Inhibition of lipopolysaccharide-induced cyclooxygenase-2 transcription by 6-(methylsulfinyl) hexyl isothiocyanate, a chemopreventive compound from Wasabia japonica (Miq.) Matsumura, in mouse macrophages.
6-(Methylsulfinyl)hexyl isothiocyanate (6-MITC) is a chemopreventive compound occurring in Wasabi (Wasabia japonica (Miq.) Matsumura), which is a very popular pungent spice in Japan. We investigated the effects of 6-MITC on the expression of cyclooxygenase-2 (COX-2) in lipopolysaccharide (LPS)-activated murine macrophage RAW264 cells. Treatment with 6-MITC suppressed LPS-mediated induction of COX-2 protein in a dose-dependent manner. Transfections with various COX-2 promoter reporter constructs revealed that the inhibitory effects of 6-MITC on COX-2 gene expression were directed by the core promoter elements including nuclear factor kappaB (NF-kappaB), CCAAT/enhancer-binding protein (C/EBP) and cyclic AMP-response element (CRE) sites. Western blotting analysis showed that 6-MITC inhibited LPS-induced activation of MAPK (ERK, p38 kinase and JNK) and transcriptional factors (CREB, c-Jun and C/EBPdelta) binding the core elements of COX-2 promoter, substantiating the involvement of these signal transduction pathways in the regulation of COX-2 expression by 6-MITC. Moreover, Western blotting experiments with MAPK-specific inhibitors (U0126 for MEK1/2, SB203580 for p38 kinase and SP600125 for JNK) demonstrated that 6-MITC suppressed LPS-induced COX-2 expression by blocking the activation of JNK-mediated AP-1 and ERK/p38 kinase-mediated CREB or C/EBPdelta. Finally, the structure-activity study revealed that the inhibitory potency of methylsulfinyl isothiocyanates (MITCs) depended on the methyl chain length. These findings demonstrate for the first time that 6-MITC is an effective agent to attenuate COX-2 production, and enhance our understanding of the anti-inflammation properties of 6-MITC.
Uto
Takuhiro
T
Department of Biochemical Science and Technology, Faculty of Agriculture, Kagoshima University, Korimoto 1-21-24, Kagoshima City 890-0065, Japan.
Fujii
Makoto
M
Hou
De-Xing
DX
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D051743:CCAAT-Enhancer-Binding Protein-delta / Q000378:metabolism; D002460:Cell Line; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000235:genetics*; D015232:Dinoprostone / Q000378:metabolism; D017879:Isothiocyanates / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D020935:MAP Kinase Signaling System; D008264:Macrophages / Q000187:drug effects / Q000201:enzymology; D051379:Mice; D010766:Phosphorylation; D013329:Structure-Activity Relationship; D014158:Transcription, Genetic / Q000187:drug effects
C505386:6-(Methylsulfinyl)hexyl isothiocyanate; D000893:Anti-Inflammatory Agents; D017362:Cyclic AMP Response Element-Binding Protein; D017879:Isothiocyanates; D008070:Lipopolysaccharides; D051743:CCAAT-Enhancer-Binding Protein-delta; D051546:Cyclooxygenase 2; D015232:Dinoprostone