Frataxin silencing inactivates mitochondrial Complex I in NSC34 motoneuronal cells and alters glutathione homeostasis.

Abstract

Friedreich's ataxia (FRDA) is a hereditary neurodegenerative disease characterized by a reduced synthesis of the mitochondrial iron chaperon protein frataxin as a result of a large GAA triplet-repeat expansion within the first intron of the frataxin gene. Despite neurodegeneration being the prominent feature of this pathology involving both the central and the peripheral nervous system, information on the impact of frataxin deficiency in neurons is scant. Here, we describe a neuronal model displaying some major biochemical and morphological features of FRDA. By silencing the mouse NSC34 motor neurons for the frataxin gene with shRNA lentiviral vectors, we generated two cell lines with 40% and 70% residual amounts of frataxin, respectively. Frataxin-deficient cells showed a specific inhibition of mitochondrial Complex I (CI) activity already at 70% residual frataxin levels, whereas the glutathione imbalance progressively increased after silencing. These biochemical defects were associated with the inhibition of cell proliferation and morphological changes at the axonal compartment, both depending on the frataxin amount. Interestingly, at 70% residual frataxin levels, the in vivo treatment with the reduced glutathione revealed a partial rescue of cell proliferation. Thus, NSC34 frataxin silenced cells could be a suitable model to study the effect of frataxin deficiency in neurons and highlight glutathione as a potential beneficial therapeutic target for FRDA.

• Authors: Barbara Carletti, Emanuela Piermarini, Giulia Tozzi, Lorena Travaglini, Alessandra Torraco, Anna Pastore, Marco Sparaco, Sara Petrillo, Rosalba Carrozzo, Enrico Bertini, Fiorella Piemonte
• Journal: International journal of molecular sciences (Int J Mol Sci) Vol. 15 Issue 4 Pg. 5789-806 (Apr 04 2014) ISSN: 1422-0067 [Electronic] Switzerland
• PMID: 24714088 (Publication Type: Journal Article)

Chemical References

• Iron-Binding Proteins
• RNA, Small Interfering
• frataxin
• Electron Transport Complex I
• Glutathione

Topics

• Animals
• Cell Line, Tumor
• Cell Proliferation (genetics)
• Electron Transport Complex I (biosynthesis, genetics)
• Friedreich Ataxia (genetics, pathology)
• Glutathione (metabolism, pharmacology)
• Homeostasis
• Iron-Binding Proteins (genetics)
• Mice
• Mitochondria (metabolism, pathology)
• Motor Neurons (cytology)
• Oxidative Stress (genetics)
• RNA Interference
• RNA, Small Interfering