title: LPS promotes pre-osteoclast activity by up-regulating CXCR4 via TLR-4.
abstract: Lipopolysaccharide (LPS) has been shown to be a prominent pathogenic factor in inflammatory bone loss. However, knowledge of the mechanisms involved is limited. The role of the SDF-1/CXCR4 (Stromal-derived factor-1 and its unique chemokine receptor) axis in LPS-induced bone loss has not been studied. The aim of this study was to investigate the role of the SDF-1/CXCR4 axis in LPS-stimulated inflammatory bone loss. The results show that LPS does not influence the expression of SDF-1/CXCR4 in osteoblasts, but up-regulates the expression of CXCR4 in pre-osteoclasts via Toll-like receptor 4, which subsequently enhances pre-osteoclast migration. Moreover, LPS promoted RANKL-induced osteoclast differentiation partially through CXCR4 up-regulation. In conclusion, the present study demonstrated, for the first time, that the up-regulated expression of CXCR4 in pre-osteoclasts by LPS stimulation is involved in LPS-induced bone resorption.
authors.affiliation: Department of Orthodontics, University Medical Centre Groningen, University of Groningen, Hanzeplein 1 triade 24, 9700 RB Groningen, The Netherlands.
authors.forename: Q
authors.initials: Q
authors.lastname: Xing
authors.forename: P
authors.initials: P
authors.lastname: de Vos
authors.forename: M M
authors.initials: MM
authors.lastname: Faas
authors.forename: Q
authors.initials: Q
authors.lastname: Ye
authors.forename: Y
authors.initials: Y
authors.lastname: Ren
mesh_terms: D016475:3T3 Cells; D016301:Alveolar Bone Loss / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D000818:Animals; D002454:Cell Differentiation; D002465:Cell Movement; D054377:Chemokine CXCL12 / Q000378:metabolism; D008070:Lipopolysaccharides / Q000276:immunology*; D051379:Mice; D009000:Monocytes; D010010:Osteoclasts / Q000276:immunology / Q000378:metabolism*; D053245:RANK Ligand / Q000378:metabolism; D019718:Receptors, CXCR4 / Q000096:biosynthesis*; D051197:Toll-Like Receptor 4 / Q000502:physiology*; D015854:Up-Regulation
chemical_list: C514936:CXCR4 protein, mouse; D054377:Chemokine CXCL12; C515256:Cxcl12 protein, mouse; D008070:Lipopolysaccharides; D053245:RANK Ligand; D019718:Receptors, CXCR4; D051197:Toll-Like Receptor 4