Academic literature on the topic 'Osteoclast inhibition'
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Journal articles on the topic "Osteoclast inhibition"
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Combs, Charlotte E., Karen Fuller, Hashethra Kumar, Anthony P. Albert, Grisha Pirianov, James McCormick, Ian C. Locke, Timothy J. Chambers, and Kevin M. Lawrence. "Urocortin is a novel regulator of osteoclast differentiation and function through inhibition of a canonical transient receptor potential 1-like cation channel." Journal of Endocrinology 212, no. 2 (November 14, 2011): 187–97. http://dx.doi.org/10.1530/joe-11-0254.
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This study investigated the role of urocortin (UCN), a member of the corticotrophin-releasing factor (CRF) family of peptides, in osteoclast maturation and function. We found that 10−7 M UCN significantly (P<0.05) suppressed osteoclast differentiation from bone marrow precursor cells in culture and reduced the expression of several osteoclastic markers. Furthermore, UCN potently suppressed osteoclast bone resorption, by significantly inhibiting both the plan area of bone resorbed by osteoclasts and actin ring formation within osteoclasts at 10−9 M (P<0.05), with complete inhibition at 10−7 M (P<0.001). UCN also inhibited osteoclast motility (10−7 M) but had no effect on osteoclast survival. Osteoclasts expressed mRNA encoding both UCN and the CRF receptor 2β subtype. Pre-osteoclasts however, expressed CRF receptor 2β alone. Unstimulated osteoclasts contained constitutively active cation channel currents with a unitary conductance of 3–4 pS, which were inhibited by over 70% with UCN (10−7 M). Compounds that regulate calcium signalling and energy status of the cell, both crucial for osteoclast activity were investigated. The non-selective cation channel blockers, lanthanum (La3+) and gadolinium (Gd3+), inhibited actin ring formation in osteoclasts, whereas modulators of voltage-dependent Ca2+ channels and KATP channels had no effect. These findings show for the first time that UCN is a novel anti-resorptive molecule that acts through a direct effect on osteoclasts and their precursor cells.
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Kameda, Takashi, Hiroshi Mano, Tatsuhisa Yuasa, Yoshihisa Mori, Koshi Miyazawa, Miho Shiokawa, Yukiya Nakamaru, et al. "Estrogen Inhibits Bone Resorption by Directly Inducing Apoptosis of the Bone-resorbing Osteoclasts." Journal of Experimental Medicine 186, no. 4 (August 18, 1997): 489–95. http://dx.doi.org/10.1084/jem.186.4.489.
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Estrogen deficiency causes bone loss, which can be prevented by estrogen replacement therapy. Using a recently developed technique for isolation of highly purified mammalian osteoclasts, we showed that 17 β-estradiol (E2) was able to directly inhibit osteoclastic bone resorption. At concentrations effective for inhibiting bone resorption, E2 also directly induced osteoclast apoptosis in a dose- and time-dependent manner. ICI164,384 and tamoxifen, as pure and partial antagonists, respectively, completely or partially blocked the effect of E2 on both inhibition of osteoclastic bone resorption and induction of osteoclast apoptosis. These data suggest that the protective effects of estrogen against postmenopausal osteoporosis are mediated in part by the direct induction of apoptosis of the bone-resorbing osteoclasts by an estrogen receptor– mediated mechanism.
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Zavrski, Ivana, Monica Hecht, Holger Krebbel, Claudia Fleissner, Maren Mieth, Martin Kaiser, Ulrike Heider, et al. "Bortezomib Inhibits Human Osteoclastogenesis." Blood 108, no. 11 (November 16, 2006): 1395. http://dx.doi.org/10.1182/blood.v108.11.1395.1395.
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Abstract Enhanced osteoclastogenesis in cancer-induced bone disease may be caused by intercellular interactions between tumor cells and cells of the bone marrow microenvironment. In multiple myeloma, overexpression of RANKL in the bone marrow microenvironment may lead to the activation of TRAF-signaling and in consequence to increased NF-κB and AP-1 transcriptional activities in osteoclastic lineage cells. This results in enhanced osteoclast differentiation, activation and increased bone resorption. In this study, we have examined the effects of two NF-κB inhibitors towards their inhibitory potency on human osteoclastogenesis: proteasome inhibitor bortezomib and selective IKK inhibitor PS-1145. CD14+ osteoclast precursors from peripheral blood were stimulated with RANKL and M-CSF up to four weeks. Using MTT- and TUNEL-assays, cytotoxicity levels of each drug were determined on the differentiation stage day +1 (early osteoclast precursors), day +8 (preosteoclasts) and day +21 (osteoclasts). To evaluate the effects of both drugs considering osteoclast differentiation and -function, 2 sub-apoptotic doses of bortezomib, one sub-apoptotic and one low-apoptotic dose of PS-1145 were used. As revealed by the microscopic quantification of mature osteoclasts (TRAP-positive and multi-nucleated cells), the osteoclast differentiation was diminished by both drugs, whereas the effects were dose- and time-dependent. The microscopic quantification of resorption lacunae on dentine pits revealed that the resorptional activity was reduced by 65% for 0.1 nM bortezomib (p=0.007), by 79% for 1 nM bortezomib (p<0.0005), by 60% for 1 μM PS-1145 (p=0.023) and by 91% for 10 μM PS-1145 (p<0.0005). As shown by immunoblotting and by ELISA-based methods, the subcellular mechanisms of action involved in inhibition of early osteoclast differentiation were found to be related to the inhibition of p38 mitogen-activated protein kinase (MAPK) pathways, whereas the advanced differentiation and activation occurred in course of inhibition of AP-1 and NF-κB activation. The AP-1 blockade contributed to significant reduction of osteoclastic vascular endothelial growth factor (VEGF) production. In conclusion, our data demonstrate that proteasomal inhibition should be considered as a novel therapeutical principle of cancer-induced lytic bone disease.
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Lentzsch, Suzanne, Gulsum Anderson, Noriyoshi Kurihara, Tadashi Honjo, Judith Anderson, Markus Y. Mapara, David Stirling, and David Roodman. "Thalidomide Derivative CC-4047 Inhibits Osteoclast Formation by down Regulation of PU.1." Blood 106, no. 11 (November 16, 2005): 629. http://dx.doi.org/10.1182/blood.v106.11.629.629.
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Abstract CC-4047 (Actimid) is an immunomodulatory analog of thalidomide that has stronger anti-myeloma and anti-angiogenic activity than thalidomide, but its effects on human osteoclast lineage are unknown. Early osteoclast progenitors are of hematopoietic origin and progressively differentiate into mature bone resorbing multinucleated osteoclasts. We investigated the effects of CC-4047 and thalidomide on human osteoclastogenesis, using in vitro receptor activator of NFκ-B ligand/M-CSF stimulated culture system of bone marrow cells. Three weeks of treatment of primary bone marrow cultures with 100 μM CC-4047 decreased osteoclast formation accompanied by complete inhibition of bone resorption. Interestingly, osteoclast formation was also inhibited when cultures were treated with CC-4047 only for the first week (90% inhibition). In contrast, inhibitory effect was greatly diminished when the drug was given for only the last week (25% inhibition), indicating that inhibition of osteoclast formation is an early event. The inhibitory effect of CC-4047 on osteoclastogenesis was not induced by cell death, but by a shift of lineage commitment to granulocyte-CFU at the expense of GM-CFU that are osteoclast progenitors. Further studies revealed that this shift is mediated through down regulation of the transcription factor PU.1, which is critical for early osteoclast formation. In contrast to CC-4047, thalidomide was a significantly less potent inhibitor of osteoclast formation and bone resorption. These results provide the first evidence that CC-4047 blocks osteoclast differentiation at the early phase of osteoclastogenesis. Therefore, CC-4047 might be a valuable drug targeting both the tumor and osteoclastic activity in patients with multiple myeloma and potentially other diseases associated with the development of osteolytic lesions.
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Klein-Nulend, J., M. A. van Duin, T. P. Green, V. Everts, and T. J. de Vries. "The dual specific Src/Abl kinase inhibitor AZD0530 inhibits the formation and activity of human osteoclasts." Journal of Clinical Oncology 25, no. 18_suppl (June 20, 2007): 3602. http://dx.doi.org/10.1200/jco.2007.25.18_suppl.3602.
