title: Effects of protein kinase C activation and inhibition on endothelin-1 release from human aortic and pulmonary artery endothelial cells: comparison with effects on bovine endothelin-1 and human prostaglandin I2 release.
abstract: Protein kinase C (PKC) has been implicated in the regulation of endothelin-1 production by bovine and porcine endothelial cells. The role of PKC in the synthesis and release of endothelin-1 has not been demonstrated previously in human arterial endothelial cells. The effects of activators and an inhibitor of PKC on endothelin-1 release from cultured human arterial endothelial cells have now been examined. Endothelial monolayers were incubated with the PKC activators phorbol 12-myristate 13-acetate (PMA) or 1-oleoyl 2-acetyl glycerol (OAG) for 30 min to 8 h and the amount of endothelin-1 released into the medium was determined. PMA (0.1 micromol/L) and OAG (0.1 mmol/L) stimulated endothelin-1 release, with maximal increases of 85% and 90%, respectively, apparent at 30 min in aortic endothelial cells, and of 81% and 75%, respectively, apparent at 1 h in pulmonary artery endothelial cells. Endothelin-1 release had returned to control values by 4 h and was approximately one-third to one-half of control values after 8 h of continuous exposure of both cell types to PMA or OAG. Long-term exposure of both types of cells to the PKC inhibitor staurosporine (0.1 micromol/L) reduced both basal endothelin-1 release and the enhancement of release by PMA or OAG. The PKC agonists also stimulated endothelin-1 release by bovine aortic endothelial cells. The maximal effects of PMA and OAG in these cells were apparent at 4 h, at which time endothelin-1 release was increased by 154% and 125%, respectively; after 4 h, endothelin-1 release had decreased, but was still 132% and 120%, respectively, of the control value at 8 h. The PKC activators markedly stimulated prostaglandin I2 (PGI2) release by human pulmonary artery endothelial cells. The enhancement of PGI2 release continued for up to 8 h, at which time 109-fold and threefold increases in PGI2 release were apparent with PMA and OAG, respectively. Therefore, activation of PKC results in a rapid increase in endothelin-1 release by human arterial endothelial cells. The subsequent decrease in endothelin-1 release in the presence of PMA or OAG is presumably attributable to activator-induced downregulation of PKC, which was apparent earlier in human than in nonhuman endothelial cells. The downregulation of endothelin-1 release also occurred much earlier than that of PGI2 release in human pulmonary artery endothelial cells.
authors.affiliation: Department of Geriatric Research, National Institute for Longevity Sciences, and Division of Cardiology, National Chubu Hospital, Obu, Aichi, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Yamada
authors.forename: M
authors.initials: M
authors.lastname: Yokota
mesh_terms: D000818:Animals; D001011:Aorta / Q000166:cytology / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D004075:Diglycerides / Q000494:pharmacology; D019332:Endothelin-1 / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D011464:Epoprostenol / Q000378:metabolism*; D006801:Humans; D011493:Protein Kinase C / Q000378:metabolism*; D011651:Pulmonary Artery / Q000166:cytology / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D004075:Diglycerides; D019332:Endothelin-1; C038237:1-oleoyl-2-acetylglycerol; D011464:Epoprostenol; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate