TNF-alpha and IL-5 gene induction in IgE plus antigen-stimulated mast cells require common and distinct signaling pathways.
BACKGROUND
Mast cells produce a variety of cytokines and chemokines in a timely and tightly controlled fashion if stimulated via the FcepsilonRI. Evidence is accumulating that the transcriptional induction of the corresponding genes and the release of these mediators are dependent on common and mediator-specific components of the signal transduction and transcription factor machinery.


METHODS
We addressed this issue by comparing the effects of mitogen activated protein (MAP) kinase pathway inhibitors and protein kinase C (PKC) inhibitors on the induction of TNF-alpha and IL-5 after IgE plus antigen (Ag) stimulation in CPII mouse mast cells using Western blot analyses and transient transfections of reporter gene plasmids.


RESULTS
TNF-alpha shows a strict dependence on the MAP kinase pathway, while IL-5 is either activated by PMA-dependent PKCs or along the MAP kinase pathway. In addition, both mediators are sensitive to PKCmu inhibition, suggesting involvement of this atypical, non-PMA dependent PKC in the overall induction process.


CONCLUSIONS
While the two cytokines were recently shown to be regulated by a member of the nuclear factor of activated T-cells (NF-AT) transcription factor family, activator protein 1 (AP1) was identified as a cofactor at the TNF-alpha promoter while a GATA family member comprised the cofactor at the IL-5 promoter. This suggests that the differences in requirement for signal transduction cascades are the result of a different usage of NF-AT cofactors for transcription of each cytokine in mast cells.
Baumruker
T
T
Department of Immunology, Novartis Research Institute, Vienna, Austria.
Csonga
R
R
Jaksche
D
D
Novotny
V
V
Prieschl
E E
EE
D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects / Q000276:immunology*; D007073:Immunoglobulin E / Q000276:immunology*; D015848:Interleukin-5 / Q000235:genetics / Q000276:immunology*; D008407:Mast Cells / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000276:immunology; D015533:Transcriptional Activation; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000276:immunology*
D004791:Enzyme Inhibitors; D015848:Interleukin-5; D014409:Tumor Necrosis Factor-alpha; D007073:Immunoglobulin E; D011493:Protein Kinase C; D017871:Calcium-Calmodulin-Dependent Protein Kinases