title: Oxidative stress-induced posttranslational modification of TRPV1 expressed in esophageal epithelial cells.
abstract: Human esophageal epithelium is continuously exposed to physical stimuli or to gastric acid that sometimes causes inflammation of the mucosa. Transient receptor potential vanilloid 1 (TRPV1) is a nociceptive, Ca(2+)-selective ion channel activated by capsaicin, heat, and protons. It has been reported that activation of TRPV1 expressed in esophageal mucosa is involved in gastroesophageal reflux disease (GERD) or in nonerosive GERD symptoms. In this study, we examined the expression and function of TRPV1 in the human esophageal epithelial cell line Het1A, focusing in particular on the role of oxidative stress. Interleukin-8 (IL-8) secreted by Het1A cells upon stimulation by capsaicin or acid with/without 4-hydroxy-2-nonenal (HNE) was measured by ELISA. Following capsaicin stimulation, the intracellular production of reactive oxygen species (ROS) was determined using a redox-sensitive fluorogenic probe, and ROS- and HNE-modified proteins were determined by Western blotting using biotinylated cysteine and anti-HNE antibody, respectively. HNE modification of TRPV1 proteins was further investigated by immunoprecipitation after treatment with synthetic HNE. Capsaicin and acid induced IL-8 production in Het1A cells, and this production was diminished by antagonists of TRPV1. Capsaicin also significantly increased the production of intracellular ROS and ROS- or HNE-modified proteins in Het1A cells. Moreover, IL-8 production in capsaicin-stimulated Het1A cells was enhanced by synthetic HNE treatment. Immunoprecipitation studies revealed that TRPV1 was modified by HNE in synthetic HNE-stimulated Het1A cells. We concluded that TRPV1 functions in chemokine production in esophageal epithelial cells, and this function may be regulated by ROS via posttranslational modification of TRPV1.
authors.affiliation: Department of Inflammation and Immunology, Kyoto Prefectural University of Medicine, Japan.
authors.forename: Etsuko
authors.initials: E
authors.lastname: Kishimoto
authors.forename: Yuji
authors.initials: Y
authors.lastname: Naito
authors.forename: Osamu
authors.initials: O
authors.lastname: Handa
authors.forename: Hitomi
authors.initials: H
authors.lastname: Okada
authors.forename: Katsura
authors.initials: K
authors.lastname: Mizushima
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Hirai
authors.forename: Nami
authors.initials: N
authors.lastname: Nakabe
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Uchiyama
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ishikawa
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Takagi
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Yagi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Kokura
authors.forename: Norimasa
authors.initials: N
authors.lastname: Yoshida
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Yoshikawa
mesh_terms: D000143:Acids / Q000494:pharmacology; D000447:Aldehydes / Q000494:pharmacology; D000818:Animals; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism*; D002211:Capsaicin / Q000494:pharmacology; D002460:Cell Line; D004847:Epithelial Cells / Q000378:metabolism*; D004947:Esophagus / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D016209:Interleukin-8 / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D009092:Mucous Membrane / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism*; D050916:TRPV Cation Channels / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000143:Acids; D000447:Aldehydes; D015220:Calcium Channels; D016209:Interleukin-8; D017382:Reactive Oxygen Species; D050916:TRPV Cation Channels; C494482:TRPV1 protein, human; C027576:4-hydroxy-2-nonenal; D002211:Capsaicin