Neve E P, Boyer C S, Moldéus P
Division of Toxicology, Karolinska Institute, Stockholm, Sweden.
Biochem Pharmacol. 1995 Jan 6;49(1):57-63. doi: 10.1016/0006-2952(94)00308-9.
Treatment of bovine endothelial cells with the alkylator N-ethyl maleimide results in arachidonic acid mobilization. N-ethyl maleimide-stimulated arachidonic acid release was dose and time dependent and maximum release was achieved after 10-15 min with 50 microM N-ethyl maleimide, N-ethyl maleimide-stimulated arachidonic acid release could be prevented by pretreating the cells with the phospholipase A2 inhibitor quinacrine. Based on the finding that N-ethyl maleimide was not able to release oleic acid from oleic acid-preloaded cells, it was clear that the effect of N-ethyl maleimide was limited to an arachidonic acid-specific phospholipase. The effect of N-ethyl maleimide does not appear to be dependent on calcium, as shown by the observation that N-ethyl maleimide was not able to increase intracellular calcium concentration in FURA2-loaded cells. Pretreatment of the cells with staurosporine totally inhibited N-ethyl maleimide-stimulated arachidonic acid liberation. The tyrosine kinase inhibitor genistein was also able to significantly inhibit arachidonic acid release. It is concluded from the results obtained in this study that N-ethyl maleimide stimulates arachidonic acid release by stimulating the activity of a specific, signal-responsive phospholipase A2. Furthermore this activation is not mediated by intracellular calcium fluxes but by a stimulation of intracellular kinase activity which eventually leads to the activation of this signal-responsive phospholipase A2.
用烷基化剂N - 乙基马来酰亚胺处理牛内皮细胞会导致花生四烯酸的动员。N - 乙基马来酰亚胺刺激的花生四烯酸释放呈剂量和时间依赖性，在使用50 microM N - 乙基马来酰亚胺处理10 - 15分钟后达到最大释放量。用磷脂酶A2抑制剂奎纳克林预处理细胞可防止N - 乙基马来酰亚胺刺激的花生四烯酸释放。基于N - 乙基马来酰亚胺不能从预先加载油酸的细胞中释放油酸这一发现，很明显N - 乙基马来酰亚胺的作用仅限于花生四烯酸特异性磷脂酶。如观察到N - 乙基马来酰亚胺不能增加加载FURA2的细胞内钙浓度所示，N - 乙基马来酰亚胺的作用似乎不依赖于钙。用星形孢菌素预处理细胞完全抑制了N - 乙基马来酰亚胺刺激的花生四烯酸释放。酪氨酸激酶抑制剂染料木黄酮也能够显著抑制花生四烯酸释放。从本研究获得的结果得出结论，N - 乙基马来酰亚胺通过刺激一种特定的、信号响应性磷脂酶A2的活性来刺激花生四烯酸释放。此外，这种激活不是由细胞内钙通量介导的，而是由细胞内激酶活性的刺激介导的，最终导致这种信号响应性磷脂酶A2的激活。
