LPS promotes pre-osteoclast activity by up-regulating CXCR4 via TLR-4

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. © international & american associations for dental research.