Wortmannin inhibits translation of tumor necrosis factor-alpha in superantigen-activated T cells.
The superantigen toxic shock syndrome toxin (TSST)-1 can induce tumor necrosis factor (TNF)-alpha expression in T cells and monocytes, through different signaling pathways. We have stimulated peripheral blood mononuclear cells with TSST-1 and found that the major cell producers of TNF-alpha as detected by cytofluorimetry and immunocytochemistry were CD4(+) T lymphocytes. The expression of TNF-alpha by CD4(+) T cells can be inhibited by either, wortmannin (WN) or LY 294002, two phosphatidylinositol 3-kinase (PI 3-K) inhibitors. The inhibitory effect is not transcriptional as WN does not change the mRNA steady state of TNF-alpha at any of the concentrations tested and LY 294002 when preincubated with mononuclear cells at its median inhibitory concentration (IC(50) = 1. 4 microM) significantly inhibited the expression of TNF-alpha but not its mRNA. Immunoprecipitation of pulse-labeled intracellular TNF-alpha showed a specific decrease in the synthesis of this cytokine on cells treated with PI 3-K inhibitors. The p38 mitogen-activated protein kinase (MAPK) is involved in control of TNF-alpha translation in human macrophages. In T cells, we have found that the p38 MAPK inhibitor SB 203580 significantly decreased the secretion of TNF-alpha but not its mRNA. In addition, the combined use of WN and SB 203580 had an additive inhibitory effect on secretion of TNF-alpha. Therefore, both PI 3-K and p38 MAPK signaling pathways control TNF-alpha production in T cells.
Ramírez
M
M
Departament de Fisiologia, Facultat de Biologia, Universitat de Barcelona, Avenue Diagonal 645, 08028 Barcelona, Spain.
Fernández-Troy
N
N
Buxadé
M
M
Casaroli-Marano
R P
RP
Benítez
D
D
Pérez-Maldonado
C
C
Espel
E
E
D000730:Androstadienes / Q000494:pharmacology*; D001427:Bacterial Toxins; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects* / Q000378:metabolism; D002867:Chromones / Q000494:pharmacology; D004768:Enterotoxins / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D009025:Morpholines / Q000494:pharmacology; D019869:Phosphatidylinositol 3-Kinases / Q000494:pharmacology; D011725:Pyridines / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D018089:Superantigens / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects; D014409:Tumor Necrosis Factor-alpha / Q000187:drug effects* / Q000378:metabolism; D000077191:Wortmannin
D000730:Androstadienes; D001427:Bacterial Toxins; D002867:Chromones; D004768:Enterotoxins; D004791:Enzyme Inhibitors; D007093:Imidazoles; D007166:Immunosuppressive Agents; D009025:Morpholines; D011725:Pyridines; D012333:RNA, Messenger; D018089:Superantigens; D014409:Tumor Necrosis Factor-alpha; C030107:enterotoxin F, Staphylococcal; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; D019869:Phosphatidylinositol 3-Kinases; C093642:SB 203580; D000077191:Wortmannin