantly increased in MSCs from collagen-induced arthritis (CIA) mice. The enhanced Ahr suppressed the mRNA levels of osteoblastic markers including Alkaline phosphatase (Alp) and Runt-related transcription factor 2 (Runx2) in the differentiation of MSCs to osteoblasts in CIA. The 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD)-mediated activation of Ahr dose-dependently suppressed the expression of osteoblastic markers. In addition, the expression of β-catenin was reduced in CIA MSCs compared with control, and the TCDD-mediated activation of the Ahr significantly inhibited β-catenin expression. The Wnt3a-induced the activation of Wnt/β-catenin pathway partly rescued the osteogenesis decline induced by TCDD. Taken together, these results indicate that activated Ahr plays a negative role in CIA MSCs osteogenesis, possibly by suppressing the expression of β-catenin. - Highlights: • The Ahr pathway displays an activated profile in CIA MSCs. • The activation of Ahr suppresses osteogenesis in CIA MSCs. • TCDD suppresses osteogenesis in a dose-dependent manner. • The activation of Ahr inhibits β-catenin expression to exacerbate bone erosion.

Involvement of multiple myeloma cell-derived exosomes in osteoclast differentiation

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Raimondi, Lavinia; De Luca, Angela; Amodio, Nicola; Manno, Mauro; Raccosta, Samuele; Taverna, Simona; Bellavia, Daniele; Naselli, Flores; Fontana, Simona; Schillaci, Odessa; Giardino, Roberto; Fini, Milena; Tassone, Pierfrancesco; Santoro, Alessandra; De Leo, Giacomo; Giavaresi, Gianluca; Alessandro, Riccardo

2015-01-01

Bone disease is the most frequent complication in multiple myeloma (MM) resulting in osteolytic lesions, bone pain, hypercalcemia and renal failure. In MM bone disease the perfect balance between bone-resorbing osteoclasts (OCs) and bone-forming osteoblasts (OBs) activity is lost in favour of OCs, thus resulting in skeletal disorders. Since exosomes have been described for their functional role in cancer progression, we here investigate whether MM cell-derived exosomes may be involved in OCs differentiation. We show that MM cells produce exosomes which are actively internalized by Raw264.7 cell line, a cellular model of osteoclast formation. MM cell-derived exosomes positively modulate pre-osteoclast migration, through the increasing of CXCR4 expression and trigger a survival pathway. MM cell-derived exosomes play a significant pro-differentiative role in murine Raw264.7 cells and human primary osteoclasts, inducing the expression of osteoclast markers such as Cathepsin K (CTSK), Matrix Metalloproteinases 9 (MMP9) and Tartrate-resistant Acid Phosphatase (TRAP). Pre-osteoclast treated with MM cell-derived exosomes differentiate in multinuclear OCs able to excavate authentic resorption lacunae. Similar results were obtained with exosomes derived from MM patient's sera. Our data indicate that MM-exosomes modulate OCs function and differentiation. Further studies are needed to identify the OCs activating factors transported by MM cell-derived exosomes. PMID:25944696

Osteoclasts in multiple myeloma are derived from Gr-1+CD11b+myeloid-derived suppressor cells.

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Junling Zhuang

Full Text Available Osteoclasts play a key role in the development of cancer-associated osteolytic lesions. The number and activity of osteoclasts are often enhanced by tumors. However, the origin of osteoclasts is unknown. Myeloid-derived suppressor cells (MDSCs are one of the pre-metastatic niche components that are induced to expand by tumor cells. Here we show that the MDSCs can differentiate into mature and functional osteoclasts in vitro and in vivo. Inoculation of 5TGM1-GFP myeloma cells into C57BL6/KaLwRij mice led to a significant expansion of MDSCs in blood, spleen, and bone marrow over time. When grown in osteoclastogenic media in vitro, MDSCs from tumor-challenged mice displayed 14 times greater potential to differentiate into mature and functional osteoclasts than those from non-tumor controls. Importantly, MDSCs from tumor-challenged LacZ transgenic mice differentiated into LacZ+osteoclasts in vivo. Furthermore, a significant increase in tumor burden and bone loss accompanied by increased number of osteoclasts was observed in mice co-inoculated with tumor-challenged MDSCs and 5TGM1 cells compared to the control animals received 5TGM1 cells alone. Finally, treatment of MDSCs from myeloma-challenged mice with Zoledronic acid (ZA, a potent inhibitor of bone resorption, inhibited the number of osteoclasts formed in MDSC cultures and the expansion of MDSCs and bone lesions in mice. Collectively, these data provide in vitro and in vivo evidence that tumor-induced MDSCs exacerbate cancer-associated bone destruction by directly serving as osteoclast precursors.

The Use of Patient-Specific Induced Pluripotent Stem Cells (iPSCs to Identify Osteoclast Defects in Rare Genetic Bone Disorders

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I-Ping Chen

2014-12-01

Full Text Available More than 500 rare genetic bone disorders have been described, but for many of them only limited treatment options are available. Challenges for studying these bone diseases come from a lack of suitable animal models and unavailability of skeletal tissues for studies. Effectors for skeletal abnormalities of bone disorders may be abnormal bone formation directed by osteoblasts or anomalous bone resorption by osteoclasts, or both. Patient-specific induced pluripotent stem cells (iPSCs can be generated from somatic cells of various tissue sources and in theory can be differentiated into any desired cell type. However, successful differentiation of hiPSCs into functional bone cells is still a challenge. Our group focuses on the use of human iPSCs (hiPSCs to identify osteoclast defects in craniometaphyseal dysplasia. In this review, we describe the impact of stem cell technology on research for better treatment of such disorders, the generation of hiPSCs from patients with rare genetic bone disorders and current protocols for differentiating hiPSCs into osteoclasts.

c-Fms signaling mediates neurofibromatosis Type-1 osteoclast gain-in-functions.

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Yongzheng He

Full Text Available Skeletal abnormalities including osteoporosis and osteopenia occur frequently in both pediatric and adult neurofibromatosis type 1 (NF1 patients. NF1 (Nf1 haploinsufficient osteoclasts and osteoclast progenitors derived from both NF1 patients and Nf1(+/- mice exhibit increased differentiation, migration, and bone resorptive capacity in vitro, mediated by hyperactivation of p21(Ras in response to limiting concentrations of macrophage-colony stimulating factor (M-CSF. Here, we show that M-CSF binding to its receptor, c-Fms, results in increased c-Fms activation in Nf1(+/ (- osteoclast progenitors, mediating multiple gain-in-functions through the downstream effectors Erk1/2 and p90RSK. PLX3397, a potent and selective c-Fms inhibitor, attenuated M-CSF mediated Nf1(+/- osteoclast migration by 50%, adhesion by 70%, and pit formation by 60%. In vivo, we administered PLX3397 to Nf1(+/- osteoporotic mice induced by ovariectomy (OVX and evaluated changes in bone mass and skeletal architecture. We found that PLX3397 prevented bone loss in Nf1(+/--OVX mice by reducing osteoclast differentiation and bone resorptive activity in vivo. Collectively, these results implicate the M-CSF/c-Fms signaling axis as a critical pathway underlying the aberrant functioning of Nf1 haploinsufficient osteoclasts and may provide a potential therapeutic target for treating NF1 associated osteoporosis and osteopenia.

NHE10, a novel osteoclast-specific member of the Na+/H+ exchanger family, regulates osteoclast differentiation and survival

International Nuclear Information System (INIS)

Lee, Seoung Hoon; Kim, Taesoo; Park, Eui-Soon; Yang, Sujeong; Jeong, Daewon; Choi, Yongwon; Rho, Jaerang

2008-01-01

Bone homeostasis is tightly regulated by the balanced actions of osteoblasts (OBs) and osteoclasts (OCs). We previously analyzed the gene expression profile of OC differentiation using a cDNA microarray, and identified a novel osteoclastogenic gene candidate, clone OCL-1-E7 [J. Rho, C.R. Altmann, N.D. Socci, L. Merkov, N. Kim, H. So, O. Lee, M. Takami, A.H. Brivanlou, Y. Choi, Gene expression profiling of osteoclast differentiation by combined suppression subtractive hybridization (SSH) and cDNA microarray analysis, DNA Cell Biol. 21 (2002) 541-549]. In this study, we have isolated full-length cDNAs corresponding to this clone from mice and humans to determine the functional roles of this gene in osteoclastogenesis. The full-length cDNA of OCL-1-E7 encodes 12 membrane-spanning domains that are typical of isoforms of the Na + /H + exchangers (NHEs), indicating that this clone is a novel member of the NHE family (hereafter referred to as NHE10). Here, we show that NHE10 is highly expressed in OCs in response to receptor activator of nuclear factor-κB ligand signaling and is required for OC differentiation and survival

Chondroitin Sulfate-E Binds to Both Osteoactivin and Integrin αVβ3 and Inhibits Osteoclast Differentiation.

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Miyazaki, Tatsuya; Miyauchi, Satoshi; Anada, Takahisa; Tawada, Akira; Suzuki, Osamu

2015-10-01

Integrins and their ligands have been suggested to be associated with osteoclast-mediated bone resorption. The present study was designed to investigate whether chondroitin sulfate E (CS-E), which is one of the sulfated glycosaminoglycans (GAGs), is involved in osteoactivin (OA) activity, and osteoclast differentiation. The binding affinity of sulfated GAGs to integrin and its ligand was measured using biotin-labeled CS-E, and the osteoclast differentiation was evaluated by tartrate-resistant acid phosphatase staining and a pit formation assay. CS-E as well as CS-B, synthetic chondroitin polysulfate, and heparin inhibited osteoclast differentiation of bone marrow-derived macrophages. Pre-coating of OA to synthetic calcium phosphate-coated plates enhanced the osteoclastic differentiation of RAW264 cells, and addition of a neutralizing antibody to OA inhibited its differentiation. CS-E bound not only to OA, fibronectin, and vitronectin, but also to its receptor integrin αVβ3, and inhibited the direct binding of OA to integrin αVβ3. Furthermore, CS-E blocked the binding of OA to cells and inhibited OA-induced osteoclastic differentiation. On the other hand, heparinase treatment of RAW264 cells inhibited osteoclastic differentiation. Since binding of OA to the cells was inhibited by the presence of heparan sulfate or heparinase treatment of cells, heparan sulfate proteoglycan (HSPG) was also considered to be an OA receptor. Taken together, the present results suggest that CS-E is capable of inhibiting OA-induced osteoclast differentiation by blocking the interaction of OA to integrin αVβ3 and HSPG. © 2015 Wiley Periodicals, Inc.

Proinflammatory and proosteoclastogenic potential of peripheral blood mononuclear cells from Gaucher patients: Implication for bone pathology.

Science.gov (United States)

Mucci, J M; Cuello, M F; Kisinovsky, I; Larroude, M; Delpino, M V; Rozenfeld, P A

2015-08-01

Gaucher disease (GD) is caused by mutations in the GBA gene that confer a deficient level of activity of glucocerebrosidase (GCase). This deficiency leads to the accumulation of the glycolipid glucocerebroside in the lysosomes of cells of monocyte/macrophage system. Bone compromise in Gaucher disease patients is the most disabling aspect of the disease. However, pathophysiological aspects of skeletal alterations are still poorly understood. On the other hand it is well known that inflammation is a key player in GD pathology. In this work, we revealed increased levels of the proinflammatory CD14(+)CD16(+) monocyte subset and increased inflammatory cytokine production by monocytes and T cells in the circulation of GD patients. We showed increased levels of osteoclast precursors in PBMC from patients and a higher expression of RANKL in the surface of T cells. PBMC from patients presented higher osteoclast differentiation compared to healthy controls when cultured in the presence of M-CSF alone or in combination with RANKL. In vitro treatment with Velaglucerase reduced osteoclast levels to control levels. On the other hand THP-1 derived osteoclast precursors cultured in the presence of conditioned media from PBMC of GD patients presented higher differentiation to active osteoclasts. This induction involved TNF-α and RANKL. Copyright © 2015 Elsevier Inc. All rights reserved.

MECHANICAL VIBRATION INHIBITS OSTEOCLAST FORMATION BY REDUCING DC-STAMP RECEPTOR EXPRESSION IN OSTEOCLAST PRECURSOR CELLS

OpenAIRE

Kulkarni, R.N.; Voglewede, P.A.; Liu, D.

2013-01-01

It is well known that physical inactivity leads to loss of muscle mass, but it also causes bone loss. Mechanistically, osteoclastogenesis and bone resorption have recently been shown to be regulated by vibration. However, the underlying mechanism behind the inhibition of osteoclast formation is yet unknown. Therefore, we investigated whether mechanical vibration of osteoclast precursor cells affects osteoclast formation by the involvement of fusion-related molecules such as dendritic cell-spe...

Apatite-mediated actin dynamics in resorbing osteoclasts.

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Saltel, Frédéric; Destaing, Olivier; Bard, Frédéric; Eichert, Diane; Jurdic, Pierre

2004-12-01

The actin cytoskeleton is essential for osteoclasts main function, bone resorption. Two different organizations of actin have been described in osteoclasts, the podosomes belt corresponding to numerous F-actin columns arranged at the cell periphery, and the sealing zone defined as a unique large band of actin. To compare the role of these two different actin organizations, we imaged osteoclasts on various substrata: glass, dentin, and apatite. Using primary osteoclasts expressing GFP-actin, we found that podosome belts and sealing zones, both very dynamic actin structures, were present in mature osteoclasts; podosome belts were observed only in spread osteoclasts adhering onto glass, whereas sealing zone were seen in apico-basal polarized osteoclasts adherent on mineralized matrix. Dynamic observations of several resorption cycles of osteoclasts seeded on apatite revealed that 1) podosomes do not fuse together to form the sealing zone; 2) osteoclasts alternate successive stationary polarized resorption phases with a sealing zone and migration, nonresorption phases without any specific actin structure; and 3) apatite itself promotes sealing zone formation though c-src and Rho signaling. Finally, our work suggests that apatite-mediated sealing zone formation is dependent on both c-src and Rho whereas apico-basal polarization requires only Rho.

Osteocyte Alterations Induce Osteoclastogenesis in an In Vitro Model of Gaucher Disease

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Constanza Bondar

2017-01-01

Full Text Available Gaucher disease (GD is caused by mutations in the glucosylceramidase β (GBA 1 gene that confer a deficient level of activity of glucocerebrosidase (GCase. This deficiency leads to the accumulation of the glycolipid glucocerebroside in the lysosomes of cells, mainly in the monocyte/macrophage lineage. Its mildest form is Type I GD, characterized by non-neuronopathic involvement. Bone compromise is the most disabling aspect of the Gaucher disease. However, the pathophysiological aspects of skeletal alterations are not yet fully understood. The bone tissue homeostasis is maintained by a balance between resorption of old bone by osteoclasts and new bone formation by osteoblasts. A central player in this balance is the osteocyte as it controls both processes. We studied the involvement of osteocytes in an in vitro chemical model of Gaucher disease. The osteocyte cell line MLO-Y4 was exposed to conduritol-β-epoxide (CBE, an inhibitor of GCase, for a period of 7, 14 and 21 days. Conditioned media from CBE-treated osteocytes was found to induce osteoclast differentiation. GCase inhibition caused alterations in Cx43 expression and distribution pattern and an increase in osteocyte apoptosis. Osteoclast differentiation involved osteocyte apoptotic bodies, receptor activator of nuclear factor κ-B ligand (RANKL and soluble factors. Thus, our results indicate that osteocytes may have a role to play in the bone pathophysiology of GD.

Osteoclasts prefer aged bone

DEFF Research Database (Denmark)

Henriksen, K; Leeming, Diana Julie; Byrjalsen, I

2007-01-01

We investigated whether the age of the bones endogenously exerts control over the bone resorption ability of the osteoclasts, and found that osteoclasts preferentially develop and resorb bone on aged bone. These findings indicate that the bone matrix itself plays a role in targeted remodeling...... of aged bones....

Sphingosine 1-phosphate (S1P)/S1P receptor 1 signaling regulates receptor activator of NF-κB ligand (RANKL) expression in rheumatoid arthritis

International Nuclear Information System (INIS)

Takeshita, Harunori; Kitano, Masayasu; Iwasaki, Tsuyoshi; Kitano, Sachie; Tsunemi, Sachi; Sato, Chieri; Sekiguchi, Masahiro; Azuma, Naoto; Miyazawa, Keiji; Hla, Timothy; Sano, Hajime

2012-01-01

Highlights: ► MH7A cells and CD4 + T cells expressed S1P1 and RANKL. ► S1P increased RANKL expression in MH7A cells and CD4 + T cells. ► The effect of S1P in MH7A cells was inhibited by specific Gi/Go inhibitors. -- Abstract: Sphingosine 1-phosphate (S1P)/S1P receptor 1 (S1P1) signaling plays an important role in synovial cell proliferation and inflammatory gene expression by rheumatoid arthritis (RA) synoviocytes. The purpose of this study is to clarify the role of S1P/S1P1 signaling in the expression of receptor activator of NF-κB ligand (RANKL) in RA synoviocytes and CD4 + T cells. We demonstrated MH7A cells, a human RA synovial cell line, and CD4 + T cells expressed S1P1 and RANKL. Surprisingly, S1P increased RANKL expression in MH7A cells and CD4 + T cells in a dose-dependent manner. Moreover, S1P enhanced RANKL expression induced by stimulation with TNF-α in MH7A cells and CD4 + T cells. These effects of S1P in MH7A cells were inhibited by pretreatment with PTX, a specific Gi/Go inhibitor. These findings suggest that S1P/S1P1 signaling may play an important role in RANKL expression by MH7A cells and CD4 + T cells. S1P/S1P1 signaling of RA synoviocytes is closely connected with synovial hyperplasia, inflammation, and RANKL-induced osteoclastogenesis in RA. Thus, regulation of S1P/S1P1 signaling may become a novel therapeutic target for RA.

