Open AccessEnhancement of cAMP levels and of protein kinase activity by tumor necrosis factor and interleukin 1 in human fibroblasts: role in the induction of interleukin 6.
Author(s) -
Yihong Zhang,
Jian-Xin Lin,
Y. K. Yip,
Ján Vilček
Publication year - 1988
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.85.18.6802
Subject(s) - protein kinase a , forskolin , tumor necrosis factor alpha , biology , interleukin , microbiology and biotechnology , signal transduction , kinase , protein kinase inhibitor , cytokine , endocrinology , immunology , stimulation
Although tumor necrosis factor (TNF) and interleukin 1 (IL-1) affect many cell functions, the molecular mechanisms of TNF and IL-1 action are not understood. Our present study shows that exposure of human FS-4 fibroblasts to TNF or IL-1 caused a rapid accumulation of intracellular cAMP and an increase in protein kinase activity. Intracellular cAMP levels peaked 3-5 min after the addition of TNF or IL-1 and returned to basal level by 15 min. Increased phosphorylation of histone HII-B protein was demonstrated with extracts prepared from TNF- or IL-1-treated cells, suggesting an increase in cAMP-dependent protein kinase activity. No evidence was obtained for protein kinase C activation in TNF-treated FS-4 cells. TNF, IL-1, and forskolin all stimulated interleukin 6 (IL-6) mRNA levels in FS-4 cells. The protein kinase inhibitor H-8, inhibiting preferentially cAMP-dependent kinase activity, reduced forskolin-stimulated IL-6 mRNA induction more strongly than TNF- or IL-1-driven IL-6 mRNA induction. These results suggest that activation of cAMP-dependent protein kinase by TNF and IL-1 is important in some actions of these cytokines. In addition, our data on IL-6 induction by TNF and IL-1 suggest that other, yet unidentified, signal transduction mechanisms contribute to TNF and IL-1 actions on gene expression in human fibroblasts.