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Anandarajah AP, Schwarz EM. Anti-RANKL therapy for inflammatory bone disorders: Mechanisms and potential clinical applications. J Cell Biochem 2006; 97:226-32. [PMID: 16240334 DOI: 10.1002/jcb.20674] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Focal bone loss around inflamed joints in patients with autoimmune disease, such as rheumatoid arthritis, remains a serious clinical problem. The recent elucidation of the RANK/RANK-ligand/OPG pathway and its role as the final effector of osteoclastogenesis and bone resorption has brought a tremendous understanding of the pathophysiology of inflammatory bone loss, and has heightened expectation of a novel intervention. Here, we review the etiology of inflammatory bone loss, the RANK/RANK-ligand/OPG pathway, and the clinical development of anti-RANK-ligand therapy.
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Affiliation(s)
- Allen P Anandarajah
- Department of Allergy, Immunology and Rheumatology, University of Rochester Medical Center, Rochester, New York 14642, USA.
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52
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Thammasitboon K, Goldring SR, Boch JA. Role of macrophages in LPS-induced osteoblast and PDL cell apoptosis. Bone 2006; 38:845-52. [PMID: 16377271 DOI: 10.1016/j.bone.2005.10.013] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2005] [Revised: 10/12/2005] [Accepted: 10/14/2005] [Indexed: 01/20/2023]
Abstract
In periradicular lesions and periodontal disease, bacterial invasion leads to chronic inflammation resulting in disruption of the structural integrity of the periodontal ligament and progressive alveolar bone destruction. The pathogenesis of these conditions has been attributed not only to bacterial-induced tissue destruction but also to a defect in periodontal tissue repair. Accumulated data have also shown that lipopolysaccharide (LPS) can directly induce cell death or apoptosis in many cell types, including macrophages, osteoblasts, vascular endothelial cells, hepatocytes and myocytes. The present study hypothesized that bacterial LPS-induced apoptosis in osteoblasts and periodontal ligament fibroblasts (PDL cells) is an important contributing factor to the defect in periodontal tissue repair in periodontal and periapical disease. Macrophages have been shown to respond to bacterial LPS by increasing the production of proinflammatory cytokines. In addition, large numbers of macrophages are present in inflamed periodontal tissue. We speculated that macrophages were a potential candidate cell for mediating apoptosis in osteoblasts and PDL cells in response to bacteria-derived LPS. The macrophage-like cell line, RAW 264.7, was stimulated with LPS, and the conditioned medium was used to treat osteoblasts and PDL cells. Bacterial LPS had no direct apoptotic effect on mouse osteoblasts or PDL cells, whereas the conditioned medium from LPS-activated macrophages was able to induce apoptosis in these cells. To evaluate the contribution of tumor necrosis factor-alpha (TNF-alpha) released from macrophages on osteoblast and PDL cell apoptosis, cells were incubated with conditioned medium from LPS-treated macrophages in the presence and absence of anti-TNF-alpha neutralizing antibodies. TNF-alpha neutralizing antibody pretreatment inhibited the effect of conditioned medium from LPS-treated macrophages on osteoblast and PDL cell apoptosis in a dose-dependent manner. These results suggest that LPS could indirectly induce apoptosis in osteoblasts and PDL cells through the induction of TNF-alpha release from macrophages. These studies provide insight into a potential mechanism by which bacterial-derived LPS could contribute to defective periodontal and bone tissue repair in periodontal and periapical disease.
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Abstract
Intra-articular bleeding is the most common clinical manifestation of hemophilia, and can adversely affect joints and lead to arthropathy. Affected joints are associated with changes to the synovium, bone, cartilage and blood vessels. Iron plays a critical role in the pathogenesis of this condition, and may exert its effects through a variety of different mechanisms. Hemophilic arthropathy shares some injury characteristics with rheumatoid arthritis, although the degree of analogy is a matter of some debate. The influences of the mechanisms underlying joint inflammation are better understood for rheumatoid arthritis than for hemophilia, and it is hoped that this knowledge can be used to provide a more comprehensive knowledge of the pathological process of hemophilic arthropathy. This, in turn, may enable novel targets for therapeutic intervention to be identified.
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Affiliation(s)
- W Keith Hoots
- Gulf States Hemophilia and Thrombophilia Center, Houston, TX 77030, USA.
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Kuo PL, Huang YT, Chang CH, Chang JK. Fraxetin inhibits the induction of anti-Fas IgM, tumor necrosis factor-alpha and interleukin-1beta-mediated apoptosis by Fas pathway inhibition in human osteoblastic cell line MG-63. Int Immunopharmacol 2006; 6:1167-75. [PMID: 16714221 DOI: 10.1016/j.intimp.2006.02.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2005] [Revised: 07/19/2005] [Accepted: 02/27/2006] [Indexed: 11/26/2022]
Abstract
The survival of osteoblast cells is one of the determinants of the development of osteoporosis in patients with inflamed synovium, such as in rheumatoid arthritis (RA). By means of alkaline phosphatase (ALP) activity and osteocalcin ELISA assay, we have shown that fraxetin exhibits a significant induction of differentiation in the human osteoblast-like cell line MG-63. In addition, we also assessed whether fraxetin affects inflammatory cytokine-mediated apoptosis in osteoblast cells. TNF-alpha or IL-1beta enhance apoptotic DNA fragmentation in anti-Fas IgM-treated MG-63 cells by increasing Fas receptor expression. However, TNF-alpha or IL-1beta treatment alone does not induce apoptosis. Treatment of MG-63 cells with fraxetin not only inhibited anti-Fas IgM-induced apoptosis, but also blocked the synergetic effect of anti-Fas IgM with TNF-alpha or IL-1beta on cell death. The apoptotic inhibition of fraxetin is associated with inhibition of TNF-alpha and IL-1beta-mediated Fas expression and enhancement of FLIP expression, resulting in a decrease of caspase-8 and caspase-3 activation. These results indicate a potential use of fraxetin in preventing osteoporosis by inhibiting inflammatory cytokine-mediated apoptosis in osteoblast cells.
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Affiliation(s)
- Po-Lin Kuo
- Department of Biotechnology, Chia-Nan University of Pharmacy and Science, Tainan, Taiwan.
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55
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Graves DT, Liu R, Alikhani M, Al-Mashat H, Trackman PC. Diabetes-enhanced inflammation and apoptosis--impact on periodontal pathology. J Dent Res 2006; 85:15-21. [PMID: 16373675 DOI: 10.1177/154405910608500103] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Diabetes, particularly type 2 diabetes, is a looming health issue with many ramifications. Because diabetes alters the cellular microenvironment in many different types of tissues, it causes myriad untoward effects, collectively referred to as 'diabetic complications'. Two cellular processes affected by diabetes are inflammation and apoptosis. This review discusses how diabetes-enhanced inflammation and apoptosis may affect the oral environment. In particular, dysregulation of tumor necrosis factor and the formation of advanced glycation products, both of which occur at higher levels in diabetic humans and animal models, potentiate inflammatory responses and induce apoptosis of matrix-producing cells. The enhanced loss of fibroblasts and osteoblasts through apoptosis in diabetics could contribute to limited repair of injured tissue, particularly when combined with other known deficits in diabetic wound-healing. These findings may shed light on diabetes-enhanced risk of periodontal diseases.
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Affiliation(s)
- D T Graves
- Department of Periodontology and Oral Biology, Boston University School of Dental Medicine, W-202 D, 700 Albany Street, Boston, MA 02118, USA.
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Schierano G, Canuto RA, Navone R, Peirone B, Martinasso G, Pagano M, Maggiora M, Manzella C, Easton M, Davit A, Trombetta A, Amedeo S, Biolatti B, Carossa S, Preti G. Biological factors involved in the osseointegration of oral titanium implants with different surfaces: a pilot study in minipigs. J Periodontol 2006; 76:1710-20. [PMID: 16253093 DOI: 10.1902/jop.2005.76.10.1710] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND The stability of titanium implants is determined by the rigid load-bearing connections that are formed by the bone, a process that involves a complex network of cells, pro- and anti-inflammatory mediators, and growth factors. The osseointegration processes at the interfaces of machined and porous implants were studied using molecular and histological techniques. METHODS Two machined and two porous titanium implants were inserted into the tibiae of four minipigs. The animals were sacrificed at 15, 30, 60, and 90 days post-implantation. The levels of bone morphogenetic protein (BMP)-4, transforming growth factor (TGF)-beta1, and tumor necrosis factor (TNF)-alpha were quantified in the peri-implant osseous samples. The levels of interleukin (IL)-1beta, IL-6, IL-10, and TNF-alpha in the serum were also assessed. RESULTS Histomorphological analysis showed evidence of bone ossification around the porous implant at 60 days. Surrounding the machined implants, highly sclerotic fibrous pads started the healing response at 90 days, and the levels of TGF-beta1 and BMP-4 began to increase at 60 days, at which time bone ossification around the porous implants was already evident. TNF-alpha was not present in the bone next to the implants. The serum levels of cytokines IL-1beta, IL-6, and IL-10 were not increased. The serum level of TNF-alpha increased during the healing process. CONCLUSIONS We observed that the levels of BMP-4 and TGF-beta1, which play essential roles in the osteogenesis process, increased earlier around the porous implants than around the machined implants. Similarly, the ossification process was initiated earlier at the surfaces of the porous implants than at the surfaces of the machined implants.
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Affiliation(s)
- Gianmario Schierano
- Department of Biomedical Sciences and Human Oncology, Section of Prosthetic Dentistry, School of Dentistry, University of Turin, Turin, Italy
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57
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Abreu MT, Geller JL, Vasiliauskas EA, Kam LY, Vora P, Martyak LA, Yang H, Hu B, Lin YC, Keenan G, Price J, Landers CJ, Adams JS, Targan SR. Treatment with infliximab is associated with increased markers of bone formation in patients with Crohn's disease. J Clin Gastroenterol 2006; 40:55-63. [PMID: 16340635 DOI: 10.1097/01.mcg.0000190762.80615.d4] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Osteoporosis is a common complication of Crohn's disease (CD). Glucocorticoid use and detrimental effects of inflammatory cytokines including tumor necrosis factor-alpha (TNF-alpha) can lead to osteoporosis. The aim of this study was to assess the ability of treatment with the TNF-alpha antagonist infliximab to increase bone formation as measured by surrogate markers of bone turnover in patients with active CD. METHODS Sera from 38 prospectively enrolled CD patients were examined for levels of bone alkaline phosphatase (BAP), N-telopeptide of type I collagen (NTX), immunoreactive parathyroid hormone (iPTH), calcium, and pro-inflammatory cytokines at baseline and 4 weeks following infliximab infusion. Crohn's Disease Activity Index (CDAI), Inflammatory Bowel Disease Questionnaire (IBDQ), and glucocorticoid dose also were collected. RESULTS In this cohort, CDAI and IBDQ scores were significantly improved at week 4 (P<0.001). Infliximab therapy was associated with an increase in BAP, a marker of bone formation (P=0.010), whereas NTX, a marker of bone resorption, was not increased (P=0.801). Among 22 patients who were taking glucocorticoids, mean glucocorticoid dose decreased 36% (P<0.001; -7.9 mg). CONCLUSIONS Treatment with infliximab was associated with increased markers of bone formation (BAP) without increasing bone resorption (NTX). This effect may be due to a beneficial effect of TNF-alpha blockade on bone turnover, a beneficial effect on CD activity resulting in decreased glucocorticoid dose, or both. Studies of longer duration are needed to assess the effect of infliximab on bone mineral density.
