Abstract
TNF-alpha is a key factor in a variety of inflammatory diseases. This study examines the role of p38 MAPK in the regulation of TNF-alpha 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-alpha 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-alpha transcription. This is mediated through p38 MAPK regulation of NF-kappaB. 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-alpha 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.
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
3' Untranslated Regions / physiology
-
Adenoviridae / genetics
-
Alanine / genetics
-
Arthritis, Rheumatoid / drug therapy*
-
Arthritis, Rheumatoid / enzymology
-
Arthritis, Rheumatoid / immunology
-
Arthritis, Rheumatoid / metabolism
-
Aspartic Acid / genetics
-
Cell Line
-
Cells, Cultured
-
Fibroblasts / enzymology
-
Fibroblasts / immunology
-
Fibroblasts / metabolism
-
Genes, Reporter / physiology
-
Genetic Vectors
-
Humans
-
Lipopolysaccharides / antagonists & inhibitors
-
Lipopolysaccharides / pharmacology
-
Macrophages / enzymology
-
Macrophages / immunology
-
Macrophages / metabolism
-
Mutagenesis, Site-Directed
-
NF-kappa B / antagonists & inhibitors
-
NF-kappa B / metabolism
-
NF-kappa B / physiology*
-
Promoter Regions, Genetic / physiology
-
Protein Kinase Inhibitors / therapeutic use
-
RNA, Messenger / antagonists & inhibitors
-
RNA, Messenger / biosynthesis
-
Synovial Membrane / enzymology
-
Synovial Membrane / immunology
-
Synovial Membrane / metabolism
-
Tumor Necrosis Factor-alpha / antagonists & inhibitors
-
Tumor Necrosis Factor-alpha / biosynthesis*
-
Tumor Necrosis Factor-alpha / genetics
-
Tumor Necrosis Factor-alpha / metabolism
-
p38 Mitogen-Activated Protein Kinases / antagonists & inhibitors
-
p38 Mitogen-Activated Protein Kinases / genetics
-
p38 Mitogen-Activated Protein Kinases / physiology*
Substances
-
3' Untranslated Regions
-
Lipopolysaccharides
-
NF-kappa B
-
Protein Kinase Inhibitors
-
RNA, Messenger
-
Tumor Necrosis Factor-alpha
-
Aspartic Acid
-
p38 Mitogen-Activated Protein Kinases
-
Alanine