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3602 Background: Gene knockout studies have demonstrated the critical importance of the non-receptor TK Src to osteoclast bone resorptive function. Deregulated Src TK activity is also reported as a hallmark of the invasive cancer cell. Bone metastatic cancer cells interact with and activate osteoclasts in a destructive cycle of bone degradation and stimulation of tumor cell growth. Therefore targeting Src activity would appear to be a rational therapeutic approach in treating metastatic bone disease. We have reported previously (AACR 2005) on the activity of the dual Src/Abl kinase inhibitor AZD0530 in inhibiting the bone resorptive activity of mature rabbit osteoclasts in a bone slice model. Here we tested the effect of AZD0530 in a human co-culture system, examining its activity on i) osteoclast formation by peripheral blood mononuclear cells (PBMCs) co-cultured with osteoblasts, and ii) osteoclastic bone resorption. Methods and Results: PBMC adhesion to osteoblasts and osteoblast morphology was not affected by AZD0530 (0.1–10 μM). However, AZD0530 inhibited the formation of multinucleated osteoclast-like cells dose dependently. PBMC-osteoblast co-cultures were then exposed to 1 μM AZD0530 for different time intervals. AZD0530 was most effective in inhibiting the formation of osteoclast-like cells when added at the onset of osteoclastogenesis, suggesting that Src activity is important during the initial induction of osteoclast formation. Formation of actin rings, to which c-Src co-localizes, is a prerequisite for osteoclastic bone resorption. The effect of AZD0530 on formation of actin rings was analyzed using the co-culture system on cortical bone slices. AZD0530 prevented migration of osteoclast precursors to the bone surface, and the subsequent formation of actin rings. On withdrawal of the drug, this process was reversible. Conclusions: Our data suggest that Src activity is pivotal for the formation, migration and activity of osteoclasts. Data reported elsewhere suggest AZD0530 will also impact on tumor cells directly. AZD0530 is a promising new anti-cancer drug with potential to additionally treat metastatic bone disease through its inhibition of both osteoclast activity and tumor cell invasion into and within the bone micro-environment. No significant financial relationships to disclose.
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Bouyer, Patrice, Hiroaki Sakai, Takashi Itokawa, Tsutomu Kawano, Christiaan M. Fulton, Walter F. Boron, and Karl L. Insogna. "Colony-Stimulating Factor-1 Increases Osteoclast Intracellular pH and Promotes Survival via the Electroneutral Na/HCO3 Cotransporter NBCn1." Endocrinology 148, no. 2 (February 1, 2007): 831–40. http://dx.doi.org/10.1210/en.2006-0547.
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Colony-stimulating factor-1 (CSF-1) promotes the survival of osteoclasts, short-lived cells that resorb bone. Although a rise in intracellular pH (pHi) has been linked to inhibition of apoptosis, the effect of CSF-1 on pHi in osteoclasts has not been reported. The present study shows that, in the absence of CO2/HCO3−, CSF-1 causes little change in osteoclast pHi. In contrast, exposing these cells to CSF-1 in the presence of CO2/HCO3− causes a rapid and sustained cellular alkalinization. The CSF-1-induced rise in pHi is not blocked by 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid, an inhibitor of HCO3− transporters but is abolished by removing extracellular sodium. This inhibition profile is similar to that of the electroneutral Na/HCO3 cotransporter NBCn1. By RT-PCR, NBCn1 transcripts are present in both osteoclasts and osteoclast-like cells (OCLs), and by immunoblotting, the protein is present in OCLs. Moreover, CSF-1 promotes osteoclast survival in the presence of CO2/HCO3− buffer but not in its absence. Preventing the activation of NBCn1 markedly attenuates the ability of CSF-1 to 1) block activation of caspase-8 and 2) prolong osteoclast survival. Inhibiting caspase-3 or caspase-8 in OCLs prolongs osteoclast survival to the same extent as does CSF-1. This study provides the first evidence that osteoclasts express a CSF-1-regulated Na/HCO3 cotransporter, which may play a role in cell survival.
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Brooks, Kalia, C. Ireland, Beeton, and Rushton. "Direct Inhibition of Osteoclast Formation and Activity by the Vitamin E Isomer gamma-Tocotrienol." International Journal for Vitamin and Nutrition Research 81, no. 6 (November 1, 2011): 358–67. http://dx.doi.org/10.1024/0300-9831/a000087.
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Vitamin E homologues, specifically tocotrienols, have been shown to have favorable effects on bone. They possess properties that are indicative of anti-resorptive activity, suggesting the potential for vitamin E in preventing bone loss. To investigate the anti-resorptive activity of the various vitamin E homologues, we cultured human osteoclasts from blood-derived CD14+ cells on collagen, dentin, and calcium phosphate substrates, with some samples supplemented with vitamin E homologues in their cell culture medium. These were compared to the clinically used bisphosphonate, pamidronate. Compounds were either added at the start of culture to study effects on osteoclast formation, or at the start of osteoclastic resorption to determine their effects on activity. The alpha- and gamma-tocotrienol isomers inhibited osteoclast formation without consequent reduction in total cell number. Only gamma-tocotrienol inhibited osteoclast activity without toxicity. Gamma-tocotrienol was the most potent inhibitor of both osteoclast formation and activity and requires further investigation into its anti-resorptive effects on bone.
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Anderson, Gülsüm, Margarete Gries, Noriyoshi Kurihara, Tadashi Honjo, Judy Anderson, Vera Donnenberg, Albert Donnenberg, et al. "Thalidomide derivative CC-4047 inhibits osteoclast formation by down-regulation of PU.1." Blood 107, no. 8 (April 15, 2006): 3098–105. http://dx.doi.org/10.1182/blood-2005-08-3450.
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Abstract CC-4047, an immunomodulatory analog of thalidomide, inhibits multiple myeloma with unknown effects on the human osteoclast lineage. Early osteoclast progenitors are of hematopoietic origin and differentiate into mature bone resorbing multinucleated osteoclasts. We investigated the effects of CC-4047 and thalidomide on human osteoclastogenesis, using in vitro receptor activator of NFκ-B ligand/macrophage colony-stimulating factor–stimulated bone marrow cell cultures. Treating bone marrow cultures with CC-4047 for 3 weeks decreased osteoclast formation accompanied by complete inhibition of bone resorption. The inhibitory effect was similar when cultures were treated for 3 weeks or for only the first week (90% inhibition), indicating that CC-4047 inhibits early stages of osteoclast formation. Inhibition of osteoclastogenesis by CC-4047 was mediated by a shift of lineage commitment to granulocyte colony-forming units at the expense of granulocyte-macrophage colony-forming units. Further studies revealed that this shift in lineage commitment was mediated through down-regulation of PU.1. Treatment with thalidomide resulted in significantly less potent inhibition of osteoclast formation and bone resorption. These results provide evidence that CC-4047 blocks osteoclast differentiation during early phases of osteoclastogenesis. Therefore, CC-4047 might be a valuable drug for targeting both tumors and osteoclastic activity in patients with multiple myeloma and other diseases associated with osteolytic lesions.
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Kim, Hyo Jeong, and Youngkyun Lee. "Endogenous Collagenases Regulate Osteoclast Fusion." Biomolecules 10, no. 5 (May 1, 2020): 705. http://dx.doi.org/10.3390/biom10050705.
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The precise regulation of osteoclast differentiation and function is crucial for the maintenance of healthy bone. Despite several reports of collagenase expression in bone tissues, the precise isoform expression as well as the role in osteoclasts are still unclear. In the present report, the expression of matrix metalloprotease (MMP)8 and MMP13 was confirmed in mouse bone marrow macrophage osteoclast precursors. The mRNA and protein expressions of both collagenases were significantly reduced by receptor activator of nuclear factor κB ligand (RANKL) stimulation. Notably, either inhibition of MMP expression by siRNA or treatment of cells with collagenase inhibitor Ro 32-3555 significantly augmented osteoclast fusion and resorption activity without affecting the osteoclast number. The inhibition of collagenase by Ro 32-3555 increased the expression of osteoclast fusion genes, Atp6v0d2 and Dcstamp, without affecting nuclear factor of activated T-cells, cytoplasmic 1 (NFATc1) protein expression. The enhanced osteoclast fusion by collagenase inhibition appears to be mediated through an extracellular signal regulated kinase (ERK)-dependent pathway. Collectively, these data provide novel information on the regulation of osteoclast fusion process.