Sphingosine 1-phosphate (S1P)/S1P receptor 1 signaling regulates receptor activator of NF-{kappa}B ligand (RANKL) expression in rheumatoid arthritis

Energy Technology Data Exchange (ETDEWEB)

Takeshita, Harunori [Division of Rheumatology, Department of Internal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501 (Japan); Kitano, Masayasu, E-mail: mkitano6@hyo-med.ac.jp [Division of Rheumatology, Department of Internal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501 (Japan); Iwasaki, Tsuyoshi [Department of Pharmacy, Hyogo University of Health Sciences, 1-3-6 Minatojima Kobe, Hyogo 650-8530 (Japan); Kitano, Sachie; Tsunemi, Sachi; Sato, Chieri; Sekiguchi, Masahiro; Azuma, Naoto [Division of Rheumatology, Department of Internal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501 (Japan); Miyazawa, Keiji [Discovery Research III, Research and Development, Kissei Pharmaceutical Company, 4365-1 Hodakakashiwara, Azumino, Nagano 399-8304 (Japan); Hla, Timothy [Center for Vascular Biology, Department of Pathology and Laboratory Medicine, Weill Medical College of Cornell University, 1300 York Avenue, Box 69, NY 10065 (United States); Sano, Hajime [Division of Rheumatology, Department of Internal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501 (Japan)

2012-03-09

Highlights: Black-Right-Pointing-Pointer MH7A cells and CD4{sup +} T cells expressed S1P1 and RANKL. Black-Right-Pointing-Pointer S1P increased RANKL expression in MH7A cells and CD4{sup +} T cells. Black-Right-Pointing-Pointer The effect of S1P in MH7A cells was inhibited by specific Gi/Go inhibitors. -- Abstract: Sphingosine 1-phosphate (S1P)/S1P receptor 1 (S1P1) signaling plays an important role in synovial cell proliferation and inflammatory gene expression by rheumatoid arthritis (RA) synoviocytes. The purpose of this study is to clarify the role of S1P/S1P1 signaling in the expression of receptor activator of NF-{kappa}B ligand (RANKL) in RA synoviocytes and CD4{sup +} T cells. We demonstrated MH7A cells, a human RA synovial cell line, and CD4{sup +} T cells expressed S1P1 and RANKL. Surprisingly, S1P increased RANKL expression in MH7A cells and CD4{sup +} T cells in a dose-dependent manner. Moreover, S1P enhanced RANKL expression induced by stimulation with TNF-{alpha} in MH7A cells and CD4{sup +} T cells. These effects of S1P in MH7A cells were inhibited by pretreatment with PTX, a specific Gi/Go inhibitor. These findings suggest that S1P/S1P1 signaling may play an important role in RANKL expression by MH7A cells and CD4{sup +} T cells. S1P/S1P1 signaling of RA synoviocytes is closely connected with synovial hyperplasia, inflammation, and RANKL-induced osteoclastogenesis in RA. Thus, regulation of S1P/S1P1 signaling may become a novel therapeutic target for RA.

Protective protein/cathepsin A down-regulates osteoclastogenesis by associating with and degrading NF-kappaB p50/p65.

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Masuhara, Masaaki; Sato, Takuya; Hada, Naoto; Hakeda, Yoshiyuki

2009-01-01

Disruption of the cooperative function balance between osteoblasts and osteoclasts causes various bone disorders, some of which are attributed to abnormal osteoclast recruitment. Osteoclast differentiation is dependent on the receptor activator of nuclear factor (NF)-kappaB ligand (RANKL) as well as the macrophage colony-stimulating factor. The osteoclast formation induced by cytokines requires activation of NF-kappaB, AP-1 and nuclear factor of activated T cells c1. However, osteoclasts are not the only cell types that express these transcription factors, suggesting that some unknown molecules specific for osteoclasts may associate with the transcription factors. Here, we explored the possibility of molecules binding directly to NF-kappaB and cloned protective protein/cathepsin A (PPCA) by yeast two-hybrid screening using a cDNA library of osteoclast precursors. Forced expression of PPCA with p50/p65 in HEK293 cells decreased both the level of p50/p65 proteins and the transcriptional activity. Abundant PPCA was detected in the lysosomes of the transfected HEK293 cells, but a small amount of this enzyme was also present in the cytosolic fraction. In addition, over-expression of PPCA caused the disappearance of p50/p65 in both the lysosomal and cytosolic fractions. PPCA was expressed throughout osteoclastogenesis, and the expression was slightly up-regulated by RANKL signaling. Knockdown of PPCA in osteoclast precursors with PPCA siRNA stimulated binding of nuclear proteins to oligonucleotides containing an NF-kappaB binding motif and increased osteoclastogenesis. Our present results indicate a novel role for PPCA in osteoclastogenesis via down-regulation of NF-kappaB activity and suggest a new function for PPCA as an NF-kappaB-degrading enzyme in addition to its known multifunctional properties.

Effects of extracellular magnesium extract on the proliferation and differentiation of human osteoblasts and osteoclasts in coculture.

Science.gov (United States)

Wu, Lili; Feyerabend, Frank; Schilling, Arndt F; Willumeit-Römer, Regine; Luthringer, Bérengère J C

2015-11-01

Coculture of osteoblasts and osteoclasts is a subject of interest in the understanding of how magnesium (Mg)-based implants influence the bone metabolism and remodeling upon degradation. Human telomerase reverse transcriptase (hTERT) transduced mesenchymal stem cells (SCP-1) were first differentiated into osteoblasts with osteogenic supplements and then further cocultured with peripheral blood mononucleated cells (PBMC) without the addition of osteoclastogenesis promoting factors. Concomitantly, the cultures were exposed to variable Mg extract dilutions (0, 30×, 10×, 5×, 3×, 2× and 1×). Phenotype characterization documented that while 2× dilution of Mg extract was extremely toxic to osteoclast monoculture, monocytes in coculture with osteoblasts exhibited a greater tolerance to higher Mg extract concentration. The dense growth of osteoblasts in cultures with 1× dilution of Mg extract suggested that high concentration of Mg extract promoted osteoblast proliferation/differentiation behavior. The results of intracellular alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase (TRAP) activities as well as protein and gene expressions of receptor activator of nuclear factor kappa-B ligand (RANKL), macrophage colony-stimulating factor (M-CSF), and osteoclast-associated receptor (OSCAR) revealed significantly enhanced formation of osteoblasts whereas decreased osteoclastogenesis in the cultures with high concentrations of Mg extract (2× and 1× dilutions). In conclusion, while an increased osteoinductivity has been demonstrated, the impact of potentially decreased osteoclastogenesis around the Mg-based implants should be also taken into account. Cocultures containing both bone-forming osteoblasts and bone-resorbing osteoclasts should be preferentially performed for in vitro cytocompatibility assessment of Mg-based implants as they more closely mimic the in vivo environment. An attractive human osteoblasts and osteoclasts cocultivation regime was

Effect of Zn and Mg in tricalcium phosphate and in culture medium on apoptosis and actin ring formation of mature osteoclasts

International Nuclear Information System (INIS)

Li Xia; Ito, Atsuo; Sogo, Yu; Senda, Koji; Yamazaki, Atsushi

2008-01-01

This study investigated the resorptive activity of osteoclasts on tricalcium phosphate (TCP), zinc-containing tricalcium phosphate (ZnTCP) and magnesium-containing tricalcium phosphate (MgTCP) ceramics in different Zn- or Mg-containing culture media. On the TCP ceramic, an increase in Zn ions in the culture medium within the range between 0.3 and 6.8 ppm significantly induced an increase in osteoclast apoptosis and a decrease in actin ring formation. However, even a high level of Mg ions up to 100 ppm in the culture medium was unlikely to induce an increase in osteoclast apoptosis. Mg ions in the MgTCP ceramics have no effect on osteoclast apoptosis and actin ring formation. There was almost no significant difference in osteoclast apoptosis and actin ring formation between ZnTCP and MgTCP ceramics which have the same solubility and dissolution rates. It is indicated that only an increase in Zn level outside resorption lacuna has an inhibitory effect on osteoclast resorption and that an increase in Zn level inside resorption lacuna could not influence the osteoclast activity.

Role of miR-222-3p in c-Src-Mediated Regulation of Osteoclastogenesis

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Shinya Takigawa

2016-02-01

Full Text Available MicroRNAs (miRNAs are small non-coding RNAs that play a mostly post-transcriptional regulatory role in gene expression. Using RAW264.7 pre-osteoclast cells and genome-wide expression analysis, we identified a set of miRNAs that are involved in osteoclastogenesis. Based on in silico analysis, we specifically focused on miR-222-3p and evaluated its role in osteoclastogenesis. The results show that the inhibitor of miR-222-3p upregulated the mRNA levels of nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1 and tartrate-resistant acid phosphatase (TRAP, while its mimicking agent downregulated their mRNA levels. Western blot analysis showed that its inhibitor increased the protein levels of TRAP and cathepsin K, while its mimicking agent decreased their levels. Genome-wide mRNA expression analysis in the presence and absence of receptor activator of nuclear factor κ-B ligand (RANKL predicted c-Src as a potential regulatory target of miR-222-3p. Live cell imaging using a fluorescence resonance energy transfer (FRET technique revealed that miR-222-3p acted as an inhibitor of c-Src activity, and a partial silencing of c-Src suppressed RANKL-induced expression of TRAP and cathepsin K, as well as the number of multi-nucleated osteoclasts and their pit formation. Collectively, the study herein demonstrates that miR-222-3p serves as an inhibitor of osteoclastogenesis and c-Src mediates its inhibition of cathepsin K and TRAP.

Production and Functional Characterization of Murine Osteoclasts Differentiated from ER-Hoxb8-Immortalized Myeloid Progenitor Cells.

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Frank Zach

Full Text Available In vitro differentiation into functional osteoclasts is routinely achieved by incubation of embryonic stem cells, induced pluripotent stem cells, or primary as well as cryopreserved spleen and bone marrow-derived cells with soluble receptor activator of nuclear factor kappa-B ligand and macrophage colony-stimulating factor. Additionally, osteoclasts can be derived from co-cultures with osteoblasts or by direct administration of soluble receptor activator of nuclear factor kappa-B ligand to RAW 264.7 macrophage lineage cells. However, despite their benefits for osteoclast-associated research, these different methods have several drawbacks with respect to differentiation yields, time and animal consumption, storage life of progenitor cells or the limited potential for genetic manipulation of osteoclast precursors. In the present study, we therefore established a novel protocol for the differentiation of osteoclasts from murine ER-Hoxb8-immortalized myeloid stem cells. We isolated and immortalized bone marrow cells from wild type and genetically manipulated mouse lines, optimized protocols for osteoclast differentiation and compared these cells to osteoclasts derived from conventional sources. In vitro generated ER-Hoxb8 osteoclasts displayed typical osteoclast characteristics such as multi-nucleation, tartrate-resistant acid phosphatase staining of supernatants and cells, F-actin ring formation and bone resorption activity. Furthermore, the osteoclast differentiation time course was traced on a gene expression level. Increased expression of osteoclast-specific genes and decreased expression of stem cell marker genes during differentiation of osteoclasts from ER-Hoxb8-immortalized myeloid progenitor cells were detected by gene array and confirmed by semi-quantitative and quantitative RT-PCR approaches. In summary, we established a novel method for the quantitative production of murine bona fide osteoclasts from ER-Hoxb8 stem cells generated from

Two cases of breast carcinoma with osteoclastic giant cells: Are the osteoclastic giant cells pro-tumoural differentiation of macrophages?

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Shishido-Hara Yukiko

2010-08-01

Full Text Available Abstract Breast carcinoma with osteoclastic giant cells (OGCs is characterized by multinucleated OGCs, and usually displays inflammatory hypervascular stroma. OGCs may derive from tumor-associated macrophages, but their nature remains controversial. We report two cases, in which OGCs appear in common microenvironment despite different tumoural histology. A 44-year-old woman (Case 1 had OGCs accompanying invasive ductal carcinoma, and an 83-year-old woman (Case 2 with carcinosarcoma. Immunohistochemically, in both cases, tumoural and non-tumoural cells strongly expressed VEGF and MMP12, which promote macrophage migration and angiogenesis. The Chalkley count on CD-31-stained sections revealed elevated angiogenesis in both cases. The OGCs expressed bone-osteoclast markers (MMP9, TRAP, cathepsin K and a histiocyte marker (CD68, but not an MHC class II antigen, HLA-DR. The results indicate a pathogenesis: regardless of tumoural histology, OGCs derive from macrophages, likely in response to hypervascular microenvironments with secretion of common cytokines. The OGCs have acquired bone-osteoclast-like characteristics, but lost antigen presentation abilities as an anti-cancer defense. Appearance of OGCs may not be anti-tumoural immunological reactions, but rather pro-tumoural differentiation of macrophage responding to hypervascular microenvironments induced by breast cancer.

Osteoblast and osteoclast behaviors in the turnover of attachment bones during medaka tooth replacement.

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Mantoku, Akiko; Chatani, Masahiro; Aono, Kazushi; Inohaya, Keiji; Kudo, Akira

2016-01-15

Tooth replacement in polyphyodont is a well-organized system for maintenance of homeostasis of teeth, containing the dynamic structural change in skeletal tissues such as the attachment bone, which is the supporting element of teeth. Histological analyses have revealed the character of tooth replacement, however, the cellular mechanism of how skeletal tissues are modified during tooth replacement is largely unknown. Here, we showed the important role of osteoblasts for controlling osteoclasts to modify the attachment bone during tooth replacement in medaka pharyngeal teeth, coupled with an osterix-DsRed/TRAP-GFP transgenic line to visualize osteoblasts and osteoclasts. In the turnover of the row of attachment bones, these bones were resorbed at the posterior side where most developed functional teeth were located, and generated at the anterior side where teeth were newly erupted, which caused continuous tooth replacement. In the cellular analysis, osteoclasts and osteoblasts were located at attachment bones separately, since mature osteoclasts were localized at the resorbing side and osteoblasts gathered at the generating side. To demonstrate the role of osteoclasts in tooth replacement, we established medaka made deficient in c-fms-a by TALEN. c-fms-a deficient medaka showed hyperplasia of attachment bones along with reduced bone resorption accompanied by a low number of TRAP-positive osteoclasts, indicating an important role of osteoclasts in the turnover of attachment bones. Furthermore, nitroreductase-mediated osteoblast-specific ablation induced disappearance of osteoclasts, indicating that osteoblasts were essential for maintenance of osteoclasts for the proper turnover. Taken together, our results suggested that the medaka attachment bone provides the model to understand the cellular mechanism for tooth replacement, and that osteoblasts act in the coordination of bone morphology by supporting osteoclasts. Copyright © 2015 Elsevier Inc. All rights reserved.

Individual and combining effects of anti-RANKL monoclonal antibody and teriparatide in ovariectomized mice

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Naoto Tokuyama

2015-06-01

Full Text Available We examined the individual and combined effects of teriparatide and anti-RANKL (receptor activator of nuclear factor κB ligand monoclonal antibody in ovariectomized mice. Three-month-old female C57BL/6 mice were ovariectomized (OVX or sham operated. Four weeks after OVX, they were assigned to 3 different groups to receive anti-RANKL monoclonal antibody (Ab alone (5 mg/kg single injection at 4 weeks after OVX, Ab group, teriparatide alone (80 μg/kg daily injection for 4 weeks from 4 weeks after OVX, PTH group, or mAb plus teriparatide (Ab + PTH group. Mice were sacrificed 8 weeks after OVX. Bone mineral density (BMD was measured at the femur and lumbar spine. Hind limbs were subjected to histological and histomorphometric analysis. Serum osteocalcin and CTX-I levels were measured to investigate the bone turnover. Compared with Ab group, Ab + PTH group showed a significant increase in BMD at distal femur and femoral shaft. Cortical bone volume was significantly increased in PTH and Ab + PTH groups compared with Ab group. Bone turnover in Ab + PTH group was suppressed to the same degree as in Ab group. The number of TRAP-positive multinucleated cells was markedly reduced in Ab and Ab + PTH groups. These results suggest that combined treatment of teriparatide with anti-RANKL antibody has additive effects on BMD in OVX mice compared with individual treatment.

Potential of Resveratrol Analogues as Antagonists of Osteoclasts and Promoters of Osteoblasts

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Kupisiewicz, Katarzyna; Boissy, Patrice; Abdallah, Basem M

2010-01-01

The plant phytoalexin resveratrol was previously demonstrated to inhibit the differentiation and bone resorbing activity of osteoclasts, to promote the formation of osteoblasts from mesenchymal precursors in cultures, and inhibit myeloma cell proliferation, when used at high concentrations....... In the current study, we screened five structurally modified resveratrol analogues for their ability to modify the differentiation of osteoclasts and osteoblasts and proliferation of myeloma cells. Compared to resveratrol, analogues showed an up to 5,000-fold increased potency to inhibit osteoclast...... differentiation. To a lesser extent, resveratrol analogues also promoted osteoblast maturation. However, they did not antagonize the proliferation of myeloma cells. The potency of the best-performing candidate in vitro was tested in vivo in an ovariectomy-induced model of osteoporosis, but an effect on bone loss...

Intercellular calcium signaling occurs between human osteoblasts and osteoclasts and requires activation of osteoclast P2X7 receptors

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Jørgensen, Niklas R; Henriksen, Zanne; Sørensen, Ole

2002-01-01

that human osteoclasts expressed functional P2Y1 receptors, but, unexpectedly, desensitization of P2Y1 did not block calcium signaling to osteoclasts. We also found that osteoclasts expressed functional P2X7 receptors and showed that pharmacological inhibition of these receptors blocked calcium signaling...

Matrix metalloproteinase-12 (MMP-12) in osteoclasts

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Hou, Peng; Troen, Tine; Ovejero, Maria C

2004-01-01

Osteoclasts require matrix metalloproteinase (MMP) activity and cathepsin K to resorb bone, but the critical MMP has not been identified. Osteoclasts express MMP-9 and MMP-14, which do not appear limiting for resorption, and the expression of additional MMPs is not clear. MMP-12, also called...... bone show MMP-12 expression in osteoclasts in calvariae and long bones. We also demonstrate that recombinant MMP-12 cleaves the putative functional domains of osteopontin and bone sialoprotein, two bone matrix proteins that strongly influence osteoclast activities, such as attachment, spreading...

Effects of total flavonoids from Drynariae Rhizoma prevent bone loss in vivo and in vitro

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Shuang-hong Song

2016-12-01

Full Text Available Estrogen deficiency is one of the major causes of osteoporosis in postmenopausal women. Drynariae Rhizoma is a widely used traditional Chinese medicine for the treatment of bone diseases. In this study, we investigated the therapeutic effects of the total Drynariae Rhizoma flavonoids (DRTF on estrogen deficiency-induced bone loss using an ovariectomized rat model and osteoblast-like MC3T3-E1 cells. Our results indicated that DRTF produced osteo-protective effects on the ovariectomized rats in terms of bone loss reduction, including decreased levels of bone turnover markers, enhanced biomechanical femur strength and trabecular bone microarchitecture deterioration prevention. In vitro experiments revealed that the actions of DRTF on regulating osteoblastic activities were mediated by the estrogen receptor (ER dependent pathway. Our data also demonstrated that DRTF inhibited osteoclastogenesis via up-regulating osteoprotegrin (OPG, as well as down-regulating receptor activator of NF–κB ligand (RANKL expression. In conclusion, this study indicated that DRTF treatment effectively suppressed bone mass loss in an ovariectomized rat model, and in vitro evidence suggested that the effects were exerted through actions on both osteoblasts and osteoclasts. Keywords: Osteoporosis, Osteoblast, Osteoclast, Ovariectomy, Drynariae Rhizoma

Targeted deletion of RANKL in M cell inducer cells by the Col6a1-Cre driver.

