title: 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 translocation. We then established a direct NF-kB inhibition approach by utilizing a TAT-bound, mutant IkB (TAT:IkB(46-317)), and demonstrated an inhibitory effect evidenced by decreased NF-kB DNA binding activity. Having established that these strategies (TPCK, CPI, TAT: IkB(46-317)) 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:IkB(46-317) 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.
authors.affiliation: Department of Orthopaedic Surgery, Barnes-Jewish Hospital at Washington University School of Medicine, One Barnes-Jewish Hospital Plaza, Suite 11300, West Pavillion, St. Louis, MO 63110, USA. jclohisy@msnotes.wustl.edu
authors.forename: John C
authors.initials: JC
authors.lastname: Clohisy
authors.forename: Teruhisa
authors.initials: T
authors.lastname: Hirayama
authors.forename: Elfaridah
authors.initials: E
authors.lastname: Frazier
authors.forename: Suk-Ku
authors.initials: SK
authors.lastname: Han
authors.forename: Yousef
authors.initials: Y
authors.lastname: Abu-Amer
mesh_terms: D000818:Animals; D001843:Bone Cements / Q000494:pharmacology*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D006023:Glycoproteins / Q000494:pharmacology; D066298:In Vitro Techniques; D051379:Mice; D008810:Mice, Inbred C57BL; D016328:NF-kappa B / Q000378:metabolism*; D010010:Osteoclasts / Q000166:cytology / Q000187:drug effects*; D019904:Polymethyl Methacrylate / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects*; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects
chemical_list: D001843:Bone Cements; D015853:Cysteine Proteinase Inhibitors; D006023:Glycoproteins; D016328:NF-kappa B; C039304:calpain inhibitors; D019904:Polymethyl Methacrylate