title: 6-(Methylsulfinyl)hexyl isothiocyanate suppresses inducible nitric oxide synthase expression through the inhibition of Janus kinase 2-mediated JNK pathway in lipopolysaccharide-activated murine macrophages.
abstract: 6-(Methylsulfinyl)hexyl isothiocyanate (6-MITC) is an active ingredient of Wasabi (Wasabia japonica (Miq.) Matsumura), which is a very popular pungent spice in Japan. To clarify the cellular signaling mechanism underlying the anti-inflammatory action of 6-MITC, we investigated the effects of 6-MITC on the expression of inducible nitric oxide synthase (iNOS) in lipopolysaccharide (LPS)-activated murine macrophage RAW264 cells. 6-MITC showed a dose-dependent inhibition of LPS-induced nitric oxide (NO), iNOS mRNA and protein. LPS caused the c-Jun phosphorylation (a major component of AP-1) and IkappaB-alpha degradation. 6-MITC suppressed LPS-induced c-Jun phosphorylation, but did not inhibit IkappaB-alpha degradation. Cellular signaling analysis using MAPK-(U0126 for MEK1/2, SB203580 for p38 kinase and SP600125 for JNK) and Jak2-specific (AG490) inhibitors demonstrated that LPS stimulated iNOS expression via activating Jak2-mediated JNK, but not ERK and p38, pathway. 6-MITC suppressed iNOS expression through the inhibition of Jak2-mediated JNK signaling cascade with the attendant to AP-1 activation. In addition, the structure-activity study revealed that the inhibitory potency of methylsulfinyl isothiocyanates (MITCs) depended on the methyl chain length. These findings provide the molecular basis for the first time that 6-MITC is an effective agent to attenuate iNOS production.
authors.affiliation: Department of Biochemical Science and Technology, Faculty of Agriculture, Kagoshima University, Japan.
authors.forename: Takuhiro
authors.initials: T
authors.lastname: Uto
authors.forename: Makoto
authors.initials: M
authors.lastname: Fujii
authors.forename: De-Xing
authors.initials: DX
authors.lastname: Hou
mesh_terms: D000818:Animals; D001483:Base Sequence; D017931:DNA Primers; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D017879:Isothiocyanates / Q000494:pharmacology*; D053614:Janus Kinase 2; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008262:Macrophage Activation; D008264:Macrophages / Q000187:drug effects* / Q000201:enzymology; D051379:Mice; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics
chemical_list: C505386:6-(Methylsulfinyl)hexyl isothiocyanate; D017931:DNA Primers; D004791:Enzyme Inhibitors; D017879:Isothiocyanates; D008070:Lipopolysaccharides; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D011505:Protein-Tyrosine Kinases; C507926:Jak2 protein, mouse; D053614:Janus Kinase 2