title: Epigallocatechin-3-O-gallate, a green tea polyphenol, induces expression of pim-1 kinase via PPARγ in human vascular endothelial cells.
abstract: Pim-1 is a serine/threonine kinase and involved in cell survival and proliferation. Recently, it has been shown that pim-1 signaling pathway plays an important role in cardiovascular protection and differentiation. In this study, we sought to explore the expression of pim-1 in human vascular endothelial cells (ECs) and its regulation by epigallocatechin-3-O-gallate (EGCG), a green tea polyphenol which has anti-oxidant, anti-inflammatory and vascular protective effects. By using quantitative reverse transcriptase PCR (qRT-PCR) and Western blotting, we showed that EGCG dose-dependently increased the expression of pim-1 in cultured umbilical vein endothelial cells. Next, we showed that EGCG activated a luciferase reporter driven by peroxisome proliferators-activated receptor (PPAR)-responsive elements. The induced expression of pim-1 was inhibited in ECs pretreated with GW9662, a specific antagonist of PPARγ. In addition, pim-1 was also up-regulated in endothelial cells treated with rosiglitazone, a specific agonist for PPARγ, or those infected with the adenovirus expressing a constitutively active PPARγ. Collectively, our results provided new evidence that pim-1 can be up-regulated by EGCG via a PPARγ-mediated mechanism and may mediate its vascular protective effects.
authors.affiliation: Institute of Cardiovascular Science, Peking University Health Science Center, 38 Xueyuan Rd., Beijing, 100191, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.forename: Beilei
authors.initials: B
authors.lastname: Zhao
authors.forename: Guangmei
authors.initials: G
authors.lastname: Mao
authors.forename: Xi
authors.initials: X
authors.lastname: Fang
authors.forename: Yahan
authors.initials: Y
authors.lastname: Liu
authors.forename: Yu
authors.initials: Y
authors.lastname: Huang
authors.forename: Nanping
authors.initials: N
authors.lastname: Wang
mesh_terms: D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects / Q000201:enzymology*; D006801:Humans; D047495:PPAR gamma / Q000502:physiology*; D059808:Polyphenols / Q000494:pharmacology*; D051573:Proto-Oncogene Proteins c-pim-1 / Q000096:biosynthesis*; D013662:Tea
chemical_list: D047495:PPAR gamma; D059808:Polyphenols; D013662:Tea; D002392:Catechin; C045651:epigallocatechin gallate; D051573:Proto-Oncogene Proteins c-pim-1