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Masarachia, Patricia, Michiko Yamamoto, Chih-Tai Leu, Gideon Rodan, and Le Duong. "Histomorphometric Evidence for Echistatin Inhibition of Bone Resorption in Mice with Secondary Hyperparathyroidism." Endocrinology 139, no. 3 (March 1, 1998): 1401–10. http://dx.doi.org/10.1210/endo.139.3.5828.
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Echistatin, an RGD-containing peptide, was shown to inhibit the acute calcemic response to exogenous PTH or PTH-related protein (PTH-rP) in thyroparathyroidectomized rats, suggesting that echistatin inhibits bone resorption. In this study: 1) we present histological evidence for echistatin inhibition of bone resorption in mice with secondary hyperparathyroidism, and show that 2) echistatin binds to osteoclasts in vivo, 3) increases osteoclast number, and 4) does not detectably alter osteoclast morphology. Infusion of echistatin (30μ g/kg·min) for 3 days prevented the 2.6-fold increase in tibial cancellous bone turnover and the 36% loss in bone volume, produced by a low calcium diet. At the light microscopy level, echistatin immunolocalized to osteoclasts and megakaryocytes. Echistatin treatment increased osteoclast-covered bone surface by about 50%. At the ultrastructural level, these osteoclasts appeared normal, and the fraction of cells containing ruffled borders and clear zones was similar to controls. Echistatin was found on the basolateral membrane and in intracellular vesicles of actively resorbing osteoclasts. Weak labeling was found in the ruffled border, and no immunoreactivity was detected at the clear zone/bone surface interface. These findings provide histological evidence for echistatin binding to osteoclasts and for inhibition of bone resorption in vivo, through reduced osteoclast efficacy, without apparent changes in osteoclast morphology.
Dissertations / Theses on the topic "Osteoclast inhibition"
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Tan, Jamie We-Yin. "The investigation of RANKL TNF-like core domain by truncation mutation." University of Western Australia. School of Surgery and Pathology, 2003. http://theses.library.uwa.edu.au/adt-WU2004.0032.
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Osteoclasts are multinucleated cells found exclusively in bone and are derived from the haematopoietic cells of monocytes/macrophage lineage. The cell-to-cell interaction between osteoblastic/stromal cells and osteoclast precursor cells is necessary for osteoclastogenesis. Receptor Activator of NF-κB ligand (RANKL) was identified as a membrane-bound TNF ligand family member that is the ‘master’ cytokine expressed on osteoblastic/stromal cells, which stimulate osteoclastogenesis through cell-to-cell contact with osteoclast precursors. RANKL is considered to be a factor that is necessary and sufficient for the induction of osteoclastogenesis (Lacey, et al., 1998). RANKL is a type II transmembrane cytokine of the TNF ligand superfamily and has an active TNF-like core domain at the extracellular domain. This active TNF-like core domain is thought to be the region through which it binds to it’s active receptor, RANK, for the activation of signal transduction pathways for the initiation of processes leading to osteoclastogenesis (Lacey, et al., 1998; Li, et al., 1999). It was hypothesized that any change in the active TNF-like core domain might affect the ability of RANKL binding to RANK and consequently affect the activation of signal transduction pathways and osteoclastogenesis. Hence, this thesis sought to investigate the effects of changes in the active TNF-like core domain by truncation mutation on the ability of RANKL binding to RANK and consequently affect the activation of signal transduction pathways and osteoclastogenesis. A cDNA fragment encoding the full-length TNF-like core domain of rat RANKL (rRANKL) (aa160-318) was cloned into the bacterial expression pGEX vectors and stably expressed in Eschechia coli as a fusion protein with the C-terminus of glutathione S-transferase (GST). Four mutants (aa160-302, aa160-268, aa239-318 and aa246-318) were also generated by truncation mutation in the TNF-like core domain, and cloned into the pGEX vector to produce GST-rRANKL mutants. The proteins were over-expressed and affinity purified to 95% in purity. GST-rRANKL (160-318) containing the full length TNF-like core domain was able to induced osteoclastogenesis in spleen cells in the presence of M-CSF and in RAW264.7 cells in the absence of M-CSF. It was also found to activate mature osteoclast activity in vitro, ex vivo and in vivo. It has the highest binding affinity to RANK and the greatest potency for NF-κB activation as well as the induction of osteoclastogenesis compared to the truncated mutants. Mutants generated by truncation of the TNF-like core domain revealed that the TNF-like core domain is important for the interaction with the RANK, for high binding affinity, NF-κB activation and induction of osteoclastogenesis. In general, the truncated mutants not only displayed a reduction in the binding affinity to RANK, but also a reduction in NF-κB activation, and significantly reduced potency in the induction of osteoclastogenesis. Interestingly, mutant GST-rRANKL (160-268) showed a higher affectivity than the other mutants did, in that it had greater binding affinity to RANK, and in NF-κB activation than the rest of the truncated mutants. Mutants GST-rRANKL (239-318) and GST-rRANKL (246-318) on the other hand, showed little potency in the induction of osteoclast formation, however, might have an inhibitory effect through competition with full length GST-rRANKL (160-318) as well as inducing a response in vivo resulting in an increase in the serum calcium level. In conclusion, this thesis demonstrated that the TNF-like core domain of RANKL is active, and imperative in the binding to RANK, activating signal transduction pathways and induction of osteoclastogenesis. Changes in the active TNF-like core domain affected the ability, affinity and efficiency of RANKL binding to the receptor, RANK and consequently affected the activation of signal transduction pathways and osteoclastogenesis.
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Pappalardo, Angela. "Defining the role of γδ cells in bone loss associated with chronic inflammation." Thesis, University of Aberdeen, 2013. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=203414.
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The extensive infiltration of immune cells in the joints of patients affected by rheumatoid arthritis (RA), and the subsequent production of pro-inflammatory cytokines triggers bone erosion through the extensive stimulation of bone resorbing osteoclasts (OCs). The activity of γδ T cells has been implicated to influence the onset and severity of the disease pathology in murine models of human RA. With this study the effects of γδ T cells for influencing OC differentiation and resorptive activity were assessed in vitro. Activated γδ T cells exerted inhibitory effects on OC differentiation and resorptive activity, these effects were mediated by the release of soluble factors, since similar inhibitory effects were obtained using conditioned medium (CM) from activated γδ T cells. The primary mediator of such effects was determined to be IFN, since neutralisation markedly restored OC differentiation and resorptive activity. γδ T cell proliferation, activation and survival following culture with autologous mature OCs were assessed by flow cytometry. Interestingly, OCs and OC-derived CM induced activation of γδ T cells as determined by the expression of the early activation marker CD69. A mediator of this stimulatory effect on T cells was found to be TNF, since neutralisation of TNFα decreased the stimulatory effect of OCs on CD69 expression. Consistently, OCs, but not OC-derived CM, increased the proliferation of IL-2-stimulated γδ T cells and also supported the survival of resting γδ T cells. This study provides new insights into the in vitro interactions between human γδ T cells and OCs, moreover it defines osteoclasts as immune competent cells capable of influencing the activation status and the viability of T lymphocytes, and provide evidence for a novel stimulatory effect of OCs on γδ T cells.
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Dai, Rongchen. "Development of an osteoclast-targeted cathespin K inhibitor for postmenopausal osteoporosis : in vitro evaluation and pharmacokinetic profile." HKBU Institutional Repository, 2020. https://repository.hkbu.edu.hk/etd_oa/840.
