title: A crucial role for reactive oxygen species in RANKL-induced osteoclast differentiation.
abstract: Signaling by receptor activator of NF-kappaB (nuclear factor-kappaB) ligand (RANKL) is essential for differentiation of bone marrow monocyte-macrophage lineage (BMM) cells into osteoclasts. Here, we show RANKL stimulation of BMM cells transiently increased the intracellular level of reactive oxygen species (ROS) through a signaling cascade involving TNF (tumor necrosis factor) receptor-associated factor (TRAF) 6, Rac1, and NADPH (nicotinamide adenine dinucleotide phosphate) oxidase (Nox) 1. A deficiency in TRAF6 or expression of a dominant-interfering mutant of TRAF6 blocks RANKL-mediated ROS production. Application of N-acetylcysteine (NAC) or blocking the activity of Nox, a protein leading to the formation of ROS, with diphenylene iodonium (DPI) inhibits the responses of BMM cells to RANKL, including ROS production, activation of c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein (MAP) kinase, and extracellular signal-regulated kinase (ERK), and osteoclast differentiation. Moreover, both RANKL-mediated ROS production and osteoclast differentiation were completely blocked in precursors depleted of Nox1 activity by RNA interference or by expressing a dominant-negative mutant of Rac1. Together, these results indicate that ROSs act as an intracellular signal mediator for osteoclast differentiation.
authors.affiliation: Division of Molecular Life Sciences and Center for Cell Signaling Research, Ewha Womans University, Seoul, 120-750, Korea.
authors.forename: Na Kyung
authors.initials: NK
authors.lastname: Lee
authors.forename: Young Geum
authors.initials: YG
authors.lastname: Choi
authors.forename: Ji Youn
authors.initials: JY
authors.lastname: Baik
authors.forename: Song Yi
authors.initials: SY
authors.lastname: Han
authors.forename: Dae-Won
authors.initials: DW
authors.lastname: Jeong
authors.forename: Yun Soo
authors.initials: YS
authors.lastname: Bae
authors.forename: Nacksung
authors.initials: N
authors.lastname: Kim
authors.forename: Soo Young
authors.initials: SY
authors.lastname: Lee
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells; D002352:Carrier Proteins / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects*; D019070:Cell Lineage; D020935:MAP Kinase Signaling System; D008264:Macrophages / Q000166:cytology; D008562:Membrane Glycoproteins / Q000494:pharmacology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009000:Monocytes / Q000166:cytology; D009247:NADH, NADPH Oxidoreductases / Q000378:metabolism; D000074624:NADPH Oxidase 1; D009479:Neuropeptides / Q000378:metabolism; D010010:Osteoclasts / Q000166:cytology*; D053245:RANK Ligand; D017382:Reactive Oxygen Species / Q000378:metabolism*; D053246:Receptor Activator of Nuclear Factor-kappa B; D048029:TNF Receptor-Associated Factor 6 / Q000378:metabolism; D020744:rac GTP-Binding Proteins / Q000378:metabolism; D020830:rac1 GTP-Binding Protein
chemical_list: D002352:Carrier Proteins; D008562:Membrane Glycoproteins; D009479:Neuropeptides; D053245:RANK Ligand; C484602:Rac1 protein, mouse; D017382:Reactive Oxygen Species; D053246:Receptor Activator of Nuclear Factor-kappa B; D048029:TNF Receptor-Associated Factor 6; C505687:Tnfrsf11a protein, mouse; C505689:Tnfsf11 protein, mouse; D009247:NADH, NADPH Oxidoreductases; D000074624:NADPH Oxidase 1; C000614711:NOX1 protein, mouse; D020744:rac GTP-Binding Proteins; D020830:rac1 GTP-Binding Protein