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Affiliation(s)
- Maria T Abreu
- Department of Medicine, Division of Gastroenterology, Inflammatory Bowel Disease Center, Mount Sinai School of Medicine, New York, NY, USA
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58
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Kaneki H, Guo R, Chen D, Yao Z, Schwarz EM, Zhang YE, Boyce BF, Xing L. Tumor necrosis factor promotes Runx2 degradation through up-regulation of Smurf1 and Smurf2 in osteoblasts. J Biol Chem 2005; 281:4326-33. [PMID: 16373342 PMCID: PMC2647592 DOI: 10.1074/jbc.m509430200] [Citation(s) in RCA: 230] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Tumor necrosis factor (TNF) plays an important role in the pathogenesis of inflammatory bone loss through stimulation of osteoclastic bone resorption and inhibition of osteoblastic bone formation. Compared with the well established role of TNF in osteoclastogenesis, mechanisms by which TNF inhibits osteoblast function have not been fully determined. Runx2 is an osteoblast-specific transcription factor whose steady-state protein levels are regulated by proteasomal degradation, mediated by the E3 ubiquitin ligases, Smurf1 and Smurf2. We hypothesized that TNF inhibits osteoblast function through Smurf-mediated Runx2 degradation. We treated C2C12 and 2T3 osteoblast precursor cell lines and primary osteoblasts with TNF and found that TNF, but not interleukin-1, significantly increased Smurf1 and Smurf2 expression. TNF increased the degradation of endogenous or transfected Runx2 protein, which was blocked by treating cells with a proteasomal inhibitor or by infecting cells with small interfering (si)RNA against Smurf1 or Smurf2. TNF inhibited the expression of bone morphogenetic protein and transforming growth factor-beta signaling reporter constructs, and the inhibition of each was blocked by Smurf1 siRNA and Smurf2 siRNA, respectively. Overexpression of Smurf1 and/or Smurf2 siRNAs prevented the inhibitory effect of TNF on Runx2 reporter. Consistent with these in vitro findings, bones from TNF transgenic mice or TNF-injected wild type mice had increased Smurf1 and decreased Runx2 protein levels. We propose that one of the mechanisms by which TNF inhibits bone formation in inflammatory bone disorders is by promoting Runx2 proteasomal degradation through up-regulation of Smurf1 and Smurf2 expression.
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Affiliation(s)
- Hiroyuki Kaneki
- Department of Pathology and Laboratory Medicine, University of Rochester, School of Medicine and Dentistry, NY 14642, USA
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59
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Malizos KN, Papatheodorou LK. The healing potential of the periosteum molecular aspects. Injury 2005; 36 Suppl 3:S13-9. [PMID: 16188544 DOI: 10.1016/j.injury.2005.07.030] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2005] [Accepted: 07/25/2005] [Indexed: 02/02/2023]
Abstract
The presence of pluripotential mesenchymal cells in the under surface of the periosteum in combination with growth factors regularly produced or released after injury, provide this unique tissue with an important role in the healing of bone and cartilage. The periosteum contributes in the secondary callus formation with cells and growth factors and should always be preserved and protected when surgery is performed for the management of a fracture. The current evidence about the cellular interactions, the stimulants and the signalling pathways related to osteogenesis and chondrogenesis is described. An essential knowledge of the basics related to the contribution of the periosteum in the healing of fractures, osteotomies, during the process of distraction osteogenesis and in some degree in the repair of cartilagenous defects, provides the surgeons with a better insight to understand the upcoming "biological" interventions in the management of skeletal injuries.
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Affiliation(s)
- Konstantinos N Malizos
- Orthopaedic Department, University Hospital of Larissa, P.O. Box 1425, 41110 Larissa, Greece.
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60
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Kuo PL. Myricetin inhibits the induction of anti-Fas IgM-, tumor necrosis factor-α- and interleukin-1β-mediated apoptosis by Fas pathway inhibition in human osteoblastic cell line MG-63. Life Sci 2005; 77:2964-76. [PMID: 15982670 DOI: 10.1016/j.lfs.2005.05.026] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2005] [Accepted: 05/02/2005] [Indexed: 11/26/2022]
Abstract
The survival of osteoblast cells is one of the determinants of the development of osteoporosis in patients with inflamed synovium, such as in rheumatoid arthritis (RA). By means of alkaline phosphatase (ALP) activity and osteocalcin ELISA assay, I have shown that myricetin exhibits a significant induction of differentiation in the human osteoblast-like cell line MG-63. In addition, I also assessed whether myricetin affects inflammatory cytokines-mediated apoptosis in osteoblast cells. TNF-alpha or IL-1beta enhances apoptotic DNA fragmentation in anti-Fas IgM-treated MG-63 cells by increasing Fas receptor expression. However, TNF-alpha or IL-1beta treatment alone does not induce apoptosis. Treatment of MG-63 cells with myricetin not only inhibited anti-Fas IgM-induced apoptosis, but also blocked the synergetic effect of anti-Fas IgM with TNF-alpha or IL-1beta on cell death. The apoptotic inhibition of myricetin is associated with inhibition of TNF-alpha and IL-1beta-mediated Fas expression and enhancement of FLIP expression, resulting in a decrease of caspase-8 and caspase-3 activation. These results indicate a potential use of myricetin in preventing osteoporosis by inhibiting inflammatory cytokines-mediated apoptosis in osteoblast cells.
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Affiliation(s)
- Po-Lin Kuo
- Department of Biotechnology, Chia-Nan University of Pharmacy and Science, No. 60, Erh-Jen Road, Sec.1, Jen-Te, Tainan 717, Taiwan.
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61
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Soung DY, Chung HY, Rhee SH, Park KY. Age-Related Male Osteoporosis, and Soy, Its Alternative Therapy - Review-. Prev Nutr Food Sci 2005. [DOI: 10.3746/jfn.2005.10.3.298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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62
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Xing L, Boyce BF. Regulation of apoptosis in osteoclasts and osteoblastic cells. Biochem Biophys Res Commun 2005; 328:709-20. [PMID: 15694405 DOI: 10.1016/j.bbrc.2004.11.072] [Citation(s) in RCA: 116] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2004] [Indexed: 11/24/2022]
Abstract
In postnatal life, the skeleton undergoes continuous remodeling in which osteoclasts resorb aged or damaged bone, leaving space for osteoblasts to make new bone. The balance of proliferation, differentiation, and apoptosis of bone cells determines the size of osteoclast or osteoblast populations at any given time. Bone cells constantly receive signals from adjacent cells, hormones, and bone matrix that regulate their proliferation, activity, and survival. Thus, the amount of bone and its microarchitecture before and after the menopause or following therapeutic intervention with drugs, such as sex hormones, glucocorticoids, parathyroid hormone, and bisphosphonates, is determined in part by effects of these on survival of osteoclasts, osteoblasts, and osteocytes. Understanding the mechanisms and regulation of bone cell apoptosis will enhance our knowledge of bone cell function and help us to develop better therapeutics for the management of osteoporosis and other bone diseases.
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Affiliation(s)
- Lianping Xing
- Department of Pathology and Laboratory Medicine, University of Rochester Medical Center, NY, USA.
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63
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Mastro AM, Gay CV, Welch DR, Donahue HJ, Jewell J, Mercer R, DiGirolamo D, Chislock EM, Guttridge K. Breast cancer cells induce osteoblast apoptosis: a possible contributor to bone degradation. J Cell Biochem 2004; 91:265-76. [PMID: 14743387 DOI: 10.1002/jcb.10746] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Breast cancer cells exhibit a predilection for metastasis to bone. There, the metastases usually bring about bone loss with accompanying pain and loss of function. One way that breast cancer cells disrupt the normal pattern of bone remodeling is by activating osteoclasts, the bone degrading cells. Nevertheless, targeting the osteoclasts does not cure the disease or result in bone repair. These observations indicate that osteoblast function also may be compromised. The objective of this study was to investigate the interaction of metastatic breast cancer cells with osteoblasts. Human metastatic breast cancer cells, MDA-MB-435 or MDA-MB-231, or their conditioned media were co-cultured with a human osteoblast line hFOB1.19. The breast cancer cells caused an increase in the prevalence of apoptotic osteoblasts. Apoptotic osteoblasts detected by the TUNEL assay or by caspase activity increased approximately two to fivefold. This increase was not seen with non-metastatic MDA-MB-468 cells. In an investigation of the mechanism, it was determined that the hFOB1.19 cells expressed fas and that fas was functional. Likewise the hFOB1.19 cells were susceptible to TNF-alpha, but this cytokine was not detected in the conditioned medium of the breast cancer cells. This study indicates that osteoblasts are the target of breast cancer cell-induced apoptosis, but fas/fas-ligand and TNF-alpha, two common initiators of cell death, are probably not involved in this aspect of the metastases/bone cell axis. There are several mechanisms that remain to be explored in order to determine how breast cancer cells bring about osteoblast apoptosis. Even though the specific initiator of apoptosis remains to be identified, the results of this study suggest that the mechanism is likely to be novel.
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Affiliation(s)
- Andrea M Mastro
- Department of Biochemistry and Molecular Cell Biology, The Pennsylvania State University, University Park, Pennsylvania, USA.
