Ohlstein E H, Storer B L, Butcher J A, Debouck C, Feuerstein G
Department of Pharmacology, SmithKline Beecham Research Laboratories, King of Prussia, Pa. 19406-0939.
Circ Res. 1991 Sep;69(3):832-41. doi: 10.1161/01.res.69.3.832.
Modulation of the biosynthesis of the vasoconstrictor peptide endothelin was studied in cultured endothelial cells. Immunoreactive endothelin (irET) levels were significantly elevated in conditioned medium from bovine pulmonary artery endothelial (BPAE) or human umbilical vein endothelial cells when coincubated with washed human platelets. Platelets (approximately 200,000 cells/microliters) enhanced irET levels approximately 250% over basal levels. Stimulation of irET levels in BPAE cell-conditioned medium by platelets was time and platelet number dependent. Platelets, as well as thrombin and transforming growth factor-beta 1, stimulated the expression of preproendothelin-1 mRNA in a time-dependent manner. Coincubation of low doses of thrombin (0.1 unit/ml) and subthreshold concentrations of platelets with BPAE cells resulted in a further enhancement of irET levels in conditioned medium. Platelet-mediated stimulation of irET production was not significantly affected by indomethacin (1 microM) or the platelet-activating factor receptor antagonist WEB 2086 (1 microM); however, coincubation of endotoxin (100 ng/ml) with platelets and BPAE cells resulted in significantly higher levels of irET. Whether direct contact or adhesion between platelets and endothelial cells is necessary for stimulating irET release was studied by separating platelets from BPAE cells with a 0.4 microns permeable membrane. Under these conditions, platelets still produced significant elevations (approximately 190% over basal levels) in irET levels in BPAE cell-conditioned medium. In addition, platelet-free buffer from agonist-induced platelet aggregation also significantly enhanced irET production (200% over basal values). These data indicate that a platelet-derived regulatory factor can induce the biosynthesis of endothelin from cultured endothelial cells and also suggest that platelets might play a role in vasomotor regulation via a novel intercellular interaction with the endothelium.
在培养的内皮细胞中研究了血管收缩肽内皮素生物合成的调节。当与洗涤过的人血小板共同孵育时，来自牛肺动脉内皮（BPAE）或人脐静脉内皮细胞的条件培养基中免疫反应性内皮素（irET）水平显著升高。血小板（约200,000个细胞/微升）使irET水平比基础水平提高约250%。血小板对BPAE细胞条件培养基中irET水平的刺激具有时间和血小板数量依赖性。血小板以及凝血酶和转化生长因子-β1以时间依赖性方式刺激前内皮素-1 mRNA的表达。低剂量凝血酶（0.1单位/毫升）和亚阈值浓度的血小板与BPAE细胞共同孵育导致条件培养基中irET水平进一步升高。血小板介导的irET产生刺激不受吲哚美辛（1微摩尔）或血小板活化因子受体拮抗剂WEB 2086（1微摩尔）的显著影响；然而，内毒素（100纳克/毫升）与血小板和BPAE细胞共同孵育导致irET水平显著更高。通过用0.4微米可渗透膜将血小板与BPAE细胞分离，研究了血小板与内皮细胞之间直接接触或粘附对于刺激irET释放是否必要。在这些条件下，血小板仍使BPAE细胞条件培养基中的irET水平显著升高（比基础水平高约190%）。此外，激动剂诱导的血小板聚集产生的无血小板缓冲液也显著增强了irET的产生（比基础值高200%）。这些数据表明，一种血小板衍生的调节因子可诱导培养的内皮细胞合成内皮素，也表明血小板可能通过与内皮的新型细胞间相互作用在血管舒缩调节中发挥作用。
