Evidence against an early signalling role for ceramide in Fas-mediated apoptosis.
Evidence against an early signalling role for ceramide in Fas-mediated apoptosis.
复制标题
神经酰胺在 Fas 介导的细胞凋亡中发挥早期信号作用的证据。
DOI：
10.1042/bj3240029
复制
发表时间：
1997
期刊：
影响因子：
--
通讯作者：
D. Allan
中科院分区：
文献类型：
--
作者：
D. Sillence;D. Allan
我们研究了抗Fas抗体诱导的SKW 6.4细胞凋亡过程中神经酰胺水平的增加是否依赖于半胱天冬酶的激活。使用用[14C]乙酸盐预先标记至平衡的细胞，结果表明，与抗Fas孵育24小时后，神经酰胺的量大约增加了一倍，但神经酰胺变化的时间进程比抗Fas诱导的细胞死亡慢。当半胱天冬酶抑制剂 N-苄氧基羰基-Val-Ala-Asp-(O-甲基)氟甲烷 (zVAD.fmk) 与抗 Fas 一起添加时，观察到抗 Fas 对细胞死亡和神经酰胺产生的影响完全抑制，但 N-苄氧基羰基-Phe-Ala-氟甲烷（一种结构相似的组织蛋白酶 B 抑制剂）没有效果。用 Ca2+-离子载体 A23187 处理细胞也使神经酰胺水平加倍，但在这种情况下，效果在 2 小时内完成，没有被 zVAD.fmk 阻断，并且与核碎片的增加无关。这些结果表明，神经酰胺不是 Fas 介导的细胞凋亡的上游信使，而是可能是半胱天冬酶激活下游过程和胞质钙浓度增加的结果。
We have investigated whether the increases in ceramide levels that occur during apoptosis in SKW 6.4 cells induced by anti-Fas antibody depend on the activation of caspases. Using cells prelabelled to equilibrium with [14C]acetate, it was shown that the amount of ceramide approximately doubled after 24 h incubation with anti-Fas, but the time course of ceramide changes was slower than that of anti-Fas-induced cell death. Complete inhibition of the effects of anti-Fas on cell death and on ceramide production was observed when the caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp-(O-methyl)fluoromethane (zVAD.fmk) was added together with anti-Fas, but N-benzyloxycarbonyl-Phe-Ala-fluoromethane (a structurally similar cathepsin B inhibitor) had no effect. Treatment of cells with the Ca2+-ionophore A23187 also doubled ceramide levels, but in this case the effect was complete within 2 h, was not blocked by zVAD.fmk and was not associated with increases in nuclear fragmentation. These results suggest that ceramide is not an upstream messenger in Fas-mediated apoptosis and may instead be produced as a consequence of processes downstream of the activation of caspases and increases in cytosolic calcium concentration.