title: Isothiocyanates from Wasabia japonica activate transient receptor potential ankyrin 1 channel.
abstract: 6-(Methylsulfinyl)hexyl isothiocyanate (6-MSITC) and 6-(methylthio)hexyl isothiocyanate (6-MTITC) have low pungency and are responsible for the fresh flavor of wasabi (Wasabia japonica [Miq] Matsumura). In this study, we found that these two isothiocyanates activate transient receptor potential ankyrin 1 (TRPA1), and 6-MSITC activates transient receptor potential vanilloid 1 (TRPV1), but not other transient receptor potential channels expressed in sensory neurons. Both 6-MSITC and 6-MTITCinduced intracellular Ca(2+) increases in human embryonic kidney-derived 293 cells expressing mouse TRPA1 (mTRPA1) as measured by Ca(2+) imaging. In whole-cell patch-clamp recordings, 6-MSITC and 6-MTITC dose-dependently activated both mTRPA1 (EC(50) = 147±26 µM for 6-MSITC and 30±3 µM for 6-MTITC) and human TRPA1 (hTRPA1; EC(50) = 39±4 µM for 6-MSITC and 34±3 µM for 6-MTITC). In addition, TRPA1 N-terminal cysteines, which are reported to be important for channel activation by electrophilic ligands, were involved in 6-MSITC- and 6-MTITC-evoked TRPA1 activation. These isothiocyanates also activated endogenous TRPA1 expressed in mouse dorsal root ganglion neurons and intraplantar injection of 10-30 mM 6-MSITC-evoked pain-related behaviors in mice. These results indicate the following: 1) 6-MSITC and 6-MTITC activate both mTRPA1 and hTRPA1; 2) 6-MSITC activates mTRPV1; and 3) the pharmacological functions of these isothiocyanates could be derived from TRPA1 activation.
authors.affiliation: Division of Cell Signaling, Okazaki Institute for Integrative Bioscience (National Institute for Physiological Sciences), National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan. kuchida@nips.ac.jp
authors.forename: Kunitoshi
authors.initials: K
authors.lastname: Uchida
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Miura
authors.forename: Masashi
authors.initials: M
authors.lastname: Nagai
authors.forename: Makoto
authors.initials: M
authors.lastname: Tominaga
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000378:metabolism; D005727:Ganglia, Spinal / Q000187:drug effects / Q000502:physiology; D057809:HEK293 Cells; D006801:Humans; D017879:Isothiocyanates / Q000737:chemistry / Q000494:pharmacology*; D051379:Mice; D018345:Mice, Knockout; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000378:metabolism; D018408:Patch-Clamp Techniques; D011984:Sensory Receptor Cells / Q000187:drug effects* / Q000502:physiology; D013440:Sulfides / Q000737:chemistry / Q000494:pharmacology*; D000074025:TRPA1 Cation Channel; D050051:Transient Receptor Potential Channels / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D031228:Wasabia / Q000378:metabolism*
chemical_list: C505386:6-(Methylsulfinyl)hexyl isothiocyanate; D015220:Calcium Channels; D017879:Isothiocyanates; D009419:Nerve Tissue Proteins; D013440:Sulfides; D000074025:TRPA1 Cation Channel; C473350:TRPA1 protein, human; D050051:Transient Receptor Potential Channels; C475685:Trpa1 protein, mouse; C410683:6-methylthiohexyl isothiocyanate; D002118:Calcium