Saito S, Hirata Y, Imai T, Marumo F
Second Department of Internal Medicine, Tokyo Medical and Dental University, Japan.
J Cardiovasc Pharmacol. 1995;26 Suppl 3:S84-7.
We studied whether endothelin (ET)-1 regulates its own transcription in cultured rat aortic endothelial cells (ECs) in an autocrine manner and attempted to elucidate its cellular and molecular mechanism. By Northern blot analysis using rat preproET-1 cDNA as a probe, ET-1 increased steady-state levels of preproET-1 mRNA as early as 30 min, which persisted during 4 h incubation. ET-1 also increased steady-state c-fos mRNA levels, which returned to an undetectable level by 2 h. ET-1 dose-dependently upregulated preproET-1 mRNA expression. The effect was inhibited by nonselective ETA/ETB receptor antagonist but not a selective ETA receptor antagonist. The ET-1-induced preproET-1 mRNA expression was suppressed by a protein kinase C (PKC) inhibitor and by pretreatment with phorbol ester, which depeleted engdogenous PKC. The approximate half-life of preproET-1 mRNA stimulated by ET-1 (approximately 20 min) was similar to that stimulated by phorbol ester. Our data demonstrate that ET-1 upregulates its own gene expression through ETB receptor-mediated PKC activation, suggesting a possible autocrine positive feedback system in vascular endothelium.
我们研究了内皮素（ET）-1是否以自分泌方式调节其在培养的大鼠主动脉内皮细胞（ECs）中的自身转录，并试图阐明其细胞和分子机制。通过使用大鼠前体ET-1 cDNA作为探针进行Northern印迹分析，ET-1早在30分钟时就增加了前体ET-1 mRNA的稳态水平，在4小时的孵育过程中持续存在。ET-1还增加了稳态c-fos mRNA水平，到2小时时恢复到不可检测的水平。ET-1剂量依赖性地上调前体ET-1 mRNA表达。该作用被非选择性ETA/ETB受体拮抗剂抑制，但不被选择性ETA受体拮抗剂抑制。ET-1诱导的前体ET-1 mRNA表达被蛋白激酶C（PKC）抑制剂和用佛波酯预处理所抑制，佛波酯可耗尽内源性PKC。ET-1刺激的前体ET-1 mRNA的近似半衰期（约20分钟）与佛波酯刺激的相似。我们的数据表明，ET-1通过ETB受体介导的PKC激活上调其自身基因表达，提示血管内皮中可能存在自分泌正反馈系统。
