Regulation of RANKL (receptor activator of nuclear factor κB ligand)-induced osteoclast differentiation is of current interest in the development of antiresorptive agents. Osteoclasts are multinucleated cells that play a crucial role in bone resorption. In this study, we investigated the effects of N-methylpyrrolidone (NMP) on the regulation of RANKL-induced osteoclastogenesis. NMP inhibited RANKL-induced tartrate-resistant acid phosphatase activity and the formation of tartrate-resistant acid phosphatase-positive multinucleated cells. The RANKL-induced expression of NFATc1 (nuclear factor of activated T cells, cytoplasmic 1) and c-Fos, which are key transcription factors for osteoclastogenesis, was also reduced by treatment with NMP. Furthermore, NMP induced disruption of the actin rings and decreased the mRNAs of cathepsin K and MMP-9 (matrix metalloproteinase-9), both involved in bone resorption. Taken together, these results suggest that NMP inhibits osteoclast differentiation and ...
TY - JOUR. T1 - Effects of stem cell factor on osteoclast-like cell formation in long-term human marrow cultures. AU - Demulder, A.. AU - Suggs, S. V.. AU - Zsebo, K. M.. AU - Scarcez, T.. AU - Roodman, G. David. PY - 1992/11. Y1 - 1992/11. N2 - Stem cell factor (SCF) is a newly described hematopoietic growth factor that stimulates the growth of primitive hematopoietic progenitors and mast cells. Since the osteoclast precursor is hematopoietic in origin, we tested SCF for its capacity to stimulate the formation of osteoclast-like multinucleated cells (MNC) in long-term human marrow cultures. These MNC express an osteoclast phenotype and form resorption lacunae on calcified matrices. Addition of SCF alone (0.1 pg/ml to 100 ng/ml) to long-term marrow cultures did not increase MNC formation. However, treatment of these cultures sequentially with SCF for 1 week followed by 1,25-(OH)2D3 for the second and third weeks of culture significantly enhanced MNC formation. [3H]Thymidine incorporation studies ...
Soy isoflavones and docosahexaenoic acid (DHA) are effective for maintaining bone health. This study investigated the combined effects of soy isoflavones and DHA on osteoclast formation. Mouse bone marrow cells were pre-cultured with macrophage colony-stimulating factor (M-CSF) for 3 days and then cultured with M-CSF and receptor activator of nuclear factor κB ligand (RANKL) for 6 days. RAW 264.7 cells were cultured with RANKL for 5 days. In mouse bone marrow cells, daidzein, genistein, and DHA significantly decreased the number of tartrate-resistant acid phosphatase-positive multinucleated cells (TRAP(+)MNCs), and the combination of soy isoflavones and DHA further decreased the number of TRAP(+)MNCs. Nuclear factor of activated T-cells c1 (NFATc1) mRNA expression tended to be decreased by daidzein, and was significantly decreased by genistein and DHA. Furthermore, the combination of daidzein and DHA caused significant reduction in NFATc1 mRNA expression compared to the control. In RAW 264.7 cells,
Interleukin-6 (IL-6) and interleukin-11 (IL-11) are known to influence osteoclast formation and bone resorption. In order to determine whether IL-6 and IL-11 could independently support human osteoclast formation, these factors were added to cultures of human peripheral blood mononuclear cells of the monocyte (CD14(+)) fraction in the presence of macrophage colony-stimulating factor (M-CSF). Under these conditions, IL-6 and IL-11 induced the formation of multinucleated cells which were positive for TRAP, VNR, and calcitonin receptor and capable of lacunar resorption. Osteoclastogenesis induced by IL-6 and IL-11 was inhibited by the addition of an anti-gp130 antibody but not by osteoprotegerin. These results indicate that IL-6 and IL-11, which are thought to play a role in several osteolytic bone disorders, are directly capable of inducing osteoclast formation by a RANKL-independent mechanism.
TY - JOUR. T1 - Eriodictyol Inhibits RANKL-Induced Osteoclast Formation and Function Via Inhibition of NFATc1 Activity. AU - Song, Fangming. AU - Zhou, Lin. AU - Zhao, J.. AU - Liu, Q.. AU - Yang, Mingli. AU - Tan, R.. AU - Xu, J.. AU - Zhang, G.. AU - Quinn, J.M.W.. AU - Tickner, Jennifer. AU - Huang, Y.. AU - Xu, Jiake. PY - 2016/9. Y1 - 2016/9. N2 - © 2016 Wiley Periodicals, Inc. Receptor activator of nuclear factor kappa-B ligand (RANKL) induces differentiation and function of osteoclasts through triggering multiple signaling cascades, including NF-?B, MAPK, and Ca2+-dependent signals, which induce and activate critical transcription factor NFATc1. Targeting these signaling cascades may serve as an effective therapy against osteoclast-related diseases. Here, by screening a panel of natural plant extracts with known anti-inflammatory, anti-tumor, or anti-oxidant properties for possible anti-osteoclastogenic activities we identified Eriodictyol. This flavanone potently suppressed ...