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64
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Sutherland MK, Geoghegan JC, Yu C, Turcott E, Skonier JE, Winkler DG, Latham JA. Sclerostin promotes the apoptosis of human osteoblastic cells: a novel regulation of bone formation. Bone 2004; 35:828-35. [PMID: 15454089 DOI: 10.1016/j.bone.2004.05.023] [Citation(s) in RCA: 155] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2004] [Revised: 05/13/2004] [Accepted: 05/25/2004] [Indexed: 12/11/2022]
Abstract
A null mutation in the SOST gene is associated with sclerosteosis, an inherited disorder characterized by a high bone mass phenotype. The protein product of the SOST gene, sclerostin, is a bone morphogenetic protein (BMP) antagonist that decreases osteoblast activity and reduces the differentiation of osteoprogenitors. We sought to delineate the mechanism by which sclerostin modulated osteoblastic function by examining the effects of the protein on differentiating cultures of human mesenchymal stem cells (hMSC). Sclerostin significantly decreased alkaline phosphatase (ALP) activity and the proliferation of hMSC cells. In addition, hMSC cells treated with sclerostin displayed a marked increase in caspase activity. Elevated levels of fragmented histone-associated DNA in these cells were detected by ELISA and by TUNEL staining. Other BMP antagonists including noggin, Chordin, Gremlin, and Twisted gastrulation did not affect caspase activity. The sclerostin-mediated increase in caspase activity was blocked by caspase-1 and caspase-3 inhibitors. Sclerostin-induced changes in ALP activity and the survival of hMSC cells were partially restored by BMP-6, suggesting the involvement of additional growth factors. These findings show that sclerostin selectively controls the apoptosis of bone cells. The ability of sclerostin to interact with important growth factors such as BMPs likely serves as the basis by which it modulates the survival of osteoblasts. By making these growth factors unavailable for cell function, sclerostin promotes the apoptosis of bone cells, providing a novel level of control in the regulation of bone formation.
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Affiliation(s)
- May Kung Sutherland
- Department of Gene Function & Target Validation, Celltech R & D, Inc, Bothell, WA 98021, USA
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65
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Silvestris F, Cafforio P, Calvani N, Dammacco F. Impaired osteoblastogenesis in myeloma bone disease: role of upregulated apoptosis by cytokines and malignant plasma cells. Br J Haematol 2004; 126:475-86. [PMID: 15287939 DOI: 10.1111/j.1365-2141.2004.05084.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Bone remodelling is severely affected in myeloma bone disease as a consequence of skeletal metastatization of malignant plasma cells. We investigated whether defective bone replacement is dependent on increased osteoblast apoptosis and/or on deregulated events within the bone microenvironment. Circulating tumour necrosis factor (TNF)-alpha, interferon-gamma, interleukin (IL)-1beta, and IL-6 levels were higher in myeloma patients with overt bone disease, whose osteoblasts constitutively overexpressed Fas, DR4/DR5 complex as receptors to TNF-related apoptosis inducing ligand, intercellular adhesion molecule-1 (ICAM-1), and monocyte chemotactic protein-1 (MCP-1). They were functionally exhausted and promptly underwent apoptosis in vitro, in contrast to the minor tendency to death detected in control osteoblasts from patients without bone involvement and normal donors. Osteoblasts dramatically enhanced their apoptosis in co-cultures with MCC-2 myeloma cells and upregulated both ICAM-1 and MCP-1 in a manner similar to control osteoblasts. Pretreating MCC-2 cells with soluble ICAM-1 led to a striking inhibition of their adhesion to osteoblasts, suggesting that the ICAM-1/lymphocyte function-associated antigen-1 system plays a role in the reciprocal membrane contact to trigger apoptogenic signals. Our data suggest that, in the myeloma bone microenvironment, both high cytokine levels and physical interaction of malignant plasma cells with osteoblasts drive the accelerated apoptosis in these cells leading to defective new bone formation.
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Affiliation(s)
- Franco Silvestris
- Department of Internal Medicine and Oncology, University of Bari, Bari, Italy.
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66
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Franchimont N, Putzeys V, Collette J, Vermeire S, Rutgeerts P, De Vos M, Van Gossum A, Franchimont D, Fiasse R, Pelckmans P, Malaise M, Belaiche J, Louis E. Rapid improvement of bone metabolism after infliximab treatment in Crohn's disease. Aliment Pharmacol Ther 2004; 20:607-14. [PMID: 15352908 DOI: 10.1111/j.1365-2036.2004.02152.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Crohn's disease is associated with low bone mineral density and altered bone metabolism. AIM To assess the evolution of bone metabolism in Crohn's disease patients treated with infliximab. METHODS We studied 71 Crohn's disease patients treated for the first time with infliximab for refractory Crohn's disease. Biochemical markers of bone formation (type-I procollagen N-terminal propeptide, bone-specific alkaline phosphatase, osteocalcin) and of bone resorption (C-telopeptide of type-I collagen) were measured in the serum before and 8 weeks after infliximab therapy and compared with values in a matched healthy control group. RESULTS Eight weeks after treatment with infliximab, a normalization of bone markers was observed with a median increase in formation markers of 14-51% according to marker and a lower but significant decrease in resorption marker (median 11%). A clinically relevant increase in bone formation markers was present in 30-61% of patients according to the marker. A clinically relevant decrease in C-telopeptide of type-I collagen was present in 38% of patients. No association was found with any tested demographic or clinical parameter. CONCLUSION Infliximab therapy in Crohn's disease may rapidly influence bone metabolism by acting either on bone formation or bone resorption. This improvement seems to be independent of clinical response to infliximab.
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67
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Habib GS, Haj S. Bone mineral density in patients with early rheumatoid arthritis treated with corticosteroids. Clin Rheumatol 2004; 24:129-33. [PMID: 15372317 DOI: 10.1007/s10067-004-0989-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2004] [Accepted: 06/18/2004] [Indexed: 10/26/2022]
Abstract
The aim of this study was to evaluate the bone mineral density (BMD) in patients with early rheumatoid arthritis (RA) prior to and 6 months after adding low-dose corticosteroid (CS) treatment. Adult patients (>21 years old) with early RA (symptom duration <1 year) and severe joint pain under maximal dose of nonsteroidal anti-inflammatory drugs (NSAIDS) were started on low-dose prednisone (10 mg/day). Patients were evaluated after 1, 3, and 6 months. Disease activity measures including swollen and tender joint count, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) were documented, and the dose of prednisone was adjusted according to the level of pain at each visit. BMD of the femoral neck (FN) and lumbar spine (LS) was measured using dual energy X-ray absorptiometry prior to and 6 months after starting CS treatment. Calcium supplements, vitamin D, bisphosphonates, or hormonal therapy that may affect BMD were not permitted during the study. Twenty patients were eligible and 16 completed the study; 75% were female. The mean age was 47.2+/-12 years and mean duration of symptoms was 7+/-2 months. The mean BMD at the FN prior to and 6 months after starting CS treatment were 0.8080 g/cm(2)+/-0.1145 and 0.8242 g/cm(2)+/-0.1122, respectively (p=0.04). The mean BMD at the LS prior to and 6 months after starting CS treatment were 0.9429 g/cm(2)+/-0.1406 and 0.9490 g/cm(2)+/-0.1277, respectively (p=0.423). There was a significant correlation between the mean change of BMD at the FN and mean change of tender joint count (p=0.01), ESR (p=0.008), and CRP (p=0.006) but not with swollen joint count (p=0.099). However, there was no correlation between the change of BMD at the FN or LS and the change of any of the disease activity measures of every patient. Also, no correlation was seen between the cumulative dose of CS and the change in BMD. BMD increases significantly at the FN in early RA patients 6 months after adding low-dose CS to the treatment.
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Affiliation(s)
- George S Habib
- Rheumatology Clinic, Nazareth Hospital, Nazareth, Israel.
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Debiais F, Lefèvre G, Lemonnier J, Le Mée S, Lasmoles F, Mascarelli F, Marie PJ. Fibroblast growth factor-2 induces osteoblast survival through a phosphatidylinositol 3-kinase-dependent, -beta-catenin-independent signaling pathway. Exp Cell Res 2004; 297:235-46. [PMID: 15194439 DOI: 10.1016/j.yexcr.2004.03.032] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2003] [Revised: 02/24/2004] [Indexed: 01/20/2023]
Abstract
Fibroblast growth factor-2 (FGF-2) is an important molecule that controls bone formation through activation of osteoblastic cell replication and differentiation. The role of FGF-2 on human osteoblast survival and the signaling pathway that mediates its effect are not known. We studied the effect of FGF-2 on apoptosis induced by low serum concentration and the signal transduction pathway involved in this effect in human primary calvaria osteoblasts and immortalized osteoblastic cells. Treatment with FGF-2 for 24-48 h protected against osteoblast apoptosis induced by low serum concentration, through specific inhibition of caspase-2 and caspase-3 activity. Pharmacological inhibition of MEK-1 and p38 MAPK had no effect on the inhibition of caspases-2 and -3 induced by FGF-2. In contrast, inhibition of PI3K with LY294002 abolished the FGF-2-induced inhibition of caspases-2 and -3. FGF-2 increased PI3K activity but did not induce phosphorylation of Akt or the downstream effector p70 S6 kinase. FGF-2 also induced GSK-3alpha and beta phosphorylation in osteoblastic cells, which however did not result in beta-catenin accumulation or Lef/Tcf transcriptional activity. In contrast, lithium induced beta-catenin accumulation, Lef/Tcf transcriptional activation and increased caspase-2 and -3 activity. The results indicate that the immediate protective effect of FGF-2 on human osteoblastic cell apoptosis involves PI3K and inhibition of downstream caspases, independently of GSK-3 and beta-catenin-Lef/Tcf-mediated transcription.
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Affiliation(s)
- F Debiais
- INSERM U 606, Lariboisière Hospital, Paris, France
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69
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Duque G, El Abdaimi K, Henderson JE, Lomri A, Kremer R. Vitamin D inhibits Fas ligand-induced apoptosis in human osteoblasts by regulating components of both the mitochondrial and Fas-related pathways. Bone 2004; 35:57-64. [PMID: 15207741 DOI: 10.1016/j.bone.2004.03.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2003] [Revised: 02/26/2004] [Accepted: 03/08/2004] [Indexed: 10/26/2022]
Abstract
Apoptosis plays an important role in the regulation of bone turnover. Previously, we showed that 1,25(OH)2D3, the active form of vitamin D, may increase osteoblast survival by inhibiting apoptosis induced by serum deprivation. Human osteoblasts express the Fas receptor on their surface and its interaction with Fas ligand has been closely associated with human osteoblast apoptosis. To investigate the mechanism of 1,25(OH)2D3 inhibition of apoptosis in osteoblasts isolated from human calvaria, cells were exposed to Fas antibody. Visualization of apoptotic cells using annexin V revealed a significant decrease in apoptosis at 48 h in the presence of 1,25(OH)2D3 (14 +/- 4%, P < 0.04) compared with non-treated cells (52 +/- 4%). Furthermore, flow cytometric analysis of TUNEL-labeled osteoblasts showed a significant decrease in apoptotic cells in 1,25(OH)2D3-treated cultures (12 +/- 2%) at 48 h compared with non-treated cultures (44 +/- 3%, P < 0.04). Additionally, cells treated with 1,25(OH)2D3 survived longer as found by MTS analysis. To further explore the mechanism of 1,25(OH)2D3-mediated inhibition of apoptosis, we examined the changes in activation of death domain proteins, cleavage of caspases and mitochondrial regulators of apoptosis by Western blot analysis. A significant inhibition of caspase-8 cleavage and activity in 1,25(OH)2D3-treated cells was observed in conjunction with a decrease in the expression of the proapoptotic protein Bax with a significant increase in the expression of antiapoptotic protein Bcl-2. Furthermore, the levels of p21Cip1/WAF1, which inhibits the cleavage of caspase-8, was found to be highly induced in 1,25(OH)2D3-treated cells. In summary, these results demonstrate that the anti-apoptotic effect of 1,25(OH)2D3 in human osteoblasts after the activation of Fas-ligand is mediated by the regulation of components of both the mitochondrial and Fas-related pathways.
