PT  - JOURNAL ARTICLE
AU  - Ching-Chow Chen
AU  - Jia-Kae Wang
TI  - p38 but Not p44/42 Mitogen-Activated Protein Kinase Is Required for Nitric Oxide Synthase Induction Mediated by Lipopolysaccharide in RAW 264.7 Macrophages
DP  - 1999 Mar 01
TA  - Molecular Pharmacology
PG  - 481--488
VI  - 55
IP  - 3
4099  - http://molpharm.aspetjournals.org/content/55/3/481.short
4100  - http://molpharm.aspetjournals.org/content/55/3/481.full
SO  - Mol Pharmacol1999 Mar 01; 55
AB  - Protein kinase C (PKC)-α, -βI, and -δ are known to be involved in the lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW 264.7 macrophages. The role of mitogen-activated protein kinases (MAPK) p44/42 and p38 in the LPS effect was studied further. LPS-mediated NO release and the inducible form of NO synthase expression were inhibited by the p38 inhibitor, SB 203580, but not by the MAPK kinase inhibitor, PD 98059. Ten-minute treatment of cells with LPS resulted in the activation of p44/42 MAPK, p38, and c-Jun NH2-terminal kinase. Marked or slight activation, respectively, of p44/42 MAPK or p38 was also seen after 10-min treatment with 12-O-tetradecanoylphorbol-13-acetate, but c-Jun NH2-terminal kinase activation did not occur. Tyrosine kinase inhibitor, genestein, attenuated the LPS-induced activation of both p44/42 MAPK and p38, whereas the PKC inhibitors, Ro 31-8220 and calphostin C, or long-term treatment with 12-O-tetradecanoylphorbol-13-acetate resulted in inhibition of p44/42 MAPK activation, but had only a slight effect on p38 activation, indicating that LPS-mediated PKC activation resulted in the activation of p44/42 MAPK. Nuclear factor-κB (NF-κB)-specific DNA-protein-binding activity in the nuclear extracts was enhanced by 10-min, 1-h, or 24-h treatment with LPS. Analysis of the proteins involved in NF-κB binding showed translocation of p65 from the cytosol to the nucleus after 10-min treatment with LPS. The onset of NF-κB activation correlated with the cytosolic degradation of both inhibitory proteins of NF-κB, IκB-α and IκB-β. IκB-α was resynthesized rapidly after loss (1-h LPS treatment), whereas IκB-β levels were not restored until after 24-h treatment. SB 203580 but not PD 98059 inhibited the LPS-induced stimulation of NF-κB DNA-protein binding. Thus, activation of p38 but not p44/42 MAPK by LPS resulted in the stimulation of NF-κB-specific DNA-protein binding and the subsequent expression of inducible form of NO synthase and NO release in RAW 264.7 macrophages. The American Society for Pharmacology and Experimental Therapeutics