Osteoclast differentiation by human osteoblastic cell line SaOS-2 primed with bacterial lipid A.
We examined the responses of human osteoblastic cell line SaOS-2 to bacterial lipid A, a bioactive center of lipopolysaccharide, during osteoclast differentiation of human peripheral blood mononuclear cells (PBMC). SaOS-2 cells expressed mRNA for Toll-like receptor (TLR) 4, MD-2, CD14, and myeloid differentiation factor 88, whereas they failed to express mRNA for TLR2. Escherichia coli-type synthetic lipid A (compound 506) induced cytokine mRNA expression and nuclear factor (NF)-kappaB activation in SaOS-2 cells. Compound 506 also increased the expression of receptor activator of NF-kappaB ligand. Further, cells primed with compound 506 augmented the differentiation of PBMC into osteoclastic cells, and the effect was inhibited by anti-TLR4 monoclonal antibody. These findings suggest that the TLR signaling cascade in osteoblastic cells is involved in regulating the function of osteoclastogenesis.
Asai
Yasuyuki
Y
Department of Oral Microbiology, Asahi University School of Dentistry, 1851-1 Hozumi, Hozumi-cho, Motosu-gun, 501-0296 Gifu, Japan.
Hirokawa
Yoshitaka
Y
Niwa
Kin ichiro
Ki
Ogawa
Tomohiko
T
D002454:Cell Differentiation / Q000502:physiology*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000502:physiology*; D008050:Lipid A / Q000031:analogs & derivatives* / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology; D008562:Membrane Glycoproteins; D016328:NF-kappa B / Q000276:immunology; D010010:Osteoclasts / Q000166:cytology* / Q000502:physiology; D011956:Receptors, Cell Surface / Q000276:immunology; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
D008050:Lipid A; D008562:Membrane Glycoproteins; D016328:NF-kappa B; D011956:Receptors, Cell Surface; C495342:TLR2 protein, human; C495345:TLR4 protein, human; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors; D014409:Tumor Necrosis Factor-alpha