Lactosylceramide is essential for the osteoclastogenesis mediated by macrophage-colony-stimulating factor and receptor activator of nuclear factor-kappa B ligand.
Glycosphingolipids and their metabolites play important roles in a variety of biological processes. Several signal molecules are localized in a glycolipid-enriched microdomain on the cell surface, and their signals are regulated by the glycolipid composition. However, the function of glycolipids in osteoclastogenesis has not been clearly understood. We found that D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (D-PDMP), a glucosylceramide synthase inhibitor, completely inhibits the osteoclast formation induced by macrophage-colony-stimulating factor and receptor activator of nuclear factor-kappa B ligand (RANKL) in a dose-dependent manner. Expression of RANK, the receptor of RANKL, induced by macrophage colony-stimulating factor, was reduced markedly in D-PDMP-treated cells. d-PDMP also inhibited the phosphorylation of the inhibitor of nuclear factor-kappa B and extracellular signal-regulated kinase 1/2 induced by RANKL. In several experiments with the addition of glycolipids to D-PDMP-treated purified bone marrow cells, lactosylceramide (LacCer) strongly affected the differentiation into tartrate-resistant acid phosphatase mononucleated cells, but not positive multinucleated cells. GM3 and GM1 also recovered, but less effectively compared with LacCer. Moreover, exogenous LacCer recovered the reduced expression of RANK and the phosphorylation of inhibitor of NF-kappa B and extracellular signal-regulated kinase 1/2 after stimulation by RANKL at the same level of cells without D-PDMP treatment. Our data suggest that glycosphingolipids, especially LacCer, are necessary for the initiation step of RANKL-induced osteoclastogenesis.
Iwamoto
T
T
First Department of Oral and Maxillofacial Surgery, Nagasaki University School of Dentistry, Nagasaki 852-8588, Japan.
Fukumoto
S
S
Kanaoka
K
K
Sakai
E
E
Shibata
M
M
Fukumoto
E
E
Inokuchi Ji
J
J
Takamiya
K
K
Furukawa
K
K
Furukawa
K
K
Kato
Y
Y
Mizuno
A
A
D000818:Animals; D015703:Antigens, CD; D001483:Base Sequence; D002352:Carrier Proteins / Q000502:physiology*; D002455:Cell Division / Q000502:physiology*; D017931:DNA Primers; D007790:Lactosylceramides / Q000502:physiology*; D016173:Macrophage Colony-Stimulating Factor / Q000502:physiology*; D008297:Male; D008562:Membrane Glycoproteins / Q000502:physiology*; D051379:Mice; D010010:Osteoclasts / Q000166:cytology*; D010766:Phosphorylation; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B
D015703:Antigens, CD; D002352:Carrier Proteins; D017931:DNA Primers; D007790:Lactosylceramides; D008562:Membrane Glycoproteins; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; C505687:Tnfrsf11a protein, mouse; C505689:Tnfsf11 protein, mouse; C009744:CDw17 antigen; D016173:Macrophage Colony-Stimulating Factor