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Affiliation(s)
- Gustavo Duque
- Calcium Research Laboratory, McGill University, Montreal, Quebec, Canada H3A 1A1.
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70
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García-Moreno C, Catalán MP, Ortiz A, Alvarez L, De la Piedra C. Modulation of survival in osteoblasts from postmenopausal women. Bone 2004; 35:170-7. [PMID: 15207753 DOI: 10.1016/j.bone.2004.02.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2003] [Revised: 02/17/2004] [Accepted: 02/19/2004] [Indexed: 11/23/2022]
Abstract
Osteoblast survival is one of the determinants of postmenopausal osteoporosis development. Recent data from animal experiments suggest that cytokines, in particular Fas ligand (FasL), contribute to postmenopausal osteoporosis. We now address the effect of Fas activation in postmenopausal osteoblast survival and the potential modulatory effect of estrogen and raloxifene analog (LY117018). The expression of Fas mRNA, Fas protein, and the sensitivity to Fas-induced apoptosis were studied in primary cultures of human osteoblasts from postmenopausal women and in osteoblastic MG-63 cells. Human postmenopausal osteoblasts constitutively expressed Fas receptors in the cell surface. TNFalpha increased the expression of Fas mRNA and cell surface Fas expression. Neither estradiol nor raloxifene analog prevented this increase in Fas expression. In addition, activation of Fas receptor resulted in apoptosis of postmenopausal osteoblasts. While TNFalpha did not induce human osteoblast apoptosis, it did increase the lethal effect of Fas activation. Therapeutic concentrations of estradiol or raloxifene analog did not modulate lethal cytokine-induced apoptosis. Both postmenopausal osteoblasts and MG-63 cells express FasL. FasL expression was not modulated by TNFalpha. In conclusion, estrogen and raloxifene analog do not appear to affect the sensitivity of postmenopausal osteoblasts to Fas-mediated apoptosis.
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Affiliation(s)
- C García-Moreno
- Bone Pathophysiology Laboratory, Jiménez-Díaz Foundation, Madrid, Spain
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71
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Katavić V, Grcević D, Lukić IK, Vucenik V, Kovacić N, Kalajzić I, Marusić A. Non-functional Fas ligand increases the formation of cartilage early in the endochondral bone induction by rhBMP-2. Life Sci 2003; 74:13-28. [PMID: 14575809 DOI: 10.1016/j.lfs.2003.06.031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
It has previously been shown that mice with a defect in Fas ligand-mediated apoptosis have an enhancement of ectopic bone formation. We investigated the expression of bone-related markers--alkaline phosphatase, collagen, bone sialoprotein, osteocalcin, osteopontin, and bone morphogenetic proteins (BMP) -2, -4, and -7; and cytokines interleukin-1alpha (IL-1), IL-1beta, and tumor necrosis factor-alpha (TNF-alpha) in ectopic new bone induced by recombinant human (rh) BMP-2 in mice without functional Fas-ligand (gld mice). At day 6 after rhBMP-2 implantation, gld mice formed more cartilage and mesenchyme compared with their wild type littermates. At later stages, gld mice did not differ from the control mice in the volume of newly formed tissue, expressing higher level of BMP genes and lower levels of genes involved in osteoblast maturation--bone sialoprotein and osteopontin. Differences in the levels of expression of IL-1alpha and TNF-alpha were observed only at day 12 after rhBMP-2 implantation. These results suggest that gld mice have an increased recruitment of cells of mesenchymal origin and an abnormal pattern of differentiation and maturation of the newly formed mesenchymal tissues.
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Affiliation(s)
- Vedran Katavić
- Department of Anatomy, Croatian Institute for Brain Research, Zagreb University School of Medicine, Salata 11, HR-10000 Zagreb, Croatia.
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Zhang X, Carpenter D, Bokui N, Soo C, Miao S, Truong T, Wu B, Chen I, Vastardis H, Tanizawa K, Kuroda S, Ting K. Overexpression of Nell-1, a craniosynostosis-associated gene, induces apoptosis in osteoblasts during craniofacial development. J Bone Miner Res 2003; 18:2126-34. [PMID: 14672347 DOI: 10.1359/jbmr.2003.18.12.2126] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
UNLABELLED We studied the cellular function of Nell-1, a craniosynostosis-related gene, in craniofacial development. Nell-1 modulates calvarial osteoblast differentiation and apoptosis pathways. Nell-1 overexpression disrupts these pathways resulting in craniofacial anomalies such as premature suture closure. INTRODUCTION Craniosynostosis (CS), one of the most common congenital craniofacial deformities, is the premature closure of cranial sutures. Previously, we reported NELL-1 as a novel molecule overexpressed during premature cranial suture closure in patients with CS. Nell-1 overexpression induced calvarial overgrowth and resulted in premature suture closure in a rodent model. On a cellular level, Nell-1 is suggested to promote osteoblast differentiation. MATERIALS AND METHODS Different levels of Nell-1 were introduced into osteoblastic cells by viral infection and recombinant protein. Apoptosis and gene expression assays were performed. Mice overexpressing Nell-1 were examined for apoptosis. RESULTS In this report, we further showed that overexpression of Nell-1 induced apoptosis along with modulation of apoptosis-related genes. The induction of apoptosis by Nell-1 was observed only in osteoblastic cells and not in NIH3T3 or primary fibroblasts. The CS mouse model overexpressing Nell-1 showed increased levels of apoptosis in the calvaria. CONCLUSION We show that Nell-1 expression modulates calvarial osteoblast differentiation and apoptosis pathways. Nell-1 overexpression disrupts these pathways resulting in craniofacial anomalies such as premature suture closure.
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Affiliation(s)
- Xinli Zhang
- Dental and Craniofacial Research Institute, University of California at Los Angeles, Los Angeles, California, USA
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Abstract
Tumor necrosis factor-alpha (TNF) is one member of a large family of inflammatory cytokines that share common signal pathways, including activation of the transcription factor nuclear factor kappa B (Nf-kappa B) and stimulation of the apoptotic pathway. Data derived from early work supported a role for TNF as a skeletal catabolic agent that stimulates osteoclastogenesis while simultaneously inhibiting osteoblast function. The finding that estrogen deficiency was associated with increased production of cytokines led to a barrage of studies and lively debate on the relative contributions of TNF and other cytokines on bone loss, on the potential cell sources of TNF in the bone microenvironment, and on the mechanism of TNF action. TNF has a central role in bone pathophysiology. TNF is necessary for stimulation of osteoclastogenesis along with the receptor activator of Nf-kappa B ligand (RANKL). TNF also stimulates osteoblasts in a manner that hinders their bone-formative action. TNF suppresses recruitment of osteoblasts from progenitor cells, inhibits the expression of matrix protein genes, and stimulates expression of genes that amplify osteoclastogenesis. TNF may also affect skeletal metabolism by inducing resistance to 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) by a mechanism that extends to other members of the steroid hormone nuclear receptor family. Thus, TNF assails bone at many levels. This review will focus on the cellular and molecular mechanisms of TNF action in the skeleton that result in increased bone resorption and impaired formation. TNF and its signal pathway remains an important target for the development of new therapies for bone loss from osteoporosis and inflammatory arthritis.
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Affiliation(s)
- Mark S Nanes
- Department of Medicine, Division of Endocrinology and Metabolism, Emory University School of Medicine and VA Medical Center, Mail Code (111), 1670 Clairmont Road, Decatur, GA 30033, USA.
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Abstract
The objective of this study was to compare two of the inflammatory cytokines (IL-1 and IL-6) elevated in both preterm labour and preterm premature rupture of the membranes (pPROM), with respect to their ability to induce fetal membrane apoptosis. Fetal membranes collected from women at term were placed in an organ explant system and stimulated with recombinant human IL-1 beta and IL-6. The expression patterns of pro-apoptotic genes (Fas, FasL, TRADD, FADD) and caspases 2, 3, 8, 9 were studied using PCR. Caspase activity and DNA fragmentation were studied using substrate assays and TUNEL respectively. Caspase 8 and 9 expressions were induced in IL-1 beta and IL-6 treated amniochorion. Caspase 2 expression was seen only in IL-1 beta stimulated tissues. When compared to control, IL-1 beta increased caspase 2, 3, 8 and 9 activities, whereas IL-6 treated membranes did not exhibit a significant change. DNA fragmentation was seen in greater numbers after IL-1 beta treatment than after IL-6 treatment. This study demonstrates that IL-1 beta is a better inducer of apoptosis in normal human fetal membranes than IL-6.
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Affiliation(s)
- S J Fortunato
- The Perinatal Research Center of The Women's Health Research and Education Foundation and Aquinas College, 2300 Patterson Street, Nashville, TN 37203, USA.
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75
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Bu R, Borysenko CW, Li Y, Cao L, Sabokbar A, Blair HC. Expression and function of TNF-family proteins and receptors in human osteoblasts. Bone 2003; 33:760-70. [PMID: 14623051 DOI: 10.1016/j.bone.2003.07.006] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We studied how tumor necrosis-factor (TNF)-family proteins interact with osteoblasts to resolve several controversial points. We measured expression of TNFs, TNF-receptors, and nonsignaling (decoy) TNF receptors in human osteoblasts derived from mesenchymal stem cells and in MG63 human osteosarcoma cells using unamplified mRNA screening, with secondary Western or PCR analysis where indicated, and studied the effects of TNFs on osteoblasts in cell culture. Expression of TNFs and receptors was similar in MG63 cells and osteoblasts. TNF-R1 (p55), TRAIL receptor 1 and 2 (DR4 and 5), and Fas were expressed; RANK was undetectable. TNF-family ligands RANKL, TRAIL, and TNFalpha were expressed, but mRNAs were typically at low levels relative to receptors, suggesting that osteoblastic TNF signals, including RANKL, require specific stimuli. Flow cytometry of MG63 cells confirmed TNFalpha receptors and identified subpopulations with high surface-bound TNFalpha. Decoy receptors expressed included a novel soluble form of TNFRSF25 (formerly DR3 or Apo3), implicated in rheumatoid-arthritis linkage studies, as well as osteoprotegerin, a well-characterized osteoblast protein that binds TRAIL and RANKL, and DcR2, which binds TRAIL. Osteoblast apoptosis was studied using terminal deoxynucleotidyl transferase labeling and annexin V binding. MG63 cells were resistant to apoptosis by exogenous TNFalpha except when grown in media promoting osteoblast-like growth or matrix nodules. However, in media supporting osteoblast-like phenotype, apoptosis was induced by anti-Fas or TNF, in contrast to other studies with human osteoblasts. TRAIL caused cell retraction, supporting functional TRAIL response in cell differentiation, but did not cause apoptosis. We conclude that human osteoblasts have functional receptors for FasL, TNFalpha, TRAIL, but not RANKL, and that osteoblasts are protected by multiple nonsignaling TNF receptors against destruction by TNF-family proteins under conditions favoring cell growth.
