title: Cholesterol-3-beta, 5-alpha, 6-beta-triol induced PI(3)K-Akt-eNOS-dependent cyclooxygenase-2 expression in endothelial cells.
abstract: Oxidized cholesterols belong to a subgroup of oxLDLs which play major roles in atherosclerosis. In order to investigate the contribution of oxysterols from oxLDLs in atherosclerosis, cholesterol-3-beta, 5-alpha, 6-beta-triol (alpha-Triol) was studied in human umbilical vein endothelial cells. We found that alpha-Triol concentration- and time-dependently enhanced COX-2 protein expression and mRNA production followed by PGE(2) generation in human umbilical vein endothelial cells. In addition, alpha-Triol upregulated peNOS(1177) protein phosphorylation and concentration-dependently increased nitric oxide production. eNOS(1177) phosphorylation was abrogated by the PI3K inhibitor, LY294002. In studying the mechanisms involved in alpha-Triol-induced COX-2/PGE(2) production, inhibitors of NOS, PI3K, p38, and NF-kappaB, effectively attenuated COX-2 protein induction and mRNA expression, suggesting that the PI(3)K-Akt-eNOS pathway, p38MAPK, and NF-kappaB are involved in alpha-Triol-induced COX-2 expression, and following increases in p38 and Akt phosphorylation, the concentration-dependent inhibition of COX-2 protein expression by L-NAME further suggested their involvement at the translation level. We concluded that alpha-Triol increases COX-2 mRNA and protein expression via coordination with the PI(3)K-Akt-eNOS pathway and NF-kappaB. Moreover, COX-2 gene expression might be regulated by activated p38 MAPK in another unknown regulation pathway. Our findings also suggested that alpha-Triol might contribute to the effect of induced atherosclerosis in humans through COX-2 production in endothelial cells.
authors.affiliation: Institute of Toxicology, College of Medicine, National Taiwan University, Jen-Ai Road, Section 1, Taipei 100, Taiwan, ROC.
authors.forename: Po-Lin
authors.initials: PL
authors.lastname: Liao
authors.forename: Yu-Wen
authors.initials: YW
authors.lastname: Cheng
authors.forename: Ching-Hao
authors.initials: CH
authors.lastname: Li
authors.forename: Yi-Ling
authors.initials: YL
authors.lastname: Lo
authors.forename: Jaw-Jou
authors.initials: JJ
authors.lastname: Kang
mesh_terms: D015153:Blotting, Western; D002470:Cell Survival / Q000187:drug effects; D002784:Cholesterol / Q000031:analogs & derivatives* / Q000494:pharmacology; D002867:Chromones / Q000494:pharmacology; D051546:Cyclooxygenase 2 / Q000096:biosynthesis*; D015232:Dinoprostone / Q000032:analysis / Q000096:biosynthesis; D042783:Endothelial Cells / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D009025:Morpholines / Q000494:pharmacology; D016328:NF-kappa B / Q000096:biosynthesis; D009569:Nitric Oxide / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism*; D051058:Oncogene Protein v-akt / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D012313:RNA / Q000096:biosynthesis / Q000302:isolation & purification; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014471:Umbilical Veins / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D002784:Cholesterol; D002867:Chromones; D051546:Cyclooxygenase 2; D015232:Dinoprostone; D004791:Enzyme Inhibitors; D009025:Morpholines; D016328:NF-kappa B; D009569:Nitric Oxide; D052250:Nitric Oxide Synthase Type III; D051058:Oncogene Protein v-akt; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D012313:RNA; D048051:p38 Mitogen-Activated Protein Kinases; C543846:cholesterol-3-beta,5-alpha, 6-beta-triol; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one