title: Osteopontin as a positive regulator in the osteoclastogenesis of arthritis.
abstract: We examined the role of osteopontin (OPN) in the osteoclastogenesis of arthritis using collagen-induced arthritis (CIA). Cells from arthritic joints of wild-type (OPN +/+) mice spontaneously developed bone-resorbing osteoclast-like cells (OCLs). The cultured cells showed an enhanced expression of receptor activator of nuclear factor kappaB ligand (RANKL) and a decreased expression of osteoprotegerin (OPG). The addition of OPG reduced the number of OCLs, indicating that the osteoclastogenesis depends on the RANK/RANKL/OPG system. The cells also produced OPN abundantly and anti-OPN neutralizing antibodies suppressed the development of OCLs. Moreover, the addition of OPN increased the expression of RANKL and augmented differentiation of OCLs from OPN-deficient (OPN -/-) cells. OPN, like the combination of 1alpha,25-dihydroxyvitamin D(3) and dexamethasone, also enhanced the RANKL expression and decreased OPG expression in a stromal cell line, ST2. These results suggest that OPN acts as a positive regulator in the osteoclastogenesis of arthritis through the RANK/RANKL/OPG system.
authors.affiliation: Department of Molecular Medicine, Osaka University Graduate School of Medicine, Suita, Japan.
authors.forename: Taeko
authors.initials: T
authors.lastname: Ishii
authors.forename: Shiro
authors.initials: S
authors.lastname: Ohshima
authors.forename: Tetsushi
authors.initials: T
authors.lastname: Ishida
authors.forename: Toru
authors.initials: T
authors.lastname: Mima
authors.forename: Youichiro
authors.initials: Y
authors.lastname: Tabunoki
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Maeda
authors.forename: Toshimitsu
authors.initials: T
authors.lastname: Uede
authors.forename: Lucy
authors.initials: L
authors.lastname: Liaw
authors.forename: Naokazu
authors.initials: N
authors.lastname: Kinoshita
authors.forename: Ichiro
authors.initials: I
authors.lastname: Kawase
authors.forename: Yukihiko
authors.initials: Y
authors.lastname: Saeki
mesh_terms: D000818:Animals; D001168:Arthritis / Q000209:etiology / Q000378:metabolism*; D002117:Calcitriol / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D002454:Cell Differentiation; D002460:Cell Line; D002478:Cells, Cultured; D003094:Collagen / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation; D006023:Glycoproteins / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism; D051379:Mice; D008811:Mice, Inbred DBA; D008822:Mice, Transgenic; D008957:Models, Genetic; D010010:Osteoclasts / Q000378:metabolism; D053495:Osteopontin; D053244:Osteoprotegerin; D053245:RANK Ligand; D012333:RNA, Messenger / Q000378:metabolism; D053246:Receptor Activator of Nuclear Factor-kappa B; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D018124:Receptors, Tumor Necrosis Factor; D011994:Recombinant Proteins / Q000737:chemistry; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012795:Sialoglycoproteins / Q000502:physiology*; D017154:Stromal Cells / Q000166:cytology
chemical_list: D002352:Carrier Proteins; D006023:Glycoproteins; D008562:Membrane Glycoproteins; D053244:Osteoprotegerin; D053245:RANK Ligand; D012333:RNA, Messenger; D053246:Receptor Activator of Nuclear Factor-kappa B; D018160:Receptors, Cytoplasmic and Nuclear; D018124:Receptors, Tumor Necrosis Factor; D011994:Recombinant Proteins; D012795:Sialoglycoproteins; C506896:Spp1 protein, mouse; C505687:Tnfrsf11a protein, mouse; C506031:Tnfrsf11b protein, mouse; C505689:Tnfsf11 protein, mouse; D053495:Osteopontin; D003907:Dexamethasone; D003094:Collagen; D002117:Calcitriol