Oxidative stress has been described as a major cause of nigrostriatal degeneration in familial and idiopathic Parkinson’s disease (PD). Moreover, NADPH oxidase 2 (NOX2) and the mitochondrial electron transport chain, the major enzymatic sources of reactive oxygen species (ROS) in neural cells, appear intimately related in a redox regulatory pathway recently termed “ROS-induced ROS production”. While there is some evidence that NOX2 inhibitors may protect dopaminergic neurons against degeneration, these studies have often been hampered by the lack of highly specific inhibitors. Additionally, it has been difficult to assess the activation state of NOX2 under experimental or pathological conditions with a cellular level of resolution. We now report testing of a novel and highly specific NOX2 inhibitor, NOX2ds-tat, and development of a new proximity ligation histological assay for NOX2 activation. By utilizing this novel histological PL assay and NOX2ds-tat, for the first time, we characterized the nature of the interplay between NOX2 and mitochondria in PD progression. Specifically, we found that NOX2 is hyperactive in idiopathic PD and the rotenone rat model of PD. Moreover, NOX2 activity contributes to (i) ?-synuclein accumulation/aggregation (ii) impairment of the mitochondrial protein import machinery (iii) altered redox status of HSP70 (iv) disruption of the interaction between HSP70 and the TOM complex receptor, TOM70, with the consequence of PINK1:TOM70 interaction. Overall, the data suggest that targeting NOX2 may constitute a therapeutic approach in prevention of PD progression.
Audience Take Away:
• The findings of this study highlight the critical role of a novel PD-relevant feed-forward pathogenic pathway where NOX2-mitochondria interplay is the key factor.
• The audience will have the opportunity to acquire knowledge on these novel pathogenic mechanisms of PD as potential therapeutic targets.
• The presentation will provide to the audience the potential of developing new studies in the topic.
• In this study we developed novel techniques able to detect protein-protein interaction or protein post translational modifications (i.e. phosphorylation) with cellular resolution. These novel experimental approaches allowed us to detect in vitro and in vivo NOX2 and LRRK2 activity status and provide evidence of relevance in the human disease. We are disseminating these novel techniques to the scientific community to provide practical solutions able to improve and simplify the experimental approaches.