title: Epigallocatechin-gallate stimulates NF-E2-related factor and heme oxygenase-1 via caveolin-1 displacement.
abstract: Flavonoids, such as the tea catechin epigallocatechin-gallate (EGCG), can protect against atherosclerosis by decreasing vascular endothelial cell inflammation. Heme oxygenase-1 (HO-1) is an enzyme that plays an important role in vascular physiology, and its induction may provide protection against atherosclerosis. Heme oxygenase-1 can be compartmentalized in caveolae in endothelial cells. Caveolae are plasma microdomains important in vesicular transport and the regulation of signaling pathways associated with the pathology of vascular diseases. We hypothesize that caveolae play a role in the uptake and transport of EGCG and mechanisms associated with the anti-inflammatory properties of this flavonoid. To test this hypothesis, we explored the effect of EGCG on the induction of NF-E2-related factor (Nrf2) and HO-1 in endothelial cells with or without functional caveolae. Treatment with EGCG activated Nrf2 and increased HO-1 expression and cellular production of bilirubin. In addition, EGCG rapidly accumulated in caveolae, which was associated with caveolin-1 displacement from the plasma membrane towards the cytosol. Similar to EGCG treatment, silencing of caveolin-1 by siRNA technique also resulted in up-regulation of Nrf2, HO-1 and bilirubin production. These data suggest that EGCG-induced caveolin-1 displacement may reduce endothelial inflammation.
authors: Molecular and Cell Nutrition Laboratory, College of Agriculture, KY 40536, USA.
authors: Yuanyuan
authors: Y
authors: Zheng
authors: Andrew
authors: A
authors: Morris
authors: Manjula
authors: M
authors: Sunkara
authors: Joseph
authors: J
authors: Layne
authors: Michal
authors: M
authors: Toborek
authors: Bernhard
authors: B
authors: Hennig
mesh_terms: D000818:Animals; D001663:Bilirubin / Q000378:metabolism; D002392:Catechin / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000494:pharmacology; D021941:Caveolae / Q000187:drug effects / Q000378:metabolism; D051242:Caveolin 1 / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects; D051547:Heme Oxygenase-1 / Q000378:metabolism*; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering; D013552:Swine
chemical_list: D051242:Caveolin 1; D051267:NF-E2-Related Factor 2; D034741:RNA, Small Interfering; D002392:Catechin; C045651:epigallocatechin gallate; D051547:Heme Oxygenase-1; D001663:Bilirubin