Ceramide interaction with the respiratory chain of heart mitochondria

被引:212
作者
Di Paola, M
Cocco, T
Lorusso, M [1 ]
机构
[1] Univ Bari, Piazza G Cesare Policlin, Fac Med, Dept Med Biochem & Biol, I-70124 Bari, Italy
[2] Univ Bari, CNR, Ctr Study Mitochondria & Energy Metab, I-70124 Bari, Italy
关键词
D O I
10.1021/bi9924415
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
A study is presented on the interaction of ceramide with the respiratory chain of rat heart mitochondria, and a comparison is made between the effects elicited by short- and long-chain ceramides, N-Acecylsphingosine (C-2-ceramide) and N-palmitoylsphingosine (C-16-ceramide) inhibited to the same extent the pyruvate+malate-dependent oxygen consumption. Succinate-supported respiration was also inhibited by ceramides, but this activity was substantially restored upon the addition of cytochrome c, which, on the contrary, was ineffective toward the ceramide-inhibited NADH-linked substrate oxidation. Direct measurements showed that short- and long-chain ceramides caused a large release of cytochrome c from mitochondria. The ceramide-dependent inhibition of pyruvate+malate and succinate oxidation caused reactive oxygen species to be produced at the level of either complex I or complex III. The activity of the cytochrome c oxidase, measured as ascorbate/TMPD oxidase activity, was significantly stimulated and inhibited by C-2- and C-16-ceramide, respectively. Similar effects were observed on the activity of the individual respiratory complexes isolated from bovine heart. Short- and long-chain ceramides had definitely different effects on the mitochondrial membrane potential. C-2-ceramide caused an almost complete collapse of the respiration-dependent membrane potential, whereas C-16-ceramide had a negligible effect. Similar results were obtained when the potential was generated in liposome-reconstituted complex III respiring at the steady-state. Furthermore, C-2-ceramide caused a drop of the membrane potential generated by ATP hydrolysis instead of respiration, whereas C-16-ceramide did not. Finally, only short-chain ceramides inhibited markedly the reactive oxygen species generation associated with membrane potential-dependent reverse electron flow from succinate to complex I. The emerging indication is that the short-chain ceramide electron flow dependent collapse of membrane potential is a consequence of their ability to perturb the membrane structure, leading to an unspecific increase of its permeability.
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页码:6660 / 6668
页数:9
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