Osteoclasts demonstrate ontogenetic changes in site specificity. Figure 3 and Table 1 clearly show that TRAP-positive osteoclasts are absent during initial postnatal development. This does not preclude the presence of osteoclasts at this time. In fact, Rice et al. (1997) have shown MMP-9-positive osteoclasts at these ages. The probable reason for this is because the calvarial bone being deposited at these newborn stages is low in mineral content. The matrix metalloproteinase, MMP-9, is thought to be sufficient for the early requirements of bone resorption. Later in postnatal development as bone becomes more densely mineralized, TRAP-positive osteoclasts would be required for resorption. Congruent with this explanation, osteoclasts are observed along concave and straight sagittal suture margins at 10 days postnatal. By 21 days postnatal, one can observe osteoclasts along convex margins as well. The occurrence of osteoclasts along convex and concave regions increases incrementally until 42 days ...
IL-1 is a proinflammatory cytokine that acts as an important mediator of the peripheral immune response during infection and inflammation (33). It is also known that IL-1 can induce bone destruction in a variety of diseases such as osteoporosis, rheumatoid arthritis, and periodontal disease (34, 35). IL-1 stimulates osteoclast differentiation, fusion, and activation (35). In this paper, we examined the direct effect of IL-1 on osteoclast precursors which led to the elucidation of a previously unknown mechanism of downstream signaling pathways during IL-1-induced osteoclastogenesis.. Although TNF-α and IL-1 can activate early signaling pathways including NF-κB, JNK, and p38, which are important for RANKL-induced osteoclast differentiation, TNF-α alone has been shown to induce osteoclast differentiation in vitro (21, 36). IL-1 activates mature osteoclasts, thereby enhancing bone resorption (35), but our data along with previous studies (35, 36) demonstrate that IL-1 alone is insufficient to ...
Human osteoclast formation from monocyte precursors under the action of receptor activator of nuclear factor-{kappa}B ligand (RANKL) was suppressed by granulocyte macrophage colony-stimulating factor (GM-CSF), with down-regulation of critical osteoclast-related nuclear factors. GM-CSF in the presence of RANKL and macrophage colony-stimulating factor resulted in mononuclear cells that were negative for tartrate-resistant acid phosphatase (TRAP) and negative for bone resorption. CD1a, a dendritic cell marker, was expressed in GM-CSF, RANKL, and macrophage colony-stimulating factor-treated cells and absent in osteoclasts. Microarray showed that the CC chemokine, monocyte chemotactic protein 1 (MCP-1), was profoundly repressed by GM-CSF. Addition of MCP-1 reversed GM-CSF suppression of osteoclast formation, recovering the bone resorption phenotype. MCP-1 and chemokine RANTES (regulated on activation normal T cell expressed and secreted) permitted formation of TRAP-positive multinuclear cells in the ...
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
Wear particles derived from implant biomaterials induce a pronounced foreign body macrophage response in both the pseudocapsule and pseudomembrane surrounding arthroplasty components.28 29 The clinical severity and rapidly of onset of aseptic loosening can be correlated with both the amount of wear particle deposition and the extent of the macrophage response in these periprosthetic tissue.30-32 In this study we have shown that the capacity of arthroplasty macrophages to differentiate into osteoclasts is OPGL dependent and that this process is inhibited by OPG in a dose dependent fashion.. Our results show that the inflammatory foreign body macrophage infiltrate in periprosthetic tissues, surrounding loose arthroplasty components, contains mononuclear osteoclast precursors and that these cells express the phenotypic characteristics of macrophages and not osteoclasts. Post-mitotic osteoclast precursors of marrow origin have been shown to lose and to acquire macrophage and osteoclast markers ...
We reported that interleukin (IL) 6 alone cannot induce osteoclast formation in cocultures of mouse bone marrow and osteoblastic cells, but soluble IL-6 receptor (IL-6R) strikingly triggered osteoclast formation induced by IL-6. In this study, we examined the mechanism of osteoclast formation by IL-6 and related cytokines through the interaction between osteoblastic cells and osteoclast progenitors. When dexamethasone was added to the cocultures, IL-6 could stimulate osteoclast formation without the help of soluble IL-6R. Osteoblastic cells expressed a very low level of IL-6R mRNA, whereas fresh mouse spleen and bone marrow cells, both of which are considered to be osteoclast progenitors, constitutively expressed relatively high levels of IL-6R mRNA. Treatment of osteoblastic cells with dexamethasone induced a marked increase in the expression of IL-6R mRNA. By immunoblotting with antiphosphotyrosine antibody, IL-6 did not tyrosine-phosphorylate a protein with a molecular mass of 130 kD in ...
Kahweol is a natural product in coffee beans. It exhibits a wide variety of biological activities, including inhibiting RANKL-induced osteoclast generation, inducing cell cycle arrest and apoptosis in oral squamous cell carcinoma cells, preventing aflatoxin B1 induced DNA adduct formation, and suppressing H2O2-induced DNA damage and oxidative stress.
