Translocation of iron from lysosomes into mitochondria is a key event during oxidative stress-induced hepatocellular injury.
Translocation of iron from lysosomes into mitochondria is a key event during oxidative stress-induced hepatocellular injury.
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DOI：
10.1002/hep.22498
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发表时间：
2008-11
期刊：
影响因子：
13.5
通讯作者：
Lemasters, John J.
中科院分区：
文献类型：
--
作者：
Uchiyama, Akira;Kim, Jae-Sung;Kon, Kazuyoshi;Jaeschke, Hartmut;Ikejima, Kenichi;Watanabe, Sumio;Lemasters, John J.
铁超负荷加重各种肝脏疾病。在肝细胞中，一部分非血红素铁被隔离在溶酶体和内体中。溶酶体铁参与肝细胞损伤的确切机制尚不清楚。在这里，我们的目的是确定在氧化应激诱导的杀死C3 Heb小鼠和Sprague-Dawley大鼠培养的肝细胞的螯合铁的细胞内运动的作用。四甲基罗丹明甲酯（TMRM）的共聚焦显微镜和钙黄绿素的淬灭，分别观察线粒体极化和可螯合铁。分别使用碘化丙啶和氯甲基二氢二氯荧光素荧光测定细胞活力和氢过氧化物形成（脂质过氧化的量度）。巴弗洛霉素（50 nM），液泡质子泵ATP酶的抑制剂，溶酶体/内体酸性pH梯度崩溃后，细胞溶质钙黄绿素荧光淬灭。Desferal和淀粉-Desferal（1 mM）阻止了巴弗洛霉素诱导的钙黄绿素淬灭，表明巴弗洛霉素诱导了可螯合铁从溶酶体/内体的释放。巴弗洛霉素还淬灭了线粒体中的钙黄绿素荧光，这被20 μM Ru 360（线粒体钙单向转运体的抑制剂）阻断，这与线粒体通过单向转运体摄取铁一致。单独的巴弗洛霉素不足以诱导线粒体去极化和细胞杀伤，但在存在低剂量叔丁基过氧化氢（25 μM）的情况下，巴弗洛霉素可增强过氧化氢的生成，导致线粒体去极化和随后的细胞死亡。总之，结果与巴弗洛霉素诱导可螯合铁从溶酶体/内体释放的结论一致，其被线粒体摄取。因此，氧化应激和可螯合铁作为两个“命中”协同促进毒性自由基形成、线粒体功能障碍和细胞死亡。这种细胞内铁转运途径是对抗氧化应激介导的肝毒性的潜在治疗靶点。
Iron overload exacerbates various liver diseases. In hepatocytes, a portion of non-heme iron is sequestered in lysosomes and endosomes. The precise mechanisms by which lysosomal iron participates in hepatocellular injury remain uncertain. Here, our aim was to determine the role of intracellular movement of chelatable iron in oxidative stress-induced killing to cultured hepatocytes from C3Heb mice and Sprague-Dawley rats. Mitochondrial polarization and chelatable iron were visualized by confocal microscopy of tetramethylrhodamine methylester (TMRM) and quenching of calcein, respectively. Cell viability and hydroperoxide formation (a measure of lipid peroxidation) were measured fluorometrically using propidium iodide and chloromethyl dihydrodichlorofluorescein, respectively. After collapse of lysosomal/endosomal acidic pH gradients with bafilomycin (50 nM), an inhibitor of the vacuolar proton-pumping ATPase, cytosolic calcein fluorescence became quenched. Desferal and starch-desferal (1 mM) prevented bafilomycin-induced calcein quenching, indicating that bafilomycin induced release of chelatable iron from lysosomes/endosomes. Bafilomycin also quenched calcein fluorescence in mitochondria, which was blocked by 20 μM Ru360, an inhibitor of the mitochondrial calcium uniporter, consistent with mitochondrial iron uptake by the uniporter. Bafilomycin alone was not sufficient to induce mitochondrial depolarization and cell killing, but in the presence of low dose tert-butylhydroperoxide (25 μM), bafilomycin enhanced hydroperoxide generation leading to mitochondrial depolarization and subsequent cell death. Taken together, the results are consistent with the conclusion that bafilomycin induces release of chelatable iron from lysosomes/endosomes, which is taken up by mitochondria. Oxidative stress and chelatable iron thus act as two “hits” synergistically promoting toxic radical formation, mitochondrial dysfunction and cell death. This pathway of intracellular iron translocation is a potential therapeutic target against oxidative stress-mediated hepatotoxicity.
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影响因子：
4.1
作者：
Ma, YM;De Groot, H;Petrat, F
通讯作者：
Petrat, F
影响因子：
3.8
作者：
Jaeschke, H;Gores, GJ;Lemasters, JJ
通讯作者：
Lemasters, JJ
影响因子：
3.9
作者：
CASTILHO, RF;MEINICKE, AR;VERCESI, AE
通讯作者：
VERCESI, AE
DOI：
10.1097/01.alc.0000189274.00479.62
发表时间：
2005-11-01
影响因子：
3.2
作者：
Kohgo, Y;Ohtake, T;Kato, J
通讯作者：
Kato, J
影响因子：
7.2
作者：
Hochhauser, E;Ben-Ari, Z;Vidne, BA
通讯作者：
Vidne, BA