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Nagashima, Kazuki; Sawa, Shinichiro; Nitta, Takeshi; Prados, Alejandro; Koliaraki, Vasiliki; Kollias, George; Nakashima, Tomoki; Takayanagi, Hiroshi

2017-11-04

The gut-associated lymphoid tissues (GALTs), including Peyer's patches (PPs), cryptopatches (CPs) and isolated lymphoid follicles (ILFs), establish a host-microbe symbiosis by the promotion of immune reactions against gut microbes. Microfold cell inducer (MCi) cells in GALTs are the recently identified mesenchymal cells that express the cytokine RANKL and initiate bacteria-specific immunoglobulin A (IgA) production via induction of microfold (M) cell differentiation. In the previous study, the Twist2-Cre driver was utilized for gene deletion in mesenchymal cells including MCi cells. In order to investigate MCi cells more extensively, it will be necessary to develop experimental tools in addition to the Twist2-Cre driver mice and characterize such drivers in specificity and efficiency. Here we show that M cell differentiation and IgA production are impaired in the targeted deletion of RANKL by the Col6a1-Cre driver. We compared Col6a1-Cre with Twist2-Cre in terms of the specificity for mesenchymal cells in GALTs. Col6a1-Cre CAG-CAT-EGFP mice exhibited EGFP expression in podoplanin + CD31 - cells including MCi cells, while Twist2-Cre mice were shown to target endothelial cells and podoplanin + CD31 - cells. Tnfsf11 fl/Δ Col6a1-Cre mice exhibited the absence of M cells and severe IgA reduction together with an alteration in gut microbial composition. Moreover, we analyzed germ free mice to test whether changes in the microbiota are the cause of M cell deficiency. M cell differentiation was normal in the CPs/ILFs of germ free mice, indicating that MCi cells induce M cells independently of microbial colonization. This study demonstrates that Col6a1-Cre driver mice are as useful as Twist2-Cre driver mice for functional analyses of GALT-resident mesenchymal cells, including MCi cells. Copyright © 2017 Elsevier Inc. All rights reserved.

The elementary fusion modalities of osteoclasts

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Søe, Kent; Hobolt-Pedersen, Anne Sofie; Delaisse, Jean Marie

2015-01-01

, are not known for the osteoclast. Here we show that osteoclast fusion partners are characterized by differences in mobility, nuclearity, and differentiation level. Our demonstration was based on time-laps videos of human osteoclast preparations from three donors where 656 fusion events were analyzed. Fusions......The last step of the osteoclast differentiation process is cell fusion. Most efforts to understand the fusion mechanism have focused on the identification of molecules involved in the fusion process. Surprisingly, the basic fusion modalities, which are well known for fusion of other cell types...... between a mobile and an immobile partner were most frequent (62%), while fusion between two mobile (26%) or two immobile partners (12%) was less frequent (p fusion partner contained more nuclei than the mobile one (p

Hwangryun-Haedok-Tang Fermented with Lactobacillus casei Suppresses Ovariectomy-Induced Bone Loss

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Ki-Shuk Shim

2012-01-01

Full Text Available Hwangryun-haedok-tang (HRT is the common recipe in traditional Asian medicine, and microbial fermentation is used for the conventional methods for processing traditional medicine. We investigated the inhibitory effect of the n-butanol fraction of HRT (HRT-BU and fHRT (fHRT-BU on the RANKL-induced osteoclastogenesis in bone-marrow-derived macrophages. mRNA expression of osteoclastogenesis-related genes were evaluated by real-time QPCR. The activation of signaling pathways was determined by western blot analysis. The marker compounds of HRT-BU and fHRT-BU were analyzed by HPLC. The inhibitory effect of HRT or fHRT on ovariectomy-induced bone loss were evaluated using OVX rats with orally administered HRT, fHRT (300, 1000 mg/kg, or its vehicle for 12 weeks. fHRT-BU significantly inhibited RANKL-induced osteoclastogenesis, and phosphorylation of p38, IKKα/β, and NF-κBp65 compared to HRT-BU. In addition, fHRT-BU also significantly inhibited the mRNA expression of Nfκb2, TNF-α, NFATc1, TRAP, ATPv0d2, and cathepsin K. Furthermore, administration of fHRT had a greater effect on the increase of BMD, and greater improved bone microstructure of the femora than that of HRT in ovariectomy rats. This study demonstrated that bacterial fermentation enhances the inhibitory effect of HRT on osteoclastogenesis and bone loss. These results suggest that fermented HRT might have the beneficial effects on bone disease by inhibiting osteoclastogenesis.

Dlx homeobox gene family expression in osteoclasts.

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Lézot, F; Thomas, B L; Blin-Wakkach, C; Castaneda, B; Bolanos, A; Hotton, D; Sharpe, P T; Heymann, D; Carles, G F; Grigoriadis, A E; Berdal, A

2010-06-01

Skeletal growth and homeostasis require the finely orchestrated secretion of mineralized tissue matrices by highly specialized cells, balanced with their degradation by osteoclasts. Time- and site-specific expression of Dlx and Msx homeobox genes in the cells secreting these matrices have been identified as important elements in the regulation of skeletal morphology. Such specific expression patterns have also been reported in osteoclasts for Msx genes. The aim of the present study was to establish the expression patterns of Dlx genes in osteoclasts and identify their function in regulating skeletal morphology. The expression patterns of all Dlx genes were examined during the whole osteoclastogenesis using different in vitro models. The results revealed that Dlx1 and Dlx2 are the only Dlx family members with a possible function in osteoclastogenesis as well as in mature osteoclasts. Dlx5 and Dlx6 were detected in the cultures but appear to be markers of monocytes and their derivatives. In vivo, Dlx2 expression in osteoclasts was examined using a Dlx2/LacZ transgenic mouse. Dlx2 is expressed in a subpopulation of osteoclasts in association with tooth, brain, nerve, and bone marrow volumetric growths. Altogether the present data suggest a role for Dlx2 in regulation of skeletal morphogenesis via functions within osteoclasts. (c) 2010 Wiley-Liss, Inc.

BMI-1 Mediates Estrogen-Deficiency-Induced Bone Loss by Inhibiting Reactive Oxygen Species Accumulation and T Cell Activation.

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Li, Jinbo; Wang, Qian; Yang, Renlei; Zhang, Jiaqi; Li, Xing; Zhou, Xichao; Miao, Dengshun

2017-05-01

Previous studies have shown that estrogen regulates bone homeostasis through regulatory effects on oxidative stress. However, it is unclear how estrogen deficiency triggers reactive oxygen species (ROS) accumulation. Recent studies provide evidence that the B lymphoma Mo-MLV insertion region 1 (BMI-1) plays a critical role in protection against oxidative stress and that this gene is directly regulated by estrogen via estrogen receptor (ER) at the transcriptional level. In this study, ovariectomized mice were given drinking water with/without antioxidant N-acetyl-cysteine (NAC, 1 mg/mL) supplementation, and compared with each other and with sham mice. Results showed that ovariectomy resulted in bone loss with increased osteoclast surface, increased ROS levels, T cell activation, and increased TNF and RANKL levels in serum and in CD4 T cells; NAC supplementation largely prevented these alterations. BMI-1 expression levels were dramatically downregulated in CD4 T cells from ovariectomized mice. We supplemented drinking water to BMI-1-deficient mice with/without NAC and compared them with each other and with wild-type (WT) mice. We found that BMI-1 deficiency mimicked alterations observed in ovariectomy whereas NAC supplementation reversed all alterations induced by BMI-1 deficiency. Because T cells are critical in mediating ovariectomy-induced bone loss, we further assessed whether BMI-1 overexpression in lymphocytes can protect against estrogen deficiency-induced osteoclastogenesis and bone loss by inhibiting oxidative stress, T cell activation, and RANKL production. When WT and Eμ-BMI-1 transgenic mice with BMI-1 specifically overexpressed in lymphocytes were ovariectomized and compared with each other and with WT sham mice, we found that BMI-1 overexpression in lymphocytes clearly reversed all alterations induced by ovariectomy. Results from this study indicate that estrogen deficiency downregulates BMI-1 and subsequently increases ROS, T cell activation, and

Osteoclast differentiation inhibitors: a patent review (2008 - 2012).

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Kim, Seong Hwan; Moon, Seong-Hee

2013-12-01

Mononuclear macrophage/monocyte-lineage hematopoietic precursors differentiate into multinucleated osteoclasts. Abnormally increased numbers and/or overactivation of osteoclasts can lead to bone loss. Therefore, pharmaceutical inhibition of osteoclast differentiation is one therapeutic strategy for mitigating the occurrence of bone loss-associated disorders and related fractures. This review surveys the patents and patent applications from 2008 to 2012 that are related to inventions of therapeutics and/or methods for inhibiting osteoclast differentiation. Over the past 20 years, the identification and validation of signaling molecules involved in osteoclast differentiation has led to a better understanding of the molecular mechanism, and to the development of new therapeutic agents for treating bone loss-associated disorders. Since 2008, 34 WO patents or patent applications have been filed that relate to inventions of therapeutics and/or methods for chemical-based, natural product-based, or biological-based inhibitors of osteoclast differentiation. Here, analysis of these patents and patent applications is presented, and summarize the disclosed osteoclast differentiation-inhibiting target molecules. This report can support further advances in the development of anti-osteoclastogenic therapeutics for bone loss-associated disorders, including osteoporosis, rheumatoid arthritis, Paget's disease, periodontal disease, osteosarcoma, and cancer bone metastasis.

Experimental Study on the Effect of Calcitonin in Osteoporosis Induced by the Immobilization and Long-Term Glucocorticoid

International Nuclear Information System (INIS)

Park, Dong Jin; Lee, Sang Rae

1989-01-01

It is well known that the glucocorticoid induces osteoporosis by suppression of the osteoblast, but its effect on the osteoclast has some controversy whether it activates or suppresses the osteoclast. If the calcitonin, which is known to suppress the osteoclast, prevents the osteoporosis by glucocorticoid, then the suppression of the osteoclast by the glucocorticoid is not so significant. And if the calcitonin increases the osteoblastic activity, Tc-99m MDP uptake will be increased in spite of the glucocorticoid effect on the osteoblast. The immobilization operation was performed to the right leg of male Wistar rats weighing about 200 gm each. For 16 weeks after operation, rats were injected glucocorticoid alone or glucocorticoid and calcitonin. The bone density was measured by means of photodensitometry under reference aluminum step wedge and Tc-99m MDP uptake was available to the index of the osteoblastic activity. 1. The bone density of femoral head was markedly reduced than that of femoral shaft following ratio of cancellous and cortical components in both site. 2. glucocorticoid caused decrease in bone density of spine and femur, and there is significantly increase of it when medication of glucocorticoid and calcitonin injection simultaneously than that of glucocorticoid. 3. Tc-99m MDP uptake was revealed significant reduction in medication of glucocorticoid but increase in glucocorticoid and calcitonin injection simultaneously in later experimental period. 4. There was a slight reduction in plasma osteocalcin in medication of glucocorticoid through experimental periods and an increase in its value in case of giving glucocorticoid and calcitonin simultaneously in later experimental period. From these results, we suggest that osteoporosis by immobilization is more pronounced by glucocorticoid hormone and osteoporosis induced by immobilization and glucocorticoid use is prevented by calcitonin administration with increasing osteoblastic activity.

Effect of vibration on osteoblastic and osteoclastic activities: Analysis of bone metabolism using goldfish scale as a model for bone

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Suzuki, N.; Kitamura, K.; Nemoto, T.; Shimizu, N.; Wada, S.; Kondo, T.; Tabata, M. J.; Sodeyama, F.; Ijiri, K.; Hattori, A.

In osteoclastic activity during space flight as well as hind limb unloading by tail suspension, inconsistent results have been reported in an in vivo study. The bone matrix plays an important role in the response to physical stress. However, there is no suitable in vitro co-culture system of osteoblasts and osteoclasts including bone matrix. On the other hand, fish scale is a calcified tissue that contains osteoblasts, osteoclasts, and bone matrix, all of which are similar to those found in human bones. Recently, we developed a new in vitro model system using goldfish scale. This system can detect the activities of osteoclasts and osteoblasts with tartrate-resistant acid phosphatase and alkaline phosphatase as the respective markers and precisely analyze the co-relationship between osteoblasts and osteoclasts. Using this system, we analyzed the bone metabolism under various degrees of acceleration (0.5-, 1-, 2-, 4-, and 6-G) by vibration with a G-load apparatus. After loading for 5 and 10 min, the scales were incubated for 6 and 24 h. The osteoblastic and osteoclastic activities were then measured. The osteoblastic activities gradually increased corresponding to 1-G to 6-G acceleration. In addition, ER mRNA expression was the highest under 6-G acceleration. On the other hand, the osteoclastic activity decreased at 24 h of incubation under low acceleration (0.5- and 1-G). This change coincided with TRAP mRNA expression. Under 2-G acceleration, the strength of suppression in osteoclastic activity was the highest. The strength of the inhibitory action under 4- and 6-G acceleration was lower than that under 2-G acceleration. In our co-culture system, osteoblasts and osteoclasts in the scale sensitively responded to several degrees of acceleration. Therefore, we strongly believe that our in vitro co-culture system is useful for the analysis of bone metabolism under loading or unloading.

Cold suppresses agonist-induced activation of TRPV1.

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Chung, M-K; Wang, S

2011-09-01

Cold therapy is frequently used to reduce pain and edema following acute injury or surgery such as tooth extraction. However, the neurobiological mechanisms of cold therapy are not completely understood. Transient receptor potential vanilloid 1 (TRPV1) is a capsaicin- and heat-gated nociceptive ion channel implicated in thermosensation and pathological pain under conditions of inflammation or injury. Although capsaicin-induced nociception, neuropeptide release, and ionic currents are suppressed by cold, it is not known if cold suppresses agonist-induced activation of recombinant TRPV1. We demonstrate that cold strongly suppressed the activation of recombinant TRPV1 by multiple agonists and capsaicin-evoked currents in trigeminal ganglia neurons under normal and phosphorylated conditions. Cold-induced suppression was partially impaired in a TRPV1 mutant that lacked heat-mediated activation and potentiation. These results suggest that cold-induced suppression of TRPV1 may share a common molecular basis with heat-induced potentiation, and that allosteric inhibition may contribute, in part, to the cold-induced suppression. We also show that combination of cold and a specific antagonist of TRPV1 can produce an additive suppression. Our results provide a mechanistic basis for cold therapy and may enhance anti-nociceptive approaches that target TRPV1 for managing pain under inflammation and tissue injury, including that from tooth extraction.

Osteoprotegerin inhibits bone resorption and prevents tumor development in a xenogenic model of Ewing's sarcoma by inhibiting RANKL

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Picarda, Gaëlle; Matous, Etienne; Amiaud, Jérôme; Charrier, Céline; Lamoureux, François; Heymann, Marie-Françoise; Tirode, Franck; Pitard, Bruno; Trichet, Valérie; Heymann, Dominique; Redini, Françoise

2013-01-01

Ewing's sarcoma (ES) associated with high osyeolytic lesions typically arises in the bones of children and adolescents. The development of multi-disciplinary therapy has increased current long-term survival rates to greater than 50% but only 20% for high risk group patients (relapse, metastases, etc.). Among new therapeutic approaches, osteoprotegerin (OPG), an anti-bone resorption molecule may represent a promising candidate to inhibit RANKL-mediated osteolytic component of ES and consequently to limit the tumor development. Xenogenic orthotopic models of Ewing's sarcoma were induced by intra-osseous injection of human TC-71 ES cells. OPG was administered in vivo by non-viral gene transfer using an amphiphilic non ionic block copolymer. ES bearing mice were assigned to controls (no treatment, synthetic vector alone or F68/empty pcDNA3.1 plasmid) and hOPG treated groups. A substantial but not significant inhibition of tumor development was observed in the hOPG group as compared to control groups. Marked bone lesions were revealed by micro-computed tomography analyses in control groups whereas a normal bone micro-architecture was preserved in the hOPG treated group. RANKL over-expressed in ES animal model was expressed by tumor cells rather than by host cells. However, TRAIL present in the tumor microenvironment may interfere with OPG effect on tumor development and bone remodeling via RANKL inhibition. In conclusion, the use of a xenogenic model of Ewing's sarcoma allowed discriminating between the tumor and host cells responsible for the elevation of RANKL production observed in this tumor and demonstrated the relevance of blocking RANKL by OPG as a promising therapy in ES. PMID:26909278

Glucocorticoid Signaling and Bone Biology.

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Komori, T

2016-11-01

Since glucocorticoids remain an effective therapeutic option for the treatment of many inflammatory and autoimmune diseases, glucocorticoid-induced osteoporosis is the most common form of secondary osteoporosis. Fractures may occur in as many as 30-50% of patients receiving chronic glucocorticoid therapy. Under physiological conditions, glucocorticoids are required for normal bone development due to their regulation of osteoblast differentiation, possibly via the Wnt/β-catenin pathway and TSC22D3. However, serum levels of endogenous corticosterone are elevated in aged mice and glucocorticoids exert negative effects on the survival of osteoblasts and osteocytes as well as angiogenesis. Glucocorticoid treatments impair bone formation and enhance bone resorption. Excess glucocorticoids induce osteoblast and osteocyte apoptosis by increasing pro-apoptotic molecules, reactive oxygen species, and endoplasmic reticulum stress and suppressing the Wnt/β-catenin pathway. Autophagy protects osteocytes from glucocorticoid-induced apoptosis, but passed some threshold, the process of autophagy leads the cells to apoptosis. Excess glucocorticoids impair osteoblastogenesis by inducing Wnt antagonists, including Dkk1, Sost, and sFRP-1. However, the findings are controversial and the involvement of Wnt antagonists requires further study. Excess glucocorticoids reduce the phosphorylation of Akt and GSK3β, which enhances the degradation of β-catenin. Excess glucocorticoids have been shown to modulate the expression of miRNAs, including miR-29a, miR-34a-5p, and miR-199a-5p, which regulate the proliferation and differentiation of osteoblast lineage cells. Excess glucocorticoids also enhance bone resorption by reducing OPG expression, increasing Rankl expression and reactive oxygen species, and prolonging the life span of osteoclasts; however, they also suppress the bone-degrading capacity of osteoclasts by disturbing the organization of the cytoskeleton. © Georg Thieme Verlag KG

[Separation of osteoclasts by lectin affinity chromatography].