Transforming growth factor beta (TGFbeta) is a multifunctional growth factor that is produced by many cells in bone and is abundant in the bone matrix. TGFbeta is known to regulate RANKL-induced osteoclast formation and bone resorbing activity. In this study we sought to determine whether TGFbeta could directly induce osteoclast formation by a RANKL-independent mechanism. We found that the addition of TGFbeta to cultures of human monocytes and RAW 264.7 cells (in the presence of M-CSF and the absence of RANKL, TNFalpha or IL-6/IL-11) was sufficient to induce the formation of TRAP+ and VNR+ cells, which formed actin rings and were capable of extensive lacunar resorption. The addition of osteoprotegerin or antibodies to TNFalpha and its receptors, as well as antibodies to gp130, did not inhibit lacunar resorption, indicating that TGFbeta did not act by stimulating RANKL, TNF or IL-6 production by monocytes. TGFbeta-induced osteoclast formation was qualitatively different from that induced by RANKL with
Inoxitol hexakisphosphate (IP6) has been found to have an important role in biomineralization and a direct effect inhibiting mineralization of osteoblasts in vitro without impairing extracellular matrix production and expression of alkaline phosphatase. IP6 has been proposed to exhibit similar effects to those of bisphosphonates on bone resorption, however, its direct effect on osteoclasts (OCL) is presently unknown. The aim of the present study was to investigate the effect of IP6 on the RAW 264.7 monocyte/macrophage mouse cell line and on human primary osteoclasts. On one hand, we show that IP6 decreases the osteoclastogenesis in RAW 264.7 cells induced by RANKL, without affecting cell proliferation or cell viability. The number of TRAP positive cells and mRNA levels of osteoclast markers such as TRAP, calcitonin receptor, cathepsin K and MMP-9 was decreased by IP6 on RANKL-treated cells. On the contrary, when giving IP6 to mature osteoclasts after RANKL treatment, a significant increase of ...
Based on our earlier observation that caspase-3 is present in osteoclasts that are not undergoing apoptosis, we investigated the role of this protein in the differentiation of primary osteoclasts and RAW264.7 cells (Szymczyk KH, et al, 2005, Caspase-3 activity is necessary for RANKL-induced osteoclast differentiation. The Proceedings of the 8th ICCBMT). We noted that osteoclast numbers are decreased in long bones of procaspase-3 knockout mice and that receptor activator of NF-κB ligand (RANKL) does not promote differentiation of isolated preosteoclasts. In addition, after treatment with inhibitors of caspase-3 activity, neither the wild-type primary nor the RAW264.7 cells express TRAP or became multinucleated. We found that immediately following RANKL treatment, procaspase-3 is cleaved and the activated protein is localized to lipid regions of the plasma membrane and the cytosol. We developed RAW264.7 procaspase-3 knockdown clonal cell lines using RNAi technology. Again, treatment with RANKL fails to
An osteoclast (from the Greek words for "bone" (ὀστέον), and "broken" (κλαστός)) is a type of bone cell that breaks down bone tissue. This function is critical in the maintenance, repair, and remodelling of bones of the vertebral skeleton. The osteoclast disassembles and digests the composite of hydrated protein and mineral at a molecular level by secreting acid and a collagenase, a process known as bone resorption. This process also helps regulate the level of blood calcium. An odontoclast (/odon·to·clast/; o-don´to-klast) is an osteoclast associated with absorption of the roots of deciduous teeth. An osteoclast is a large multinucleated cell and human osteoclasts on bone typically have five nuclei and are about 150-200 µm in diameter. When osteoclast-inducing cytokines are used to convert macrophages to osteoclasts, very large cells that may reach 100 µm in diameter occur. These may have dozens of nuclei, and typically express major osteoclast proteins but have significant ...
BACKGROUND: Interleukin-32 (IL-32) is a newly described cytokine produced after stimulation by IL-2 or IL-18 and IFN-gamma. IL-32 has the typical properties of a pro-inflammatory mediator and although its role in rheumatoid arthritis has been recently reported its effect on the osteoclastogenesis process remains unclear. METHODOLOGY/PRINCIPAL FINDINGS: In the present study, we have shown that IL-32 was a potent modulator of osteoclastogenesis in vitro, whereby it promoted the differentiation of osteoclast precursors into TRAcP+ VNR+ multinucleated cells expressing specific osteoclast markers (up-regulation of NFATc1, OSCAR, Cathepsin K), but it was incapable of inducing the maturation of these multinucleated cells into bone-resorbing cells. The lack of bone resorption in IL-32-treated cultures could in part be explain by the lack of F-actin ring formation by the multinucleated cells generated. Moreover, when IL-32 was added to PBMC cultures maintained with soluble RANKL, although the number of newly
Since their discovery in 1873 there has been considerable debate about their origin. Three theories were dominant: from 1949 to 1970 the connective tissue origin was popular, which stated that osteoclasts and osteoblasts are of the same lineage, and osteoblasts fuse together to form osteoclasts. After years of controversy it is now clear that these cells develop from the self fusion of macrophages.[9] It was in the beginning of 1980 that the monocyte phagocytic system was recognized as precursor of osteoclasts.[10] Osteoclast formation requires the presence of RANKL (receptor activator of nuclear factor κβ ligand) and M-CSF (Macrophage colony-stimulating factor). These membrane-bound proteins are produced by neighbouring stromal cells and osteoblasts, thus requiring direct contact between these cells and osteoclast precursors. M-CSF acts through its receptor on the osteoclast, c-fms (colony-stimulating factor 1 receptor), a transmembrane tyrosine kinase-receptor, leading to secondary messenger ...
