title: 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.
abstract: 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.
authors.affiliation: Department of Oral Health and Preventive Dentistry, Meikai University School of Dentistry, Keyakidai, Sakado-city, Saitama 350-0283, Japan. takesita@dent.meikai.ac.jp
authors.forename: Akira
authors.initials: A
authors.lastname: Takeshita
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Shinoda
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Nakabayashi
authors.forename: Akiko
authors.initials: A
authors.lastname: Takano
authors.forename: Ken
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Mayumi
authors.initials: M
authors.lastname: Suetsugu
authors.forename: Kei
authors.initials: K
authors.lastname: Miyazawa
authors.forename: Sonoji
authors.initials: S
authors.lastname: Tanaka
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Endo
authors.forename: Susumu
authors.initials: S
authors.lastname: Tanaka
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Ueyama
authors.forename: Akiko
authors.initials: A
authors.lastname: Hanzawa
authors.forename: Yoko
authors.initials: Y
authors.lastname: Suda
authors.forename: Haruhide
authors.initials: H
authors.lastname: Kanegae
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Yasui
mesh_terms: 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
chemical_list: 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