Science.gov (United States)

Itokazu, M; Tan, A; Tanaka, S

1991-09-01

Newborn rat calvaria bone cells obtained by digestion were fractionated on columns of wheat-germ agglutinin (WGA) sepharose 6MB for osteoclast isolation. The initial nonspecific binding cells which were passed through the WGA sepharose column by a buffer acquired a high enzyme activity of alkaline phosphatase, but not that of acid phosphatase. However, elution of cells using a buffer with the addition of N-acetyl-D-glucosamine resulted in a high acid phosphatase activity but no alkaline phosphatase activity. The former WGA binding negative fraction enriched osteoblasts averaging 30 microns in size. The latter WGA binding positive fraction enriched osteoclasts ranging from 20 microns to 60 microns in size. The electron-microscope clearly demonstrated the cellular details of osteoclasts. Isolated cell counts showed a ratio of six to four. These results indicate that our method of osteoclast isolation is simple and useful in lectin affinity chromatography because all cells have sugar moieties on their surface and the binding of osteoclasts can be reversed by the addition of specific lectin-binding sugars to the eluting buffer.

Biocorrosion and uptake of titanium by human osteoclasts.

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Cadosch, Dieter; Al-Mushaiqri, Mohamed S; Gautschi, Oliver P; Meagher, James; Simmen, Hans-Peter; Filgueira, Luis

2010-12-15

All metals in contact with a biological system undergo corrosion through an electrochemical redox reaction. This study investigated whether human osteoclasts (OC) are able to grow on titanium and aluminum, and directly corrode the metals leading to the release of corresponding metal ions, which are believed to cause inflammatory reactions and activate osteoclastic differentiation. Scanning electron microscopy analysis demonstrated long-term viable OC cultures on the surface of titanium and aluminum foils. Atomic emission spectrometry investigations showed significantly increased levels of aluminum in the supernatant of OC cultured on aluminum; however, all measurements in the supernatants of cell cultures on titanium were below detection limits. Despite this, confocal microscopy analysis with Newport Green DCF diacetate ester staining depicted intense fluorescence throughout the cytoplasm and nucleolus of OC cultured on titanium foils. Comparable fluorescence intensities were not observed in monocytes and control cells cultured on glass. The present study demonstrated that human osteoclast precursors are able to grow and differentiate toward mature OC on titanium and aluminum. Furthermore, it established that the mature cells are able to directly corrode the metal surface and take up corresponding metal ions, which subsequently may be released and thereby induce the formation of osteolytic lesions in the periprosthetic bone, contributing to the loosening of the implant. Copyright © 2010 Wiley Periodicals, Inc.

Effect of Cytokines on Osteoclast Formation and Bone Resorption during Mechanical Force Loading of the Periodontal Membrane

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Hideki Kitaura

2014-01-01

Full Text Available Mechanical force loading exerts important effects on the skeleton by controlling bone mass and strength. Several in vivo experimental models evaluating the effects of mechanical loading on bone metabolism have been reported. Orthodontic tooth movement is a useful model for understanding the mechanism of bone remodeling induced by mechanical loading. In a mouse model of orthodontic tooth movement, TNF-α was expressed and osteoclasts appeared on the compressed side of the periodontal ligament. In TNF-receptor-deficient mice, there was less tooth movement and osteoclast numbers were lower than in wild-type mice. These results suggest that osteoclast formation and bone resorption caused by loading forces on the periodontal ligament depend on TNF-α. Several cytokines are expressed in the periodontal ligament during orthodontic tooth movement. Studies have found that inflammatory cytokines such as IL-12 and IFN-γ strongly inhibit osteoclast formation and tooth movement. Blocking macrophage colony-stimulating factor by using anti-c-Fms antibody also inhibited osteoclast formation and tooth movement. In this review we describe and discuss the effect of cytokines in the periodontal ligament on osteoclast formation and bone resorption during mechanical force loading.

Nanocrystallinity effects on osteoblast and osteoclast response to silicon substituted hydroxyapatite.

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Casarrubios, Laura; Matesanz, María Concepción; Sánchez-Salcedo, Sandra; Arcos, Daniel; Vallet-Regí, María; Portolés, María Teresa

2016-11-15

Silicon substituted hydroxyapatites (SiHA) are highly crystalline bioceramics treated at high temperatures (about 1200°C) which have been approved for clinical use with spinal, orthopedic, periodontal, oral and craniomaxillofacial applications. The preparation of SiHA with lower temperature methods (about 700°C) provides nanocrystalline SiHA (nano-SiHA) with enhanced bioreactivity due to higher surface area and smaller crystal size. The aim of this study has been to know the nanocrystallinity effects on the response of both osteoblasts and osteoclasts (the two main cell types involved in bone remodelling) to silicon substituted hydroxyapatite. Saos-2 osteoblasts and osteoclast-like cells (differentiated from RAW-264.7 macrophages) have been cultured on the surface of nano-SiHA and SiHA disks and different cell parameters have been evaluated: cell adhesion, proliferation, viability, intracellular content of reactive oxygen species, cell cycle phases, apoptosis, cell morphology, osteoclast-like cell differentiation and resorptive activity. This comparative in vitro study evidences that nanocrystallinity of SiHA affects the cell/biomaterial interface inducing bone cell apoptosis by loss of cell anchorage (anoikis), delaying osteoclast-like cell differentiation and decreasing the resorptive activity of this cell type. These results suggest the potential use of nano-SiHA biomaterial for preventing bone resorption in treatment of osteoporotic bone. Copyright © 2016 Elsevier Inc. All rights reserved.

Steering the osteoclast through the demineralization-collagenolysis balance

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Søe, Kent; Merrild, Ditte Marie Horslev; Delaissé, Jean-Marie

2013-01-01

are generated when collagen degradation is slower than demineralization, and trenches when collagen degradation is as fast as demineralization. Next we treated the osteoclasts with a low dose of a carbonic anhydrase inhibitor to slightly decrease the rate of demineralization, thereby allowing collagen......, forming a pit, and continues parallel to the bone surface, forming a trench. Importantly, we show that the progress of the osteoclast along this route depends on the balance between the rate of collagenolysis and demineralization. We propose that the osteocytes and bone lining cells surrounding...... the osteoclast may act on this balance to steer the osteoclast resorptive activity in order to give the excavations a specific shape....

P2X7 receptor regulates osteoclast function and bone loss in a mouse model of osteoporosis

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Wang, Ning; Agrawal, Ankita; Jørgensen, Niklas Rye

2018-01-01

Post-menopausal osteoporosis is a condition that affects millions worldwide and places a huge socio-economic burden on society. Previous research has shown an association of loss of function SNPs in the gene for the purinergic receptor P2X7R with low bone mineral density, increased rates of bone...... loss and vertebral fractures in post-menopausal women. In this study we use a mouse model of oestrogen deficiency-induced bone loss and the BALB/cJ P2X7R-/- to show that absence of the P2X7R resulted in increased bone loss. Osteoclast precursors were isolated from both BALB/cJ P2X7R-/- and BALB/cJ P2X7......R+/+ mice and then cultured in vitro to form mature resorbing osteoclasts. The BALB/cJ P2X7R-/- derived precursors generated slightly more osteoclasts but with a significant reduction in the amount of resorption per osteoclast. Furthermore, when using modified culture conditions osteoclast activity...

Hedgehog signaling in tumor cells facilitates osteoblast-enhanced osteolytic metastases.

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Shamik Das

Full Text Available The remodeling process in bone yields numerous cytokines and chemokines that mediate crosstalk between osteoblasts and osteoclasts and also serve to attract and support metastatic tumor cells. The metastatic tumor cells disturb the equilibrium in bone that manifests as skeletal complications. The Hedgehog (Hh pathway plays an important role in skeletogenesis. We hypothesized that the Hh pathway mediates an interaction between tumor cells and osteoblasts and influences osteoblast differentiation in response to tumor cells. We have determined that breast tumor cells have an activated Hh pathway characterized by upregulation of the ligand, IHH and transcription factor GLI1. Breast cancer cells interact with osteoblasts and cause an enhanced differentiation of pre-osteoblasts to osteoblasts that express increased levels of the osteoclastogenesis factors, RANKL and PTHrP. There is sustained expression of osteoclast-promoting factors, RANKL and PTHrP, even after the osteoblast differentiation ceases and apoptosis sets in. Moreover, tumor cells that are deficient in Hh signaling are compromised in their ability to induce osteoblast differentiation and consequently are inefficient in causing osteolysis. The stimulation of osteoblast differentiation sets the stage for osteoclast differentiation and overall promotes osteolysis. Thus, in the process of developing newer therapeutic strategies against breast cancer metastasis to bone it would worthwhile to keep in mind the role of the Hh pathway in osteoblast differentiation in an otherwise predominant osteolytic phenomenon.

Disruption of the Cx43/miR21 pathway leads to osteocyte apoptosis and increased osteoclastogenesis with aging.

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Davis, Hannah M; Pacheco-Costa, Rafael; Atkinson, Emily G; Brun, Lucas R; Gortazar, Arancha R; Harris, Julia; Hiasa, Masahiro; Bolarinwa, Surajudeen A; Yoneda, Toshiyuki; Ivan, Mircea; Bruzzaniti, Angela; Bellido, Teresita; Plotkin, Lilian I

2017-06-01

Skeletal aging results in apoptosis of osteocytes, cells embedded in bone that control the generation/function of bone forming and resorbing cells. Aging also decreases connexin43 (Cx43) expression in bone; and osteocytic Cx43 deletion partially mimics the skeletal phenotype of old mice. Particularly, aging and Cx43 deletion increase osteocyte apoptosis, and osteoclast number and bone resorption on endocortical bone surfaces. We examined herein the molecular signaling events responsible for osteocyte apoptosis and osteoclast recruitment triggered by aging and Cx43 deficiency. Cx43-silenced MLO-Y4 osteocytic (Cx43 def ) cells undergo spontaneous cell death in culture through caspase-3 activation and exhibit increased levels of apoptosis-related genes, and only transfection of Cx43 constructs able to form gap junction channels reverses Cx43 def cell death. Cx43 def cells and bones from old mice exhibit reduced levels of the pro-survival microRNA miR21 and, consistently, increased levels of the miR21 target phosphatase and tensin homolog (PTEN) and reduced phosphorylated Akt, whereas PTEN inhibition reduces Cx43 def cell apoptosis. miR21 reduction is sufficient to induce apoptosis of Cx43-expressing cells and miR21 deletion in miR21 fl/fl bones increases apoptosis-related gene expression, whereas a miR21 mimic prevents Cx43 def cell apoptosis, demonstrating that miR21 lies downstream of Cx43. Cx43 def cells release more osteoclastogenic cytokines [receptor activator of NFκB ligand (RANKL)/high-mobility group box-1 (HMGB1)], and caspase-3 inhibition prevents RANKL/HMGB1 release and the increased osteoclastogenesis induced by conditioned media from Cx43 def cells, which is blocked by antagonizing HMGB1-RAGE interaction. These findings identify a novel Cx43/miR21/HMGB1/RANKL pathway involved in preventing osteocyte apoptosis that also controls osteoclast formation/recruitment and is impaired with aging. © 2017 The Authors. Aging Cell published by the Anatomical Society

Myeloma cell-induced disruption of bone remodelling compartments leads to osteolytic lesions and generation of osteoclast-myeloma hybrid cells

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Andersen, Thomas L; Søe, Kent; Søndergaard, Teis Esben

2010-01-01

on the physical organisation of the myeloma cell microenvironment. The proximity between myeloma cells and osteoclasts or osteoblasts was shown to be conditioned by the recently discovered layer of flat cells that separates the osteoclasts and osteoblasts from the bone marrow, by forming a canopy over bone...

The Role of Hedgehog Signaling in Tumor Induced Bone Disease

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Shellese A. Cannonier

2015-08-01

Full Text Available Despite significant progress in cancer treatments, tumor induced bone disease continues to cause significant morbidities. While tumors show distinct mutations and clinical characteristics, they behave similarly once they establish in bone. Tumors can metastasize to bone from distant sites (breast, prostate, lung, directly invade into bone (head and neck or originate from the bone (melanoma, chondrosarcoma where they cause pain, fractures, hypercalcemia, and ultimately, poor prognoses and outcomes. Tumors in bone secrete factors (interleukins and parathyroid hormone-related protein that induce RANKL expression from osteoblasts, causing an increase in osteoclast mediated bone resorption. While the mechanisms involved varies slightly between tumor types, many tumors display an increase in Hedgehog signaling components that lead to increased tumor growth, therapy failure, and metastasis. The work of multiple laboratories has detailed Hh signaling in several tumor types and revealed that tumor establishment in bone can be controlled by both canonical and non-canonical Hh signaling in a cell type specific manner. This review will explore the role of Hh signaling in the modulation of tumor induced bone disease, and will shed insight into possible therapeutic interventions for blocking Hh signaling in these tumors.

The Role of Hedgehog Signaling in Tumor Induced Bone Disease

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Cannonier, Shellese A.; Sterling, Julie A., E-mail: Julie.sterling@vanderbilt.edu [Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN 37235 (United States); Vanderbilt Center for Bone Biology, Department of Medicine, Division of Clinical Pharmacology Vanderbilt University, Nashville, TN 372335 (United States); Department of Cancer Biology, Vanderbilt University, Nashville, TN 37235 (United States)

2015-08-26

Despite significant progress in cancer treatments, tumor induced bone disease continues to cause significant morbidities. While tumors show distinct mutations and clinical characteristics, they behave similarly once they establish in bone. Tumors can metastasize to bone from distant sites (breast, prostate, lung), directly invade into bone (head and neck) or originate from the bone (melanoma, chondrosarcoma) where they cause pain, fractures, hypercalcemia, and ultimately, poor prognoses and outcomes. Tumors in bone secrete factors (interleukins and parathyroid hormone-related protein) that induce RANKL expression from osteoblasts, causing an increase in osteoclast mediated bone resorption. While the mechanisms involved varies slightly between tumor types, many tumors display an increase in Hedgehog signaling components that lead to increased tumor growth, therapy failure, and metastasis. The work of multiple laboratories has detailed Hh signaling in several tumor types and revealed that tumor establishment in bone can be controlled by both canonical and non-canonical Hh signaling in a cell type specific manner. This review will explore the role of Hh signaling in the modulation of tumor induced bone disease, and will shed insight into possible therapeutic interventions for blocking Hh signaling in these tumors.

The Role of Hedgehog Signaling in Tumor Induced Bone Disease

International Nuclear Information System (INIS)

Cannonier, Shellese A.; Sterling, Julie A.

2015-01-01

Despite significant progress in cancer treatments, tumor induced bone disease continues to cause significant morbidities. While tumors show distinct mutations and clinical characteristics, they behave similarly once they establish in bone. Tumors can metastasize to bone from distant sites (breast, prostate, lung), directly invade into bone (head and neck) or originate from the bone (melanoma, chondrosarcoma) where they cause pain, fractures, hypercalcemia, and ultimately, poor prognoses and outcomes. Tumors in bone secrete factors (interleukins and parathyroid hormone-related protein) that induce RANKL expression from osteoblasts, causing an increase in osteoclast mediated bone resorption. While the mechanisms involved varies slightly between tumor types, many tumors display an increase in Hedgehog signaling components that lead to increased tumor growth, therapy failure, and metastasis. The work of multiple laboratories has detailed Hh signaling in several tumor types and revealed that tumor establishment in bone can be controlled by both canonical and non-canonical Hh signaling in a cell type specific manner. This review will explore the role of Hh signaling in the modulation of tumor induced bone disease, and will shed insight into possible therapeutic interventions for blocking Hh signaling in these tumors

Comparison of direct and indirect radiation effects on osteoclast formation from progenitor cells derived from different hemopoietic sources.

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Scheven, B A; Wassenaar, A M; Kawilarang-de Haas, E W; Nijweide, P J

1987-07-01

Hemopoietic stem and progenitor cells from different sources differ in radiosensitivity. Recently, we have demonstrated that the multinucleated cell responsible for bone resorption and marrow cavity formation, the osteoclast, is in fact of hemopoietic lineage. In this investigation we have studied the radiosensitivity of osteoclast formation from two different hemopoietic tissues: fetal liver and adult bone marrow. Development of osteoclasts from hemopoietic progenitors was induced by coculture of hemopoietic cell populations with fetal mouse long bones depleted of their own osteoclast precursor pool. During culture, osteoclasts developed from the exogenous cell population and invaded the calcified hypertrophic cartilage of the long bone model, thereby giving rise to the formation of a primitive marrow cavity. To analyze the radiosensitivity of osteoclast formation, either the hemopoietic cells or the bone rudiments were irradiated before coculture. Fetal liver cells were found to be less radiosensitive than bone marrow cells. The D0, Dq values and extrapolation numbers were 1.69 Gy, 5.30 Gy, and 24.40 for fetal liver cells and 1.01 Gy, 1.85 Gy, and 6.02 for bone marrow cells. Irradiation of the (pre)osteoclast-free long bone rudiments instead of the hemopoietic sources resulted in a significant inhibition of osteoclast formation at doses of 4 Gy or more. This indirect effect appeared to be more prominent in the cocultures with fetal than with adult hemopoietic cells. Furthermore, radiation doses of 8.0-10.0 Gy indirectly affected the appearance of other cell types (e.g., granulocytes) in the newly formed but underdeveloped marrow cavity. The results indicate that osteoclast progenitors from different hemopoietic sources exhibit a distinct sensitivity to ionizing irradiation. Radiation injury to long bone rudiments disturbs the osteoclast-forming capacity as well as the hemopoietic microenvironment.

[Osteoclasts and early bone remodeling after orthodontic micro-implant placement].

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Zhang, Wei; Guo, Jia-jia; Zhu, Wen-qian; Tang, Guo-hua

2013-08-01

To observe the incidence of osteoclasts during early bone remodeling after orthodontic micro-implant placement. Twenty New Zealand rabbits were randomly allotted into 4 groups. One micro-implant was implanted proximal to the epiphyseal plate of the tibia. Animals were sacrificed on day 3, 7, 14 and 28 (n=5). The sequence of histological changes around the micro-implants were evaluated by hematoxylin and eosin (HE) staining. Osteoclasts were identified by TRAP staining. The differences of the number of the osteoclasts among each time point were analyzed by one way ANOVA with SPSS 19.0 software package. After 3 days of implantation, a large number of erythrocytes, inflammatory cells, mesenchymal cells and bone debris were seen at the implant bone interfaces. Few osteoclasts were observed. On day 7, granular woven bone was formed and some osteoclasts were found in the Howship's lacunae. New bone formation and mineralization were apparent on day 14. Meanwhile, large amounts of osteoclasts were found in the latticed woven bone. On day 28, woven trabeculae with lamellate structures connected to lamellar bone and fewer osteoclasts were identified. Semi-quantitative analysis showed that the number of the osteoclasts was at peak on day 14. There were significant differences among each time point (Pmicro-implant insertion.

The inhibitors of cyclin-dependent kinases and GSK-3β enhance osteoclastogenesis

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Yosuke Akiba

2016-03-01

Full Text Available Osteoclasts are multinucleated cells with bone resorption activity that is crucial for bone remodeling. RANK‐RANKL (receptor activator of nuclear factor κB ligand signaling has been shown as a main signal pathway for osteoclast differentiation. However, the molecular mechanism and the factors regulating osteoclastogenesis remain to be fully understood. In this study, we performed a chemical genetic screen, and identified a Cdks/GSK-3β (cyclin-dependent kinases/glycogen synthase kinase 3β inhibitor, kenpaullone, and two Cdks inhibitors, olomoucine and roscovitine, all of which significantly enhance osteoclastogenesis of RAW264.7 cells by upregulating NFATc1 (nuclear factor of activated T cells, cytoplasmic 1 levels. We also determined that the all three compounds increase the number of osteoclast differentiated from murine bone marrow cells. Furthermore, the three inhibitors, especially kenpaullone, promoted maturation of cathepsin K, suggesting that the resorption activity of the resultant osteoclasts is also activated. Our findings indicate that inhibition of GSK-3β and/or Cdks enhance osteoclastogenesis by modulating the RANK–RANKL signaling pathway.

Role of denosumab in the management of skeletal complications in patients with bone metastases from solid tumors

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Stopeck AT

2012-04-01

Full Text Available Ursa Brown-Glaberman, Alison T StopeckUniversity of Arizona Cancer Center, Tucson, AZ, USAAbstract: Skeletal-related events (SREs including pain, fractures, and hypercalcemia are a major source of morbidity for cancer patients with bone metastases. The receptor activator of NF-κB ligand (RANKL is a key mediator of osteoclast formation and activity in normal bone physiology as well as cancer-induced bone resorption. The first commercially available drug that specifically targets and inhibits the RANKL pathway is denosumab, a fully human monoclonal antibody that binds and neutralizes RANKL, thereby inhibiting osteoclast function. In this review, we summarize the major studies leading to the US Food and Drug Administration-approval of denosumab for the prevention of SREs in patients with bone metastases from solid tumors. Further, we discuss the role of denosumab in the prevention and treatment of SREs and bone loss in cancer patients. As a monoclonal antibody, denosumab has several advantages over bisphosphonates, including improved efficacy, better tolerability, and the convenience of administration by subcutaneous injection. In addition, as denosumab has no known renal toxicity, it may be the preferred choice over bisphosphonates in patients with baseline renal insufficiency or receiving nephrotoxic therapies. However, other toxicities, including osteonecrosis of the jaw and hypocalcemia, appear to be class effects of agents that potently inhibit osteoclast activity and are associated with both denosumab and bisphosphonate use. The data presented highlight the differences associated with intravenous bisphosphonate and denosumab use as well as confirm the essential role bone-modifying agents play in maintaining the quality of life for patients with bone metastases.Keywords: denosumab, bone metastases, solid tumor, breast cancer, prostate cancer, skeletal related events, skeletal complications 

Effects of cadmium on osteoclast formation and activity in vitro

International Nuclear Information System (INIS)

Wilson, A.K.; Cerny, E.A.; Smith, B.D.; Wagh, A.

1996-01-01

Chronic exposure to cadmium has been linked to bone loss, low bone mass, and increased incidence of fracture. To determine if Cd could directly increase the formation of cells responsible for bone resorption, we cultured normal canine bone marrow cells containing the progenitor cells for osteoclasts. Cultures were evaluated for the number of multinucleate osteoclast-like cells (MNOCs) formed. Exposure to Cd (10-100 nM) increased the number of MNOCs formed over control values when cultured in the presence but not in the absence of a bone wafer. The MNOCs formed were functional, evidenced by pits excavated on the bone wafers included in the cultures. By 12 days, MNOCs formed in the presence of 50 nM Cd excavated significantly more pits and a greater pit area than did untreated MNOCs. By 14 days, the control values were similar to those of the Cd-exposed MNOCs, but pit formation was enhanced by Cd in that the ratio of pit complexes to single pits was increased twofold over that for untreated cultures. Mature osteoclasts, isolated from the long bones of rat neonates and cultured for 1-3 days on bone slices, provided a direct method to assess the effect of Cd on osteoclast activity. Exposure of osteoclast cultures to 100 nm Cd increased the number of nM osteoclasts present over that for untreated osteoclasts by a factor of 1.7 ± 0.1, the number of pits excavated by 2.8 ± 0.6, the area excavated by 3.2 ± 0.8, and the area excavated per osteoclast by 1.8 ± 0.4 (mean SE; n = six experiments). These data suggest that Cd accelerates the differentiation of new osteoclasts from their progenitor cells and activates or increases the activity of mature osteoclasts. 48 refs., 4 figs., 3 tabs

The potential of chitosan combined with chicken shank collagen as scaffold on bone defect regeneration process in Rattus norvegicus

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Fitria Rahmitasari

2016-12-01

Full Text Available Background: In the field of dentistry, alveolar bone damage can be caused by periodontal disease, traumatic injury due to tooth extraction, cyst enucleation, and tumor surgery. One of the ways to regenerate the bone defect is using graft scaffold. Thus, combination of chitosan and collagen can stimulate osteogenesis. Purpose: The aim of this study was to examine the potential of chitosan combined with chicken shank collagen on bone defect regeneration process. Method: Twelve Rattus norvegicus were prepared as animal models in this research. A bone defect was intentionally created at both of the right and left femoral bones of the models. Next, 24 samples were divided into four groups, namely Group 1 using chitosan – collagen scaffold (50:50, Group 2 using chitosan collagen-scaffold (80:20, Group 3 using chitosan scaffold only, and Control Group using 3% CMC-Na. On 14th day, those animals were sacrificed, and histopathological anatomy examination was conducted to observe osteoclast cells. In addition, immunohistochemistry examination was also performed to observe RANKL expressions. Result: There was a significant difference in RANKL expressions among the groups, except between Group 3 using chitosan scaffold only and control group (p value > 0.05. The highest expression of RANKL was found in Group 1 with chitosan – collagen scaffold (50:50, followed by Group 2 with chitosan-collagen scaffold (80:20. Moreover, there was also a significant difference in osteoclast generation, except between Group 1 using chitosan – collagen scaffold (50:50 and Group 2 using chitosan-collagen scaffold (80:20, p value 0.05. Less osteoclast was found in the groups using chitosan – collagen scaffold (Group 1 and Group 2. Conclusion: Combination of chitosan and chicken shank collagen scaffold can improve regeneration process of bone defect in Rattus novergicus animals through increasing of RANKL expressions, and decreasing of osteoclast.

Cadmium-induced formation of multinucleated osteoclast-like cells in vitro

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Konz, R.P.; Choi, T.T.; Seed, T.M.

1990-01-01

Mononuclear, progenitor-enriched bone marrow cells fuse into multinucleated osteoclast-like (MN-OS) cells during 10 to 20 days of culture. As cadmium (Cd) exposure has been linked to increased bone resorption, we asked if Cd would increase (1) MN-OS cell formation and (2) 45 Ca release from bone, when marrow cells were cultured in the presence of 45 Ca-prelabeled dog femur slices. Results show that, on day 21, the percentage of MN-OS cells (≥3 nuclei/cell) was 1.4 ± 0.1% (mean ± SE, n=4) for control cultures (medium + bone slice + cells), 3.6 ± 0.1% for cultures with 10 nM parathyroid hormone (PTH) added, and 7.1 ± 1.5% with 10 nM Cd added. Starting on day 10, we found MN-OS cells with centrally located nuclei, a clear zone, and ruffled borders typical of activated osteoclasts; these activated cells appeared almost exclusively in the +Cd and +PTH cultures. During 21 days, 256 ± 9 CPM 45 Ca was released per well from the bone slices in cultures with cells, compared to 209 ± 11 CPM 45 Ca was released in cultures without cells (mean ± SE, n=16). However, neither Cd nor PTH significantly increased the cell-mediated release of 45 Ca. Thus, both Cd and PTH at 10 nM stimulated the formation of MN-OS cells; however, another factor may have been required to cause MN-OS cells of resorb bone

[Observation of osteoclasts on the root surface during human deciduous teeth resorption].

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Bao, Xiang-jun; Liang, Xing; Chen, Ming; Wang, Hang; Xie, Zhi-gang; Yang, Xiao-yu

2004-08-01

To observe osteoclasts on the resorbing surface of human deciduous teeth. After fixing the collected deciduous teeth, we prepared the tooth slices without decalcification, treated them with HE and TRAP dyestuff, and observed the osteoclasts under light and scanning electron microscope. There were large quantity of various forms of overlapping and huge osteoclasts with many nuclei and silk-like protuberances on the resorbing surface of deciduous teeth. The multinucleated osteoclasts align on the surface of coarse dentin. On the resorbing surface of human deciduous teeth there are large amount of osteoclasts which can be used as a source of studying human osteoclast.

RANKL regulates differentiation of microfold cells in mouse nasopharynx-associated lymphoid tissue (NALT).

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Mutoh, Mami; Kimura, Shunsuke; Takahashi-Iwanaga, Hiromi; Hisamoto, Meri; Iwanaga, Toshihiko; Iida, Junichiro

2016-04-01

Murine nasopharynx-associated lymphoid tissue (NALT), located at the base of the nasal cavity, serves as a major site for the induction of mucosal immune responses against airway antigens. The follicle-associated epithelium (FAE) covering the luminal surface of NALT is characterized by the presence of microfold cells (M cells), which take up and transport luminal antigens to lymphocytes. Glycoprotein 2 (GP2) has recently been identified as a reliable marker for M cells in Peyer's patches of the intestine. However, the expression of GP2 and other functional molecules in the M cells of NALT has not yet been examined. We have immunohistochemically detected GP2-expressing cells in the FAE of NALT and the simultaneous expression of other intestinal M-cell markers, namely Tnfaip2, CCL9, and Spi-B. These cells have been further identified as M cells because of their higher uptake capacity of luminal microbeads. Electron microscopic observations have shown that GP2-expressing cells on the FAE display morphological features typical of M cells: they possess short microvilli and microfolds on the luminal surface and are closely associated with intraepithelial lymphocytes. We have also found that the receptor activator of nuclear factor kappa-B ligand (RANKL) is expressed by stromal cells underneath the FAE, which provides its receptor RANK. The administration of RANKL markedly increases the number of GP2(+)Tnfaip2(+) cells on the NALT FAE and that of intestinal M cells. These results suggest that GP2(+)Tnfaip2(+) cells in NALT are equivalent to intestinal M cells, and that RANKL-RANK signaling induces their differentiation.

Ionizing Radiation Stimulates Expression of Pro-Osteoclastogenic Genes in Marrow and Skeletal Tissue

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Alwood, J. S.; Shahnazari, M.; Chicana, B.; Schreurs, A. S.; Kumar, A.; Bartolini, A.; Shirazi-Fard, Y.; Globus, R. K.

2015-01-01

Exposure to ionizing radiation can cause rapid mineral loss and increase bone-resorbing osteoclasts within metabolically-active, cancellous-bone tissue leading to structural deficits. To better understand mechanisms involved in rapid, radiation-induced bone loss, we determined the influence of total-body irradiation on expression of select cytokines known both to stimulate osteoclastogenesis and contribute to inflammatory bone disease. Adult (16wk), male C57BL/6J mice were exposed to either 2Gy gamma rays (137Cs, 0.8Gy/min) or heavy ions (56Fe, 600MeV, 0.50-1.1Gy/min); this dose corresponds to either a single fraction of radiotherapy (typical total dose is =10Gy) or accumulates over long-duration, interplanetary missions. Serum, marrow, and mineralized tissue were harvested 4hrs-7d later. Gamma irradiation caused a prompt (2.6-fold within 4hrs) and persistent (peaking at 4.1-fold within 1d) rise in the expression of the obligate osteoclastogenic cytokine, receptor activator of nuclear factor kappaB-ligand (Rankl) within marrow cells over controls. Similarly, Rankl expression peaked in marrow cells within 3d of iron exposure (9.2-fold). Changes in Rankl expression induced by gamma irradiation preceded and overlapped with a rise in expression of other pro-osteoclastic cytokines in marrow (e.g., monocyte chemotactic protein-1 increased 11.9-fold, tumor necrosis factor-alpha increased 1.7- fold over controls). Marrow expression of the RANKL decoy receptor, osteoprotegerin (Opg), also rose after irradiation (11.3-fold). The ratio Rankl/Opg in marrow was increased 1.8-fold, a net pro-resorption balance. As expected, radiation increased a serum marker of resorption (tartrate resistant acid phosphatase) and led to cancellous bone loss (16% decrease in bone volume/total volume) through reduced trabecular struts. We conclude that total-body irradiation (gamma or heavy-ion) caused temporal, concerted regulation of gene expression within marrow and mineralized tissue for

Adenosine A1 receptors (A1Rs) play a critical role in osteoclast formation and function

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Kara, Firas M.; Chitu, Violeta; Sloane, Jennifer; Axelrod, Matthew; Fredholm, Bertil B.; Stanley, E. Richard; Cronstein, Bruce N.

2010-01-01

Adenosine regulates a wide variety of physiological processes via interaction with one or more G-protein-coupled receptors (A1R, A2AR, A2BR, and A3R). Because A1R occupancy promotes fusion of human monocytes to form giant cells in vitro, we determined whether A1R occupancy similarly promotes osteoclast function and formation. Bone marrow cells (BMCs) were harvested from C57Bl/6 female mice or A1R-knockout mice and their wild-type (WT) littermates and differentiated into osteoclasts in the presence of colony stimulating factor-1 and receptor activator of NF-κB ligand in the presence or absence of the A1R antagonist 1,3-dipropyl-8-cyclopentyl xanthine (DPCPX). Osteoclast morphology was analyzed in tartrate-resistant acid phosphatase or F-actin-stained samples, and bone resorption was evaluated by toluidine blue staining of dentin. BMCs from A1R-knockout mice form fewer osteoclasts than BMCs from WT mice, and the A1R antagonist DPCPX inhibits osteoclast formation (IC50=1 nM), with altered morphology and reduced ability to resorb bone. A1R blockade increased ubiquitination and degradation of TRAF6 in RAW264.7 cells induced to differentiate into osteoclasts. These studies suggest a critical role for adenosine in bone homeostasis via interaction with adenosine A1R and further suggest that A1R may be a novel pharmacologic target to prevent the bone loss associated with inflammatory diseases and menopause.—Kara, F. M., Chitu, V., Sloane, J., Axelrod, M., Fredholm, B. B., Stanley, R., Cronstein, B. N. Adenosine A1 receptors (A1Rs) play a critical role in osteoclast formation and function. PMID:20181934

Staphylococcal enterotoxin C2 promotes osteogenesis and suppresses osteoclastogenesis of human mesenchymal stem cells.

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Fu, Wei-ming; Zhu, Xiao; Wang, Hua; Wei-Mao Wang; Chen, Ju-yu; Liang, Yan; Zhang, Jin-fang; Kung, Hsiang-fu

2014-03-10

As a super-antigen, staphylococcal enterotoxin C2 (SEC2) stimulates the release of massive inflammatory cytokines such as interferon-gamma (IFN-γ), interleukin-1 (IL-1) and interleukin-2 (IL-2) which are documented to implicate osteoblast differentiation. In the present study, SEC2 was found to significantly improve the osteoblast differentiation by up-regulating BMP2 and Runx2/Cbfa1 expression. Interferon (IFN)-inducible gene IFI16, a co-activator of Runx2/Cbfa1, was also activated by SEC2 in the osteoblast differentiation. In addition, exogenous introduction of SEC2 stimulated OPG expression and suppressed RANKL, suggesting suppression of osteoclastogenesis in hMSCs. Therefore, our results displayed that SEC2 plays an important role in the commitment of MSC to the osteoblast and it might be a potential new therapeutic candidate for bone regeneration. Copyright © 2013 Elsevier Inc. All rights reserved.

A metabolomics study of the inhibitory effect of 17-beta-estradiol on osteoclast proliferation and differentiation.

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Liu, Xiaoyan; Liu, Yanqiu; Cheng, Mengchun; Zhang, Xiaozhe; Xiao, Hongbin

2015-02-01

Estradiol is a major drug used clinically to alleviate osteoporosis, partly through inhibition of the activity of osteoclasts, which play a crucial role in bone resorption. So far, little is known about the effects of estradiol on osteoclast metabolism. In this study, ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC/MS)-based metabolomics strategy was used to investigate the metabolite response to 17β-estradiol in mouse osteoclast RAW264.7, a commonly used cell model for studying osteoporosis. Our results showed that the application of estradiol altered the levels of 27 intracellular metabolites, including lysophosphatidylcholines (LysoPCs), other lipids and amino acid derivants. The changes of all the 27 metabolites were observed in the study of estradiol induced osteoclast proliferation inhibition (1 μM estradiol applied), while the changes of only 18 metabolites were observed in the study of differentiation inhibition (0.1 μM estradiol applied). Further pathway impact analysis determined glycerophospholipid metabolism as the main potential target pathway of estradiol, which was further confirmed by LCAT (phosphatidylcholine-sterol acyltransferase) activity changes and lipid peroxidative product (MDA, methane dicarboxylic aldehyde) changes caused by estradiol. Additionally, we found that estradiol significantly decreased intracellular oxidative stress during cell proliferation but not during cell differentiation. Our study suggested that estradiol generated a highly condition-dependent influence on osteoclast metabolism.

Perillyl alcohol suppresses antigen-induced immune responses in the lung

International Nuclear Information System (INIS)

Imamura, Mitsuru; Sasaki, Oh; Okunishi, Katsuhide; Nakagome, Kazuyuki; Harada, Hiroaki; Kawahata, Kimito; Tanaka, Ryoichi; Yamamoto, Kazuhiko; Dohi, Makoto

2014-01-01

Highlights: •Perillyl alcohol (POH) is an isoprenoid which inhibits the mevalonate pathway. •We examined whether POH suppresses immune responses with a mouse model of asthma. •POH treatment during sensitization suppressed Ag-induced priming of CD4 + T cells. •POH suppressed airway eosinophila and cytokine production in thoracic lymph nodes. -- Abstract: Perillyl alcohol (POH) is an isoprenoid which inhibits farnesyl transferase and geranylgeranyl transferase, key enzymes that induce conformational and functional changes in small G proteins to conduct signal production for cell proliferation. Thus, it has been tried for the treatment of cancers. However, although it affects the proliferation of immunocytes, its influence on immune responses has been examined in only a few studies. Notably, its effect on antigen-induced immune responses has not been studied. In this study, we examined whether POH suppresses Ag-induced immune responses with a mouse model of allergic airway inflammation. POH treatment of sensitized mice suppressed proliferation and cytokine production in Ag-stimulated spleen cells or CD4 + T cells. Further, sensitized mice received aerosolized OVA to induce allergic airway inflammation, and some mice received POH treatment. POH significantly suppressed indicators of allergic airway inflammation such as airway eosinophilia. Cytokine production in thoracic lymph nodes was also significantly suppressed. These results demonstrate that POH suppresses antigen-induced immune responses in the lung. Considering that it exists naturally, POH could be a novel preventive or therapeutic option for immunologic lung disorders such as asthma with minimal side effects

Suppression of radiation-induced in vitro carcinogenesis by ascorbic acid

International Nuclear Information System (INIS)

Tauchi, Hiroshi; Sawada, Shozo

1993-01-01

The effects of ascorbic acid on radiation-induced in vitro carcinogenesis have been reported using neoplastic transformation system of C3H 10T1/2 cells. In these reports, no suppressive effect on X-ray-induced transformation was observed with 6 weeks' administration of ascorbic acid (daily addition for 5 days per week) by Kennedy (1984), whereas apparent suppression was observed with daily addition for 7 days by Yasukawa et al (1989). We have tested the effects of ascorbic acid on 60 Co gamma-ray or 252 Cf fission neutron-induced transformation in Balb/c 3T3 cells. The transformation induced by both types of radiations was markedly suppressed when ascorbic acid was daily added to the medium during first 8 days of the post-irradiation period. If ascorbic acid was added for a total of 8 days but with a day's interruption in the middle, the suppression of transformation was decreased. These results suggest that continuous presence of ascorbic acid for a certain number of days is needed to suppress radiation-induced transformation. Since ascorbic acid also suppressed the promotion of radiation-induced transformation by TPA when both chemicals were added together into the medium, ascorbic acid might act on the promotion stage of transformation. Therefore, the effect of ascorbic acid on the distribution of protein kinase C activity was also investigated, and possible mechanisms of suppression of radiation-induced transformation by ascorbic acid will be discussed. (author)

RANKL-Targeted Therapies: The Next Frontier in the Treatment of Male Osteoporosis

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Alicia K. Morgans

2011-01-01

Full Text Available Male osteoporosis is an increasingly recognized problem in aging men. A common cause of male osteoporosis is hypogonadism. Thousands of men with prostate cancer are treated with androgen deprivation therapy, a treatment that dramatically reduces serum testosterone and causes severe hypogonadism. Men treated with androgen deprivation therapy experience a decline in bone mineral density and have an increased rate of fracture. This paper describes prostate cancer survivors as a model of hypogonadal osteoporosis and discusses the use of RANKL-targeted therapies in osteoporosis. Denosumab, the only RANKL-targeted therapy currently available, increases bone mineral density and decreases fracture rate in men with prostate cancer. Denosumab is also associated with delayed time to first skeletal-related event and an increase in bone metastasis-free survival in these men. It is reasonable to investigate the use of RANKL-targeted therapy in male osteoporosis in the general population.

Changes in RANKL during the first two years after cART initiation in HIV-infected cART naïve adults

DEFF Research Database (Denmark)

Mathiesen, Inger Hee Mabuza; Salem, Mohammad; Gerstoft, Jan

2017-01-01

accelerated bone loss could be mediated by increased soluble RANKL (sRANKL) levels associated with CD4+ T cell recovery. METHODS: We used multiplex immunoassays to determine sRANKL and OPG concentrations in plasma from 48 HIV patients at baseline and 12, 24, 48 and 96 weeks after cART initiation. RESULTS......: Soluble RANKL changed significantly over time (overall p = 0.02) with 25% decrease (95% CI: -42 to -5) at week 24 compared to baseline and stabilized at a lower level thereafter. We found no correlation between CD4+ T cell count increment and changes in sRANKL or between percentage change in BMD...... and changes in sRANKL. CONCLUSION: In this study there was no indication that the accelerated bone loss after cART initiation was mediated by early changes in sRANKL due to CD4+ T cell recovery. Future studies should focus on the initial weeks after initiation of cART. TRIAL REGISTRATION: Clinical...

Erk1 positively regulates osteoclast differentiation and bone resorptive activity.

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Yongzheng He

Full Text Available The extracellular signal-regulated kinases (ERK1 and 2 are widely-expressed and they modulate proliferation, survival, differentiation, and protein synthesis in multiple cell lineages. Altered ERK1/2 signaling is found in several genetic diseases with skeletal phenotypes, including Noonan syndrome, Neurofibromatosis type 1, and Cardio-facio-cutaneous syndrome, suggesting that MEK-ERK signals regulate human skeletal development. Here, we examine the consequence of Erk1 and Erk2 disruption in multiple functions of osteoclasts, specialized macrophage/monocyte lineage-derived cells that resorb bone. We demonstrate that Erk1 positively regulates osteoclast development and bone resorptive activity, as genetic disruption of Erk1 reduced osteoclast progenitor cell numbers, compromised pit formation, and diminished M-CSF-mediated adhesion and migration. Moreover, WT mice reconstituted long-term with Erk1(-/- bone marrow mononuclear cells (BMMNCs demonstrated increased bone mineral density as compared to recipients transplanted with WT and Erk2(-/- BMMNCs, implicating marrow autonomous, Erk1-dependent osteoclast function. These data demonstrate Erk1 plays an important role in osteoclast functions while providing rationale for the development of Erk1-specific inhibitors for experimental investigation and/or therapeutic modulation of aberrant osteoclast function.

Perillyl alcohol suppresses antigen-induced immune responses in the lung

Energy Technology Data Exchange (ETDEWEB)

Imamura, Mitsuru; Sasaki, Oh; Okunishi, Katsuhide; Nakagome, Kazuyuki; Harada, Hiroaki; Kawahata, Kimito; Tanaka, Ryoichi; Yamamoto, Kazuhiko [Department of Allergy and Rheumatology, Graduate School of Medicine, The University of Tokyo, Tokyo (Japan); Dohi, Makoto, E-mail: mdohi-tky@umin.ac.jp [Department of Allergy and Rheumatology, Graduate School of Medicine, The University of Tokyo, Tokyo (Japan); Institute of Respiratory Immunology, Shibuya Clinic for Respiratory Diseases and Allergology, Tokyo (Japan)

2014-01-03

Highlights: •Perillyl alcohol (POH) is an isoprenoid which inhibits the mevalonate pathway. •We examined whether POH suppresses immune responses with a mouse model of asthma. •POH treatment during sensitization suppressed Ag-induced priming of CD4{sup +} T cells. •POH suppressed airway eosinophila and cytokine production in thoracic lymph nodes. -- Abstract: Perillyl alcohol (POH) is an isoprenoid which inhibits farnesyl transferase and geranylgeranyl transferase, key enzymes that induce conformational and functional changes in small G proteins to conduct signal production for cell proliferation. Thus, it has been tried for the treatment of cancers. However, although it affects the proliferation of immunocytes, its influence on immune responses has been examined in only a few studies. Notably, its effect on antigen-induced immune responses has not been studied. In this study, we examined whether POH suppresses Ag-induced immune responses with a mouse model of allergic airway inflammation. POH treatment of sensitized mice suppressed proliferation and cytokine production in Ag-stimulated spleen cells or CD4{sup +} T cells. Further, sensitized mice received aerosolized OVA to induce allergic airway inflammation, and some mice received POH treatment. POH significantly suppressed indicators of allergic airway inflammation such as airway eosinophilia. Cytokine production in thoracic lymph nodes was also significantly suppressed. These results demonstrate that POH suppresses antigen-induced immune responses in the lung. Considering that it exists naturally, POH could be a novel preventive or therapeutic option for immunologic lung disorders such as asthma with minimal side effects.

P2X7 receptor regulates osteoclast function and bone loss in a mouse model of osteoporosis.

Science.gov (United States)

Wang, Ning; Agrawal, Ankita; Jørgensen, Niklas Rye; Gartland, Alison

2018-02-22

Post-menopausal osteoporosis is a condition that affects millions worldwide and places a huge socio-economic burden on society. Previous research has shown an association of loss of function SNPs in the gene for the purinergic receptor P2X7R with low bone mineral density, increased rates of bone loss and vertebral fractures in post-menopausal women. In this study we use a mouse model of oestrogen deficiency-induced bone loss and the BALB/cJ P2X7R -/- to show that absence of the P2X7R resulted in increased bone loss. Osteoclast precursors were isolated from both BALB/cJ P2X7R -/- and BALB/cJ P2X7R +/+ mice and then cultured in vitro to form mature resorbing osteoclasts. The BALB/cJ P2X7R -/- derived precursors generated slightly more osteoclasts but with a significant reduction in the amount of resorption per osteoclast. Furthermore, when using modified culture conditions osteoclast activity was additionally increased in the absence of the P2X7R suggest that P2X7R may regulate the lifespan and activity of osteoclasts. Finally using mechanical loading as an anabolic stimulus for bone formation, we demonstrated that the increased oestrogen-deficient bone loss could be rescued, even in the absence of P2X7R. This study paves the way for clinical intervention for women with post-menopausal osteoporosis and P2XR7 loss of function polymorphisms.

RANKL/Osteoprotegerin System and Bone Turnover in Hashimoto Thyroiditis.

Science.gov (United States)

Konca Degertekin, Ceyla; Turhan Iyidir, Ozlem; Aktas Yılmaz, Banu; Elbeg, Sehri; Pasaoglu, Ozge Tugce; Pasaoglu, Hatice; Cakır, Nuri; Arslan, Metin

2016-10-01

Hypothyroidism is associated with changes in bone metabolism. The impact of hypothyroidism and the associated autoimmunity on the mediators of bone turnover in Hashimoto's thyroiditis (HT) is not known. In this study, we assessed the levels of OPG, RANKL, and IL-6 along with markers of bone formation as osteocalcin (OC) and markers of bone resorption as type 1 collagen C telopeptide (CTX) and tartrate-resistant acid phosphatase isoform 5b (TRAcP 5b) in 30 hypothyroid and 30 euthyroid premenopausal HT patients and 20 healthy premenopausal controls. We found that TRAcP 5b (p = 0.006), CTX (p = 0.01), OC (p = 0.017), and IL-6 (p Thyroid autoimmunity might have a unique impact on OPG/RANKL levels apart from the resultant hypothyroidism.

Chafuroside B, an Oolong tea polyphenol, ameliorates UVB-induced DNA damage and generation of photo-immunosuppression related mediators in human keratinocytes.

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Tatsuya Hasegawa

Full Text Available Chafuroside B was recently isolated as a new polyphenolic constituent of oolong tea leaves. However, the effects of chafuroside B on skin function have not been examined. In this study, we investigated the protective effects of chafuroside B against UVB-induced DNA damage, apoptosis and generation of photo-immunosuppression related mediators in cultured normal human epidermal keratinocytes (NHEK. Chafuroside B at 1 µM attenuated both UVB-induced apoptosis, evaluated in terms of caspase-3/7 activity, and UVB-induced DNA damage, evaluated in terms of formation of cyclobutane pyrimidine dimers (CPD, in NHEK exposed to UVB (20 mJ/cm2. In addition, chafuroside B at 0.3 or 1 µM suppressed the UVB-induced production of interleukin (IL-10, tumor necrosis factor (TNF-α, and prostaglandin E2 (PGE2, as determined by ELISA, and conversely enhanced IL-12 mRNA expression and production, as measured by RT-PCR and ELISA. Further, chafuroside B at 1 µM also suppressed UVB-induced expression of receptor activator of nuclear factor κB ligand (RANKL mRNA. These results indicate that chafuroside B promotes repair of UVB-induced DNA damage and ameliorates the generation of IL-10, TNF-α, PGE2, and RANKL, all of which are UVB-induced immunosuppression related mediators. These effects of chafuroside B may be mediated at least in part through induction of IL-12 synthesis in human keratinocytes. Because chafuroside B might have practical value as a photoprotective agent, a further study of the in vivo effects of chafuroside B seems warranted.

In vitro formation of osteoclasts from long-term cultures of bone marrow mononuclear phagocytes

International Nuclear Information System (INIS)

Burger, E.H.; Van der Meer, J.W.; van de Gevel, J.S.; Gribnau, J.C.; Thesingh, G.W.; van Furth, R.

1982-01-01

The origin of osteoclasts was studied in an in vitro model using organ cultures of periosteum-free embryonic mouse long-bone primordia, which were co-cultured with various cell populations. The bone rudiments were freed of their periosteum-perichondrium by collagenase treatment in a stage before cartilage erosion and osteoclast formation, and co-cultured for 7 d with either embryonic liver or mononuclear phagocytes from various sources. Light and electron microscopic examination of the cultures showed that mineralized matrix-resorbing osteoclasts developed only in bones co-cultured with embryonic liver or with cultured bone marrow mononuclear phagocytes but not when co-cultured with blood monocytes or resident or exudate peritoneal macrophages. Osteoclasts developed from the weakly adherent, but not from the strongly adherent cells of bone marrow cultures, whereas 1,000 rad irradiation destroyed the capacity of such cultures to form osteoclasts. In bone cultures to which no other cells were added, osteoclasts were virtually absent. Bone-resorbing activity of in vitro formed osteoclasts was demonstrated by 45 Ca release studies. These studies demonstrate that osteoclasts develop from cells present in cultures of proliferating mononuclear phagocytes and that, at least in our system, monocytes and macrophages are unable to form osteoclasts. The most likely candidates for osteoclast precursor cells seem to be monoblasts and promonocytes

Hydrogen sulphide-releasing diclofenac derivatives inhibit breast cancer-induced osteoclastogenesis in vitro and prevent osteolysis ex vivo.

Science.gov (United States)

Frantzias, J; Logan, J G; Mollat, P; Sparatore, A; Del Soldato, P; Ralston, S H; Idris, A I

2012-03-01

Hydrogen sulphide (H(2)S) and prostaglandins are both involved in inflammation, cancer and bone turnover, and non-steroidal anti-inflammatory drugs (NSAIDs) and H(2)S donors exhibit anti-inflammatory and anti-tumour properties. H(2)S-releasing diclofenac (S-DCF) derivatives are a novel class of NSAIDs combining the properties of a H(2)S donor with those of a conventional NSAID. We studied the effects of the S-DCF derivatives ACS15 and ACS32 on osteoclast and osteoblast differentiation and activity in vitro, human and mouse breast cancer cells support for osteoclast formation and signalling in vitro, and osteolysis ex vivo. The S-diclofenac derivatives ACS15 and ACS32 inhibited the increase in osteoclast formation induced by human MDA-MB-231 and MCF-7 and mouse 4T1 breast cancer cells without affecting breast cancer cell viability. Conditioned media from human MDA-MB-231 cells enhanced IκB phosphorylation and osteoclast formation and these effects were significantly inhibited following treatment by ACS15 and ACS32, whereas the parent compound diclofenac had no effects. ACS15 and ACS32 inhibited receptor activator of NFκB ligand-induced osteoclast formation and resorption, and caused caspase-3 activation and apoptosis in mature osteoclasts via a mechanism dependent on IKK/NFκB inhibition. In calvaria organ culture, human MDA-MB-231 cells caused osteolysis, and this effect was completely prevented following treatment with ACS15 and ACS32. S-diclofenac derivatives inhibit osteoclast formation and activity, suppress breast cancer cell support for osteoclastogenesis and prevent osteolysis. This suggests that H(2)S-releasing diclofenac derivatives exhibit anti-resorptive properties, which might be of clinical value in the treatment of osteolytic bone disease. © 2011 The Authors. British Journal of Pharmacology © 2011 The British Pharmacological Society.

Proton concentrations can be a major contributor to the modification of osteoclast and osteoblast differentiation, working independently of extracellular bicarbonate ions.

Science.gov (United States)

Kato, Kohtaro; Matsushita, Misao

2014-01-01

We established a system to separately analyze the role of protons and bicarbonate ions in vitro in which the pH of the medium was controlled by HEPES at various concentrations of sodium bicarbonate (NaHCO3) in the absence of carbon dioxide (CO2). Using this system, we demonstrated that acidosis promoted osteoclast formation independently of extracellular NaHCO3 in a short-term culture. Protons and bicarbonate ions acted on osteoclast differentiation with opposite effects, the former positively and the latter negatively. The HEPES-based system maintained pH in the absence of extracellular NaHCO3 without CO2. Therefore, we could demonstrate that osteoblast differentiation was promoted at higher pH in a long-term culture system without NaHCO3 in which ALP activity and nodule mineralization were enhanced. This finding indicates that protons negatively control osteoblast differentiation independently of extracellular bicarbonate ions. However, the difference in the concentration of NaHCO3 did not have any influence on nodule mineralization. The opposite effects of protons, the promotion of osteoclast formation and the inhibition of osteoblast differentiation, were suppressed in the presence of 5 mM N-acetyl cysteine, a reagent activating the scavenging of reactive oxygen species (ROS), implying that ROS act on both systems, the promotion of large osteoclast formation and the deterioration of osteoblast formation under acidosis.

CXCL2 synthesized by oral squamous cell carcinoma is involved in cancer-associated bone destruction

International Nuclear Information System (INIS)

Oue, Erika; Lee, Ji-Won; Sakamoto, Kei; Iimura, Tadahiro; Aoki, Kazuhiro; Kayamori, Kou; Michi, Yasuyuki; Yamashiro, Masashi; Harada, Kiyoshi; Amagasa, Teruo; Yamaguchi, Akira

2012-01-01

Highlights: ► Oral cancer cells synthesize CXCL2. ► CXCL2 synthesized by oral cancer is involved in osteoclastogenesis. ► CXCL2-neutralizing antibody inhibited osteoclastogenesis induced by oral cancer cells. ► We first report the role of CXCL2 in cancer-associated bone destruction. -- Abstract: To explore the mechanism of bone destruction associated with oral cancer, we identified factors that stimulate osteoclastic bone resorption in oral squamous cell carcinoma. Two clonal cell lines, HSC3-C13 and HSC3-C17, were isolated from the maternal oral cancer cell line, HSC3. The conditioned medium from HSC3-C13 cells showed the highest induction of Rankl expression in the mouse stromal cell lines ST2 and UAMS-32 as compared to that in maternal HSC3 cells and HSC3-C17 cells, which showed similar activity. The conditioned medium from HSC3-C13 cells significantly increased the number of osteoclasts in a co-culture with mouse bone marrow cells and UAMS-32 cells. Xenograft tumors generated from these clonal cell lines into the periosteal region of the parietal bone in athymic mice showed that HSC3-C13 cells caused extensive bone destruction and a significant increase in osteoclast numbers as compared to HSC3-C17 cells. Gene expression was compared between HSC3-C13 and HSC3-C17 cells by using microarray analysis, which showed that CXCL2 gene was highly expressed in HSC3-C13 cells as compared to HSC3-C17 cells. Immunohistochemical staining revealed the localization of CXCL2 in human oral squamous cell carcinomas. The increase in osteoclast numbers induced by the HSC3-C13-conditioned medium was dose-dependently inhibited by addition of anti-human CXCL2-neutralizing antibody in a co-culture system. Recombinant CXCL2 increased the expression of Rankl in UAMS-32 cells. These results indicate that CXCL2 is involved in bone destruction induced by oral cancer. This is the first report showing the role of CXCL2 in cancer-associated bone destruction.

