Diisopropylfluorophosphate (DFP) inhibits ricin-induced apoptosis of MDCK cells
Diisopropylfluorophosphate (DFP) inhibits ricin-induced apoptosis of MDCK cells
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DOI：
10.1271/bbb.62.325
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发表时间：
1998-02-01
影响因子：
1.6
通讯作者：
Muramatsu, T
中科院分区：
文献类型：
--
作者：
Oda, T;Komatsu, N;Muramatsu, T
丝氨酸蛋白酶抑制剂氟磷酸二异丙酯（DFP）可抑制蓖麻毒素、modeccin、假单胞菌毒素和白喉毒素诱导的MDCK细胞DNA断裂和细胞死亡。胰蛋白酶样丝氨酸蛋白酶抑制剂，N-甲苯磺酰-L-赖氨酸氯甲基酮（TLCK）也防止蓖麻毒素诱导的DNA片段化和细胞死亡，但效果不如DFP。光镜观察表明，DFP能阻止蓖麻毒素诱导的MDCK细胞形态学改变。DFP不影响蓖麻毒素的结合、内化或随后的排泄，但减少了蓖麻毒素在MDCK细胞中的降解，表明DFP至少抑制了可能参与内化蓖麻毒素降解的细胞蛋白酶。此外，胞浆蛋白的SDS-PAGE分析表明，在蓖麻毒素处理的细胞中，DFP敏感的内源性蛋白酶被激活。在DFP处理的小鼠中，蓖麻毒素对蛋白质合成的抑制活性不是被抑制，而是被增强。DFP还能轻微提高Modeccin和假单胞菌毒素的活性，但对白喉毒素的活性无影响。因此，这些结果表明，蛋白质毒素具有导致细胞凋亡的DFP敏感的共同途径，该途径不同于导致细胞蛋白质合成抑制的途径。
Diisopropylfluorophosphate (DFP), a general serine protease inhibitor, inhibited the DNA fragmentation and cell death in MDCK cells treated with ricin, modeccin, Pseudomonas toxin, or diphtheria toxin. A trypsin-like serine protease inhibitor, N-tosyl-L-lysine chloromethyl ketone (TLCK) also prevented ricin-induced DNA fragmentation and cell death, albeit less effectively than DFP. Microscopic observation showed that the morphological changes of MDCK cells induced by ricin were prevented by DFP. DFP did not affect the binding, internalization, or subsequent excretion of ricin, but reduced the degradation of ricin in MDCK cells, suggesting that DFP inhibits at least the cellular protease that may be involved in the degradation of internalized ricin, In addition, SDS-PAGE analysis of cytosolic proteins suggested that DFP-sensitive endogenous proteases are activated in the ricin-treated cells. In the tells treated with DFP, the protein synthesis inhibitory activity of ricin was increased rather than inhibited. The activities of modeccin and Pseudomonas term were also slightly increased by DFP, but no effect of DFP on the activity of diphtheria toxin was observed. Therefore, these results suggest that protein toxins have a DFP-sensitive common pathway leading to apoptosis that is distinct from the pathway leading to the inhibition of cellular protein synthesis.