Wednesday, January 10, 2018

Quantitative proteomics in Friedreich's ataxia B-lymphocytes: A valuable approach to decipher the biochemical events responsible for pathogenesis

Lorène Télot, Elodie Rousseau, Emmanuel Lesuisse, Camille Garcia, Bastien Morlet, Thibaut Léger, Jean-Michel Camadro, Valérie Serre, Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease, Available online 9 January 2018, ISSN 0925-4439, doi:10.1016/j.bbadis.2018.01.010.


To better understand the biochemical sequelae of frataxin reduction, global protein expression analysis was performed using quantitative proteomic experiments in Friedreich's ataxia patient-derived B-lymphocytes as compared to controls. We were able to confirm a subset of changes in these cells and importantly, we observed previously unreported signatures of protein expression. Among the novel protein signatures that we have identified, the decrease in CHCHD4 might partly explain some aspects of the molecular pathogenesis of FRDA.

The identification of a core set of proteins changing in the FRDA pathogenesis is a useful tool in trying to decipher the function(s) of frataxin in order to clarify the mitochondrial metabolic disease process.

Effect Of Diazoxide on Friedreich Ataxia Models

Antonella Santoro, Sara Anjomani Virmouni, Eleonora Paradies, Valentina L Villalobos Coa, Sahar Al-Mahdawi, Mee Khoo, Vito Porcelli, Angelo Vozza, Mara Perrone, Nunzio Denora, Franco Taroni, Giuseppe Merla, Luigi Palmieri, Mark A Pook, Carlo M T Marobbio, Human Molecular Genetics, ddy016, doi:10.1093/hmg/ddy016

In this study, we tested diazoxide, a drug commonly used as vasodilator in the treatment of acute hypertension, on cellular and animal models of FRDA. We first showed that diazoxide increases frataxin protein levels in FRDA lymphoblastoid cell lines, via the mTOR pathway. We then explored the potential therapeutic effect of diazoxide in frataxin-deficient transgenic YG8sR mice and we found that prolonged oral administration of 3mpk/d diazoxide was found to be safe, but produced variable effects concerning efficacy. YG8sR mice showed improved beam walk coordination abilities and footprint stride patterns, but a generally reduced locomotor activity. Moreover, they showed significantly increased frataxin expression, improved aconitase activity and decreased protein oxidation in cerebellum and brain mitochondrial tissue extracts. Further studies are needed before this drug should be considered for FRDA clinical trials.