Sphingosine 1-phosphate acts as a signal molecule in ceramide signal transduction of TNF-alpha-induced activator protein-1 in osteoblastic cell line MC3T3-E1 cells.
We previously demonstrated that tumor necrosis factor (TNF)-alpha stimulated the production of activation protein (AP)-1, a transcriptional factor, in mouse osteoblastic MC3T3-E1 cells. Recent studies have shown the importance of ceramide and its metabolites as signal molecules for TNF-alpha-induced gene expression in several cell types. Therefore, our interest was to investigate whether sphingosine metabolites are involved in TNF-alpha-induced signaling in MC3T3-E1 cells. DL-threo-1-phenyl-2-hexadecanoyl-amino-3-pyrrolidino-1-propanol (PPPP), which causes accumulation of intracellular ceramide, stimulated the TNF-alpha-induced expression of the c-fos and c-jun genes. Gel shift assay clearly showed that PPPP increased the cytokine-induced specific binding of nuclear proteins to the 12-tetra-decanoyl phorbol 13-acetate-responsive element (TRE), a consensus sequence for AP-1. In addition, cell-permeable ceramide (N-acetylsphingosine, N-hexanoylsphingosine or N-octanoylsphingosine) stimulated expression of the c-fos and c-jun genes and nuclear protein binding to TRE. Interestingly, DL-threo-dihydrosphingosine (DHS), an inhibitor of sphingosine kinase, clearly blocked the ceramide analogue-induced stimulation. Sphingosine 1-phosphate (SPP) actually induced expression of these oncogenes and activated AP-1. Although TNF-alpha stimulated the AP-1-mediated expression of the monocyte chemoattractant JE/MCP-1, this stimulation was inhibited by DHS. SPP also stimulated JE/MCP-1 gene expression. The present study thus suggests that SPP acts as a signal molecule in ceramide-dependent signal transduction in TNF-alpha-induced AP-1 in osteoblastic MC3T3-E1 cells.
Takeshita
Akira
A
Department of Oral Health and Preventive Dentistry, Meikai University School of Dentistry, Keyakidai, Sakado-city, Saitama 350-0283, Japan. takesita@dent.meikai.ac.jp
Shinoda
Hiroyuki
H
Nakabayashi
Yasuo
Y
Takano
Akiko
A
Matsumoto
Ken
K
Suetsugu
Mayumi
M
Miyazawa
Kei
K
Tanaka
Sonoji
S
Endo
Hiromasa
H
Tanaka
Susumu
S
Ueyama
Yoshifumi
Y
Hanzawa
Akiko
A
Suda
Yoko
Y
Kanegae
Haruhide
H
Yasui
Toshikazu
T
D016475:3T3 Cells; D000818:Animals; D015152:Blotting, Northern; D002518:Ceramides / Q000494:pharmacology* / Q000502:physiology; D018932:Chemokine CCL2 / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D016762:Genes, fos; D016758:Genes, jun; D008246:Lysophospholipids / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009025:Morpholines / Q000494:pharmacology; D010006:Osteoblasts / Q000378:metabolism*; D011412:Propanolamines / Q000494:pharmacology; D011759:Pyrrolidines / Q000494:pharmacology; D011994:Recombinant Proteins / Q000494:pharmacology; D015290:Second Messenger Systems / Q000502:physiology*; D013108:Sphingomyelin Phosphodiesterase / Q000378:metabolism / Q000494:pharmacology; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000502:physiology*; D013755:Tetradecanoylphorbol Acetate / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000096:biosynthesis*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology* / Q000502:physiology
C110417:1-phenyl-2-hexadecanoylamino-3-pyrrolidino-1-propanol; D002518:Ceramides; D018932:Chemokine CCL2; D004791:Enzyme Inhibitors; D008246:Lysophospholipids; D009025:Morpholines; D011412:Propanolamines; D011759:Pyrrolidines; D011994:Recombinant Proteins; D018808:Transcription Factor AP-1; D014409:Tumor Necrosis Factor-alpha; C060506:sphingosine 1-phosphate; C033110:RV 538; D013108:Sphingomyelin Phosphodiesterase; D013110:Sphingosine; D013755:Tetradecanoylphorbol Acetate