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Affiliation(s)
- Rongfa Bu
- Departments of Pathology and Cell Biology & Physiology, University of Pittsburgh School of Medicine, and Veteran's Affairs Medical Center, Pittsburgh, PA 15261, USA
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76
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Silvestris F, Cafforio P, Tucci M, Grinello D, Dammacco F. Upregulation of osteoblast apoptosis by malignant plasma cells: a role in myeloma bone disease. Br J Haematol 2003; 122:39-52. [PMID: 12823344 DOI: 10.1046/j.1365-2141.2003.04374.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Typical features of multiple myeloma (MM) are osteolytic lesions and severely affected bone regeneration. This study of 53 MM patients demonstrates an enhancement of osteoblast cytotoxicity by malignant myeloma cells via the upregulation of apoptogenic receptors, including Fas ligand (Fas-L) and tumour-necrosis-factor-related apoptosis inducing ligand (TRAIL). Both were significantly increased in the marrow myeloma cells of patients with extensive osteolytic lesions in a fashion similar to the highly malignant human myeloma cell line MCC-2. Osteoblasts from these subjects over-expressed Fas and death receptor (DR) 4/5 and underwent dramatic apoptosis when co-cultured with either MCC-2 or autologous myeloma cells. In osteoblast and myeloma cell co-cultures, monocyte chemoattractant protein 1 (MCP-1) mRNA was upregulated in osteoblasts from patients with severe bone disease in parallel with increased CC-chemokine receptor R2 (CCR2) expression, the ligand of MCP-1, in the myeloma cells. This chemokine was shown to activate malignant cell migration in vitro. An upregulation of ICAM-1 expression occurred in osteoblasts from patients with active skeleton disease. This upregulation appeared to be an effect of malignant plasma cell contact, as MCC-2 co-culture greatly enhanced ICAM-1 production by resting osteoblasts from patients without skeleton involvement. Our results suggest that osteoblasts in active myeloma are functionally exhausted and promptly undergo apoptosis in the presence of myeloma cells from patients with severe bone disease. It is suggested that this cytotoxic effect plays a pivotal role in the pathogenesis of defective bone repair.
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Affiliation(s)
- Franco Silvestris
- Department of Internal Medicine and Oncology (DIMO), University of Bari, Bari, Italy.
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77
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Hoshino S, Hosoi T, Shiraki M, Orimo H, Ouchi Y, Inoue S. Association of tumor necrosis factor receptor 1 gene polymorphism with bone mineral density. Geriatr Gerontol Int 2003. [DOI: 10.1046/j.1444-1586.2003.00065.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Suh KS, Koh G, Park CY, Woo JT, Kim SW, Kim JW, Park IK, Kim YS. Soybean isoflavones inhibit tumor necrosis factor-alpha-induced apoptosis and the production of interleukin-6 and prostaglandin E2 in osteoblastic cells. PHYTOCHEMISTRY 2003; 63:209-15. [PMID: 12711143 DOI: 10.1016/s0031-9422(03)00101-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The effects of individual soybean isoflavones, genistein (4',5,7-trihydroxyisoflavone) and daidzein (4',7-dihydroxyisoflavone), on tumor necrosis factor-alpha (TNF-alpha)-induced apoptosis and the production of local factors in osteoblastic cells has been investigated. Soybean isoflavones increased DNA synthesis and the number of viable cells. When cells were treated with TNF-alpha, the number of viable cells dose-dependently decreased. The decrease in cell number caused by TNF-alpha treatment was due to apoptosis, which was confirmed by TUNEL and cell death ELISA analyses. Soybean isoflavones inhibited apoptosis of osteoblastic cells subjected to TNF-alpha treatment. MC3T3-E1 osteoblastic cells secrete interleukin-6 (IL-6), interleukin-1beta (IL-1beta), nitric oxide (NO) and prostaglandin E(2) (PGE(2)) constitutively, but at low levels. Soybean isoflavones had no effect on the constitutive production of these local factors. When cells were treated with TNF-alpha (10(-10)M), the production of IL-6 and PGE(2), but not that of IL-1beta and NO, significantly increased. Treatment with soybean isoflavones (10(-5)M), in the presence of TNF-alpha (10(-10)M), for 48 h inhibited production of IL-6 and PGE(2), suggesting the antiresorptive action of soy phytoestrogen may be mediated by decreases in these local factors. The findings of this study thus suggest that soybean isoflavones may promote the function of osteoblastic cells and play an important role in bone remodeling.
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Affiliation(s)
- Kwang Sik Suh
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Endocrine Research Institute, Kyung Hee University School of Medicine, 1 Hoeki-dong, Dongdaemun-ku, Seoul 130-702, South Korea.
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79
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Abstract
Apoptosis plays an important role in many aspects of endodontics, yet there is a paucity of information in this regard in the endodontic literature. Apoptosis is a single deletion of scattered cells by fragmentation into membrane-bound particles that are phagocytosed by other cells. It is a key process in the embryological development of the tooth, periodontal ligament and supporting oral tissue in the progression of oral disease, bone resorption, immunological response and inflammation, and in wound healing and certain pharmacological effects. The understanding of the ability of clinical materials to induce or inhibit apoptosis and the investigation of apoptosis as it relates to the pathogenesis of pulpal and periradicular pathology may eventually lead to new treatment approaches for the endodontist. The purpose of this review is to familiarize the clinical endodontist with current knowledge on apoptosis as it relates to the pulp and periradicular tissues.
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Chua CC, Chua BHL, Chen Z, Landy C, Hamdy RC. TGF-beta1 inhibits multiple caspases induced by TNF-alpha in murine osteoblastic MC3T3-E1 cells. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1593:1-8. [PMID: 12431778 DOI: 10.1016/s0167-4889(02)00257-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Tumor necrosis factor alpha (TNF-alpha) is a proinflammatory cytokine that induces apoptosis in a number of cell systems, including osteoblasts. Transforming growth factor beta1 (TGF-beta1) is an abundant growth factor that is known to stimulate bone formation. This study was designed to examine the role of TGF-beta1 on TNF-alpha-induced apoptosis in murine osteoblastic MC3T3-E1 cells. Total RNA was extracted from MC3T3-E1 cells treated with 20 ng/ml of TNF-alpha, 10 ng/ml of TGF-beta1, or combination, for 6 h. TNF-alpha exerted a variety of effects on the apoptotic gene expression in osteoblasts. Ribonuclease protection assays (RPA) revealed that TNF-alpha upregulated the mRNA levels of caspase-1, -7, -11, -12, and FAS. Western blot analysis showed enhanced processing of caspase-1, -7, -11, and -12, with the appearance of their activated enzymes 24 h after TNF-alpha treatment. In addition, caspase-3-like activity was significantly activated following TNF-alpha treatment. Levels of cleaved poly(ADP-ribose) polymerase and FAS protein were also elevated by TNF-alpha. Finally, Hoechst staining, terminal deoxynucleotidyl-transferase nick-end labeling (TUNEL) assay, and oligonucleosome ELISA all indicated that TNF-alpha induced apoptosis. In contrast, the addition of TGF-beta1 attenuated all of the aforementioned effects of TNF-alpha. Our results demonstrate that TGF-beta1 can decrease TNF-alpha-induced apoptosis in murine osteoblasts at least in part by attenuating TNF-alpha-induced caspase gene expression.
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Affiliation(s)
- Chu Chang Chua
- Osteoporosis Center, James H Quillen College of Medicine, East Tennessee State University, and Veterans Affairs Medical Center, Box 70432, Johnson City, TN 37614, USA.
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82
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Gal-Moscovici A, Scherzer P, Rubinger D, Weiss R, Dranitzki-Elhalel M, Popovtzer MM. Stimulation of osteoclastic bone resorption in a model of glycerol-induced acute renal failure: evidence for a parathyroid hormone-independent mechanism. Bone 2002; 31:488-91. [PMID: 12398944 DOI: 10.1016/s8756-3282(02)00849-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This study was undertaken to evaluate the bone changes occurring in rats with acute renal failure (ARF). Acute renal failure was induced in rats 24 hours after dehydration by an intramuscular injection of glycerol. After induction of ARF, the rats were divided into two groups, one of which underwent parathyroidectomy (PTX). Rats with normal renal function, matched for age and weight, were used as controls and divided into two groups, one of them for PTX. At termination of the study blood and urine chemistry and bone histomorphometry were analyzed. Rats with glycerol-induced ARF developed bone changes compatible with mild hyperparathyroid bone disease, characterized mainly by increased osteoclastic bone resorption when compared with control rats having normal renal function. Rats with normal renal function following PTX developed bone disease showing complete suppression of forming and resorptive parameters. Rats with glycerol-induced ARF and PTX showed abolishment of all bone forming parameters, but a dramatic increase in osteoclastic resorption was apparent. Based on these observations we suggest that, in this model of glycerol-induced ARF, osteoclastic bone resorption may develop in the absence of parathyroid hormone, probably stimulated by other potent osteoclastogenic factors.
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Affiliation(s)
- A Gal-Moscovici
- Nephrology and Hypertension Services, Hadassah University Hospital, Jerusalem, Israel.
