A crucial role for reactive oxygen species in RANKL-induced osteoclast differentiation

Blood. 2005 Aug 1;106(3):852-9. doi: 10.1182/blood-2004-09-3662. Epub 2005 Apr 7.


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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bone Marrow Cells
  • Carrier Proteins / pharmacology*
  • Cell Differentiation / drug effects*
  • Cell Lineage
  • MAP Kinase Signaling System
  • Macrophages / cytology
  • Membrane Glycoproteins / pharmacology*
  • Mice
  • Mice, Inbred C57BL
  • Monocytes / cytology
  • NADH, NADPH Oxidoreductases / metabolism
  • NADPH Oxidase 1
  • Neuropeptides / metabolism
  • Osteoclasts / cytology*
  • RANK Ligand
  • Reactive Oxygen Species / metabolism*
  • Receptor Activator of Nuclear Factor-kappa B
  • TNF Receptor-Associated Factor 6 / metabolism
  • rac GTP-Binding Proteins / metabolism
  • rac1 GTP-Binding Protein


  • Carrier Proteins
  • Membrane Glycoproteins
  • Neuropeptides
  • RANK Ligand
  • Rac1 protein, mouse
  • Reactive Oxygen Species
  • Receptor Activator of Nuclear Factor-kappa B
  • TNF Receptor-Associated Factor 6
  • Tnfrsf11a protein, mouse
  • Tnfsf11 protein, mouse
  • NADH, NADPH Oxidoreductases
  • NADPH Oxidase 1
  • NOX1 protein, mouse
  • rac GTP-Binding Proteins
  • rac1 GTP-Binding Protein