Suzuki A, Shinoda J, Oiso Y, Kozawa O
First Department of Internal Medicine, Nagoya University School of Medicine, Japan.
Atherosclerosis. 1996 Mar;121(1):119-27. doi: 10.1016/0021-9150(95)05708-0.
In the present study, we examined the effect of angiotensin II (Ang II) on phosphatidylcholine-hydrolyzing phospholipase D activity in subcultured rat aortic smooth muscle cells (SMC). Ang II dose-dependently stimulated the formation of choline and inositol phosphates. The effect of Ang II on the formation of inositol phosphates (EC50 was 0.249 +/- 0.091 nM) was more potent than that on the formation of choline (EC50 was 2.39 +/- 1.29 nM). A combination of Ang II and 12-O-tetradecanoylphorbol-13-acetate (TPA), an activator of protein kinase C, additively stimulated the formation of choline. Staurosporine, an inhibitor of protein kinases, inhibited the TPA-induced formation of choline, but had little effect on the Ang II-induced choline formation. Ang II stimulated Ca2+ influx from extracellular space time- and dose-dependently. The depletion of extracellular Ca2+ by (ethylenebis(oxyethylenenitrilo)) tetraacetic acid (EGTA) significantly reduced the Ang II-induced formation of choline. Genistein and tyrphostin, protein tyrosine kinase inhibitors, significantly suppressed the Ang II-induced Ca2+ influx. Genistein and tyrphostin also suppressed the Ang II-induced formation of choline. These results suggest that Ang II stimulates phosphatidylcholine-hydrolyzing phospholipase D due to Ca2+ influx from the extracellular space in rat aortic SMC, and that protein tyrosine kinase is involved in the Ang II-induced Ca2+ influx, resulting in the promotion of phosphatidylcholine hydrolysis.
在本研究中，我们检测了血管紧张素II（Ang II）对传代培养的大鼠主动脉平滑肌细胞（SMC）中磷脂酰胆碱水解磷脂酶D活性的影响。Ang II以剂量依赖的方式刺激胆碱和肌醇磷酸的形成。Ang II对肌醇磷酸形成的作用（半数有效浓度[EC50]为0.249±0.091 nM）比其对胆碱形成的作用（EC50为2.39±1.29 nM）更强。Ang II与蛋白激酶C激活剂12-O-十四烷酰佛波醇-13-乙酸酯（TPA）联合使用时，对胆碱的形成有累加刺激作用。蛋白激酶抑制剂星形孢菌素可抑制TPA诱导的胆碱形成，但对Ang II诱导的胆碱形成影响较小。Ang II能时间和剂量依赖性地刺激细胞外Ca2+内流。用（亚乙基双（氧亚乙基腈））四乙酸（EGTA）耗尽细胞外Ca2+可显著降低Ang II诱导的胆碱形成。蛋白酪氨酸激酶抑制剂染料木黄酮和 tyrphostin可显著抑制Ang II诱导的Ca2+内流。染料木黄酮和tyrphostin也可抑制Ang II诱导的胆碱形成。这些结果表明，在大鼠主动脉平滑肌细胞中，Ang II通过细胞外Ca2+内流刺激磷脂酰胆碱水解磷脂酶D，并且蛋白酪氨酸激酶参与了Ang II诱导的Ca2+内流过程，从而促进了磷脂酰胆碱的水解。