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Background: Postmenopausal osteoporosis which results in a reduction of bone quality and bone density is one of the most prevalent diseases affecting people around the world. Cathepsin K (CatK) is one of the most potent proteases in lysosomal cysteine proteases family, of which main function is to mediate bone resorption. Currently, the Odanacatib (ODN) developed by Merck & Co. is the only Phase III CatK inhibitor candidate with high efficacy in treating postmenopausal osteoporosis. Unfortunately, the development of ODN was finally terminated due to the cardio-cerebrovascular adverse effects. In order to enhance the specificity of ODN to osteoclasts for suppression of bone resorption in postmenopausal osteoporosis, we have previously designed and synthesized (D-Asp8)-ODN conjugate by linking ODN with a promising osteoclast-targeted moiety D-Asp8. The data showed that D-Asp8 could facilitate the conjugated ODN specifically approaching osteoclasts, with reduced distribution in non-bone tissues, to inhibit the functional CatK activity within bone tissues in healthy rats. In this thesis, we hypothesized that the in vitro antiresorptive effects of (D-Asp8)-ODN conjugate were comparable with that of ODN. On the other hand, we also developed a QQQ-LC/MS method for quantitation of (D-Asp8)-ODN conjugate in plasma, which will be a valuable tool to support further pre-clinical studies. Aim: (1) To compare the antiresorptive effect between (D-Asp8)-ODN conjugate and ODN in vitro. (2) To develop and validate a practicable method for pharmacokinetic profile of (D-Asp8)-ODN conjugate in rats. Materials and Methods: The cytotoxic effect of (D-Asp8)-ODN conjugate and ODN were evaluated and compared by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The effect of (D-Asp8)-ODN conjugate and ODN on Receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclasts formation and osteoclast function-related genes were evaluated and compared by Tartrate-resistant acid phosphatase (TRAP) staining and quantitative real time polymerase chain reaction (qRT-PCR). The effect of (D-Asp8)-ODN conjugate and ODN on osteoclast bone resorption activities were evaluated and compared by bone resorption pit assay. Moreover, the pharmacokinetic profile of (D-Asp8)-ODN conjugate in rat plasma was determined by using triple quadrupole liquid chromatography-mass spectrometry (QQQ-LC/MS) system. Result: The cytotoxicity of (D-Asp8)-ODN conjugate was significantly lower than that of ODN on the murine macrophage RAW 264.7 cell line. (D-Asp8)-ODN conjugate had no effect on RANKL-induced osteoclast formation, which was comparable with that of ODN. (D-Asp8)-ODN conjugate had no effect on the mRNA level of CTSK, but it could upregulate the mRNA levels of ACP5 and OSCAR, which was comparable with that of ODN. (D-Asp8)-ODN conjugate inhibited osteoclast bone resorption activity, which was comparable with that of ODN. The newly established QQQ-LC/MS protocol had good precision and accuracy for detecting (D-Asp8)-ODN conjugate in rat plasma. Finally, the pharmacokinetic profile of (D-Asp8)-ODN conjugate in rat plasma was determined. Following subcutaneous administration, the time to reach maximum concentration (Tmax) was 1.0 h, the antibiotics area under the concentration time-curves from time zero to infinity (AUC0-∞) was found to be 27.78 ug·mL-1·h and the terminal half-life (t½) was 1.4 h. Conclusion: (D-Asp8)-ODN conjugate had no effect on RANKL-induced osteoclast formation, which was comparable with ODN. The antiresorptive effect of (D-Asp8)-ODN conjugate was comparable with that of ODN. On the other hand, a new QQQ-LC/MS protocol has been established for the pharmacokinetic profile of (D-Asp8)-ODN conjugate in rat.
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Hussein, Hayam. "Cathepsin K Inhibition In Bone And Bone Marrow In Horses." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1449218489.
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Machin, Reinaldo Franqui. "Destabilizing NEK2 overcomes resistance to proteasome inhibition in multiple myeloma." Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6104.
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Multiple Myeloma (MM) is an incurable plasma cell malignancy and, although novel treatment regimes in the past decade have improved patient outcome, long-term treatment leads to relapse and refractory disease. The centrosomal kinase NEK2 is found overexpressed in MM and promotes chromosomal instability, drug resistance and increased proliferation. Although much research shows NEK2 having a detrimental effect in cancer, much of its mechanisms of overexpression and drug resistance has not been studied in detail. In this work we expand our understanding of NEK2 in MM.
Using Tandem Affinity Purification coupled with Mass Spectrometry, we show that NEK2 directly interacts with the de-ubiquitinase USP7. We confirm this interaction in cell lines of MM and lung cancer. Since USP7 has been shown to have important cancer-promoting roles we tested if USP7 was necessary for NEK2-driven bortezomib resistance. We found that USP7 shRNA was sufficient to sensitize the bortezomib resistant NEK2 overexpressing cells to bortezomib. Surprisingly, we found that USP7 inhibition with shRNA or by treatment with the small molecule USP7 inhibitor P5091 led to depletion of NEK2 protein in every cell line tested. Previous research shows USP7’s main function is a de-ubiquitinase and, since NEK2 is a target of the ubiquitin-proteasome system, we hypothesized USP7 may be de-ubiquitinating NEK2. Through western blots and immunoprecipitations, we show the NEK2-USP7 interaction promotes the de-ubiquitination and subsequent stabilization of NEK2, presenting USP7 as the first discovered de-ubiquitinating enzyme of NEK2. To understand how NEK2 promotes drug resistance in cancer we studied a previously published list of NEK2-regulated genes and, using the UCSC genome browser (Track Name:GM12878+TNFa RELA) ChIP-seq data, we found approximately half of these genes have the NF-κB transcription factor p65 bound throughout the gene sequence. We also produced a signaling score using an average of 11 known targets of NF-κB and patients with high NEK2 showed a significantly increased score of NF-κB signaling. Additionally, through western blots and immunofluorescence, we found that patients with high NEK2 protein levels consisitently had activation higher signal of p65 protein and phosphorylated p65 at Serine 536, indicative of increased activity. We then causally show NEK2 activates canonical NF-κB by performing western blots and a dual-luciferase reporter assay on control and NEK2 overexpressing cells. Using AKT and PP1α inhibitors, we found that NEK2 drives NF-κB by phosphorylating and inactivating PP1α, leading to hyperactive AKT. Using this model of NEK2-NF-κB activation, we aimed at targeting NEK2 directly with the small molecule drugs INH1 (depletes NEK2 protein) and P5091 (inhibits USP7 activity) in empty vector control cells, NEK2 overexpressing cells or cells with an acquired drug resistance phenotype. Our results show that both INH1 and P5091 can overcome bortezomib resistance in cell lines and in vivo.
Another aspect of MM disease we targeted in this work was bone disease. Bone disease in MM is common and causes bone pain and fractures but a much is still regarding what drives these lesions. We found that NEK2 expression in patients correlates with a presence of bone lesions, based on FDG-PET scan and MRI. Using our previously published list of NEK2 regulated genes, we found Heparanase (HPSE) is directly correlated to NEK2 expression. HPSE is an extracellular protein shown to promote differentiation of the bone destroying cell, osteoclast. Using western blots, RT-qPCR and ELISA, we found NEK2 increases HPSE expression and extracellular release. HPSE was also on the list of genes upregulated by NEK2 found to have p65 bound to the gene, thus we tested if NEK2 was driving HPSE through the NF-κB. Accordingly, we found NEK2 drives HPSE through the NF-κB pathway and, consistent with our previous results, in a USP7-dependent manner. Using bone marrow macrophages and conditioned media from empty vector control or NEK2 overexpressing cells, we found NEK2 promtoes increased differentiation of osteoclasts and inhibition of HPSE blocked this effect, strongly suggesting HPSE is the mediator of this effects. Importantly these findings were recapitulated in vivo. Empty vector or NEK2 overexpressing cells were injected through the tail vein to allow dissemination to the bone marrow. microCT and Xray revealed mice injected with NEK2 overexpressing cells showed reduced bone density, compared to empty vector cells. Additionally, H&E and TRAP staining confirmed our in vitro results by showing higher osteoclast levels in bone sections of mice injected with NEK2 overexpressing cells.
Lastly, we show a novel role for the ATPase TRIP13 as a cofactor for USP7 de-ubiquitinating activity. TRIP13 is overexpressed in cancer, has been shown to be an oncogene and promotes drug resistance. By systematically targeting TRIP13 overexpressing cells with drugs that inhibit different pathways we found TRIP13 drug resistance is diminished by inhibiting USP7. We found that TRIP13 binds with USP7 and by western blots and immunoprecipitations we show it is necessary for the de-ubiquitination of NEK2. Furthermore, we also found TRIP13 shows a hyperactive USP7 phenotype, shuttling PTEN out of the nucleus and stabilizing MDM2, in a USP7 dependent manner.
