Receptor activator of nuclear factor-kappa b ligand activates nuclear factor-kappa b in osteoclast precursors.
Receptor activator of nuclear factor-kappa B ligand [RANK ligand (RANK-L)] stimulates mature osteoclasts to resorb bone, a process associated with NF-kappa B activation. RANK-L also prompts macrophages to develop the osteoclast phenotype. Although NF-kappa B is essential for osteoclast differentiation, it is not known whether RANK-L activates this transcription complex in osteoclast precursors. We report that RANK-L rapidly induces NF-kappa B activation in both authentic osteoclast precursors, namely bone marrow macrophages, and RAW 264.7 cells, a murine macrophage line also capable of RANK-L-mediated osteoclastogenesis. Supershift studies reveal the RANK-L-induced DNA binding moiety contains p50/p65, the most common NF-kappa B complex. Subcellular translocation of p50 and p65 subunits is confirmed by Western blots and immunofluorescence analysis. RANK-L activates NF-kappa B in both bone marrow macrophages and RAW 264.7 cells by serine phosphorylation of I kappa B alpha within 5 min, resulting in rapid I kappa B alpha degradation and resynthesis. Attesting to function, RANK-L treatment of RAW 264.7 cells transiently transfected with a plasmid containing NF-kappa B consensus elements linked to luciferase greatly enhances reporter activity. Our data suggest that activation of the NF-kappa B pathway is an integral component of RANK-L-induced osteoclast differentiation.
Wei
S
S
Department of Pathology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Teitelbaum
S L
SL
Wang
M W
MW
Ross
F P
FP
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002352:Carrier Proteins / Q000494:pharmacology*; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D019281:Dimerization; D017930:Genes, Reporter / Q000187:drug effects; D020672:I-kappa B Proteins / Q000378:metabolism; D008297:Male; D008562:Membrane Glycoproteins / Q000494:pharmacology*; D051379:Mice; D008809:Mice, Inbred C3H; D016328:NF-kappa B / Q000235:genetics / Q000502:physiology*; D010010:Osteoclasts / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D012694:Serine / Q000378:metabolism; D013234:Stem Cells / Q000187:drug effects / Q000378:metabolism*
D002352:Carrier Proteins; D020672:I-kappa B Proteins; D008562:Membrane Glycoproteins; D016328:NF-kappa B; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; C505687:Tnfrsf11a protein, mouse; C505689:Tnfsf11 protein, mouse; D012694:Serine