Tumor necrosis factor-alpha induces interleukin-6 production and integrin ligand expression by distinct transduction pathways.
Tumor necrosis factor-alpha (TNF-alpha) is a pleiotropic cytokine that elicits a large number of biological effects. However, the intracellular signaling mechanisms that are responsible for the TNF-alpha effects remain largely unknown. We have previously demonstrated that cultured mouse Sertoli cells, after TNF-alpha treatment, increase the surface expression of adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) and interleukin-6 (IL-6) production (Riccioli, A., Filippini, A., De Cesaris, P., Barbacci, E., Stefanini, M., Starace, G., and Ziparo, E. (1995) Proc. Natl. Acad. Sci. U.S.A. 92, 5808-5812). Here, we show that, in cultured Sertoli cells, TNF-alpha activates the mitogen-activated protein kinase pathway (p38, c-Jun N-terminal protein kinase/stress-activated protein kinase, and the p42/p44 mitogen-activated protein kinases) as revealed by an increased phosphorylation of p38, activating transcription factor-2, c-Jun, and Elk-1. Furthermore, our data indicate that the biological effects induced by TNF-alpha in Sertoli cells (enhancement of ICAM-1, VCAM-1, and IL-6 expression) depend on the activation of different signaling pathways. SB203580, a highly specific p38 inhibitor, does not affect ICAM-1 and VCAM-1 expression, but strongly inhibits IL-6 production. Moreover, interferon-gamma, which up-regulates adhesion molecule expression and reduces IL-6 production, does not induce phosphorylation of p38. Our data strongly support the hypothesis that, in response to TNF-alpha, activation of p38 leads to IL-6 production, whereas ICAM-1 and VCAM-1 expression could be induced by activation of the c-Jun N-terminal protein kinase/stress-activated protein kinase pathway.
De Cesaris
P
P
Istituto Pasteur Fondazione Cenci Bolognetti, Rome, Italy.
Starace
D
D
Riccioli
A
A
Padula
F
F
Filippini
A
A
Ziparo
E
E
D051698:Activating Transcription Factor 2; D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002469:Cell Separation; D002478:Cells, Cultured; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005434:Flow Cytometry; D007093:Imidazoles / Q000494:pharmacology; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis*; D007371:Interferon-gamma / Q000494:pharmacology; D015850:Interleukin-6 / Q000096:biosynthesis*; D048031:JNK Mitogen-Activated Protein Kinases; D016350:Leucine Zippers; D008024:Ligands; D008297:Male; D051379:Mice; D020928:Mitogen-Activated Protein Kinases; D010766:Phosphorylation; D011725:Pyridines / Q000494:pharmacology; D012708:Sertoli Cells / Q000187:drug effects / Q000378:metabolism*; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D015854:Up-Regulation; D019010:Vascular Cell Adhesion Molecule-1 / Q000096:biosynthesis*; D048051:p38 Mitogen-Activated Protein Kinases
D051698:Activating Transcription Factor 2; C497106:Atf2 protein, mouse; D017362:Cyclic AMP Response Element-Binding Protein; D004791:Enzyme Inhibitors; D007093:Imidazoles; D015850:Interleukin-6; D008024:Ligands; D011725:Pyridines; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1; D007371:Interferon-gamma; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C093642:SB 203580