title: Nitrogen-containing bisphosphonate, YM529/ONO-5920 (a novel minodronic acid), inhibits RANKL expression in a cultured bone marrow stromal cell line ST2.
abstract: Increase in bone resorption by osteoclasts can cause metabolic bone diseases, such as osteoporosis. Recent attention has been paid to the receptor activator of the NF-kappaB ligand (RANKL), an accelerator of osteoclast differentiation. RANKL is expressed on the bone marrow-derived stromal cell membrane and induces the differentiation of osteoclasts by binding to RANK expressed on the osteoclast precursor cell membrane. Since the inhibition of RANKL expression can lead to the inhibition of osteoclastic bone resorption, the clinical application of RANKL inhibition could be expected to have a major effect on metabolic bone disease therapy. In this study, we investigated whether or not YM529/ONO-5920, a nitrogen-containing bisphosphonate (a novel minodronic acid), inhibits RANKL expression in a bone marrow-derived stromal cell line (ST2 cells). Reverse transcription-polymerase chain reaction revealed that the administration of YM529/ONO-5920 to ST2 cells inhibited RANKL mRNA expression and reduced RANKL proteins as assessed by Western blot analysis. The inhibition of RANKL mRNA expression was reversed when geranylgeranyl pyrophosphate (GGPP), an intermediate in the mevalonate pathway, was used in combination. Furthermore, YM529/ONO-5920 reduced phosphorylated extracellular signal-regulated kinase 1/2 (ERK1/2), and similarly, U0126, a mitogen-activated protein kinase kinase 1/2 inhibitor, inhibited RANKL expression. Pretreatment with GGPP reversed the YM529/ONO-5920-induced decrease in phosphorylation of ERK. Furthermore, YM529/ONO-5920 decreased TRAP-positive cells in co-culture of ST2 cells and an osteoclast cell line, C7 cells, and this decrease was inhibited by pretreatment with GGPP. This indicates that YM529/ONO-5920 inhibits GGPP biosynthesis in the mevalonate pathway and then signal transduction in the Ras-mitogen-activated protein kinase pathway, thereby inhibiting RANKL expression on ST2 cells. These results suggest a newly elucidated action of bisphosphonates in the inhibition of bone resorption.
authors.affiliation: Division of Pharmacotherapy, Kinki University School of Pharmaceutical Sciences, 3-4-1 Kowakae, Higashi-Osaka 577-8502, Japan. nishida@phar.kindai.ac.jp
authors.forename: Shozo
authors.initials: S
authors.lastname: Nishida
authors.forename: Masanobu
authors.initials: M
authors.lastname: Tsubaki
authors.forename: Mayumi
authors.initials: M
authors.lastname: Hoshino
authors.forename: Ayumi
authors.initials: A
authors.lastname: Namimatsu
authors.forename: Hiromi
authors.initials: H
authors.lastname: Uji
authors.forename: Shohei
authors.initials: S
authors.lastname: Yoshioka
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Tanimori
authors.forename: Masashi
authors.initials: M
authors.lastname: Yanae
authors.forename: Masahiro
authors.initials: M
authors.lastname: Iwaki
authors.forename: Kiyohiro
authors.initials: K
authors.lastname: Irimajiri
mesh_terms: D000818:Animals; D001853:Bone Marrow / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D001854:Bone Marrow Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D002470:Cell Survival / Q000187:drug effects; D004164:Diphosphonates / Q000008:administration & dosage* / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000187:drug effects; D007093:Imidazoles / Q000008:administration & dosage*; D008562:Membrane Glycoproteins / Q000378:metabolism*; D051379:Mice; D009584:Nitrogen / Q000008:administration & dosage / Q000737:chemistry; D010010:Osteoclasts / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D017154:Stromal Cells / Q000187:drug effects / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D004164:Diphosphonates; D007093:Imidazoles; D008562:Membrane Glycoproteins; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; C505687:Tnfrsf11a protein, mouse; C505689:Tnfsf11 protein, mouse; C087958:YM 529; D009584:Nitrogen