Dimethylbiguanide inhibits cell respiration via an indirect effect targeted on the respiratory chain complex I
Dimethylbiguanide inhibits cell respiration via an indirect effect targeted on the respiratory chain complex I
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DOI：
10.1074/jbc.275.1.223
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发表时间：
2000-01-07
影响因子：
4.8
通讯作者：
Leverve, X
中科院分区：
文献类型：
--
作者：
El-Mir, MY;Nogueira, V;Leverve, X
我们在这里报告一个新的线粒体调节只发生在完整的细胞。我们研究了二甲基双胍对离体大鼠肝细胞、透化肝细胞和离体肝线粒体的影响。二甲基双胍的加入仅降低完整细胞的耗氧量和线粒体膜电位，而不降低透化肝细胞或离体线粒体的耗氧量和线粒体膜电位。二甲基双胍暴露后的透性肝细胞和从二甲基双胍预处理的肝脏或动物中分离的线粒体的特征在于复合物I底物对氧消耗的显著抑制（谷氨酸和苹果酸），但不与复合物II（琥珀酸盐）或络合物IV（N，N，N '，N'-四甲基-1，4-苯二胺二盐酸盐（TMPD）/抗坏血酸盐）底物，使用从二甲基双胍预处理的肝脏或大鼠分离的线粒体获得的功能分离的复合物I的研究进一步证实二甲基双胍作用位于呼吸链复合物I上。二甲基双胍的效果是温度依赖性的，在37、25和15摄氏度时，耗氧量分别降低50%、20%和0%。胰岛素信号通路抑制剂、一氧化氮前体或抑制剂、氧自由基清除剂、神经酰胺合成抑制剂或细胞内或细胞外Ca 2+螯合剂均不影响这种效应。由于已确定二甲基双胍不被代谢，因此这些结果表明存在靶向呼吸链复合物I的新细胞信号传导途径，在信号传导过程停止后具有持续作用。
We report here a new mitochondrial regulation occurring only in intact cells. We have investigated the effects of dimethylbiguanide on isolated rat hepatocytes, permeabilized hepatocytes, and isolated liver mitochondria, Addition of dimethylbiguanide decreased oxygen consumption and mitochondrial membrane potential only in intact cells but not in permeabilized hepatocytes or isolated mitochondria. Permeabilized hepatocytes after dimethylbiguanide exposure and mitochondria isolated from dimethylbiguanide pretreated livers or animals were characterized by a significant inhibition of oxygen consumption with complex I substrates (glutamate and malate) but not with complex II (succinate) or complex IV (N,N,N',N'-tetramethyl-1,4-phenylenediamine dihydrochloride (TMPD)/ascorbate) substrates, Studies using functionally isolated complex I obtained from mitochondria isolated from dimethylbiguanide-pretreated livers or rats further confirmed that dimethylbiguanide action was located on the respiratory chain complex I. The dimethylbiguanide effect was temperature-dependent, oxygen consumption decreasing by 50, 20, and 0% at 37, 25, and 15 degrees C, respectively. This effect was not affected by insulin-signaling pathway inhibitors, nitric oxide precursor or inhibitors, oxygen radical scavengers, ceramide synthesis inhibitors, or chelation of intra- or extracellular Ca2+. Because it is established that dimethylbiguanide is not metabolized, these results suggest the existence of a new cell-signaling pathway targeted to the respiratory chain complex I with a persistent effect after cessation of the signaling process.