Since their discovery in 1873 there has been considerable debate about their origin. Three theories were dominant: from 1949 to 1970 the connective tissue origin was popular, which stated that osteoclasts and osteoblasts are of the same lineage, and osteoblasts fuse together to form osteoclasts. After years of controversy it is now clear that these cells develop from the self fusion of macrophages.[9] It was in the beginning of 1980 that the monocyte phagocytic system was recognized as precursor of osteoclasts.[10] Osteoclast formation requires the presence of RANKL (receptor activator of nuclear factor κβ ligand) and M-CSF (Macrophage colony-stimulating factor). These membrane-bound proteins are produced by neighbouring stromal cells and osteoblasts, thus requiring direct contact between these cells and osteoclast precursors. M-CSF acts through its receptor on the osteoclast, c-fms (colony-stimulating factor 1 receptor), a transmembrane tyrosine kinase-receptor, leading to secondary messenger ...
Bone resorption relies on the extracellular acidification function of V-ATPase (vacuolar-type proton-translocating ATPase) proton pump(s) present in the plasma membrane of osteoclasts. The exact configuration of the osteoclast-specific ruffled border V-ATPases remains largely unknown. In the present study, we found that the V-ATPase subunit Atp6v1c1 (C1) is highly expressed in osteoclasts, whereas subunits Atp6v1c2a (C2a) and Atp6v1c2b (C2b) are not. The expression level of C1 is highly induced by RANKL [receptor activator for NF-κB (nuclear factor κB) ligand] during osteoclast differentiation; C1 interacts with Atp6v0a3 (a3) and is mainly localized on the ruffled border of activated osteoclasts. The results of the present study show for the first time that C1-silencing by lentivirus-mediated RNA interference severely impaired osteoclast acidification activity and bone resorption, whereas cell differentiation did not appear to be affected, which is similar to a3 silencing. The F-actin ...
Osteoclasts are large, multinucleated cells whose primary function is bone resorption. This process is regulated at multiple levels, including the proliferation and homing of osteoclast progenitors and their fusion into multinucleated cells (reviewed by Teitelbaum, 2000). Upon identification of appropriate resorption sites, osteoclasts reorganize their small matrix adhesions - podosomes - into a circular adhesion structure at the cell periphery known as the `sealing zone, and secrete protons and lysosomal enzymes into the space between the cell and the bone surface (Nesbitt and Horton, 1997; Salo et al., 1997). These structures form readily on bone surfaces; similar organization of podosome super-structures was observed in cells grown on standard tissue culture surfaces (Calle et al., 2004; Lakkakorpi et al., 1993; Zambonin-Zallone et al., 1988).. Podosomes are small (∼1 μm in diameter) dot-like adhesion structures found in osteoclasts, macrophages, dendritic cells and several types of ...
Excessive osteoclast formation and bone resorption are key causes of osteoporosis. Natural compounds can serve as alternative therapeutic agents for the prevention and treatment of osteoporosis, and some natural compounds may have advantages over traditional drugs. Here, we report that the natural compound gambogic acid (GBA), which is bioavailable, effective, and less toxic, inhibits osteoclast formation, thereby attenuating osteoclastic bone resorption in vitro . Further in vivo studies demonstrated that GBA prevented ovariectomy(OVX)-induced bone loss in a dose-dependent manner. Moreover, we demonstrated that GBA suppressed RANKL-induced JNK, p38 and AKT phosphorylation. Taken together, our results demonstrate that GBA inhibits osteoclast formation in vitro and in vivo , suggesting that it is of potential value in the treatment of osteoclast-related diseases. ...
|i|Objective|/i|. Tumor necrosis factor (TNF) increases circulating osteoclast (OC) precursors numbers by promoting their proliferation and differentiation. The aim of this study was to assess the effect of TNF inhibitors (TNFi) on the differentiation and activity of OC in rheumatoid arthritis (RA) patients.|i| Methods.|/i| Seventeen RA patients treated with TNFi were analyzed at baseline and after a minimum follow-up period of 6 months. Blood samples were collected to assess receptor activator of nuclear factor kappa-B ligand (RANKL) surface expression on circulating leukocytes and frequency and phenotype of monocyte subpopulations. Quantification of serum levels of bone turnover markers, in vitro OC differentiation assays, and qRT-PCR for OC specific genes was performed.|i| Results|/i|. After TNFi therapy, patients had reduced RANKL surface expression in B-lymphocytes and the frequency of circulating classical |svg xmlns:xlink=http://www.w3.org/1999/xlink xmlns=http://www.w3.org/2000/svg style=
TY - JOUR. T1 - Osteoclasts, mononuclear phagocytes, and c-Fos. T2 - New insight into osteoimmunology. AU - Matsuo, Koichi. AU - Ray, Neelanjan. PY - 2004/6/1. Y1 - 2004/6/1. N2 - Osteoimmunology is the emerging concept that certain molecules link the skeletal and immune systems. The transcription factor c-Fos, a component of activator protein-1 (AP-1), is essential for osteoclast differentiation. Mice lacking c-Fos are osteopetrotic owing to impaired osteoclast development. Recent studies suggest that in contrast to this positive role in osteoclastogenesis, c-Fos expression inhibits differentiation and activation of mononuclear phagocytes. Here, we focus on the contrasting roles of c-Fos in the bone and immune lineages. Both osteoclasts and mononuclear phagocytes are derived from common myeloid precursors. Osteoclasts resorb bone, whereas macrophages and myeloid dendritic cells phagocytose microbial pathogens, initiating innate and adaptive immunity. Differentiation of the common precursors ...
