title: Piceatannol upregulates endothelial heme oxygenase-1 expression via novel protein kinase C and tyrosine kinase pathways.
abstract: Piceatannol is an anti-inflammatory and anti-proliferative plant-derived stilbene. Heme oxygenase-1 (HO-1) is a cytoprotective enzyme to activate by various phytochemicals. In this study, we examined the ability of piceatannol to upregulate HO-1 expression in endothelial cells. We found piceatannol at micromolar (10-50 microM) concentrations dramatically increased HO-1 protein levels in a time-dependent manner. Piceatannol was similarly potent in the induction of HO-1 as hemin, arsenate, and 15d-PGJ2, and was more potent than some other phytochemicals including curcumin, EGCG, baicalein, and quercetin. In contrast, the similar chemical structure compounds, trans-stilbene, stilbene oxide, and resveratrol had no HO-1-inducing effects, suggesting a critical role for the hydroxyl groups in HO-1 induction. No cytotoxicity and superoxide production was observed after 10-50 microM piceatannol treatments. Piceatannol-mediated HO-1 induction was abrogated in the presence of N-acetylcysteine and glutathione, but not by other antioxidants. Induction of HO-1 by piceatannol was further enhanced by using buthionine sulfoximine. In addition, we determined that tyrosine kinase was involved in the induction of HO-1 by using tyrosine kinase inhibitors, herbimycin A, erbstatin, and genistein; in contrast, no significant changes in the pretreatment of PI3 kinase or MAP kinase inhibitors was determined. HO-1 induction was blocked by the protein kinase C inhibitors calphostin C, rottlerin, and long PMA pretreatment, whereas conventional PKC inhibitors, Go6976, and Ca2+ chelator BAPTA/AM, had no effect. Elevated HO-1 protein levels were associated with the inhibition of tumor necrosis factor-alpha (TNFalpha)-induced intercellular adhesion molecule-1 (ICAM-1) expression. Treating ECs with zinc protoporphyrin, an HO-1 inhibito blocked the anti-inflammatory effect of piceatannol. In summary, this study identified piceatannol as a novel phytochemical inducer of HO-1 expression and identified the mechanisms involved in this process.
authors.affiliation: Department of Applied Microbiology, National Chiayi University, No. 300, Shiuefu Road, Chiayi, Taiwan. bswung@mail.ncyu.edu.tw
authors.forename: Being-Sun
authors.initials: BS
authors.lastname: Wung
authors.forename: Ming-Chun
authors.initials: MC
authors.lastname: Hsu
authors.forename: Chun-Ching
authors.initials: CC
authors.lastname: Wu
authors.forename: Chia-Wen
authors.initials: CW
authors.lastname: Hsieh
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002417:Cattle; D002470:Cell Survival; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000187:drug effects / Q000201:enzymology*; D004790:Enzyme Induction / Q000187:drug effects; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D051547:Heme Oxygenase-1 / Q000096:biosynthesis*; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis; D008163:Luminescent Measurements; D011493:Protein Kinase C / Q000502:physiology*; D011505:Protein-Tyrosine Kinases / Q000502:physiology*; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013267:Stilbenes / Q000494:pharmacology*; D013481:Superoxides / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D012333:RNA, Messenger; D013267:Stilbenes; D014409:Tumor Necrosis Factor-alpha; D013481:Superoxides; D018799:Intercellular Adhesion Molecule-1; C041525:3,3',4,5'-tetrahydroxystilbene; D051547:Heme Oxygenase-1; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C