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83
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Atkins GJ, Bouralexis S, Evdokiou A, Hay S, Labrinidis A, Zannettino ACW, Haynes DR, Findlay DM. Human osteoblasts are resistant to Apo2L/TRAIL-mediated apoptosis. Bone 2002; 31:448-56. [PMID: 12398939 DOI: 10.1016/s8756-3282(02)00858-x] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Apo2 ligand (Apo2L/TRAIL) is a member of the tumor necrosis factor (TNF) cytokine family. Apo2L/TRAIL can selectively induce programmed cell death in transformed cells, although its wide tissue distribution suggests potential physiological roles. We have investigated the expression, in human osteoblast-like cells (NHBC), of Apo2L/TRAIL and the known Apo2L/TRAIL death receptors, DR4 and DR5, and the Apo2L/TRAIL decoy receptors, DcR-1, DcR-2, and osteoprotegerin (OPG). NHBC expressed abundant mRNA corresponding to each of these molecular species. Immunofluorescence staining demonstrated that Apo2L/TRAIL protein was abundant within the cytoplasm of NHBC and OPG was strongly expressed at the cell surface. DR5 and DcR-2 were present in the cell membrane and cytoplasm and DcR-1 was confined to the nucleus. DR4 staining was weak. Neither Apo2L/TRAIL alone, nor in combination with chemotherapeutic agents of clinical relevance to treatment of osteogenic sarcoma, induced cell death in NHBC, as assessed morphologically and by activation of caspase-3. In contrast, the human osteogenic sarcoma cell lines, BTK-143 and G-292, were sensitive to exogenous Apo2L/TRAIL alone, and to the combined effect of Apo2L/TRAIL/cisplatin and Apo2L/TRAIL/doxorubicin treatments, respectively. In NHBC, we observed strong associations between the levels of mRNA corresponding to the pro-apoptotic molecules, Apo2L/TRAIL, DR4, and DR5, and those corresponding to pro-survival molecules, DcR-1, DcR-2, OPG, and FLIP, suggesting that the balance between pro-survival and pro-apoptotic molecules is a mechanism by which NHBC can resist Apo2L/TRAIL-mediated apoptosis. In contrast, osteogenic sarcoma cells had low or absent levels of DcR-1 and DcR-2. These results provide a foundation to explore the role of Apo2L/TRAIL in osteoblast physiology. In addition, they predict that therapeutic use of recombinant Apo2L/TRAIL, in combination with chemotherapeutic agents to treat skeletal malignancies, would have limited toxic effects on normal osteoblastic cells.
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Affiliation(s)
- G J Atkins
- Department of Orthopaedics and Trauma, Adelaide University and Royal Adelaide Hospital, Adelaide, SA, Australia
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84
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Abstract
Focal marginal joint erosions represent the radiographic hallmark of rheumatoid arthritis (RA). These bone changes are characteristically localized to the joint margins, but in addition, regions of focal bone resorption can be detected in the subchondral bone adjacent to the bone marrow space into which the synovial inflammatory tissues have extended. Because progressive destruction of the periarticular bone contributes significantly to joint dysfunction and disability in patients with RA, there is considerable interest in developing a better understanding of the pathologic mechanisms involved in this process and in developing therapies that can arrest these events. Previous analysis of joint tissues from patients with RA have provided morphologic evidence that osteoclasts are the cell types that mediate the focal bone resorption associated with the rheumatoid synovial lesion. Additional recent data from animal models have helped to further implicate these cells in the pathogenesis of focal bone erosions. Furthermore, analysis of RA synovium and joint tissues from animal models of inflammatory arthritis, as well as cell and tissues culture studies, have helped to define the cytokines and inflammatory mediators that are involved in the recruitment and activation of bone resorbing cells associated with focal bone erosions. These findings provide a rational framework for developing targeted therapies that can specifically inhibit or slow the progressive focal bone destruction associated with the rheumatoid synovial lesion.
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Affiliation(s)
- Steven R Goldring
- Beth Israel Deaconess Medical Center, Harvard Medical School, and New England Baptist Bone and Joint Institute, Harvard Institutes of Medicine, Boston, Massachusetts 02115, USA.
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85
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Shanahan JC, St Clair W. Tumor necrosis factor-alpha blockade: a novel therapy for rheumatic disease. Clin Immunol 2002; 103:231-42. [PMID: 12173297 DOI: 10.1006/clim.2002.5191] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Overproduction of tumor necrosis factor-alpha (TNF) plays a key role in the pathogenesis of rheumatoid arthritis (RA) and other chronic inflammatory diseases. In RA, excessive production of TNF-alpha can drive synovial inflammation and proliferation as well as degradation of articular cartilage and bone. The importance of TNF-alpha in these mechanisms is supported by the results of clinical trials. In these studies, treatment with etanercept and infliximab, two recently approved TNF-alpha inhibitors, has been shown to significantly decrease the signs and symptoms of joint inflammation and slow the progression of radiological joint damage. Although TNF-alpha inhibitors have had acceptable toxicity in clinical trials, commercial use of these agents has produced growing concerns about the potential risk for opportunistic infections, most notably the reactivation of latent tuberculosis. The TNF-alpha inhibitors stand as a powerful example of the therapeutic potential of a targeted biological agent. Longer-term clinical experience with these cytokine antagonists will illuminate their optimal use in RA and other rheumatic diseases.
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MESH Headings
- Antibodies, Blocking/administration & dosage
- Antibodies, Blocking/pharmacology
- Antibodies, Blocking/therapeutic use
- Antibodies, Monoclonal/administration & dosage
- Antibodies, Monoclonal/pharmacology
- Antibodies, Monoclonal/therapeutic use
- Antirheumatic Agents/administration & dosage
- Antirheumatic Agents/pharmacology
- Antirheumatic Agents/therapeutic use
- Arthritis, Rheumatoid/drug therapy
- Arthritis, Rheumatoid/immunology
- Etanercept
- Humans
- Immunoglobulin G/administration & dosage
- Immunoglobulin G/pharmacology
- Immunoglobulin G/therapeutic use
- Infliximab
- Randomized Controlled Trials as Topic
- Receptors, Tumor Necrosis Factor/administration & dosage
- Receptors, Tumor Necrosis Factor/therapeutic use
- Tumor Necrosis Factor-alpha/antagonists & inhibitors
- Tumor Necrosis Factor-alpha/immunology
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Affiliation(s)
- Joseph C Shanahan
- Department of Medicine, Division of Rheumatology, Allergy, and Clinical Immunology, Duke University Medical Center, Durham, North Carolina 27710, USA
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86
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Criscione LG, St Clair EW. Tumor necrosis factor-alpha antagonists for the treatment of rheumatic diseases. Curr Opin Rheumatol 2002; 14:204-11. [PMID: 11981314 DOI: 10.1097/00002281-200205000-00002] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Tumor necrosis factor-alpha (TNF-alpha) antagonists have rapidly emerged as a valuable class of antirheumatic agents. Etanercept, a dimerized version of the soluble tumor necrosis factor receptor II, and infliximab, a chimeric anti-TNF-alpha monoclonal antibody, are currently approved for the treatment of rheumatoid arthritis (RA) based on their proven beneficial effects in clinical trials. New insights into the role of TNF-alpha in disease pathogenesis have expanded our understanding about the possible mechanisms by which these agents reduce synovial inflammation and inhibit bone and cartilage degradation. The enlarging safety experience has revealed growing concerns about TNF-alpha inhibition and increased risk for opportunistic infection, most notably the reactivation of latent Mycobacterium tuberculosis infection. Recent recommendations have addressed this risk by calling for pretreatment screening for previous exposure to tuberculosis. The success of etanercept and infliximab therapy for RA has prompted the development of other TNF-alpha antagonists and extended the investigation of this therapeutic approach to other inflammatory diseases. TNF-alpha antagonists promise to shape the care of RA and other rheumatic diseases for many years to come.
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Affiliation(s)
- Lisa G Criscione
- Division of Rheumatology, Allergy, and Clinical Immunology, Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710, USA
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87
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Abstract
Cell-cell adhesion mediated by cadherins is essential for the function of bone forming cells during osteogenesis. Here, the evidence that N-cadherin is an important regulator of osteoblast differentiation and osteogenesis is reviewed. Osteoblasts express a limited number of cadherins, including the classic N-cadherin. The expression profile of N-cadherin in osteoblasts during bone formation in vivo and in vitro suggests a role of this molecule in osteogenesis. Functional studies using neutralizing antibodies or antisense oligonucleotides indicate that N-cadherin is involved in the control the expression of osteoblast marker gene expression and differentiation. Cleavage of N-cadherin during osteoblast apoptosis also suggests a role of N-cadherin-mediated-cell-cell adhesion in osteoblast survival. Hormonal and local factors that regulate osteoblast function also regulate N-cadherin expression and subsequent cell-cell adhesion associated with osteoblast differentiation or survival. Signaling mechanisms involved in N-cadherin-mediated cell-cell adhesion and osteoblast gene expression have also been identified. Alterations of N-cadherin expression are associated with abnormal osteoblast differentiation and osteogenesis in pathological conditions. These findings indicate that N-cadherin plays a role in normal and pathological bone formation and provide some insight into the process involved in N-cadherin-mediated cell-cell adhesion and differentiation in osteoblasts.
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Affiliation(s)
- Pierre J Marie
- INSERM U 349, affiliated CNRS, Biology and Pathology of Osteoblast, Lariboisière Hospital, Paris, France.
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88
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Lau WY, Chen GG, Lai PB, Chun YS, Leung BC, Chak EC, Lee JF, Chui AK. Induction of Fas and Fas ligand expression on malignant glioma cells by Kupffer cells, a potential pathway of antiliver metastases. J Surg Res 2001; 101:44-51. [PMID: 11676553 DOI: 10.1006/jsre.2001.6253] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Kupffer cells play an important role in controlling the growth and development of liver metastases. However, the pathway of Kupffer cells against tumor metastases is not clear. In the present study, we set up an experimental model to investigate the mechanisms on how Kupffer cells kill tumor cells which metastasize to the liver. Malignant glioma cells were cocultured with Kupffer cells or treated with culture medium collected from lipopolysaccharide (LPS)-activated Kupffer cells. The results showed that the interaction between Kupffer cells and malignant glioma cells significantly stimulated the generation of tumor necrosis factoralpha (TNFalpha). TNFalpha was mainly produced by Kupffer cells, as its level in culture medium obtained from LPS-treated Kupffer cells was not significantly different from that of malignant glioma cells treated with the same medium. Both Kupffer cells and LPS/Kupffer cell-conditioned supernatants induced expression of Fas and Fas ligand on malignant glioma cells. Subsequently a significant proportion of malignant glioma cells became apoptotic, as evidenced by positive staining of annexin V and propidium iodine and an increase in cellular DNA fragmentation. Therefore, this study supports a novel pathway of Kupffer cells against liver metastases, in which tumor cells were apoptotic via the Fas-Fas ligand system induced by TNFalpha released from Kupffer cells.
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Affiliation(s)
- W Y Lau
- Department of Surgery, Prince of Wales Hospital, Shatin, N.T., Hong Kong.