beta(3) integrin-null osteoclasts are dysfunctional, but their numbers are increased in vivo. In vitro, however, the number of beta(3)(-/-) osteoclasts is reduced because of arrested differentiation. This paradox suggests cytokine regulation of beta(3)(-/-) osteoclastogenesis differs in vitro and in vivo. In vitro, additional MCSF, but not receptor activator of NF-kappaB ligand (RANKL), completely rescues beta(3)(-/-) osteoclastogenesis. Similarly, activation of extracellular signal-regulated kinases (ERKs) and expression of c-Fos, both essential for osteoclastogenesis, are attenuated in beta(3)(-/-) preosteoclasts, but completely restored by additional MCSF. In fact, circulating and bone marrow cell membrane-bound MCSFs are enhanced in beta(3)(-/-) mice, correlating with the increase in the osteoclast number. To identify components of the MCSF receptor that is critical for osteoclastogenesis in beta(3)(-/-) cells, we retrovirally transduced authentic osteoclast precursors with chimeric c-Fms constructs
TY - JOUR. T1 - Cytokine regulation and the signaling mechanism of osteoclast inhibitory peptide-1 (OIP-1/hSca) to inhibit osteoclast formation. AU - Koide, Masanori. AU - Maeda, Hidefumi. AU - Roccisana, Jennifer L.. AU - Kawanabe, Noriaki. AU - Reddy, Sakamuri V.. PY - 2003/3/1. Y1 - 2003/3/1. N2 - The osteoclast (OCL) is the primary bone resorbing cell. OCL formation and activity is regulated by local factors produced in the bone microenvironment. We recently identified OCL inhibitory peptide-1 (OIP-1/ hSca) as a novel inhibitor of OCL formation and bone resorption that is produced by OCLs. OIP-1 is a glycosylphosphatidyl-inositol (GPI)-linked membrane protein (16 kDa) related to the mouse Ly-6 family of hematopoietic proteins. OIP-1 mRNA is expressed in human OCL precursors, granulocyte-macrophage colony-forming unit (GM-CFU), bone marrow cells, and osteoblast cells. We used cycle-dependent reverse transcriptase-polymerase chain reaction (RT-PCR) analysis, which further demonstrated that ...
To better understand the roles of TGF-beta in bone metabolism, we investigated osteoclast survival in response TGF-beta and found that TGF-beta inhibited apoptosis. We examined the receptors involved in promotion of osteoclast survival and found that the canonical TGF-beta receptor complex is involved in the survival response. The upstream MEK kinase TAK1 was rapidly activated following TGF-beta treatment. Since osteoclast survival involves MEK, AKT, and NFkappaB activation, we examined TGF-beta effects on activation of these pathways and observed rapid phosphorylation of MEK, AKT, IKK, IkappaB, and NFkappaB. The timing of activation coincided with SMAD activation and dominant negative SMAD expression did not inhibit NFkappaB activation, indicating that kinase pathway activation is independent of SMAD signaling. Inhibition of TAK1, MEK, AKT, NIK, IKK, or NFkappaB repressed TGF-beta-mediated osteoclast survival. Adenoviral-mediated TAK1 or MEK inhibition eliminated TGF-beta-mediated kinase pathway
Methods For in vitro validation of osteoclastogenesis mouse bone marrow derived cells were differentiated into tartrate-resistant acid phosphatase positive (TRAP+) mononuclear osteoclasts (pre-osteoclasts) and TRAP+ multinucleated mature osteoclasts in the presence of macrophage-colony stimulating factor (M-CSF) and receptor activator of nuclear factor kappaB ligand (RANKL). Cilengitide, kindly provided by Merck KGaA, was added in increasing concentrations (2nM to 20μM) to the culture. Moreover, we performed osteoclastogenesis assays on osteopontin, fibronectin and fibrinogen matrix coated plates. In order to asses for αvβ3 integrin independent adhesion, osteolastogenesis assays were performed on Poly-D-lysine coated plates. CIA was induced in male DBA/1 mice by immunisation with bovine type II collagen (CII) at day 1, followed by boosting at day 21. For the CIA prevention study mice were injected 15mg/kg cilengitide subcutaneously, 5 days per week, starting 1 day prior to CIA induction until ...