In summary, this work shows the de-ubiquitinase USP7, coupled with the ATPase TRIP13 stabilizes NEK2 by de-ubiquitination, this leads to accumulation of NEK2 and activation of the canonical NF-κB pathway through PP1α/AKT, which promotes drug resistance and activates HPSE, increasing osteoclast differentiation and bone destruction.
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GuimarÃes, Mariana Vasconcelos. "Matricaria recutita prevents ligature-induced osteoclastic alveolar bone loss induced in rats via inhibition of TNFa and IL-1β cytokines." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=14266.
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CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel SuperiorPeriodontitis is an immunoinflammatory disease in that the involvement of chemical mediators culminates in destruction of alveolar bone. Long recognized regarding its pathogenesis, however, frequently some patients do not respond insatisfactorily to conventional treatments, which makes pharmacological alternatives are sought. In this context, Matricaria recutita (MTR), known as chamomile, stands out in the literature for its anti-inflammatory and a variety of constituents, especially apigenin (APG) flavonoid. Thus, the present study evaluated the involvement of cytokines in the anti-inflammatory and antiresorptive activities of MTR in alveolar bone resorption (ABR) induced by ligature in rats. For this, we used the dry extract of MTR (apigenin content 128.5Â0.99 mg/g). The ABR was induced in 90 wistar rats (199.3 Â 3.2 g) by ligation (nylon 3.0) of 2Â upper left molar, and contralateral was used as control. The rats received v.o. Tween 80 (TW) or MTR (10, 30 and 90 mg/kg) daily until 11 d, when they were killed. The hemiarcadas were processed for macroscopic (mm2) or histometric, histological and immunohistochemical analyzes for the ligand of the receptor activator of nuclear factor kappa B (RANKL), osteoprotegerin (OPG) and tartrate-resistant acid phosphatase (TRAP). Blood samples were collected for measurement of bone alkaline phosphatase (BALP), while the gingival tissue was used for measuring of mieloperoxidase activity (MPO; mg/g) and of tumor necrosis factor-alpha (TNF-a) and interleukin-1β (IL-1β) levels (pg/mg) by ELISA. Systemically, serum bone alkaline phosphatase (BALP), AST/ALT, urea and creatinine, and white blood count were made, and we evaluated of macroscopic aspects of liver, kidneys and spleen, in addition to variation in body mass. Was set at p <0.05 (#) for Normal, (*) for TW and () for MTR 10 mg/kg; Ethical aspects: the Ethics Committee for Animal Use-UFC 70/13. It was found that ligation for 11 days caused intense ABR with furcation lesion pronounced, resorption of alveolar bone and cementum in the region between the first and second molars, reduction of serum BALP, intense leukocyte infiltrate in the periodontium these animals, increasing significant MPO, TNF-, IL-1β in challenged area underlying gingival tissue, and increased to RANKL and TRAP immunostaining, and reduced to OPG. Systemically, there was leukocytosis with a predominance of mononuclear cells. No major changes in organs and weight of animals were observed. MTR prevented, significantly, the ligature-induced ABR [TW=5.5Â0.2; MTR (10)=4.4Â0.1*; (30)=2.9Â0.1*; (90)=2.8Â0*], corroborating the reduction of furcation lesions [Normal=10.4Â0.8; TW=137.4Â23.3#; MTR (90)=81.0Â9.6*#] and the preservation of the alveolar bone and cementum [(Normal=0(0-0); TW=3(1-3)#, MTR (90)=1(1-3)#*] compared to the TW group while no bone anabolic activity was showed because MTR dit not prevent the reduction of serum BALP induced by ligature [Normal=99.4Â3.4; TW=61.3Â2.6#; MTR (10)=70.6Â3.6#; (30)=74.5Â3.7#; (90)=78.5Â2.8#); p>0.05]. However, MTR significantly prevented the leukocyte infiltration and the increase of MPO activity [Normal=3.6Â0.5; TW=9.4Â0.9#; MTR (10)=10.2Â3.3; (30)=4.5Â0.8*; (90)=4.2Â0.7*], of TNF-a [Normal=0.2Â0; TW=1.2Â0.2#; MTR (10)=0.4Â0.2*; (30)=0.2Â0.1*; (90)=0.1Â0*] and of IL-1β [Normal=1.5Â0.3; TW=8.0Â1.4#; MTR (10)=8.9Â1.9#; (30)=1.8Â1.0*; (90)=1.5Â0.9*] levels caused by ligature, and reduced immunostaining for RANKL and TRAP, and increased for OPG, comparing to TW group. Additionally, MTR prevented the leukocytosis caused by ligation and did not alter liver, kidney, spleen conditions or the variation of body mass. In short, the MTR prevented the ABR by reducing TNF-a and IL-1β, thus preventing the osteoclast activation due RANK-RANKL-OPG axis, without interfering with bone anabolism.
A periodontite à uma doenÃa imunoinflamatÃria onde a participaÃÃo de mediadores quÃmicos culmina em destruiÃÃo de osso alveolar. Muito se reconhece a respeito de sua patogÃnese, contudo, frequentemente alguns pacientes respondem de forma insatisfatÃria aos tratamentos convencionais, o que faz com que alternativas farmacolÃgicas sejam buscadas. Neste contexto, a Matricaria recutita (MTR), conhecida como camomila, destaca-se na literatura por sua propriedade anti-inflamatÃria e sua variedade de constituintes, especialmente o flavonoide apigenina. Assim, o presente estudo avaliou a participaÃÃo de citocinas nas atividades anti-inflamatÃria e antirreabsortiva da MTR na reabsorÃÃo Ãssea alveolar (POA) induzida por ligadura em ratos. Para isso, utilizou-se extrato seco de MTR (teor de apigenina de 128,5Â0,99 mg/g). A POA foi induzida em 90 ratos Wistar (199,3Â3,2 g) por ligadura (nÃilon 3.0) do 2 molar superior esquerdo, e contralateral como controle. Os ratos receberam v.o. Tween 80 (TW) ou MTR (10, 30 e 90 mg/kg) diariamente atà o 11 d, quando foram mortos. As hemiarcadas foram processadas para macroscopia (mm2) ou para anÃlises histomÃtrica, histolÃgica e imunohistoquÃmica para o ligante do receptor ativador do fator nuclear kappa-B (RANKL), a osteoprotegerina (OPG) e a fosfatase Ãcida resistente ao tartarato (TRAP). Amostras de sangue foram coletadas para dosagem de fosfatase alcalina Ãssea (FAO), enquanto que o tecido gengival foi utilizado para a dosagem da atividade de mieloperoxidase (MPO; mg/g), do fator de necrose tumoral-alfa (TNF-a) e da interleucina-1β (IL-1β) (pg/mg) por ELISA. Sistemicamente, foram feitas dosagens sÃricas AST/ALT, ureia e creatinina, avaliados leucograma, os aspectos macroscÃpicos de fÃgado, rins e baÃo, alÃm da variaÃÃo de massa corpÃrea. Considerou-se p<0,05 (#) para Normais, (*) para TW e () para MTR 10 mg/kg; Aspectos Ãticos: ComissÃo de Ãtica para Uso de Animais-UFC n 70/13. Verificou-se que a ligadura durante 11 dias causou intensa POA, com lesÃo pronunciada de furca e reabsorÃÃo de osso alveolar e cemento na regiÃo entre o primeiro e segundo molares, reduÃÃo dos nÃveis sÃricos de FAO, intenso infiltrado leucocitÃrio no periodonto destes animais, aumento significante de MPO, de TNF-a, de IL-1β no tecido gengival subjacente à Ãrea desafiada, alÃm de imunomarcaÃÃo aumentada para RANKL e TRAP, e reduzida para OPG. Sistemicamente, observou-se leucocitose com predomÃnio de mononucleares. NÃo foram observadas alteraÃÃes importantes de ÃrgÃos e peso dos animais. MTR foi capaz de prevenir, de forma significante, a POA induzida por ligadura [TW=5,5Â0,2; MTR (10)=4,4Â0,1*; (30)=2,9Â0,1*; (90)=2,8Â0*], sendo corroborada pela reduÃÃo das lesÃes de furca [Normal=10,4Â0,8; TW=137,4Â23,3#; MTR (90)=81,0Â9,6#*] e preservaÃÃo de osso alveolar e cemento [(Normal=0(0-0); TW=3(1-3)#; MTR (90)=1(1-3)#*] em comparaÃÃo ao grupo TW, embora nÃo demonstrou atividade anabÃlica Ãssea por nÃo prevenir a reduÃÃo dos nÃveis sÃricos de FAO induzida pela ligadura [Normal=99,4Â3,4; TW=61,3Â2,6#; MTR (10)=70,6Â3,6#; (30)=74,5Â3,7#; (90)=78,5Â2,8#); p>0,05]. Entretanto, MTR preveniu significantemente o infiltrado leucocitÃrio e o aumento da atividade de MPO [Normal=3,6Â0,5; TW=9,4Â0,9#; MTR (10)=10,2Â3,3; (30)=4,5Â0,8*; (90)=4,2Â0,7*], dos nÃveis de TNF-a [Normal=0,2Â0; TW=1,2Â0,2#; MTR (10)=0,4Â0,2*; (30)=0,2Â0,1*; (90)=0,1Â0*] e de IL-1β [Normal=1,5Â0,3; TW=8,0Â1,4#; MTR (10)=8,9Â1,9#; (30)=1,8Â1,0*; (90)=1,5Â0,9*], proporcionando imunomarcaÃÃo reduzida para RANKL e TRAP, e aumentada para OPG, em comparaÃÃo ao grupo TW. Adicionalmente, a MTR preveniu a leucocitose causada pela ligadura e nÃo alterou as condiÃÃes hepÃticas, renais, esplÃnicas e a variaÃÃo de massa corpÃrea. Em suma, a MTR preveniu a POA via reduÃÃo de TNF-a e IL-1β, prevenindo, assim, a ativaÃÃo osteoclÃstica decorrente do eixo RANK-RANKL-OPG, sem interferir no anabolismo Ãsseo.
