Huntingtin inclusion bodies are iron-dependent centers of oxidative events
Huntingtin inclusion bodies are iron-dependent centers of oxidative events
复制标题
DOI：
10.1111/j.1742-4658.2006.05537.x
复制
发表时间：
2006-12-01
期刊：
影响因子：
5.4
通讯作者：
Arrigo, Andre-Patrick
中科院分区：
文献类型：
--
作者：
Firdaus, Wance J. J.;Wyttenbach, Andreas;Arrigo, Andre-Patrick
最近，我们报道了在亨廷顿病细胞模型中瞬时表达含有不同大小的多聚谷氨酰胺束（httEx 1-polyQ）的亨廷顿蛋白外显子1多肽产生了氧化应激，其强度依赖于CAG重复扩增。在这里，我们分析了由httEx 1-polyQ多肽产生的氧化事件的细胞内定位。活COS-7细胞以及神经元SK-N-SH和PC 12细胞与氢乙啶或二氯荧光素二乙酸盐孵育的分析揭示了这些探针在由httEx 1-polyQ多肽形成的包涵体水平上的氧化。夹杂物之间的氧化事件的强度和频率是CAG重复扩增依赖。细胞切片的电子显微镜分析显示在httpEx 1-polyQ包涵体附近存在氧化依赖性形态学改变。此外，在部分纯化的包涵体中回收了高水平的氧化蛋白。我们还报告说，铁螯合剂deferroxamine改变的结构，定位和氧化电位的httEx 1-polyQ包涵体。因此，尽管包涵体的形成可能代表细胞消除httEx 1突变多肽的防御反应，但这种现象似乎是产生对细胞有害的铁依赖性氧化事件所固有的。
Recently, we reported that the transient expression of huntingtin exon1 polypeptide containing polyglutamine tracts of various sizes (httEx1-polyQ) in cell models of Huntington disease generated an oxidative stress whose intensity was CAG repeat expansion-dependent. Here, we have analyzed the intracellular localization of the oxidative events generated by the httEx1-polyQ polypeptides. Analysis of live COS-7 cells as well as neuronal SK-N-SH and PC12 cells incubated with hydroethidine or dichlorofluorescein diacetate revealed oxidation of these probes at the level of the inclusion bodies formed by httEx1-polyQ polypeptides. The intensity and frequency of the oxidative events among the inclusions were CAG repeat expansion-dependent. Electron microscopic analysis of cell sections revealed the presence of oxidation-dependent morphologic alterations in the vicinity of httEx1-polyQ inclusion bodies. Moreover, a high level of oxidized proteins was recovered in partially purified inclusions. We also report that the iron chelator deferroxamine altered the structure, localization and oxidative potential of httEx1-polyQ inclusion bodies. Hence, despite the fact that the formation of inclusion bodies may represent a defense reaction of the cell to eliminate httEx1 mutant polypeptide, this phenomenon appears inherent to the generation of iron-dependent oxidative events that can be deleterious to the cell.