LETHAL HYDROGEN-PEROXIDE TOXICITY INVOLVES LYSOSOMAL IRON-CATALYZED REACTIONS WITH MEMBRANE DAMAGE
LETHAL HYDROGEN-PEROXIDE TOXICITY INVOLVES LYSOSOMAL IRON-CATALYZED REACTIONS WITH MEMBRANE DAMAGE
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DOI：
10.1080/13510002.1995.11746997
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发表时间：
1995-08-01
期刊：
影响因子：
3.8
通讯作者：
OLLINGER, K
中科院分区：
文献类型：
--
作者：
BRUNK, UT;ZHANG, H;OLLINGER, K
次级溶酶体含有低分子量的铁复合物，这是各种金属蛋白正常自噬降解的结果。因此，过氧化氢进入这些细胞器可能会诱导铁催化的氧化反应，从而损害溶酶体膜和破坏性内容物的泄漏。溶酶体活性铁的量和细胞降解过氧化氢的能力将是细胞抗氧化应激的重要决定因素。在培养的J-774细胞的模型系统中，研究了过氧化氢对细胞活力的影响，特别是对溶酶体膜完整性的影响，这些影响通过吖啶橙子、荧光黄、中性红和组织蛋白酶D重新定位来评价。铁螯合剂Desferal的保护作用在普通培养条件下暴露于药物后和抑制细胞内吞作用后进行了研究。过氧化氢暴露（500 μ M的PBS溶液，37 ℃，5-90分钟）表现为细胞活力的时间依赖性降低。这之前是一个快速减少的质子梯度穿过溶酶体膜，作为判断重新定位的吖啶橙子。损伤的另一个早期迹象是质膜起泡，在过氧化氢暴露开始后几分钟内在许多细胞上发现。细胞还显示出溶酶体标志物荧光黄、中性红和组织蛋白酶D的部分重新分布，表明溶酶体不稳定。在培养中，细胞预先暴露于去铁蛋白可以防止所有这些现象，除非药物的内吞摄取被阻止。
Secondary lysosomes contain low-molecular weight iron-complexes as a consequence of normal autophagocytotic degradation of various metallo-proteins. Thus, entry of hydrogen peroxide into these organelles may induce iron-catalyzed oxidative reactions with ensuing damage to lysosomal membranes and leakage of destructive contents. The amount of lysosomal reactive iron and the cellular capacity to degrade hydrogen peroxide would then be important determining factors in cellular resistance to oxidative stress. The effects of hydrogen peroxide on cell viability and, in particular, on lysosomal membrane integrity, evaluated by acridine orange, lucifer yellow, neutral red, and cathepsin D relocalization, were investigated in a model system of cultured J-774 cells. The protective effect of the iron-chelator desferal was studied after exposure to the drug under ordinary culture conditions and after inhibition of cellular endocytosis. Hydrogen peroxide-exposure (500 mu M in PBS, 37 degrees C, 5-90 min) was manifested as a time-dependent decrease in cell viability. This was preceded by a rapid reduction of the proton gradient across the lysosomal membranes, as judged by relocalization of acridine orange. Another early sign of damage was plasma membrane blebbing, found on many cells within minutes after the initiation of hydrogen peroxide-exposure. The cells also showed a partial redistribution of the lysosomal markers lucifer yellow, neutral red, and cathepsin D, indicating lysosomal destabilization. The preexposure of cells to desferal in culture prevented all these phenomena, unless endocytotic uptake of the drug was prevented.