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Ren, Zhongyuan. "Small molecules regulated bone resorption and enzyme activity in osseous cells." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10291/document.
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La Cathepsine K est parmi la plus efficace des collagénases de mammifère pour cliver la triple hélice de collagène de type-1. Nous avons développé une série d'azanitriles, (CKI-8 and CKI-13) inhibiteurs de cathepsine K. CKI-8 (un isomère de CKI-13) et CKI-13 ne sont pas toxiques sur les osteoblastes Saos-2 et les cellules RAW 264.7 jusqu' à une concentration de 1000 nM, tandis qu'ils ne le sont pas jusqu'à une concentration de 100 nM sur les osteoclastes. CKI-8 n'affecte pas l'activité de la phosphatase alkaline ainsi que la minéralisation induite par les Saos-2 et par les osteoblastes primaires. CKI-13 diminue de 35 % la minéralisation induite par les Saos-2 tandis qu'il n'affecte pas la minéralisation induite par les osteoblastes primaires. L'addition de CKI-13 diminue l'activité de la phosphatase alkaline d'environ 20% (Saos-2) et de 40 % (osteoblastes primaires). La résorption osseuse sur des tranches d'os d'origine bovine est diminuée avec 10 nM de CKI-13, 100 nM de CKI- 8 et 100 nM d'inhibiteur commercial E64. CKI-8 et CKI-13 diminuent la mobilité des osteoclastes. Nous avons développé un dosage d'hydrolyse de PPi par la phosphatase alkaline au moyen de l'IR, ayant l'avantage de fonctionner sur des vésicules matricielles et des cellules avec des substrats naturels à un pH physiologique. La bande de PPi localisée à 1107 cm-1 (∑= 2158 ± 211 M-1.cm-1) et celles de Pi localisées à 1076 cm-1 (∑= 1346 ± 116 M-1.cm- 1) et à 991 cm-1 (∑= 493 ± 49 M-1.cm-1) ont servis à mesurer les concentrations du substrat et du produitCathepsin K is among the most potent mammalian collagenase, capable of cleaving the triple helix in type-I collagen. We developed a series of azanitriles (CKI-8 and CKI-13) which are inhibitors of cathepsin K. CKI-8 (an isomer of CKI-13) and CKI-13 did not induce significant toxicity on osteoblasts Saos-2 and RAW 264.7 cells up to 1000 nM, while they were not toxic on mature osteoclasts up to 100 nM. Commercial E64 inhibitor was not toxic in primary osteoclast cells up to 1000 nM. CKI-8 did not affect alkaline phosphatase activity as well the mineralization induced by Saos-2 cells and by primary osteoblasts. CKI-13 decreased by 35% the mineralization induced by Saos-2 cells while it did not on mineralization induced by primary osteoblasts. Addition of CKI-13 decreased alkaline phosphatase activity by around 20% (Saos-2 cells) and 45% (primary osteoblasts). Bone resorption on bovine slices decreased significantly with 10 nM of CKI-13, with 100 nM of CKI-8 and commercial inhibitor E64. Our findings indicated that CKI-8 and CKI-13 inhibited bone resorption and affected the mobility of osteoclast. To monitor directly the PPi hydrolytic activity by alkaline phosphatase, we developed an infrared (IR) assay taking the advantage to use natural substrate under physiological pH in matrix vesicles and in living cells. PPi band located at 1107 cm-1 (∑= 2158 ± 211 M-1.cm-1) and Pi bands located at 1076 cm-1 (∑= 1346 ± 116 M-1.cm-1) and at 991 cm-1 (∑= 493 ± 49 M-1.cm-1) served to measure the substrate and the product concentrations
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Valkealahti, M. (Maarit). "The effects of bisphosphonates and COX-2 inhibitors on the bone remodelling unit." Doctoral thesis, University of Oulu, 2008. http://urn.fi/urn:isbn:9789514288548.
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Abstract Bone remodelling occurs in humans throughout life, therefore bone is continuously renewed to better respond to changes in weightbearing circumstances. Bone remodelling is extremely vulnerable during fracture healing and integration of prostheses into the surrounding bone. Bone remodelling is a complex system in which many growth factors, cytokines and enzymes, which are essential for the differentiation of osteoblasts and osteoclasts, are involved. Some widely used drugs can affect this sensitive system of remodellation in unexpected manner. Painkillers such as cyclooxygenase (COX) inhibitors have been demonstrated in animal studies to interfere with fracture healing and a few retrospective clinical studies confirm these observations. Bisphosphonates (BP), main target of which is the bone resorbing osteoclast, have been suggested to be the drug of choice to improve periprosthetic bone density and thus prevent aseptic loosening of implants. The exact mechanism of action of clodronate (CLO), a non-amino-BP, which was selected for the study, has not been clarified thus far. In order to gain a deeper understanding of the role of the COX enzyme in the differentiation of osteoblasts we studied human mesenchymal stem cell (hMSC) cultures in the presence of different COX-inhibitors; indomethacine, parecoxib and NS398, a specific COX-2 inhibitor. We used the liposome encapsulated CLO metabolite (AppCCl2p) to study in detail the mechanism of BP induced apoptosis in osteoclast. The effects of different BPs CLO, pamidronate (PAM) and zoledronic acid (ZOL), on the differentiation of osteoblasts and osteoclasts were tested in vitro. The optimal concentration for in situ CLO rinsing in clinical study was found. Finally, the effects of in situ and per oral CLO on the periimplant bone density and integration of prostheses were studied in vivo. All tested COX-inhibitors significantly inhibited osteoblast differentiation from hMSCs and stimulated the differentiation of adipocytes. It was also demonstrated that AppCCl2p inhibits mitochondrial function by a mechanism that involves competitive inhibition of ADP/ATP translocase. In the comparison of BPs, ZOL seemed to posses the properties of both non-amino- and amino-BPs and it thus belongs to a new class of BPs. Peroral and in situ CLO seemed to have different mechanisms of action. Peroral CLO delayed the integration of prosthesis to the bone and increased peri-implant osteolysis while is situ CLO accelerated integration. In conclusion, we can alter normal bone remodellation during fracture healing and prosthesis integration. On the other hand, we can also improve the circumstances for the integration of implant to the surrounding bone by in situ BP rinsing, thus creating a better environment for bone ingrowthTiivistelmä Läpi elämän luustossa tapahtuu uudelleenmuotoutumista, remodelaatiota, jonka seurauksena luu pystyy paremmin vastaamaan muuttuneisiin kuormitusolosuhteisiin. Remodelaatioprosessi on hyvin haavoittuvainen murtuman luutumisen aikana sekä proteesin kiinnittyessä ympäröivään luuhun. Luun remodelaatioon osallistuvat kasvutekijät, sytokiinit ja entsyymit, jotka puolestaan ovat välttämättömiä osteoblastien ja osteoklastien erilaistumiselle. Monet lääkeaineet voivat yllättävällä tavalla vahingoittaa tätä herkkää remodelaatiosysteemiä. Kipulääkkeet, kuten syklo-oksygenaasi (COX) estäjät, voivat häiritä murtuman luutumista aikaisempien eläintöiden ja muutamien retrospektiivisten potilastutkimusten mukaan. Lisäksi bisfosfonaatit, joiden päävaikutuskohde on luuta hajoittava osteoklasti, voisivat olla lupaavia lääkkeitä myös parantamaan proteesia ympäröivän luun laatua ja siten estämään aseptista implantin irtoamista. Tutkimuksen