2924 Genrally, prostatic cancer shows osteoblastic metastases, whereas the lesion also causes osteolysis. The present study was undertaken to test the effects of prostate cancer cell lines (LNCaP, DU145, PC3, and MDA PCa 2b) on osteoclastogenesis. Using a reverse transcription-polymerase chain reaction approach, we investigated the effects of crude conditioned medium (CM) obtained from prostate cancer cell lines on mRNA level of receptor activator of NF-κB ligand (RANKL) and its decoy receptor, osteoprotegerin (OPG) in mouse osteoblastic cell line, MC3T3-E1. Then we cocultured MC3T3-E1 with prostate cancer cell lines and evaluated mRNA level of RANKL and OPG in MC3T3-E1. Next, to investigate the effects on osteoclast precursor generated from mouse bone marrow treated with RANKL and MCSF, we cultured osteoclast precursor with crude CM obtained from prostate cancer cell lines in the presence or absence of RANKL or OPG. The number of multinucleated osteoclasts was evaluated by TRAP staining. Crude ...
... ,Osteoclast cells form from a hematopoietic stem cells called monocytes. Osteoclasts resorb bone by attaching to the bone surface and lowering the surrounding pH to an acidic level of around 4.5. The bone mineral is then solubilized and the collagen degraded. Osteoclast differentiation and function,biological,biology supply,biology supplies,biology product
Summary: Rapid progress has been made in recent years in our understanding of the mechanisms regulating the formation, activation, and survival of osteoclasts, which are derived from precursor cells in the myeloid lineage. In contrast, study of the regulation of osteoclast precursors (OCPs) has been relatively slow, in part because it has been hard to accurately identify them. However, following the discovery of cell-surface markers that facilitated purification of OCPs, recent studies have demonstrated that peripheral blood OCP numbers are increased in tumor necrosis factor (TNF)-mediated arthritis, both in animals and humans, and these numbers correlate with serum TNF levels. The increase can be reversed by anti-TNF therapy. Furthermore, the precursor cells that give rise to osteoclasts can also differentiate into other cell types, including dendritic cells. Receptor activator nuclear factor-κB ligand (RANKL) stimulates OCPs to produce pro-inflammatory cytokines and chemokines, and RANKL ...
Runt-related transcription factor 1 (Runx1), a master regulator of hematopoiesis, is expressed in preosteoclasts. Previously we evaluated the bone phenotype of CD11b-Cre Runx1(fl/fl) mice and demonstrated enhanced osteoclasts and decreased bone mass in males. However, an assessment of the effects of Runx1 deletion in female osteoclast precursors was impossible with this model. Moreover, the role of Runx1 in myeloid cell differentiation into other lineages is unknown. Therefore, we generated LysM-Cre Runx1(fl/fl) mice, which delete Runx1 equally (∼80% deletion) in myeloid precursor cells from both sexes and examined the capacity of these cells to differentiate into osteoclasts and phagocytic and antigen-presenting cells. Both female and male LysM-Cre Runx1(fl/fl) mice had decreased trabecular bone mass (72% decrease in bone volume fraction) and increased osteoclast number (2-3 times) (P < .05) without alteration of osteoblast histomorphometric indices. We also demonstrated that loss of Runx1 in ...
Bone formation and resorption coupling is a process wherein osteoclastic bone resorption is followed by osteoblastic bone formation. For resorption, two classes of axon guidance molecules, SLITs (SLIT3) and semaphorins (SEMA3a), act together to fine-tune repulsive signals for osteoclast migration, while inhibiting differentiation and cell fusion. SLIT3 is produced by mature osteoclasts, whereas the critical bone actions of SEMA3a originate from nerves. These repulsive and inhibitory effects of SEMA3a and SLIT3 on osteoclasts are countered by netrin-1, another molecule originally identified for its role in axon guidance. Netrin-1 attracts osteoclasts and promotes their fusion. Additional molecular pathways controlling osteoclasts include ephrin/ephrin receptor tyrosine kinase (ephrin/EPH) signaling via cell contact between osteoblasts and osteoclasts, and the RANKL/RANK pathway for osteoclastogenesis. For bone formation, signals released from mineralized matrix, such as TGF-β and IGF-1, in ...
The multinucleated bone-resorbing osteoclast has a hematopoietic origin. We have demonstrated previously that osteoclasts are derived from the monocytic lineage by fusion of mononuclear macrophage precursors. Using an in vitro-osteoclast differentiation model derived from pure populations of chick macrophage cultures, osteoclast-like multinucleated giant cells (MNGCs) can be formed by fusion following an active proliferation phase. However, after reaching a peak with 70% of the culture being MNGCs, a new round of expansion of the mononuclear cells is observed. The following experiments suggest that these mononuclear cells were derived directly from the MNGCs by a budding process, selectively from the central zone of the apical surface. After microinjection of the membrane-impermeable probe, Lucifer Yellow, into single MNGCs, initially only diffuse fluorescence, limited to the whole MNGC injected, was observed. However, after 24-48 hours fluorescent mononuclear cells were observed adjacent but ...
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, ...