CXCL2 synthesized by oral squamous cell carcinoma is involved in cancer-associated bone destruction

Energy Technology Data Exchange (ETDEWEB)

Oue, Erika [Section of Oral Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (Japan); Section of Maxillofacial Surgery, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (Japan); Global Center of Excellence (GCOE) Program, International Research Center for Molecular Science in Tooth and Bone Diseases, Tokyo Medical and Dental University, Tokyo (Japan); Lee, Ji-Won; Sakamoto, Kei [Section of Oral Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (Japan); Iimura, Tadahiro [Section of Oral Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (Japan); Global Center of Excellence (GCOE) Program, International Research Center for Molecular Science in Tooth and Bone Diseases, Tokyo Medical and Dental University, Tokyo (Japan); Aoki, Kazuhiro [Section of Pharmacology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (Japan); Kayamori, Kou [Section of Diagnostic Oral Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (Japan); Department of Pathology, Ome Municipal General Hospital, Ome, Tokyo (Japan); Michi, Yasuyuki; Yamashiro, Masashi; Harada, Kiyoshi; Amagasa, Teruo [Section of Maxillofacial Surgery, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (Japan); Yamaguchi, Akira, E-mail: akira.mpa@tmd.ac.jp [Section of Oral Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University (Japan); Global Center of Excellence (GCOE) Program, International Research Center for Molecular Science in Tooth and Bone Diseases, Tokyo Medical and Dental University, Tokyo (Japan)

2012-08-03

Highlights: Black-Right-Pointing-Pointer Oral cancer cells synthesize CXCL2. Black-Right-Pointing-Pointer CXCL2 synthesized by oral cancer is involved in osteoclastogenesis. Black-Right-Pointing-Pointer CXCL2-neutralizing antibody inhibited osteoclastogenesis induced by oral cancer cells. Black-Right-Pointing-Pointer We first report the role of CXCL2 in cancer-associated bone destruction. -- Abstract: To explore the mechanism of bone destruction associated with oral cancer, we identified factors that stimulate osteoclastic bone resorption in oral squamous cell carcinoma. Two clonal cell lines, HSC3-C13 and HSC3-C17, were isolated from the maternal oral cancer cell line, HSC3. The conditioned medium from HSC3-C13 cells showed the highest induction of Rankl expression in the mouse stromal cell lines ST2 and UAMS-32 as compared to that in maternal HSC3 cells and HSC3-C17 cells, which showed similar activity. The conditioned medium from HSC3-C13 cells significantly increased the number of osteoclasts in a co-culture with mouse bone marrow cells and UAMS-32 cells. Xenograft tumors generated from these clonal cell lines into the periosteal region of the parietal bone in athymic mice showed that HSC3-C13 cells caused extensive bone destruction and a significant increase in osteoclast numbers as compared to HSC3-C17 cells. Gene expression was compared between HSC3-C13 and HSC3-C17 cells by using microarray analysis, which showed that CXCL2 gene was highly expressed in HSC3-C13 cells as compared to HSC3-C17 cells. Immunohistochemical staining revealed the localization of CXCL2 in human oral squamous cell carcinomas. The increase in osteoclast numbers induced by the HSC3-C13-conditioned medium was dose-dependently inhibited by addition of anti-human CXCL2-neutralizing antibody in a co-culture system. Recombinant CXCL2 increased the expression of Rankl in UAMS-32 cells. These results indicate that CXCL2 is involved in bone destruction induced by oral cancer. This is the first

Influence of Bisphosphonate Treatment on Medullary Macrophages and Osteoclasts: An Experimental Study

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Natalia Daniela Escudero

2012-01-01

Full Text Available Nitrogen-containing bisphosphonates are widely used for treating diverse bone pathologies. They are anticatabolic drugs that act on osteoclasts inhibiting bone resorption. It remains unknown whether the mechanism of action is by decreasing osteoclast number, impairing osteoclast function, or whether they continue to effectively inhibit bone resorption despite the increase in osteoclast number. There is increasing evidence that bisphosphonates also act on bone marrow cells like macrophages and monocytes. The present work sought to evaluate the dynamics of preosteoclast fusion and possible changes in medullary macrophage number in bisphosphonate-treated animals. Healthy female Wistar rats received olpadronate, alendronate, or vehicle during 5 weeks, and 5-bromo-2-deoxyuridine (BrdU on day 7, 28, or 34 of the experiment. Histomorphometric studies were performed to study femurs and evaluate: number of nuclei per osteoclast (N.Nu/Oc; number of BrdU-positive nuclei (N.Nu BrdU+/Oc; percentage of BrdU-positive nuclei per osteoclast (%Nu.BrdU+/Oc; medullary macrophage number (mac/mm2 and correlation between N.Nu/Oc and mac/mm2. Results showed bisphosphonate-treated animals exhibited increased N.Nu/Oc, caused by an increase in preosteoclast fusion rate and evidenced by higher N.Nu BrdU+/Oc, and significantly decreased mac/mm2. Considering the common origin of osteoclasts and macrophages, the increased demand for precursors of the osteoclast lineage may occur at the expense of macrophage lineage precursors.

"Ruffled border" formation on a CaP-free substrate: A first step towards osteoclast-recruiting bone-grafts materials able to re-establish bone turn-over.

Science.gov (United States)

Merolli, Antonio; Fung, Stephanie; Murthy, N Sanjeeva; Pashuck, E Thomas; Mao, Yong; Wu, Xiaohuan; Steele, Joseph A M; Martin, Daniel; Moghe, Prabhas V; Bromage, Timothy; Kohn, Joachim

2018-03-21

Osteoclasts are large multinucleated giant cells that actively resorb bone during the physiological bone turnover (BTO), which is the continuous cycle of bone resorption (by osteoclasts) followed by new bone formation (by osteoblasts). Osteoclasts secrete chemotactic signals to recruit cells for regeneration of vasculature and bone. We hypothesize that a biomaterial that attracts osteoclasts and re-establishes BTO will induce a better healing response than currently used bone graft materials. While the majority of bone regeneration efforts have focused on maximizing bone deposition, the novelty in this approach is the focus on stimulating osteoclastic resorption as the starter for BTO and its concurrent new vascularized bone formation. A biodegradable tyrosine-derived polycarbonate, E1001(1k), was chosen as the polymer base due to its ability to support bone regeneration in vivo. The polymer was functionalized with a RGD peptide or collagen I, or blended with β-tricalcium phosphate. Osteoclast attachment and early stages of active resorption were observed on all substrates. The transparency of E1001(1k) in combination with high resolution confocal imaging enabled visualization of morphological features of osteoclast activation such as the formation of the "actin ring" and the "ruffled border", which previously required destructive forms of imaging such as transmission electron microscopy. The significance of these results is twofold: (1) E1001(1k) is suitable for osteoclast attachment and supports osteoclast maturation, making it a base polymer that can be further modified to optimize stimulation of BTO and (2) the transparency of this polymer makes it a suitable analytical tool for studying osteoclast behavior.

Psoralidin, a prenylated coumestan, as a novel anti-osteoporosis candidate to enhance bone formation of osteoblasts and decrease bone resorption of osteoclasts

DEFF Research Database (Denmark)

Zhai, Yuankun; Li, Yingying; Wang, Yanping

2017-01-01

Traditional Chinese medicines (TCM) have been proven to prevent osteoporosis, but their clinical applications are not widely recognized due to their complicated ingredients. Psoralidin, a prenylated coumestan, has been reported to prevent bone loss of ovariectomized rats, but detailed mechanisms...... and osteoclastic bone resorption, as demonstrated by the lower tartrate-resistant acid phosphatase activity and smaller area, with fewer resorption pits formed. Interestingly, psoralidin showed much stronger effects than coumestrol at enhancing osteoblast proliferation/differentiation or inhibiting osteoclast...... differentiation and bone resorption. Moreover, we found that both psoralidin and coumestrol suppressed COX-2 and ROS production in rat osteoblastic calvarias cells, and psoralidin showed stronger effects than coumestrol. Furthermore, we detected that by blocking estrogen receptors with ICI 182.780 (an estrogen...

Arctigenin Inhibits Osteoclast Differentiation and Function by Suppressing Both Calcineurin-Dependent and Osteoblastic Cell-Dependent NFATc1 Pathways

OpenAIRE

Yamashita, Teruhito; Uehara, Shunsuke; Udagawa, Nobuyuki; Li, Feng; Kadota, Shigetoshi; Esumi, Hiroyasu; Kobayashi, Yasuhiro; Takahashi, Naoyuki

2014-01-01

Arctigenin, a lignan-derived compound, is a constituent of the seeds of Arctium lappa. Arctigenin was previously shown to inhibit osteoclastogenesis; however, this inhibitory mechanism has yet to be elucidated. Here, we showed that arctigenin inhibited the action of nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1), a key transcription factor for osteoclastogenesis. NFATc1 in osteoclast precursors was activated through two distinct pathways: the calcineurin-dependent and osteoblasti...

Periapical fluid RANKL and IL-8 are differentially regulated in pulpitis and apical periodontitis.

Science.gov (United States)

Rechenberg, Dan-K; Bostanci, Nagihan; Zehnder, Matthias; Belibasakis, Georgios N

2014-09-01

The dental pulp space can become infected due to a breach in the surrounding hard tissues. This leads to inflammation of the pulp (pulpitis), soft tissue breakdown, and finally to bone loss around the root apex (apical periodontitis). The succession of the molecular events leading to apical periodontitis is currently not known. The main inflammatory mediator associated with neutrophil chemotaxis is interleukin-8 (IL-8), and with bone resorption the dyad of receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG). The levels of RANKL, OPG and IL-8 were studied in periapical tissue fluid of human teeth (n = 48) diagnosed with symptomatic irreversible pulpitis (SIP) and asymptomatic apical periodontitis (AAP). SIP represents the starting point, and AAP an established steady state of the disease. Periapical tissue fluid samples were collected using paper points and then evaluated using enzyme-linked immunosorbent assays (ELISAs). Target protein levels per case were calibrated against the corresponding total protein content, as determined fluorometrically. RANKL was expressed at significantly higher levels in SIP compared to AAP (P apical periodontitis, periapical bone resorption signaling, as determined by RANKL, occurs prior to inflammatory cell recruitment signaling, as determined by IL-8. Copyright © 2014 Elsevier Ltd. All rights reserved.

Porphyromonas gingivalis decreases osteoblast proliferation through IL-6-RANKL/OPG and MMP-9/TIMPs pathways

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Le Xuan

2009-01-01

Full Text Available Background: Porphyromonas gingivalis, an important periodontal pathogen, is closely associated with inflammatory alveolar bone resorption. This bacterium exerts its pathogenic effect indirectly through multiple virulence factors, such as lipopolysaccharides, fimbriae, and proteases. Another possible pathogenic path may be through a direct interaction with the host′s soft and hard tissues (e.g., alveolar bone, which could lead to periodontitis. Aims and Objectives: The aim of the present study was to investigate the direct effect of live and heat-inactivated P gingivalis on bone resorption, using an in vitro osteoblast culture model. Results: Optical microscopy and 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide MTT assay revealed that live P gingivalis induced osteoblast detachment and reduced their proliferation. This effect was specific to live bacteria and was dependent on their concentration. Live P gingivalis increased IL-6 mRNA expression and protein production and downregulated RANKL and OPG mRNA expression. The effect of live P gingivalis on bone resorption was strengthened by an increase in MMP-9 expression and its activity. This increase was accompanied by an increase in TIMP-1 and TIMP-2 mRNA expression and protein production by osteoblasts infected with live P gingivalis. Conclusion: Overall, the results suggest that direct contact of P gingivalis with osteoblasts induces bone resorption through an inflammatory pathway that involves IL-6, RANKL/OPG, and MMP-9/TIMPs.

Bisphosphonate-modified gold nanoparticles: a useful vehicle to study the treatment of osteonecrosis of the femoral head

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Fanord, Fedena; Fairbairn, Korie; Bhethanabotla, Venkat; Gupta, Vinay K [Department of Chemical and Biomedical Engineering, University of South Florida, 4202 E. Fowler Avenue, ENB 118, Tampa, FL 33620 (United States); Kim, Harry [Shriners Hospitals for Children, 12502 USF Pine Drive, Tampa, FL 33612 (United States); Garces, Amanda, E-mail: vkgupta@usf.edu [Lisa Muma Weitz Microscopy and Cell Imaging, Department of Pathology and Cell Biology, University of South Florida, 12901 Bruce B Downs Boulevard, Tampa, FL 33612 (United States)

2011-01-21

Legg-Calve-Perthes disease (LCPD) is a juvenile form of osteonecrosis of the femoral head that presents in children aged 2-14 years. To date, there is no effective medical therapy for treating LCPD largely due to an inability to modulate the repair process, including the predominance of bone resorption. This investigation aims to evaluate the feasibility of using gold nanoparticles (GNPs) that are surface modified with a bisphosphonate compound for the treatment of osteonecrosis at the cellular level. Studies have found osteoclast-mediated resorption to be a process that contributes significantly to the pathogenesis of femoral head deformities arising from Perthes disease. Our in vitro model was designed to elucidate the effect of alendronate-(a bisphosphonate) modified GNPs, on osteoclastogenesis and osteoclast function. RAW 264.7 macrophage cells were cultured with recombinant mouse receptor activator of NF-{kappa}B ligand (RANKL), which stimulates osteoclastogenesis, and were then treated with alendronate-modified GNPs for 24, 48, and 72 h. Cell proliferation, osteoclast function, and osteoclast morphology were evaluated by trypan blue dye exclusion assay, tartrate-resistant acid phosphatase (TRAP) staining, and transmission electron microscopy (TEM) imaging. Comparative studies were performed with GNPs that were only stabilized with citrate ions and with alendronate alone. Neither osteoclastogenesis nor osteoclast function were adversely affected by the presence of the citrate-GNP. Alendronate-modified GNPs had an enhanced effect on inducing osteoclast apoptosis and impairing osteoclast function when compared to unbound alendronate populations.

Bisphosphonate-modified gold nanoparticles: a useful vehicle to study the treatment of osteonecrosis of the femoral head

International Nuclear Information System (INIS)

Fanord, Fedena; Fairbairn, Korie; Bhethanabotla, Venkat; Gupta, Vinay K; Kim, Harry; Garces, Amanda

2011-01-01

Legg-Calve-Perthes disease (LCPD) is a juvenile form of osteonecrosis of the femoral head that presents in children aged 2-14 years. To date, there is no effective medical therapy for treating LCPD largely due to an inability to modulate the repair process, including the predominance of bone resorption. This investigation aims to evaluate the feasibility of using gold nanoparticles (GNPs) that are surface modified with a bisphosphonate compound for the treatment of osteonecrosis at the cellular level. Studies have found osteoclast-mediated resorption to be a process that contributes significantly to the pathogenesis of femoral head deformities arising from Perthes disease. Our in vitro model was designed to elucidate the effect of alendronate-(a bisphosphonate) modified GNPs, on osteoclastogenesis and osteoclast function. RAW 264.7 macrophage cells were cultured with recombinant mouse receptor activator of NF-κB ligand (RANKL), which stimulates osteoclastogenesis, and were then treated with alendronate-modified GNPs for 24, 48, and 72 h. Cell proliferation, osteoclast function, and osteoclast morphology were evaluated by trypan blue dye exclusion assay, tartrate-resistant acid phosphatase (TRAP) staining, and transmission electron microscopy (TEM) imaging. Comparative studies were performed with GNPs that were only stabilized with citrate ions and with alendronate alone. Neither osteoclastogenesis nor osteoclast function were adversely affected by the presence of the citrate-GNP. Alendronate-modified GNPs had an enhanced effect on inducing osteoclast apoptosis and impairing osteoclast function when compared to unbound alendronate populations.

Azilsartan increases levels of IL-10, down-regulates MMP-2, MMP-9, RANKL/RANK, Cathepsin K and up-regulates OPG in an experimental periodontitis model.

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Aurigena Antunes de Araújo

Full Text Available AIMS: The aim of this study was to evaluate the effects of azilsartan (AZT on bone loss, inflammation, and the expression of matrix metallo proteinases (MMPs, receptor activator of nuclear factor κB ligand (RANKL, receptor activator of nuclear factor κB (RANK, osteoprotegerin (OPG, cyclooxygenase-2 (COX-2, and cathepsin K in periodontal tissue in a rat model of ligature-induced periodontitis. MATERIALS AND METHODS: Male Wistar albino rats were randomly divided into 5 groups of 10 rats each: (1 nonligated, water; (2 ligated, water; (3 ligated, 1 mg/kg AZT; (4 ligated, 5 mg/kg AZT; and (5 ligated, 10 mg/kg AZT. All groups were treated with saline or AZT for 10 days. Periodontal tissues were analyzed by histopathology and immunohistochemical detection of MMP-2, MMP-9, COX-2, RANKL, RANK, OPG, and cathepsin K. Levels of IL-1β, IL-10, TNF-α, myeloperoxidase (MPO, and glutathione (GSH were determined by ELISA. RESULTS: Treatment with 5 mg/kg AZT resulted in reduced MPO (p<0.05 and IL-1β (p<0.05, increased levels of IL-10 (p<0.05, and reduced expression of MMP-2, MMP-9, COX-2, RANK, RANKL, cathepsin K, and increased expression of OPG. CONCLUSIONS: These findings reveal that AZT increases anti-inflammatory cytokines and GSH and decreases bone loss in ligature-induced periodontitis in rats.

The Effects of Kaempferol-Inhibited Autophagy on Osteoclast Formation.

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Kim, Chang-Ju; Shin, Sang-Hun; Kim, Bok-Joo; Kim, Chul-Hoon; Kim, Jung-Han; Kang, Hae-Mi; Park, Bong-Soo; Kim, In-Ryoung

2018-01-02

Kaempferol, a flavonoid compound, is derived from the rhizome of Kaempferia galanga L ., which is used in traditional medicine in Asia. Autophagy has pleiotropic functions that are involved in cell growth, survival, nutrient supply under starvation, defense against pathogens, and antigen presentation. There are many studies dealing with the inhibitory effects of natural flavonoids in bone resorption. However, no studies have explained the relationship between the autophagic and inhibitory processes of osteoclastogenesis by natural flavonoids. The present study was undertaken to investigate the inhibitory effects of osteoclastogenesis through the autophagy inhibition process stimulated by kaempferol in murin macrophage (RAW 264.7) cells. The cytotoxic effect of Kaempferol was investigated by MTT assay. The osteoclast differentiation and autophagic process were confirmed via tartrate-resistant acid phosphatase (TRAP) staining, pit formation assay, western blot, and real-time PCR. Kaempferol controlled the expression of autophagy-related factors and in particular, it strongly inhibited the expression of p62/SQSTM1. In the western blot and real time-PCR analysis, when autophagy was suppressed with the application of 3-Methyladenine (3-MA) only, osteoclast and apoptosis related factors were not significantly affected. However, we found that after cells were treated with kaempferol, these factors inhibited autophagy and activated apoptosis. Therefore, we presume that kaempferol-inhibited autophagy activated apoptosis by degradation of p62/SQSTM1. Further study of the p62/SQSTM1 gene as a target in the autophagy mechanism, may help to delineate the potential role of kaempferol in the treatment of bone metabolism disorders.