yhtenä tarkoituksena oli selvittää klodronaatin, ensimmäisen polven typpi-ryhmää sisältämättömän bisfosfonaatin tarkka vaikutusmekanismi. Viljelemällä ihmisen luuytimen kantasoluja indometasiinia, parekoksibia tai spesifistä COX-2 estäjää NS 398:a, sisältävässä kasvatusliuoksessa selvitettiin COX-entsyymin merkitys osteoblastien erilaistumiselle. Liposomien sisälle pakattua klodronaatin metaboliittia (AppCCl2p) käytettiin tutkittaessa millä vaikutusmekanismilla klodronaatti aiheuttaa osteoklastien apoptoosin. Bisfosfonaattien; klodronaatin, pamidronaatin ja tsoledronaatin vaikutusta osteoklastien ja osteoblastien erilaistumiseen tutkittiin soluviljelmämallissa ja määritettiin kliinisessä potilastyössä paikallisesti käytettävän klodronaattiliuoksen pitoisuus. Lopuksi potilastyössä selvitettiin paikallisen klodronaattihuuhtelun ja suun kautta annostellun klodronaatin vaikutus proteesia ympäröivän luun tiheyteen ja proteesin kiinnittymiseen ympäristöönsä. Tutkimukseen valitut COX-estäjät vähensivät ihmisen kantasolujen erilaistumista osteoblasteiksi ja lisäsivät erilaistumista rasvasoluiksi. Lisäksi todettiin, että AppCCl2p estää mitokondrioissa tapahtuvaa hengitystä estämällä ADP/ATP-vaihtajan toiminnan, saaden aikaan solukuoleman. Vertailtaessa bisfosfonaatteja, tsoledronaatilla vaikutti olevan sekä ensimmäisen, että kolmannen polven (sisältää typpi-ryhmän) bispfosfonaattien vaikutuksia, joten tsoledronaatti kuuluu aivan uuteen bisfosfonaattiryhmään. Potilastutkimuksessa suun kautta ja paikallisesti reisiluun ytimeen annostellulla klodronaatilla oli täysin erilainen vaikutus. Suun kautta syötynä klodronaatti hidasti proteesin kiinnittymistä ja aiheutti osteolyysiä. Sen sijaan paikallinen klodronaatti nopeutti merkittävästi proteesin kiinnittymistä ympäröivään luuhun. Näiden tutkimustulosten perusteella voidaan olettaa, että COX-estäjät, samoin kuin peroraalinen bisfosfonaatti, voivat tahattomasti häiritä luun remodelaatiota
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Hum, Julia M. "Signaling mechanisms that suppress the anabolic response of osteoblasts and osteocytes to fluid shear stress." Thesis, 2014. http://hdl.handle.net/1805/4652.
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Indiana University-Purdue University Indianapolis (IUPUI)Bone is a dynamic organ that responds to its external environment. Cell signaling cascades are initiated within bone cells when changes in mechanical loading occur. To describe these molecular signaling networks that sense a mechanical signal and convert it into a transcriptional response, we proposed the mechanosome model. “GO” and “STOP” mechansomes contain an adhesion-associated protein and a nucleocytoplasmic shuttling transcription factor. “GO” mechanosomes functions to promote the anabolic response of bone to mechanical loading, while “STOP” mechanosomes function to suppress the anabolic response of bone to mechanical loading. While much work has been done to describe the molecular mechanisms that enhance the anabolic response of bone to loading, less is known about the signaling mechanisms that suppress bone’s response to loading. We studied two adhesion-associated proteins, Src and Pyk2, which may function as “STOP” mechanosomes. Src kinase is involved in a number of signaling pathways that respond to changes in external loads on bone. An inhibition of Src causes an increase in the expression of the anabolic bone gene osteocalcin. Additionally, mechanical stimulation of osteoblasts and osteocytes by fluid shear stress further enhanced expression of osteocalcin when Src activity was inhibited. Importantly, fluid shear stress stimulated an increase in nuclear Src activation and activity. The mechanism by which Src participates in attenuating anabolic gene transcription remains unknown. The studies described here suggest Src and Pyk2 increase their association in response to fluid shear stress. Pyk2, a protein-tyrosine kinase, exhibits nucleocytoplasmic shuttling, increased association with methyl-CpG-binding protein 2 (MBD2), and suppression of osteopontin expression in response to fluid shear stress. MBD2, known to be involved in DNA methylation and interpretation of DNA methylation patterns, may aid in fluid shear stress-induced suppression of anabolic bone genes. We conclude that both Src and Pyk2 play a role in regulating bone mass, possibly through a complex with MBD2, and function to limit the anabolic response of bone cells to fluid shear stress through the suppression of anabolic bone gene expression. Taken together, these data support the hypothesis that “STOP” mechanosomes exist and their activity is simulated in response to fluid shear stress.
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Wang, Yu-Wen, and 王玉文. "Calcitonin-induced Detachment of Osteoclasts by Inhibiting PYK2 Activity : Involvement of PKC, SHPTP1, and [Ca2+]i." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/86725699032334706478.
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碩士國防醫學院
生物及解剖學研究所
88
Osteoclastic bone resorption is initiated by integrin (avb3) adhesion to the bone surface RGD-containing peptide, followed by cytoskeletal rearrangement and formation of the sealing zone that polarizes the cell. Calcitonin (CT) inhibits bone resorption by causing detachment of osteoclasts. In HEK-293 cells, CT induced G protein-coupled signaling cascades, which involve adenylyl cyclase, phospholipase C, protein kinase A, protein kinase C, Erk1/2, and HEF1. However, the CT-induced signaling effectors in osteoclasts are not well characterized. Proline-rich tyrosine kinase 2 (PYK2) is a member of the focal adhesion kinase family. PYK2 localized in the sealing zone of osteoclasts, activated by ligation of integrin, and then activated src, is an important signaling molecule for bone resorption. Role of PYK2 in the signaling pathways that link G protein-coupled receptors with mitogen-activated protein kinase has been reported. In the present study, we address the role played by PYK2 as a potential effector downstream of CT-induced signaling pathways. In isolated authentic rabbit osteoclasts cultured on collagen-I coated plate, CT-induced detachment of the cells, effects on PYK2 tyrosine phosphorylation and distribution were examined. CT induced a dose-dependent decrease of PYK2 tyrosine phosphorylation which is blocked by pre-treatment of the protein kinase C inhibitor calphostin C and the phosphatase inhibitors pervanadate and okadaic acid, but not the protein kinase A inhibitor H89 or the Erk1/2 inhibitor PD98059. Similar results were obtained in the CT-induced detachment assay. Transient increase of intracellular calcium concentration following CT treatments also appeared to modulate both osteoclast retraction/detachment and PYK2 phosphorylation. Furthermore, confocal microscopy analysis indicated that CT treatments caused redistribution of PYK2 from cell periphery to central portion of the cytosol and decrease of tyrosine phosphorylation levels of PYK2. SHPTP1 (Src homology 2 domain-containing phosphatase) coimmuno-precipitated with PYK2 and its tyrosine phosphorylation state was increased by CT. Taken together, our findings suggest that PYK2 may play an important role in mediating CT-induced cytoskeletal rearrangement in osteoclasts by modulating protein kinase C, SHPTP1, and intracellular calcium concentration.
