Effect of ceramide on interleukin-6 synthesis in osteoblast-like cells.
We previously showed that prostaglandin (PG) E1 stimulates the synthesis of interleukin-6 (IL-6) through activation of protein kinase (PK) A in osteoblast-like MC3T3-E1 cells and that PGF2alpha induces IL-6 synthesis through PKC activation. In other studies, we demonstrated that thrombin stimulates IL-6 synthesis, which depends on intracellular Ca2+ mobilisation in these cells and that tumour necrosis factor-alpha (TNF) induces IL-6 synthesis through sphingosine 1-phosphate, a product of sphingomyelin turnover. In the present study, among sphingomyelin metabolites, we examined the effect of ceramide on the IL-6 synthesis induced by various agonists in MC3T3-E1 cells. C2-ceramide, a cell-permeable ceramide analogue, suppressed the PGE1-induced IL-6 synthesis. C2-ceramide inhibited the IL-6 synthesis induced by PGF2alpha or 12-O-tetradecanoylphorbol-13-acetate, an activator of PKC. C2-ceramide reduced the IL-6 synthesis induced by cholera toxin, forskolin or dibutyryl cAMP. C2-ceramide inhibited the IL-6 synthesis induced by thrombin. The IL-6 synthesis stimulated by thapsigargin, which is known to stimulate Ca2+ mobilisation from intracellular Ca2+ stores, or A23187, a Ca-ionophore, was also inhibited by C2-ceramide. C2-ceramide did not affect the IL-6 synthesis induced by interleukin-1. On the contrary, C2-ceramide enhanced the TNF-induced IL-6 synthesis. D,L-threo-dihydrosphingosine, an inhibitor of sphingosine kinase, inhibited the enhancement by C2-ceramide as well as the TNF-effect. These results strongly suggest that ceramide modulates the IL-6 synthesis stimulated by various agonists in osteoblasts.
Department of Internal Medicine, Toyota Memorial Hospital, Aichi, Japan.
J
J
Shinoda
O
O
Kozawa
H
H
Tokuda
T
T
Uematsu
D000527:Alprostadil / Q000494:pharmacology; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D002460:Cell Line; D002772:Cholera Toxin / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D015237:Dinoprost / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology; D015850:Interleukin-6 / Q000096:biosynthesis*; D051379:Mice; D010006:Osteoblasts / Q000187:drug effects* / Q000378:metabolism; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D019284:Thapsigargin / Q000494:pharmacology; D013917:Thrombin / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D007375:Interleukin-1; D015850:Interleukin-6; C064769:N-acetylsphingosine; D014409:Tumor Necrosis Factor-alpha; D005576:Colforsin; D000001:Calcimycin; D003994:Bucladesine; D019284:Thapsigargin; D002772:Cholera Toxin; D015237:Dinoprost; D013917:Thrombin; D000527:Alprostadil; D013110:Sphingosine; D013755:Tetradecanoylphorbol Acetate