Treatment with ROS detoxifying gold quantum clusters alleviates the functional decline in a mouse model of Friedreich ataxia

Abstract

Gold quantum clusters are therapeutic in preclinical models of Friedreich ataxia. Friedreich ataxia golden age Patients with Friedreich ataxia (FRDA) present neurological deficits and impaired muscle coordination. Mitochondrial energy conversion and oxidative phosphorylation have been shown to contribute to disease pathophysiology. Now, Villa et al. tested whether gold cluster superstructures (Au8-pXs), previously shown to have antioxidant properties, could be effective in reducing the hallmarks of FRDA in vitro and in vivo. Au8-pXs improved mitochondrial function, rescued autophagy flux, and increased FXN protein expression in mesenchymal stem cells from patients. In vivo, the treatment had therapeutic effects in a mouse mode, suggesting that Au8-pXs might be effective in reducing FRDA symptoms. Friedreich ataxia (FRDA) is caused by the reduced expression of the mitochondrial protein frataxin (FXN) due to an intronic GAA trinucleotide repeat expansion in the FXN gene. Although FRDA has no cure and few treatment options, there is research dedicated to finding an agent that can curb disease progression and address symptoms as neurobehavioral deficits, muscle endurance, and heart contractile dysfunctions. Because oxidative stress and mitochondrial dysfunctions are implicated in FRDA, we demonstrated the systemic delivery of catalysts activity of gold cluster superstructures (Au8-pXs) to improve cell response to mitochondrial reactive oxygen species and thereby alleviate FRDA-related pathology in mesenchymal stem cells from patients with FRDA. We also found that systemic injection of Au8-pXs ameliorated motor function and cardiac contractility of YG8sR mouse model that recapitulates the FRDA phenotype. These effects were associated to long-term improvement of mitochondrial functions and antioxidant cell responses. We related these events to an increased expression of frataxin, which was sustained by reduced autophagy. Overall, these results encourage further optimization of Au8-pXs in experimental clinical strategies for the treatment of FRDA.