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89
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Abstract
Tumor necrosis factor alpha (TNF-alpha) induces apoptosis in a number of cell types and plays an essential role in bone remodeling, both stimulating the proliferation of osteoblasts and activating osteoclasts. During endochondral ossification, apoptosis of chondrocytes occurs concurrently with new bone formation and the resorption and replacement of mineralized cartilage with woven bone. In the present study, the role of TNF-alpha in promoting chondrocyte apoptosis was examined. Chondrocyte cell populations, enriched in either hypertrophic or non-hypertrophic cells, were isolated from the cephalic and caudal portions of 17-day chick embryo sterna, respectively, and treated in vitro with 0.1-10 nM recombinant human TNF-alpha. As a positive control, apoptosis was also induced by Fas receptor antibody binding. Dye exclusion assays of the live/dead ratios of cells showed that TNF-alpha caused a dose-dependent 1.5- and 2.0-fold increase in the number of dead cells in both hypertrophic and non-hypertrophic chondrocytes. Induction of apoptosis was independently assayed by measurement of interleukin-1beta-converting enzyme (ICE) activity, and analyzed by a semi-quantitative determination of DNA fragmentation. When compared to untreated cells, these analyses also showed dose-dependent increases in TNF-alpha induced apoptosis in both chondrocyte populations, with increases in the levels of ICE activity for all doses of TNF-alpha (from approximately 5 to approximately 20 fold). Osteoblasts, however, were not affected by treatment with TNF-alpha or by Fas antibody/protein G induction. Immunostaining of chondrocytes for Fas receptor and caspase-2 protein expression showed that most of the chondrocytes expressed these two markers of apoptosis after treatment with TNF-alpha. Although cell killing and ICE induction were higher in the more hypertrophic cells, TNF-alpha induced apoptosis in both hypertrophic and non-hypertrophic chondrocyte populations. These results demonstrate that apoptosis may be induced in both hypertrophic and non-hypertrophic chondrocytes through both Fas and TNF-alpha receptor mediated signaling, and suggest that chondrocytes are more sensitive to apoptotic effects of TNF-alpha within the skeletal lineage than are osteoblasts.
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Affiliation(s)
- T Aizawa
- Department of Orthopaedic Surgery, Boston University School of Medicine, MA 02118-2526, USA
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90
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Fromigué O, Kheddoumi N, Lomri A, Marie PJ, Body JJ. Breast cancer cells release factors that induced apoptosis in human bone marrow stromal cells. J Bone Miner Res 2001; 16:1600-10. [PMID: 11547830 DOI: 10.1359/jbmr.2001.16.9.1600] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Breast cancer is associated frequently with skeletal metastases, which cause significant morbidity. The main mechanism is an increase in osteoclast-mediated bone resorption. We postulated that osteoblasts could be other essential target cells and previously showed that conditioned medium (CM) of breast cancer cells (BCCs) inhibits the proliferation of osteoblast-like cells. In this study, we investigated the effects of BCC-secreted products on osteoprogenitor cells using a clonal fetal human bone marrow stromal preosteoblastic cell line (FHSO-6) that expresses alkaline phosphatase (ALP) activity, type I collagen (COLI), and increased osteocalcin (OC) and osteopontin under treatment with dexamethasone (Dex), 1,25-dihydroxyvitamin D [1,25(OH)2D], or recombinant human bone morphogenetic protein 2 (rhBMP-2). Treatment with MCF-7 CM inhibited FHSO-6 cell survival in a dose-dependent and irreversible manner. Morphological investigation indicated that MCF-7 CM increased both apoptotic and necrotic cell number. MCF-7 CM increased caspases activity and a broad inhibitor of caspase activity (benzyloxycarbonyl-Val-Ala-Asp(OMe)-fluoromethyl ketone [z-VAD-fmk]) partly reversed the CM-induced inhibition of FHSO-6 cell survival. Western blot analyses revealed an increased bax/bcl-2 ratio in MCF-7 CM-treated FHSO-6 cells. MCF-7 cells exhibit FasLigand as membrane-bound protein and as a soluble cytokine in the CM. Deprivation of MCF-7 CM from active FasLigand by saturation with a soluble Fas molecule suppressed the induction of FHSO-6 apoptosis, whereas fibroblast CM, which did not contain FasLigand, only weakly modified FHSO-6 cell survival because of increased cell necrosis. These data indicate that FasLigand secreted by BCCs induces apoptosis and necrosis of human preosteoblastic stromal cells through caspase cascade modulated by the bax and bcl-2 protein level. The induction of apoptosis in human bone marrow stromal cells by BCCs may contribute to the inappropriately low osteoblast reaction and bone formation during tumor-induced osteolysis in bone metastases.
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Affiliation(s)
- O Fromigué
- Laboratory of Endocrinology and Breast Cancer Research, Institut J. Bordet, Bruxelles, Belgium
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91
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Haÿ E, Lemonnier J, Fromigué O, Marie PJ. Bone morphogenetic protein-2 promotes osteoblast apoptosis through a Smad-independent, protein kinase C-dependent signaling pathway. J Biol Chem 2001; 276:29028-36. [PMID: 11395480 DOI: 10.1074/jbc.m011265200] [Citation(s) in RCA: 138] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Bone morphogenetic protein-2 (BMP-2), a member of the transforming growth factor-beta (TGF-beta) family, regulates osteoblast differentiation and bone formation. Here we show a novel function of BMP-2 in human osteoblasts and identify a signaling pathway involved in this function. BMP-2 promotes apoptosis in primary human calvaria osteoblasts and in immortalized human neonatal calvaria osteoblasts, as shown by terminal deoxynucleotidyl transferase-mediated nick end labeling analysis. In contrast, TGF-beta 2 inhibits apoptosis in human osteoblasts. Studies of the mechanisms of action showed that BMP-2 increases the Bax/Bcl-2 ratio, whereas TG beta-2 has a negative effect. Moreover, BMP-2 increases the release of mitochondrial cytochrome c to the cytosol. Consistent with these results, BMP-2 increases caspase-9 and caspase-3, -6, and -7 activity, and an anti-caspase-9 agent suppresses BMP-2-induced apoptosis. Overexpression of dominant-negative Smad1 effectively blocks BMP-2-induced expression of the osteoblast transcription factor Runx2 but not the activation of caspases or apoptosis induced by BMP-2, indicating that the Smad1 signaling pathway is not involved in the BMP-2-induced apoptosis. The proapoptotic effect of BMP-2 is PKC-dependent, because BMP-2 increases PKC activity, and the selective PKC inhibitor calphostin C blocks the BMP-2-induced increased Bax/Bcl-2, caspase activity, and apoptosis. In contrast, the cAMP-dependent protein kinase A inhibitor H89, the p38 MAPK inhibitor SB203580, and the MEK inhibitor PD-98059 have no effect. The results show that BMP-2 uses a Smad-independent, PKC-dependent pathway to promote apoptosis via a Bax/Bcl-2 and cytochrome c-caspase-9-caspase-3, -6, -7 cascade in human osteoblasts.
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Affiliation(s)
- E Haÿ
- Laboratory of Osteoblast Biology and Pathology, INSERM U 349, Affiliated CNRS, Lariboisière Hospital, 75475 Cedex 10 Paris, France
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92
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Abstract
With the discoveries of different death mechanisms, an emerging definition of apoptosis is the process of cell death associated with caspase activation or caspase-mediated cell death. This definition accepts that caspases represent the final common mechanistic pathway in apoptosis. Apoptosis may be triggered either by activation events that target mitochondria or endoplasmic reticulum or by activation of cell surface "death receptors," for example, those in the tumor necrosis factor (TNF) superfamily. In the postnatal and adult skeleton, apoptosis is integral to physiological bone turnover, repair, and regeneration. The balance of osteoblast proliferation, differentiation, and apoptosis determines the size of the osteoblast population at any given time. Although apoptosis has been recorded in many studies of bone, the selective mechanisms invoked in the different models studied rarely have been identified. This review offers a broad overview of the current general concepts and controversies in apoptosis research and then considers specific examples of osteoblast apoptosis pertinent to skeletal development and to the regulation of bone turnover. In reviewing selected work on interdigital apoptosis in the developing skeleton, we discuss the putative roles of the bone morphogenetic proteins (BMPs), Msx2, RAR-gamma, and death inducer obliterator 1 (DIO-1). In reviewing factors regulating apoptosis in the postnatal skeleton, we discuss roles of cytokines, growth factors, members of the TNF pathway, and the extracellular matrix (ECM). Finally, the paradoxical effects of parathyroid hormone (PTH) on osteoblast apoptosis in vivo are considered in the perspective of a recent hypothesis speculating that this may be a key mechanism to explain the anabolic effects of the hormone. An improved understanding of the apoptotic pathways and their functional outcomes in bone turnover and fracture healing may facilitate development of more targeted therapeutics to control bone balance in patients with osteoporosis and other skeletal diseases.
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Affiliation(s)
- J M Hock
- School of Medicine, Indiana University, Indianapolis 46202, USA
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93
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Lemonnier J, Haÿ E, Delannoy P, Fromigué O, Lomri A, Modrowski D, Marie PJ. Increased osteoblast apoptosis in apert craniosynostosis: role of protein kinase C and interleukin-1. THE AMERICAN JOURNAL OF PATHOLOGY 2001; 158:1833-42. [PMID: 11337381 PMCID: PMC1891948 DOI: 10.1016/s0002-9440(10)64139-9] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 02/08/2001] [Indexed: 01/09/2023]
Abstract
Apert syndrome is an autosomal dominant disorder characterized by premature cranial ossification resulting from fibroblast growth factor receptor-2 (FGFR-2)-activating mutations. We have studied the effects of the prominent S252W FGFR-2 Apert mutation on apoptosis and the underlying mechanisms in human mutant osteoblasts. In vivo analysis of terminal deoxynucleotidyl transferase-mediated nick-end labeling revealed premature apoptosis of mature osteoblasts and osteocytes in the Apert suture compared to normal coronal suture. In vitro, mutant osteoblasts showed increased apoptosis, as demonstrated by terminal deoxynucleotidyl transferase-mediated nick-end labeling analysis, trypan blue staining, and DNA fragmentation. Mutant osteoblasts also showed increased activity of caspase-8 and effector caspases (-3, -6, -7) constitutively. This was related to protein kinase C activation because the selective protein kinase C inhibitor calphostin C inhibited caspase-8, effector caspases, and apoptosis in mutant osteoblasts. Apert osteoblasts also showed increased expression of interleukin (IL)-1alpha, IL-1beta, Fas, and Bax, and decreased Bcl-2 levels. Specific neutralizing anti-IL-1 antibody reduced Fas levels, Bax expression, effector caspases activity, and apoptosis in mutant cells. Thus, the Apert S252W FGFR-2 mutation promotes apoptosis in human osteoblasts through activation of protein kinase C, overexpression of IL-1 and Fas, activation of caspase-8, and increased Bax/Bcl-2 levels, leading to increased effector caspases and DNA fragmentation. This identifies a complex FGFR-2 signaling pathway involved in the premature apoptosis induced by the Apert S252W FGFR-2 mutation in human calvaria osteoblasts.