Parallel Assessment of Bone Mineral Density and RANKL/OPG Ratio in Saudi Females

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AI Hassan

2016-02-01

Full Text Available Background: Osteoporosis is a significant risk factor for morbidity, and its high prevalence among Saudi women should be considered to be a public health problem. Quantitative ultrasound was recommended for bone mineral density (BMD screening. Receptor activator of nuclear factor kappa-B ligand (RANKL and osteoprotegerin (OPG and their ratio are critical for physiological bone remodelling, and related abnormalities may lead to several osteopathies. Methods: The BMD of 499 Saudi females aged 20 to 65 years was measured using quantitative ultrasound from the beginning of October 2013 to the end of March 2014 at the female medical unit of Taibah University, Madinah, KSA. Possible associated risk factors for low BMD were studied. Blood RANKL and OPG were measured by enzyme-linked immunosorbent assay (ELISA. Results: No significant differences were found between participants with normal and low BMD regarding the studied risk factors. However, there was a significant association (p < 0.05 between BMD and regular physical activity among participants aged 20 years to less than 35 years, and women aged 35–50 years with higher body mass index (BMI had higher BMD. The RANKL/OPG ratio was inversely associated (p = 0.04 with BMD. Conclusions: Regular physical activity is crucial for maximizing BMD in young females and decreasing the possibility of developing osteoporosis with ageing. The RANKL/OPG ratio might be considered a useful and easy-to-use tool for the prediction of low BMD.

Breast carcinoma with osteoclast-like giant cells

DEFF Research Database (Denmark)

Gjerdrum, L M; Lauridsen, M C; Sørensen, Flemming Brandt

2001-01-01

Primary carcinoma with osteoclast-like giant cells is a very rare tumour of the female breast. The clinical course, histological, immunohistochemical and ultrastructural features of 61 cases of invasive duct carcinoma with osteoclast-like multinucleated giant cells (OMGCs) are reviewed and a new...... in the literature have shown that 86% of patients with these tumours are still alive after 5 years. Histologically, these tumours are invasive ductal carcinomas with OMGCs next to the neoplastic glands and within their lumen. Signs of recent and past haemorrhage are ubiquitously present in the highly vascularized...

Dextromethorphan upregulates osteoblast and osteoclast activity but does not attenuate ovariectomy-induced osteoporosis.

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Wu, Jia-Lin; Tsai, Wei-Yuan; Chen, Jian-Horng; Wong, Chih-Shung

2017-03-15

Study on the in vivo regulatory role of glutamate in osteoblast (OB) and osteoclast (OC) differentiation is less advanced. The present study investigated the effect of dextromethorphan (DXM), an N-methyl-d-aspartate receptors (NMDARs) antagonist, on osteoporosis development. In order to examine the role of glutamate in bone metabolism, ovariectomized (Ovx) female Wistar rats were injected three times per week for 8weeks with either saline, or 15μg/kg of β-estrodiol, or DXM (40mg/kg) intraperitoneally. Serum samples were collected every two weeks for measuring osteocalcin and C-terminal telopeptide of type I collagen (CTX-1) level. Rats were then sacrificed at week 8 and the femurs harvested for micro-CT scanning and mechanical strength. In saline-treated group, osteocalcin level significantly lower than that of sham-operated rats at 8weeks after operation, while CTX-1 levels were not affected. Estrogen treatment, as a positive control, partially inhibited the Ovx-induced reduction of osteocalcin serum level. DXM injection prevented the Ovx-induced reduction of osteocalcin expression and significantly upregulated CTX-1 expression. The micro-CT scan showed that the bone volume density decreased significantly in DXM treated rats compared to the sham-operated rats. In the mechanical strength assay, the maximum failure load for DXM treatment was significantly lower than the other groups. Treatment with DXM upregulated OB and OC markers in Ovx rats, however with a greater effect on the OC marker, and had no significant benefit on bone volume density or bone strength. Copyright © 2017 Elsevier Inc. All rights reserved.

[Correlation of RANKL/OPG, dickkopf-1 and bone marrow edema in rheumatoid arthritis with the complaint of knee pain].

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Li, Min; Wu, Xiao-hui; Yin, Geng; Xie, Qi-bing

2015-03-01

To investigate the correlation of the receptor activator of nuclear factor kappa-B ligand (RANKL)/serum osteoprotegerin (OPG) system, Dickkopf-1 (DKK-1) and bone marrow edema (BME) in rheumatoid arthritis (RA) with the complaint of knee pain. The clinical data of 50 cases of RA with the complaint of knee pain were collected. According to MRI finding, half of them (25 cases) had bone marrow edema (BME). Each patient received the measurement of serum OPG, RANKL, DKK-1, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), anti cyclic citrullinated peptide antibody (CCP), rheumatoid factort(RF). The clinical symptoms, disease activity score 28 (DAS28), were compared between BME and non-BME griups, and the correlation between RANKL/OPG system, DKK-1 and BME of RA was analyzed. Compared with non BME group, BME group had shorter course (P=0.000), higher DAS28 score (P=0.009), CRP (P=0:000), RF (P=0.033) and CCP (P=0.012). lower level of serum OPG (P=0.000), higher level of RANKL (P=0.000), RANKL/OPG (P=0.000), and DKK-1 (P=0.001). The severity of bone marrow edema was correlated with the serum RANKL (volume r(s)=0.31, P=0.027; degree r(s)=0.33, P=0.022), RANKL/OPG (volume r(s)=0.29, P=0.039; degree r(s)=0.28, P=0.043), DKK-1 (volume r(s)=0.33, P=0.021; degree r(s)=0.34, P=0.019). BME is one of the early signs of bone erosion in RA, there were more active inflammation, autoantibodies, and osteocasts in RA patients with BME.

Mechanical loading prevents the stimulating effect of IL-1{beta} on osteocyte-modulated osteoclastogenesis

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Kulkarni, Rishikesh N.; Bakker, Astrid D.; Everts, Vincent [Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, Research Institute MOVE, Amsterdam (Netherlands); Klein-Nulend, Jenneke, E-mail: j.kleinnulend@acta.nl [Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and VU University Amsterdam, Research Institute MOVE, Amsterdam (Netherlands)

2012-03-30

Highlights: Black-Right-Pointing-Pointer Osteocyte incubation with IL-1{beta} stimulated osteocyte-modulated osteoclastogenesis. Black-Right-Pointing-Pointer Conditioned medium from IL-1{beta}-treated osteocytes increased osteoclastogenesis. Black-Right-Pointing-Pointer IL-1{beta} upregulated RANKL and downregulated OPG gene expression by osteocytes. Black-Right-Pointing-Pointer CYR61 is upregulated in mechanically stimulated osteocytes. Black-Right-Pointing-Pointer Mechanical loading of osteocytes may abolish IL-1{beta}-induced osteoclastogenesis. -- Abstract: Inflammatory diseases such as rheumatoid arthritis are often accompanied by higher plasma and synovial fluid levels of interleukin-1{beta} (IL-1{beta}), and by increased bone resorption. Since osteocytes are known to regulate bone resorption in response to changes in mechanical stimuli, we investigated whether IL-1{beta} affects osteocyte-modulated osteoclastogenesis in the presence or absence of mechanical loading of osteocytes. MLO-Y4 osteocytes were pre-incubated with IL-1{beta} (0.1-1 ng/ml) for 24 h. Cells were either or not subjected to mechanical loading by 1 h pulsating fluid flow (PFF; 0.7 {+-} 0.3 Pa, 5 Hz) in the presence of IL-1{beta} (0.1-1 ng/ml). Conditioned medium was collected after 1 h PFF or static cultures. Subsequently mouse bone marrow cells were seeded on top of the IL-1{beta}-treated osteocytes to determine osteoclastogenesis. Conditioned medium from mechanically loaded or static IL-1{beta}-treated osteocytes was added to co-cultures of untreated osteocytes and mouse bone marrow cells. Gene expression of cysteine-rich protein 61 (CYR61/CCN1), receptor activator of nuclear factor kappa-B ligand (RANKL), and osteoprotegerin (OPG) by osteocytes was determined immediately after PFF. Incubation of osteocytes with IL-1{beta}, as well as conditioned medium from static IL-1{beta}-treated osteocytes increased the formation of osteoclasts. However, conditioned medium from mechanically loaded IL

Mechanical loading prevents the stimulating effect of IL-1β on osteocyte-modulated osteoclastogenesis

International Nuclear Information System (INIS)

Kulkarni, Rishikesh N.; Bakker, Astrid D.; Everts, Vincent; Klein-Nulend, Jenneke

2012-01-01

Highlights: ► Osteocyte incubation with IL-1β stimulated osteocyte-modulated osteoclastogenesis. ► Conditioned medium from IL-1β-treated osteocytes increased osteoclastogenesis. ► IL-1β upregulated RANKL and downregulated OPG gene expression by osteocytes. ► CYR61 is upregulated in mechanically stimulated osteocytes. ► Mechanical loading of osteocytes may abolish IL-1β-induced osteoclastogenesis. -- Abstract: Inflammatory diseases such as rheumatoid arthritis are often accompanied by higher plasma and synovial fluid levels of interleukin-1β (IL-1β), and by increased bone resorption. Since osteocytes are known to regulate bone resorption in response to changes in mechanical stimuli, we investigated whether IL-1β affects osteocyte-modulated osteoclastogenesis in the presence or absence of mechanical loading of osteocytes. MLO-Y4 osteocytes were pre-incubated with IL-1β (0.1–1 ng/ml) for 24 h. Cells were either or not subjected to mechanical loading by 1 h pulsating fluid flow (PFF; 0.7 ± 0.3 Pa, 5 Hz) in the presence of IL-1β (0.1–1 ng/ml). Conditioned medium was collected after 1 h PFF or static cultures. Subsequently mouse bone marrow cells were seeded on top of the IL-1β-treated osteocytes to determine osteoclastogenesis. Conditioned medium from mechanically loaded or static IL-1β-treated osteocytes was added to co-cultures of untreated osteocytes and mouse bone marrow cells. Gene expression of cysteine-rich protein 61 (CYR61/CCN1), receptor activator of nuclear factor kappa-B ligand (RANKL), and osteoprotegerin (OPG) by osteocytes was determined immediately after PFF. Incubation of osteocytes with IL-1β, as well as conditioned medium from static IL-1β-treated osteocytes increased the formation of osteoclasts. However, conditioned medium from mechanically loaded IL-1β-treated osteocytes prevented osteoclast formation. Incubation with IL-1β upregulated RANKL and downregulated OPG gene expression by static osteocytes. PFF upregulated

C3 rho-inhibitor for targeted pharmacological manipulation of osteoclast-like cells.

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Andrea Tautzenberger

Full Text Available The C3 toxins from Clostridium botulinum (C3bot and Clostridium limosum (C3lim as well as C3-derived fusion proteins are selectively taken up into the cytosol of monocytes/macrophages where the C3-catalyzed ADP-ribosylation of Rho results in inhibition of Rho-signalling and characteristic morphological changes. Since the fusion toxin C2IN-C3lim was efficiently taken up into and inhibited proliferation of murine macrophage-like RAW 264.7 cells, its effects on RAW 264.7-derived osteoclasts were investigated. C2IN-C3lim was taken up into differentiated osteoclasts and decreased their resorption activity. In undifferentiated RAW 264.7 cells, C2IN-C3lim-treatment significantly decreased their differentiation into osteoclasts as determined by counting the multi-nucleated, TRAP-positive cells. This inhibitory effect was concentration- and time-dependent and most efficient when C2IN-C3lim was applied in the early stage of osteoclast-formation. A single-dose application of C2IN-C3lim at day 0 and its subsequent removal at day 1 reduced the number of osteoclasts in a comparable manner while C2IN-C3lim-application at later time points did not reduce the number of osteoclasts to a comparable degree. Control experiments with an enzymatically inactive C3 protein revealed that the ADP-ribosylation of Rho was essential for the observed effects. In conclusion, the results indicate that Rho-activity is crucial during the early phase of osteoclast-differentiation. Other bone cell types such as pre-osteoblastic cells were not affected by C2IN-C3lim. Due to their cell-type selective and specific mode of action, C3 proteins and C3-fusions might be valuable tools for targeted pharmacological manipulation of osteoclast formation and activity, which could lead to development of novel therapeutic strategies against osteoclast-associated diseases.

Osteoclastic finger arthrosis - a subtype of polyarthrosis of the hand

International Nuclear Information System (INIS)

Dihlmann, W.; Dihlmann, A.

1998-01-01

Aim: Description of a subtype of arthrosis deformans of the hand which is characterised as osteoclastic arthrosis. Patients and methods: Retrospective analysis of radiographs of the hands of 150 women and 100 men with radiological findings of arthrosis deformans. Results: 5% of women and 2% of men showed at least one digital joint with subchondral osteolysis of one or both articulating bones involving at least a third of the phalanx. This subchondral osteolysis far exceeds the cysts which are situated in the epiphyseal part of the articular region. It may develop within a year. Conclusion: Osteoclastic arthrosis of the finger is a subtype of polyarthrosis of the hand. Serial observations suggest that an osteoclast stimulating substance is produced by the cysts or arises directly from the synovial fluid; this enters the subchondral part of the bone through clefts which may or may not be visible radiologically and that this produces osteoclastic activity. The most important differential diagnoses are chronic tophacious gout and a benign tumor. (orig.) [de

Calorie-induced ER stress suppresses uroguanylin satiety signaling in diet-induced obesity.

Science.gov (United States)

Kim, G W; Lin, J E; Snook, A E; Aing, A S; Merlino, D J; Li, P; Waldman, S A

2016-05-23

The uroguanylin-GUCY2C gut-brain axis has emerged as one component regulating feeding, energy homeostasis, body mass and metabolism. Here, we explore a role for this axis in mechanisms underlying diet-induced obesity (DIO). Intestinal uroguanylin expression and secretion, and hypothalamic GUCY2C expression and anorexigenic signaling, were quantified in mice on high-calorie diets for 14 weeks. The role of endoplasmic reticulum (ER) stress in suppressing uroguanylin in DIO was explored using tunicamycin, an inducer of ER stress, and tauroursodeoxycholic acid (TUDCA), a chemical chaperone that inhibits ER stress. The impact of consumed calories on uroguanylin expression was explored by dietary manipulation. The role of uroguanylin in mechanisms underlying obesity was examined using Camk2a-Cre-ER(T2)-Rosa-STOP(loxP/loxP)-Guca2b mice in which tamoxifen induces transgenic hormone expression in brain. DIO suppressed intestinal uroguanylin expression and eliminated its postprandial secretion into the circulation. DIO suppressed uroguanylin through ER stress, an effect mimicked by tunicamycin and blocked by TUDCA. Hormone suppression by DIO reflected consumed calories, rather than the pathophysiological milieu of obesity, as a diet high in calories from carbohydrates suppressed uroguanylin in lean mice, whereas calorie restriction restored uroguanylin in obese mice. However, hypothalamic GUCY2C, enriched in the arcuate nucleus, produced anorexigenic signals mediating satiety upon exogenous agonist administration, and DIO did not impair these responses. Uroguanylin replacement by transgenic expression in brain repaired the hormone insufficiency and reconstituted satiety responses opposing DIO and its associated comorbidities, including visceral adiposity, glucose intolerance and hepatic steatosis. These studies reveal a novel pathophysiological mechanism contributing to obesity in which calorie-induced suppression of intestinal uroguanylin impairs hypothalamic mechanisms

Deletion of Adseverin in Osteoclasts Affects Cell Structure But Not Bone Metabolism.

Science.gov (United States)

Cao, Yixuan; Wang, Yongqiang; Sprangers, Sara; Picavet, Daisy I; Glogauer, Michael; McCulloch, Christopher A; Everts, Vincent

2017-08-01

Adseverin is an actin-severing/capping protein that may contribute to osteoclast differentiation in vitro but its role in bone remodeling of healthy animals is not defined. We analyzed bone and osteoclast structure in adseverin conditional null mice at alveolar and long bone sites. In wild-type and adseverin null mice, as measured by dual-energy X-ray absorptiometry, there were no differences of bone mineral content or bone mineral density, indicating no change of bone metabolism. In tibiae, TRAcP + osteoclasts were formed in comparable numbers in adseverin null and wild-type mice. Ultrastructural analysis showed normal and similar abundance of ruffled borders, sealing zones, and mitochondria, and with no difference of osteoclast nuclear numbers. In contrast, analyses of long bone showed that in the absence of adseverin osteoclasts were smaller (120 ± 13 vs. 274 ± 19 µm 2 ; p structure but not to bone metabolism in vivo.

Osteoclast cell-surface specializations and nuclear kinetics during egg-laying in Japanese quail

International Nuclear Information System (INIS)

Miller, S.C.

1981-01-01

Medullary bone deposits serve as a reservoir of labile calcium for egg-shell calcification in birds. Quantitative transmission-electron-microscope methods and light-microscope autoradiographic cell-population-kinetic analyses were used to determine changes in cell-surface specializations and population dynamics of medullary bone osteoclasts during egg-laying in Japanese quail. Prior to egg-shell formation, from 0 to about 8 hours after the previous oviposition, very few osteoclast profiles had ruffled borders. The appearance of ruffled borders coincided with the beginning of egg-shell calcification, about 9-10 hours after the previous oviposition. During egg-shell calcification, about 10-21 hours after the previous oviposition, most osteoclast profiles had ruffled borders. Ruffled borders disappeared at the completion of egg-shell calcification and commencement of egg-shell pigmentation. Thus, functional activities of medullary bone osteoclasts appear to be closely synchronized with egg-shell calcification during egg-laying. From 1 to 48 hours after a single injection of 3H-thymidine (3H-TdR), very few labeled osteoclast nuclei were seen during egg-laying. Following multiple injections of 3H-TdR, the percentage of labeled nuclei reached a peak at about 170 hours after the first injection. At this peak-labeling time, relatively few of the osteoclast profiles that had labeled nuclei had two or more; although the average number of nuclei per osteoclast profile was about 3.6. These kinetic data suggest that the medullary bone osteoclast population has a prolonged rate of turnover compared to rapid changes in cell activities associated with each 24-hour egg-laying cycle; and collectively they would suggest that rapid changes in osteoclast functions occur independently of changes in cell-population dynamics

Facilitation of bone resorption activities in synovial lavage fluid patients with mandibular condyle fractures.

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