Huntingtin inclusion bodies are iron-dependent centers of oxidative events

Firdaus, Wance J.J., Wyttenbach, Andreas, Giuliano, Paola, Kretz-Remy, Carole, Currie, R. William and Arrigo, André-Patrick (2006) Huntingtin inclusion bodies are iron-dependent centers of oxidative events. Febs Journal, 273 (23), 5428-5441. (doi:10.1111/j.1742-4658.2006.05537.x).

Abstract

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.

This record has no associated files available for download.

Contributors

Download statistics