Tumor necrosis factor‐α/nuclear transcription factor‐κB signaling in periprosthetic osteolysis

Abstract

Due to irreversible joint destruction caused by the various arthritides, more than 400,000 total joint arthroplasties are performed each year in the United States. As many as 20% of these require revision surgery because of aseptic loosening. The current paradigm to explain aseptic loosening is that wear debris generated from the prosthesis stimulates the release of proinflammatory cytokines (i.e., tumor necrosis factor-alpha and interleukins 1 and 6) following phagocytosis by resident macrophages. These cytokines, in turn, initiate an inflammatory response, with the development of an erosive pannus that stimulates bone resorption by osteoclasts. In support of this model, we have previously shown that human monocytes produce large quantities of tumor necrosis factor-alpha in response to titanium particles in vitro. In the current study, we characterized the role of tumor necrosis factor-alpha/nuclear transcription factor-kappaB signaling in the proinflammatory response to titanium particles in vitro and in vivo. Using the mouse macrophage cell line J774, we showed that these cells produce an amount of tumor necrosis factor-alpha in response to titanium particles similar to that produced by human peripheral blood monocytes. The production of tumor necrosis factor-alpha was preceded by a drop in cellular levels of inhibitory factor-kappaBalpha protein and translocation of p50/p65 nuclear transcription factor-KB to the nucleus 30 minutes after stimulation. Levels of tumor necrosis factor-alpha and inhibitory factor-kappaBalpha mRNA increased 30 minutes after stimulation, consistent with the activation of nuclear transcription factor-kappaB. Interleukin-6 mRNA was first seen 4 hours after the addition of the titanium particles, indicating that the production of this cytokine is secondary to the immediate nuclear transcription factor-kappaB response. To test the relevance of tumor necrosis factor-alpha/nuclear transcription factor-kappaB signaling in response to titanium particles in vivo, we adopted an animal model in which the particles were surgically implanted on the calvaria of mice. The animals displayed a dramatic histological response to the debris, with the formation of fibrous tissue and extensive bone resorption after only 1 week. With use of immunohistochemistry and tartrate-resistant acid phosphatase staining, tumor necrosis factor-alpha and osteoclasts were readily detected at the site of inflammation and bone resorption in the calvaria of the treated mice. By testing mice that genetically over-produce tumor necrosis factor-alpha (hTNFalpha-Tg), those defective in tumor necrosis factor-alpha signaling (TNF-RI-/-), and those that are nuclear transcription factor-kappaB1-deficient (NFkappaB1-/-), we evaluated the importance of tumor necrosis factor-alpha/nuclear transcription factor-kappaB signaling in the biological processes responsible for aseptic loosening. The hTNFalpha-Tg mice had a grossly exaggerated response, the TNF-RI(-/-) mice showed little evidence of inflammation or bone resorption, and the n...

Large-scale gene expression analysis of osteoblasts cultured on three different Ti–6Al–4V surface treatments

“…Without the expression of NF-kB, or CSFs, osteoblasts are unable to secrete cytokines such as IL-1 or IL-6 involved in the differentiation and apoptosis of osteoclasts [25,26,29]. This confirms the observation of IL-1 or IL-6 expressions not being detected in our experiment.…”

“…It is possible that either the concentration of metal ions released from the aged sample is unable to stimulate the PTK pathway in osteoblasts or the induced signal pathway is different between particles and ions. Several genes involved in the apoptosis process [25][26][27] such as TRAIL, TRAIL-R3, RANK, TRANCE, CSFs were not detected while NF-kB1, NF-kB p65, TFAR15 had their expression decreased. In addition, the up-regulation of Bcl-xL, which is an inhibitor of apoptosis [28], increased with time.…”

Activation of NF-KB signalling and TNFα-expression in THP-1 macrophages by TiAlV- and polyethylene-wear particles

“…These findings are complementary to the transfection assay study by Merkel et al [35] showing that PMMA-particles induce activation of TNFa promoter almost 5-fold. Several studies [19,36,41,45] have shown that titanium alloy-, mixed-and PMMA-particles activate NF-KB using electrophoretic mobility assays (EMSA). These studies include a methodical limitation because EMSAs do not provide a basis for quantitative and functional analysis of factors that potentially regulate gene expression.…”

Implant wear induces inflammation, but not osteoclastic bone resorption, in RANK–/– mice

“…1 Enhanced osteoclastogenesis (formation of mature osteoclasts from their precursor stem cells) is a hallmark of osteoporotic complications, including the bone loss associated with AL. 2 Two important regulators of osteoclastogenesis have been recently identified. 3,4 Receptor activator of nuclear factor kappa B (RANK, TNFR11B) is a novel type I transmembrane receptor of the TNF receptor superfamily (TNFRSF) that was originally identified using a dendritic cell cDNA library.…”