title: mu-Calpain regulates receptor activator of NF-kappaB ligand (RANKL)-supported osteoclastogenesis via NF-kappaB activation in RAW 264.7 cells.
abstract: To clarify the role of calpain in the receptor activator of NF-kappaB ligand (RANKL)-supported osteoclastogenesis, RANKL-induced calpain activation was examined by using murine RAW 264.7 cells and bone marrow-derived monocyte/macrophage progenitors. We found that calpain activity increased in response to RANKL in both cell types based on alpha-spectrinolysis and that mu-calpain, rather than m-calpain, was activated during RANKL-supported osteoclastogenesis in RAW 264.7 cells. Overexpression of mu-calpain clearly augmented RANKL-supported osteoclastogenesis in RAW 264.7 cells, thereby implicating its pivotal role in this process. Cell-permeable calpain inhibitors, including calpastatin and calpeptin, were sufficient to suppress RANKL-supported osteoclastogenesis based on decreased expression of the osteoclastogenic marker, matrix metalloproteinase 9, and the generation of tartrate-resistant acid phosphatase-positive multinucleated cells in both cell types. Calpain inhibitors suppressed NF-kappaB activation via inhibition of the cleavage of inhibitor of NF-kappaB(IkappaBalpha)in RAW 264.7 cells. Taken together, our findings suggest that mu-calpain is essential to the regulation of RANKL-supported osteoclastogenesis via NF-kappaB activation.
authors.affiliation: Center for Orthopaedic Research, Department of Orthopaedic Surgery, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA.
authors.forename: Francis Young-In
authors.initials: FY
authors.lastname: Lee
authors.forename: Dae-Won
authors.initials: DW
authors.lastname: Kim
authors.forename: Jaime A
authors.initials: JA
authors.lastname: Karmin
authors.forename: Daewha
authors.initials: D
authors.lastname: Hong
authors.forename: Seong-Sil
authors.initials: SS
authors.lastname: Chang
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Fujisawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Takayanagi
authors.forename: Louis U
authors.initials: LU
authors.lastname: Bigliani
authors.forename: Theodore A
authors.initials: TA
authors.lastname: Blaine
authors.forename: Hahn-Jun
authors.initials: HJ
authors.lastname: Lee
mesh_terms: D000818:Animals; D002154:Calpain / Q000502:physiology*; D002352:Carrier Proteins / Q000494:pharmacology*; D002454:Cell Differentiation; D002460:Cell Line; D020672:I-kappa B Proteins / Q000378:metabolism; D008264:Macrophages / Q000166:cytology; D008562:Membrane Glycoproteins / Q000494:pharmacology*; D051379:Mice; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000502:physiology*; D010010:Osteoclasts / Q000502:physiology*; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B
chemical_list: D002352:Carrier Proteins; D020672:I-kappa B Proteins; D008562:Membrane Glycoproteins; D016328:NF-kappa B; C000606205:Nfkbia protein, mouse; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; C505687:Tnfrsf11a protein, mouse; C505689:Tnfsf11 protein, mouse; D000072000:NF-KappaB Inhibitor alpha; D002154:Calpain; C449002:mu-calpain