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A Novel Mechanism for TNF-α Regulation by p38 MAPK: Involvement of NF-κB with Implications for Therapy in Rheumatoid Arthritis

2004; American Association of Immunologists; Volume: 173; Issue: 11 Linguagem: Inglês

10.4049/jimmunol.173.11.6928

1550-6606

Jamie I. D. Campbell, Cathleen J. Ciesielski, Abigail E. Hunt, Nicole J. Horwood, Jonathan T. Beech, Louise A. Hayes, A Denys, Marc Feldmann, Fionula M. Brennan, Brian M. J. Foxwell,

Melanoma and MAPK Pathways

Abstract TNF-α is a key factor in a variety of inflammatory diseases. This study examines the role of p38 MAPK in the regulation of TNF-α in primary human cells relevant to inflammation, e.g., macrophages and rheumatoid synovial cells. Using a dominant negative variant (D168A) of p38 MAPK and a kinase inhibitor, SB203580, we confirm in primary human macrophages that p38 MAPK regulates TNF-α production using a posttranscriptional mechanism requiring the 3′ untranslated region of the gene. However, in LPS-activated primary human macrophages we also detect a second previously unidentified mechanism, the p38 MAPK modulation of TNF-α transcription. This is mediated through p38 MAPK regulation of NF-κB. Interestingly this mechanism was not observed in rheumatoid synovial cells. Importantly however, the dominant negative mutant of p38 MAPK, but not SB203580 was effective at inhibiting spontaneous TNF-α production in these ex vivo rheumatoid synovial cell cultures. These data indicate there are potential major differences in the role of p38 MAPK in inflammatory signaling that have a bearing on the use of this kinase as a target for therapy. These results indicate despite disappointing results with p38 MAPK inhibitors in the clinic, this kinase is a valid target in rheumatoid disease.