tailieunhanh - Báo cáo khoa học: Huntingtin inclusion bodies are iron-dependent centers of oxidative events

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. | ễFEBS Journal Huntingtin inclusion bodies are iron-dependent centers of oxidative events Wance J. J. Firdaus1 Andreas Wyttenbach2 Paola Giuliano3 Carole Kretz-Remy1 R. William Currie1 4 and Andre-Patrick Arrigo1 1 Laboratoire Stress Oxydant Chaperons et Apoptose Universite Claude Bernard Lyon-1 Villeurbanne France 2 Southampton Neuroscience Group Schoolof BiologicalSciences University of Southampton UK 3 Department of ClinicalImmunology NationalCancer Institute G. Pascale Foundation Naples Italy 4 Department of Anatomy and Neurobiology Dalhousie University Halifax NS Canada Keywords Hsps Huntingtin inclusion bodies iron ROS Correspondence . Arrigo Laboratoire Stress Oxydant Chaperons et Apoptose CNRS UMR 5534 Centre de Genetique Moleculaire et Cellulaire Universite Claude Bernard Lyon-1 43 Blvd du 11 Novembre 69622 Villeurbanne Cedex France Fax 33 0 472432685 Tel 33 0 472448595 E-mail arrigo@ Received 31 August 2006 accepted 11 October 2006 doi Recently we reported that the transient expression of huntingtin exonl 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 expansiondependent. 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 .