The alternative or noncanonical nuclear factor kappa B (NF-κB) pathway regulates the osteoclast (OC) response to receptor activator of nuclear factor kappa B ligand (RANKL) and thus bone metabolism. Although several lines of evidence support the emerging concept that nucleotide-binding leucine-rich repeat and pyrin domain-containing receptor 12 (NLRP12) impedes alternative NF-κB activation in innate immune cells, a functional role for NLRP12 outside an inflammatory disease model has yet to be reported. Our study demonstrates that NLRP12 has a protective role in bone via suppression of alternative NF-κB-induced osteoclastogenesis and is down-modulated in response to osteoclastogenic stimuli. Here, we show that retroviral overexpression of NLRP12 suppressed RelB nuclear translocation and OC formation. Conversely, genetic ablation of NLRP12 promoted NIK stabilization, RelB nuclear translocation, and increased osteoclastogenesis in vitro. Using radiation chimeras, we demonstrated these in vitro ...
Pathological bone resorption by osteoclasts is primarily treated with bisphosphonates. Because the administration of bisphosphonates is associated with a risk for multiple adverse symptoms, a precise understanding of the mechanisms underlying osteoclastogenesis is required to develop drugs with minimal side-effects. Osteoclastogenesis depends on receptor activator of nuclear factor kappa B (RANK) signaling mediated by TRAF6. We previously identified a highly conserved domain in the cytoplasmic tail of RANK (HCR), which did not share any significant homology with other proteins and was essential for osteoclastogenesis. HCR acts as a platform for the formation of Gab2- and Vav3-containing signal complexes, and ectopic expression of the HCR peptide inhibits osteoclastogenesis. Here, we uncover the mechanisms of HCR peptide-mediated inhibition of osteoclastogenesis. Expression of either the amino- or carboxyl-terminal half of the HCR peptide (N- or C-peptide) independently inhibited RANK signaling ...
The osteoclasts, multinucleared cells originating from the hematopoietic monocyte-macrophage lineage, are responsible for bone resorption. Osteoclastogenesis is mainly regulated by signaling pathways activated by RANK and immune receptors, whose ligands are expressed on the surface of osteoblasts. Signaling from RANK changes gene expression patterns through transcription factors like NFATc1 and characterizes the active osteoclast ...
The osteoclasts, multinucleared cells originating from the hematopoietic monocyte-macrophage lineage, are responsible for bone resorption. Osteoclastogenesis is mainly regulated by signaling pathways activated by RANK and immune receptors, whose ligands are expressed on the surface of osteoblasts. Signaling from RANK changes gene expression patterns through transcription factors like NFATc1 and characterizes the active osteoclast ...
They display a characteristic ruffled border where proteases and acid are secreted, allowing for bone resorption and formation of resorption pits in the bone surface [25]. Osteoclast morphology varies between mammals and teleosts (bony fishes), and also between different groups of teleosts [20]. In the skeleton of young zebrafish for example, osteoclast activity is carried out by both mononucleated and multinucleated cells [26]. In fact, there is an ontogenetic progression from mono- towards multinucleated osteoclasts. In juvenile zebrafish, bone resorbing cells in the developing lower jaw are. at first mononucleated. In thin skeletal tissues such as the neural arch, mononucleated cells are even predominant in adults [26]. In rainbow trout, scale resorption Selleck BIBF1120 PD0325901 is predominantly carried out by mononucleated osteoclasts [27]. Although in mammals these mononucleated cells are often just regarded as osteoclast precursors, in fish mononucleated osteoclasts are active bone ...
Ectopic calcification (EC) is a complex disease in which mineral develops in abnormal locations. It can develop in a variety of locations throughout the body, including the vasculature, heart valves, and in orthopedic settings where it is more commonly referred to as heterotopic ossification (HO). Current therapies for these conditions are limited and new treatment modalities would benefit a wide variety of patients. Osteoclasts resorb mineral in vivo and we hypothesized that a cell therapy based on inducible osteoclast differentiation could be used as a cell therapy to treat EC and HO. The RANK/RANKL pathway is a critical step in osteoclast differentiation and we created an inducible RANK (iRANK) fusion protein which could be activated by a small molecule chemical inducer of dimerization (CID). This fusion protein was introduced into a macrophage cell line, and the resulting RAW264.7+iRANK cells were characterized using in vitro assays. In the presence of CID, the cells formed large, ...
How is osteoclast-specific colony-stimulating factor abbreviated? O-CSF stands for osteoclast-specific colony-stimulating factor. O-CSF is defined as osteoclast-specific colony-stimulating factor rarely.
Osteoclasts, the only cells with bone tissue resorption functions through the usage of prostheses can inevitably result in the era of wear contaminants, the effective inhibition of osteoclast development, and bone tissue resorption could be a good way to avoid the loosening of prostheses and for that reason extend their lives. precursor cells in localized lesions in Varespladib RA. The overexpression of RANKL by energetic lymphocytes, macrophages, osteoblasts, etc. qualified prospects to extreme proliferation and irregular activation of osteoclasts due to the binding of RANKL to RANK on the top of osteoclast precursor cells and mature osteoclasts. As well as the overexpression of RANKL in broken joint bone tissue tissue, mRNA can be indicated by fibroblasts in the synovial cells, which leads towards the production from the RANKL proteins (36). Kotake et al. isolated multinucleated cells through the synovial lesions of RA individuals and demonstrated that they can form bone tissue absorption ...
