NF‐kB signaling blockade abolishes implant particle‐induced osteoclastogenesis

Abstract

In this study we investigated the effect of NF‐kB signaling blockade on polymethylmethacrylate (PMMA) particle‐induced osteoclastogenesis in vitro. We first established effective blockade of NF‐kB activity as tested by electrophoretic mobility shift assays (EMSA). Particle‐induced NF‐kB activation in murine osteoclast precursor cells (CSF‐1‐dependent bone marrow macrophages) was markedly reduced by co‐treatment of the cells with the NF‐kB inhibitors N‐tosyl‐L‐phenylalanine chloromethyl ketone (TPCK) and Calpain Inhibitor I (CPI). This inhibition of NF‐kB activity was associated with blockade of p50 NF‐kB subunit nuclear trans‐location. We then established a direct NF‐kB inhibition approach by utilizing a TAT‐bound, mutant IkB (TAT:IkB46‐317), and demonstrated an inhibitory effect evidenced by decreased NF‐kB DNA binding activity. Having established that these strategies (TPCK, CPI, TAT: IkB46‐317) effectively block NF‐kB activation, we next investigated the effect of these agents on particle‐stimulated osteoclast formation. PMMA particle stimulation of mature osteoclast formation from RANKL‐primed osteoclast precursor cells was blocked by all three inhibitors. To further test the efficacy of NF‐kB blockade, experiments were performed with the TAT:IkB46‐317 mutant peptide in whole bone marrow cultures that contain supporting stromal cells. Again, this inhibitor efficiently blocked particle‐induced osteoclastogenesis. Thus, we have shown that pharmaceutical and molecular blockade of NF‐kB activation inhibits PMMA particle‐directed osteoclastogenesis in vitro. © 2003 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.

Telomerase-deficient mice exhibit bone loss owing to defects in osteoblasts and increased osteoclastogenesis by inflammatory microenvironment

“…Interestingly, RANKL was upregulated (1.1-fold) and OPG was downregulated (1.4-fold), suggesting increased RANKL/ OPG (2-fold). Additionally, several signaling pathways known to affect osteoclastogensis were upregulated (eg, NF-kB (43) and interleukin 6 signaling). (42) Similar to our findings, Ju and colleagues described the presence of microenvironmental changes in the bone marrow of Terc À/À mice that limited the engraftment of transplanted wild-type hematopoietic stem cells owing to increased production of a number of cytokines, including granulocyte colony-stimulating factor (G-CSF).…”

μ-Calpain Regulates Receptor Activator of NF-κB Ligand (RANKL)-supported Osteoclastogenesis via NF-κB Activation in RAW 264.7 Cells

“…Although it has been suggested that the calpain-calpastatin system is involved in pre-osteoblastic proliferation and differentiation (25), its function in the regulation of RANKL-supported osteoclastogenesis remains unclear. To date, it has been only weakly suggested to play a part in implant particle-induced osteoclastogenesis (26).…”

Map kinase c-Jun N-terminal kinase mediates PMMA induction of osteoclasts

“…16,19,20 Further evidence suggests that activation of the transcription factor NF-kB appears to be central to particle induction of both pathways, that is, TNF and RANKLmediated osteoclastogenesis. 1,18,34,35 Other studies investigating signal transduction by osteoclasts have documented that TNF family members strongly induce MAP kinase-related pathways including c-Jun/JNK and ERKs, 15 as evident by using TNF-receptor compromised mice. 36 The complex response to PMMA particles that involves multiple cytokines and triggers multiple pathways prompted us to further delineate the role of a key pro-inflammatory pathway, namely the JNK pathway, in PMMA-induced signaling in osteoclast precursors and its role in particle-stimulated osteoclastogenesis.…”

“…1,17,18 Particles were rinsed in ethanol four times, sterilized in ethanol overnight, and then rinsed four times with PBS. Particles were resuspended in serum-free MEM and stored at À208C.…”

“…1,2 Revision surgery for implant failure is associated with significant cost and potential morbidity. [3][4][5] Periprosthetic osteolysis culminates from chronic inflammatory responses triggered by implantderived particulate debris, which in turn cause recruitment of various cell types, primarily lymphocytes, macrophages, and osteoclasts.…”