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PubMed | Unit of Flow Cytometry., Laboratory of Biochemistry, Unit of Muscular and Neurodegenerative Diseases. and Unit of Muscular and Neurodegenerative Diseases
Type: Journal Article | Journal: Human molecular genetics | Year: 2016

To elucidate the pathogenesis of axonopathy in Friedreichs Ataxia (FRDA), a neurodegenerative disease characterized by axonal retraction, we analyzed the microtubule (MT) dynamics in an in vitro frataxin-silenced neuronal model (shFxn). A typical feature of MTs is their dynamic instability, in which they undergo phases of growth (polymerization) and shrinkage (depolymerization). MTs play a fundamental role in the physiology of neurons and every perturbation of their dynamicity is highly detrimental for neuronal functions. The aim of this study is to determine whether MTs are S-glutathionylated in shFxn and if the glutathionylation triggers MT dysfunction. We hypothesize that oxidative stress, determined by high GSSG levels, induces axonal retraction by interfering with MT dynamics. We propose a mechanism of the axonopathy in FRDA where GSSG overload and MT de-polymerization are strictly interconnected. Indeed, using a frataxin-silenced neuronal model we show a significant reduction of neurites extension, a shift of tubulin toward the unpolymerized fraction and a consistent increase of glutathione bound to the cytoskeleton. The live cell imaging approach further reveals a significant decrease in MT growth lifetime due to frataxin silencing, which is consistent with the MT destabilization. The in vitro antioxidant treatments trigger the axonal re-growth and the increase in stable MTs in shFxn, thus contributing to identify new neuronal targets of oxidation in this disease and providing a novel approach for antioxidant therapies.

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