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Affiliation(s)
- J Lemonnier
- INSERM U 349 Affiliated CNRS, Lariboisière Hospital, Paris, France
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94
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Lomri A, Lemonnier J, Delannoy P, Marie PJ. Increased expression of protein kinase Calpha, interleukin-1alpha, and RhoA guanosine 5'-triphosphatase in osteoblasts expressing the Ser252Trp fibroblast growth factor 2 receptor Apert mutation: identification by analysis of complementary DNA microarray. J Bone Miner Res 2001; 16:705-12. [PMID: 11315998 DOI: 10.1359/jbmr.2001.16.4.705] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Apert (Ap) syndrome is a craniofacial malformation characterized by premature fusion of cranial sutures (craniosynostosis). We previously showed that the Ser252Trp fibroblast growth factor receptor 2 (FGFR-2) mutation in Ap syndrome increases osteoblast differentiation and subperiosteal bone matrix formation, leading to premature calvaria ossification. In this study, we used the emerging technology of complementary DNA (cDNA) microarray to identify genes that are involved in osteoblast abnormalities induced by the Ser252Trp FGFR-2 mutation. To identify the signaling pathways involved in this syndrome, we used radioactively labeled cDNAs derived from two sources of cellular messenger RNAs (mRNAs) for hybridization: control (Co) and mutant Ap immortalized osteoblastic cells. Among genes that were differentially expressed, protein kinase Ca (PKC-alpha), interleukin-1alpha (IL-1alpha), and the small guanosine-5'-triphosphatase (GTPase) RhoA were increased in FGFR-2 mutant Ap cells compared with Co cells. The validity of the hybridization array was confirmed by Northern blot analysis using mRNAs derived from different cultures. Furthermore, immunochemical and Western blot analyses showed that mutant Ap cells displayed increased PKC-alpha, IL-1alpha, and RhoA protein levels compared with Co cells. Treatment of Co and Ap cells with the PKC inhibitor calphostin C decreased IL-1alpha and RhoA mRNA and protein levels in Ap cells, indicating that PKC is upstream of IL-1alpha and RhoA. Moreover, SB203580, a specific inhibitor of p38 mitogen-activated protein kinase (MAPK), and PD-98059, a specific inhibitor of MAPK kinase (MEKK), also reduced IL-1alpha and RhoA expression in Ap cells. These data show that the Ser252Trp FGFR-2 mutation in Ap syndrome induces constitutive overexpression of PKC-alpha, IL-1alpha, and small GTPase RhoA, suggesting a role for these effectors in osteoblast alterations induced by the mutation. The cDNA microarray technology appears to be a useful tool to gain information on abnormal gene expression and molecular pathways induced by genetic mutations in bone cells.
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Affiliation(s)
- A Lomri
- Institut National de la Santé et de la Recherche Médicale Unit 349, Lariboisiere Hospital, Paris, France
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95
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Kinoshita H, Yoshikawa H, Shiiki K, Hamada Y, Nakajima Y, Tasaka K. Cisplatin (CDDP) sensitizes human osteosarcoma cell to Fas/CD95-mediated apoptosis by down-regulating FLIP-L expression. Int J Cancer 2000; 88:986-91. [PMID: 11093825 DOI: 10.1002/1097-0215(20001215)88:6<986::aid-ijc23>3.0.co;2-b] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The mechanisms of escape from Fas/CD95-mediated apoptosis induced by immunosurveillance(NK cells and T cells) in tumor cells are correlated to tumorigenicity. Human osteosarcoma cell MG-63 constitutively expressed cell surface Fas antigen but was resistant to apoptosis by Fas stimulation. However, suboptimal dose of cisplatin(CDDP) could sensitize MG-63 cells to Fas-mediated apoptosis without up-regulation of cell-surface Fas antigen. Western blotting analysis showed that MG-63 cells constitutively expressed FLICE inhibitory protein long form(FLIP-L), which was a novel anti-apoptotic protein and had a potency of tumorigenicity. CDDP down-regulated FLIP-L in a time-dependent manner in MG-63 cells but did not influence expression of other anti-apoptotic molecules such as XIAP, c-IAP-1, c-IAP-2, FADD or pro-caspase-8. Moreover, antisense oligonucleotide to FLIP-L confirmed that down-regulation of FLIP-L induced sensitization to Fas-mediated apoptosis. These findings suggest that FLIP-L contributes to resistance to Fas-mediated apoptosis in MG-63 cells, and sensitization to Fas-mediated apoptosis by CDDP can be a new application of immune therapy.
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Affiliation(s)
- H Kinoshita
- Department of Orthopeadic Surgery, Yamanashi Medical University, Yamanashi, Japan
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96
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Gilbert L, He X, Farmer P, Boden S, Kozlowski M, Rubin J, Nanes MS. Inhibition of osteoblast differentiation by tumor necrosis factor-alpha. Endocrinology 2000; 141:3956-64. [PMID: 11089525 DOI: 10.1210/endo.141.11.7739] [Citation(s) in RCA: 331] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Tumor necrosis factor-alpha (TNF-alpha) has a key role in skeletal disease in which it promotes reduced bone formation by mature osteoblasts and increased osteoclastic resorption. Here we show that TNF inhibits differentiation of osteoblasts from precursor cells. TNF-alpha treatment of fetal calvaria precursor cells, which spontaneously differentiate to the osteoblast phenotype over 21 days, inhibited differentiation as shown by reduced formation of multilayered, mineralizing nodules and decreased secretion of the skeletal-specific matrix protein osteocalcin. The effect of TNF was dose dependent with an IC50 of 0.6 ng/ml, indicating a high sensitivity of these precursor cells. Addition of TNF-alpha from days 2-21, 2-14, 7-14, and 7-10 inhibited nodule formation but addition of TNF after day 14 had no effect. Partial inhibition of differentiation was observed with addition of TNF on only days 7-8, suggesting that TNF could act during a critical period of phenotype selection. Growth of cells on collagen-coated plates did not prevent TNF inhibition of differentiation, suggesting that inhibition of collagen deposition into matrix by proliferating cells could not, alone, explain the effect of TNF. Northern analysis revealed that TNF inhibited the expression of insulin-like growth factor I (IGF-I). TNF had no effect on expression of the osteogenic bone morphogenic proteins (BMPs-2, -4, and -6), or skeletal LIM protein (LMP-1), as determined by semiquantitative RT-PCR. Addition of IGF-I or BMP-6 to fetal calvaria precursor cell cultures enhanced differentiation but could not overcome TNF inhibition, suggesting that TNF acted downstream of these proteins in the differentiation pathway. The clonal osteoblastic cell line, MC3T3-E1-14, which acquires the osteoblast phenotype spontaneously in postconfluent culture, was also studied. TNF inhibited differentiation of MC3T3-E1-14 cells as shown by failure of mineralized matrix formation in the presence of calcium and phosphate. TNF was not cytotoxic to either cell type as shown by continued attachment and metabolism in culture, trypan blue exclusion, and Alamar Blue cytotoxicity assay. These results demonstrate that TNF-alpha is a potent inhibitor of osteoblast differentiation and suggest that TNF acts distal to IGF-I, BMPs, and LMP-1 in the progression toward the osteoblast phenotype.
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Affiliation(s)
- L Gilbert
- Division of Endocrinology and Metabolism, Emory University School of Medicine and Veterans Affairs Medical Center, Atlanta, Georgia 30033, USA
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97
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Abe Y, Kawakami A, Nakashima T, Ejima E, Fujiyama K, Kiriyama T, Ide A, Sera N, Usa T, Tominaga T, Ashizawa K, Yokoyama N, Eguchi K. Etidronate inhibits human osteoblast apoptosis by inhibition of pro-apoptotic factor(s) produced by activated T cells. THE JOURNAL OF LABORATORY AND CLINICAL MEDICINE 2000; 136:344-54. [PMID: 11079461 DOI: 10.1067/mlc.2000.109757] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Humoral factors produced by activated T cells are thought to be important in the development of bone loss in patients with rheumatoid arthritis (RA). We investigated the inhibitory effect of etidronate disodium (EHDP) on apoptosis of human osteoblasts induced by supernatants from in vitro activated T cell cultures. Human osteoblastic cell line MG63 cells and human primary osteoblast-like cells were used in the present study as human osteoblasts. T cells were incubated with interleukin-2 and further activated with 1 2-o-tetradecanoyl-phorbol 13-acetate and ionomycin, either in the presence or absence of EHDP. After we carried out the cultivation, we examined the cytotoxicity of cultured T cell supernatants toward MG63 cells and human primary osteoblast-like cells. Supernatants from activated but not resting T cell cultures efficiently induced apoptosis of MG63 cells and primary osteoblast-like cells. Supernatants from activated T cell cultures, incubated with EHDP, exhibited significantly less cytotoxicity than did supernatants incubated in the absence of EHDP. In contrast, the cytotoxicity of activated T cell culture supernatants was not affected by direct treatment of human osteoblasts with EHDP. The concentration of soluble Fas ligand in activated T cell culture supernatants was actually increased by EHDP. However, EHDP did not influence soluble Fas and tumor necrosis factor-alpha concentrations in the supernatant. Furthermore, treatment of human osteoblasts with EHDP did not alter their expression of Bcl-2/Bcl-xL or their sensitivity to anti-Fas immunoglobulin M-induced apoptosis. Our results suggest that EHDP inhibits the production of soluble factor that induces apoptosis of human osteoblasts and thus exhibits a protective action toward human osteoblast apoptosis induced by activated T cell culture supernatants. Although the exact EHDP-regulated molecule that induces apoptosis of human osteoblasts is unknown at present, our study may explain part of the therapeutic action of bisphosphonates in RA complicated by bone loss.
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Affiliation(s)
- Y Abe
- The First Department of Internal Medicine, Nagasaki University School of Medicine, Japan
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García Meijide JA, Gómez-Reino JJ. [Osteoporosis in rheumatoid arthritis]. Med Clin (Barc) 2000; 114:454-5. [PMID: 10846699 DOI: 10.1016/s0025-7753(00)71330-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Clohisy DR. Could apoptosis be responsible for localized imbalances in bone cell homeostasis? THE JOURNAL OF LABORATORY AND CLINICAL MEDICINE 1999; 134:190-1. [PMID: 10482302 DOI: 10.1016/s0022-2143(99)90197-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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