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RANKL is an essential cytokine mediator of polymethylmethacrylate particle‐induced osteoclastogenesis
Author(s) -
Clohisy John C.,
Frazier Elfaridah,
Hirayama Teruhisa,
AbuAmer Yousef
Publication year - 2003
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1016/s0736-0266(02)00133-x
Subject(s) - rankl , osteoclast , cytokine , osteolysis , chemistry , microbiology and biotechnology , rank ligand , tumor necrosis factor alpha , stromal cell , mediator , cancer research , immunology , in vitro , receptor , activator (genetics) , medicine , biology , biochemistry , dentistry
RANKL is a TNF superfamily member and an essential cytokine mediator of developmental osteoclastogenesis. We examined the role of RANKL in PMMA particle‐induced osteoclastogenesis in vitro. In murine whole bone marrow cultures, PMMA particles stimulate a 2.5 fold increase in secreted RANKL, a 5–8 fold increase in osteoclast number and induce the formation of giant multinuclear osteoclasts. RANKL and TNF, potential cytokine mediators of PMMA, had similar osteoclastogenic effects. The RANKL inhibitor OPG was utilized to define the role of RANKL in mediating the PMMA response and was found to inhibit basal and PMMA particle‐induced osteoclastogenesis. Additionally, particles stimulate osteoclast formation in RANKL‐primed osteoclast precursor cells (devoid of supporting stromal cells) while RANKL untreated osteoclast precursors demonstrate no osteoclastogenic response to particles. Since TNF can potentiate RANKL action and is thought to mediate implant osteolysis we analyzed TNF −/− whole bone marrow cultures to elucidate the role of this cytokine. In TNF ‐/‐ cultures basal osteoclastogenesis remains intact, yet the PMMA effect is blunted. Finally, we show that PMMA, RANKL and TNF all activate the NF‐kB and c‐jun/AP‐1 signaling pathways which are both fundamental to osteoclast formation and are potential sites of signal convergence in RANKL‐mediated particle osteoclastogenesis. © 2002 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.