Books on the topic "Osteoclast inhibition"
1
Ruabens, Robert D. The Management of Bone Metastases and Hypercalcaemia by Osteoclast Inhibition: An International Symposium Held During the 5th European Conference on. Hogrefe & Huber Pub, 1990.
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2
Maria, Bijvoet Olav Leonardus, Lipton Allan, and International Cancer Congress (15th : 1990 : Hamburg, Germany), eds. Osteoclast inhibition in the management of malignancy-related bone disorders: An international symposium held during the 15th International Cancer Congress, Hamburg, Germany, August 1990. Seattle: Hogrefe & Huber, 1993.
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3
Bijvoet, O. L. M. Osteoclast Inhibition in the Management of Malignancy-Related Bone Disorders: An International Symposium Held During the 15th International Cancer Co. Hogrefe & Huber Pub, 1992.
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D, Rubens R., and European Conference on Clinical Oncology (5th : 1989 : London, England), eds. The Management of bone metastases and hypercalcaemia by osteoclast inhibition: An international symposium held during the 5th European Conference on Clinical Oncology (ECCO 5), London, September 1989. Toronto: Hogrefe & Huber, 1990.
Find full textBook chapters on the topic "Osteoclast inhibition"
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Woo, Je-Tae, Yasuo Ohba, Kahori Tagami, Koji Sumitani, Kohji Yamaguchi, Tomoko Tsuji, Takao Kataoka, and Kazuo Nagai. "Low Molecular Weight Microbial Metabolites that Suppress Bone Resorption by Inhibiting Vacuolar Type Proton Pump Activity of Osteoclasts." In Animal Cell Technology: Basic & Applied Aspects, 627–32. Dordrecht: Springer Netherlands, 1997. http://dx.doi.org/10.1007/978-94-011-5746-9_102.
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Abdel-Meguid, Sherin S., Baoguang Zhao, Ward W. Smith, Cheryl A. Hanson, Judith LaLonde, Thomas Carr, Karla D'Alessio, et al. "Rational Approaches to Inhibition of Human Osteoclast Cathepsin K and Treatment of Osteoporosis." In ACS Symposium Series, 141–52. American Chemical Society, 1999. http://dx.doi.org/10.1021/bk-1999-0719.ch009.
Full textConference papers on the topic "Osteoclast inhibition"
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Yoshiga, Y., F. Hosoi, S. Iguchi, R. Kaneko, Y. Nakachi, D. Akasaka, K. Tanaka, et al. "FRI0079 TAS5315, a novel bruton's tyrosine kinase inhibitor, improve bone mineral density (BMD) and bone erosion via inhibition of osteoclast activation in murine model for rheumatoid arthritis." In Annual European Congress of Rheumatology, 14–17 June, 2017. BMJ Publishing Group Ltd and European League Against Rheumatism, 2017. http://dx.doi.org/10.1136/annrheumdis-2017-eular.1761.
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Kuboi, Y., K. Hoshino-Negishi, M. Ohkuro, W. Ikeda, T. Nakatani, N. Ishii, N. Yasuda, and T. Imai. "THU0053 Anti-fractalkine monoclonal antibody ameliorates joint destruction in collagen-induced arthritis model by inhibition of osteoclast precursor cell survival and migration." In Annual European Congress of Rheumatology, EULAR 2018, Amsterdam, 13–16 June 2018. BMJ Publishing Group Ltd and European League Against Rheumatism, 2018. http://dx.doi.org/10.1136/annrheumdis-2018-eular.4407.
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Chen, Show-Huie, Chia-Ching Wu, Shyh-Hau Wang, and Weng-Tyng Li. "The inhibition effect of low-intensity pulsed ultrasound on osteoclasts progenitor cells." In 2012 IEEE International Ultrasonics Symposium. IEEE, 2012. http://dx.doi.org/10.1109/ultsym.2012.0151.
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Rübner, M., R. Detsch, AR Boccaccini, E. Strasser, PA Steininger, R. Steigleder, DL Wachter, et al. "Zell-Zell-Fusion von Monozyten zu Osteoclast-like Zellen und deren Inhibiton durch Chemo- und Immuntherapeutika." In 62. Kongress der Deutschen Gesellschaft für Gynäkologie und Geburtshilfe – DGGG'18. Georg Thieme Verlag KG, 2018. http://dx.doi.org/10.1055/s-0038-1671652.
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Penninger, Charles L., Andre´s Tovar, Glen L. Niebur, and John E. Renaud. "Signaling Pathways for Bone Resorption Predicted as a Hybrid Cellular Automaton Process." In ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-39358.
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The bone remodeling process provides for various functions such as mineral homeostasis, damage repair, and adaptation to mechanical loading. At present, a clear link between the mechanical stimulation of bones and the biochemical response is not fully understood. Computational simulations can provide a means to test hypotheses and gain insight into processes that are difficult to examine experimentally. The objective of this work is to predict the effect of damage and strain as the stimulus for regulating the cellular signaling activity of remodeling. In this study, potential signaling pathways that mediate this cellular activity were incorporated in a hybrid cellular automaton (HCA) algorithm. Biological rules were implemented in this model to control recruitment, differentiation, and activation of osteoclasts. Prominent processes for describing recruitment and inhibition of the bone cells, as reported from experimental studies, are utilized. This work focuses on the resorption of a damaged site on a trabecular strut.
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Chen, Haiming, Eric Sanchez, Cathy S. Wang, Mingjie Li, Jennifer Li, Kevin D. Delijani, Zhiwei Li, Benjamin Bonavida, Daniel Levitt, and James R. Berenson. "Abstract LB-305: The tyrosine kinase inhibitor bafetinib (INNO-406) inhibits osteoclast formation and bone resorption." In Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL. American Association for Cancer Research, 2011. http://dx.doi.org/10.1158/1538-7445.am2011-lb-305.
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van den Bosch, MH, G. Ascone, I. Di Ceglie, B. Walgreen, AW Sloetjes, E. Lindhout, I. Bot, et al. "P073 High LDL levels lessen bone destruction during antigen-induced arthritis by inhibiting osteoclast formation and function." In 39th European Workshop for Rheumatology Research, 28 February–2 March 2019, Lyon, France. BMJ Publishing Group Ltd and European League Against Rheumatism, 2019. http://dx.doi.org/10.1136/annrheumdis-2018-ewrr2019.62.
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Ascone, Giuliana, Irene DI Ceglie, Ilze Bot, Fons van de Loo, Marije Koenders, Peter van der Kraan, Arjen Blom, Martijn van den Bosch, and Peter van Lent. "FRI0527 HIGH LDL LEVELS LESSEN BONE DESTRUCTION DURING ANTIGEN-INDUCED ARTHRITIS BY INHIBITING OSTEOCLAST FORMATION AND FUNCTION." In Annual European Congress of Rheumatology, EULAR 2019, Madrid, 12–15 June 2019. BMJ Publishing Group Ltd and European League Against Rheumatism, 2019. http://dx.doi.org/10.1136/annrheumdis-2019-eular.3479.
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van der Kraan, A. Gabrielle J., Ryan R. Chai, Michelle M. Kouspou, Ben J. Lang, Preetinder P. Singh, Jiake Xu, Damien Eeles, Matthew T. Gillespie, Julian M. Quinn, and John T. Price. "Abstract 2933: HSP90 inhibiting anti-cancer therapeutics enhance bone loss by increasing osteoclast formation: Mechanism of action." In Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC. American Association for Cancer Research, 2013. http://dx.doi.org/10.1158/1538-7445.am2013-2933.
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Sun, Huiqiang, Guoxia Sun, Xing Liang, and Ju Liu. "Influence of Joint Action of Fluid Shear Stress and Signal Transduction Ligand Inhibitor on Osteoclasts' Differentiation and Maturation." In Third International Conference on Intelligent Information Hiding and Multimedia Signal Processing. IEEE, 2007. http://dx.doi.org/10.1109/iihmsp.2007.4457605.
Full textReports on the topic "Osteoclast inhibition"
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Morgans, Alicia K., David F. Penson, Amy J. Graves, Parul Chaudhuri, and Daniel Sonnenburg. Osteoclast inhibitor treatment among men with metastatic castration-resistant prostate cancer. Science Repository OÜ, September 2018. http://dx.doi.org/10.31487/j.cor.2018.03.001.
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