A new inhibitor, placotylene A (1), of the receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation, and a regioisomer of placotylene A, placotylene B (2), were isolated from a Korean marine sponge Placospongia sp. The chemical structures of placotylenes A and B were elucidated on the basis of 1D and 2D NMR, along with MS spectral analysis and revealed as an iodinated polyacetylene class of natural products. Placotylene A (1) displayed inhibitory activity against RANKL-induced osteoclast differentiation at 10 μM while placotylene B (2) did not show any significant activity up to 100 μM, respectively.
DC-STAMP was identified from a screening of human monocyte cDNA libraries (17) as a putative seven-transmembrane-spanning receptor with no homology to any other known protein or multimembrane-spanning receptor. DC-STAMP is expressed both in immature and mature dendritic cells (DCs), and its mRNA levels fall upon activation of DCs with CD40 ligand (CD40L). DC-STAMP is overexpressed in giant cell tumors together with receptor activator of NF-κB ligand (RANKL), a protein required for the development of osteoclasts (18). In a recent study, Kukita et al. showed, using small interfering RNAs and specific antibodies, that DC-STAMP is essential for osteoclastogenesis in mice (2). They reported that overexpression of DC-STAMP enhanced osteoclastogenesis and induced the expression of a marker of osteoclasts, tartrate-resistant acid phosphatase. In this issue, Yagi et al. (1) used gene targeting to demonstrate that DC-STAMP is also essential for the fusion of osteoclast precursor cells and macrophages. ...
p38 mitogen-activated protein kinase (MAPK), which is constitutively activated in human myeloma, has been implicated in bone destruction by this cancer, but the processes it recruits are obscure. In this study, we show that p38 activity in myeloma inhibits osteoblast differentiation and bone formation, but also enhances osteoclast maturation and bone resorption. p38 regulated the expression and secretion of the Wnt pathway antagonist DKK-1 and the monocyte chemoattractant MCP-1. Attenuating p38, DKK-1, or MCP-1 were each sufficient to reduce bone lesions in vivo. Although it is well known that DKK-1 inhibits osteoblast differentiation, we found that together with MCP-1, it could also promote osteoclast differentiation and bone resorption. The latter effects were mediated by enhancing expression of RANK in osteoclast progenitor cells and by upregulating secretion of its ligand RANKL from stromal cells and mature osteoblasts. In summary, our study defined the mechanisms by which p38 signaling in ...
Bone cancer. Coloured scanning electron micrograph (SEM) of a cancerous osteoclast cell (blue) on the surface of a bone (grey). Osteoclasts are large, multi-nucleated cells that form from the fusion of several macrophage cells in bone and they move by extending cellular processes (yellow). Normally, osteoclasts break down worn out bone and work with bone-forming cells called osteoblasts to repair bone. However, osteoclasts may become cancerous causing an osteoclastoma or giant cell tumour, a type of bone cancer that usually affects the ends of the long bones. Treatment is by surgical removal and the use of liquid nitrogen to kill remaining cells. - Stock Image M132/0781
TRAIL induced osteoclast differentiation is dependent on TRAF6.(A) Human peripheral blood mononuclear cells (PBMCs) were plated in 96-well plates at 1.5 × 105
Parathyroid hormone (PTH), an 84-amino-acid peptide, acts on membrane G protein-coupled receptors to increase cyclic adenosine monophosphate (cAMP) in bone and renal tubular cells. In the kidney, PTH inhibits calcium excretion, promotes phosphate excretion, and stimulates the production of active vitamin D metabolites (Figure 42-1, Table 42-1). In bone, PTH promotes bone turnover by increasing the activity of both osteoblasts and osteoclasts (Figure 42-2B). Osteoclast activation is not a direct effect and instead results from PTH stimulation of osteoblast formation of RANK ligand (RANKL), a member of the tumor necrosis factor (TNF) cytokine family that stimulates the activity of mature osteoclasts and the differentiation of osteoclast precursors. ...
Previously we established an arthritis-prone FcγRIIB-deficient mouse strain (designated KO1). Anti-mouse CD11b mAb (5C6) has been reported to inhibit the recruitment of peripheral CD11b+ myelomonocytic cells from the blood to the inflammatory site. These cells include neutrophils and monocytes, both of which play important roles in the development of arthritis. Here we treated KO1 mice with 5C6 mAb in order to study its effect on arthritis development. To evaluate the disease-preventive effect of 5C6, 4-month-old preclinical KO1 mice were divided into three groups: the first treated with 5C6 for 6 months, the second treated with normal rat IgG for 6 months, as a control, and the third left untreated. Arthritis severity and immunological abnormalities were compared among the groups, along with transcriptional levels of several important arthritis-related factors in ankle joints, spleen, and peripheral blood cells. The 5C6 treatment ameliorated arthritis in KO1 mice, showing decreases in inflammatory