Elucidating the link between oxidative stress and neurodegeneration by merging plant, zebrafish and human research approaches

In this research program we have had five main projects. In project one we have shown that DJ-1 can bind copper and mercury at a cellular level and also trough the determination of its 3D structure. We have further shown that DJ-1 shows extensive cellular trafficking which is determined by its homedimeric and heterodimeric interactions ith wild-type DJ-1 and clinical mutations. In project two we have shown that LRRK2 is involved in kidney and neuronal development in zebrafish and also that LRRK2 downregulation and the G2019S mutation have profound effects on neuronal proteomes. In project three have have demonstrated that synuclein is present as different subcellular-specific multimers that change upon oxidative stress and Parkinson´s disease pathogenesis. We have also identified Parkinson´s disease specific multimers that have been purified and will be injected into zebrafish neurons to test for toxicity. In project four we have shown that PARK13 confers thermotolerance in plants and that PARK13 can degrade synuclein and DJ-1. We have further shown that PARK13 has a relationship with PINK1 leading to altered localization dynamics in response to oxidative stress. In project five we have shown that two microRNAs regulate not only LRRK2 and SNCA but also many central neuronal proteins. We have further demonstrated that microRNAs act as robust biomarkers for disease.

Parkinsons Disease (PD) represents a multifaceted neurodegenerative disorder characterized by extensive loss of dopaminergic neurons in the substantia nigra linked to excess oxidative stress. Several genes are linked to familial PD including DJ-1 which ca uses early-onset PD. Despite intense research the precise cause, mechanisms and disease progression are unclear. Likewise, no efficient PD prognostic biomarkers are available nor a cure. In this proposal we will dissect the DJ-1 protein complex mode of ac tion and brain characteristics in response to oxidative stress and PD states. To date PD research efforts have focused on the use of single or dual model systems. We take a unique approach combining several complementary models including plant cells, mam malian neuronal cells, and brains from zebrafish and humans. Using all systems in concert we employ overlapping but also unique methodologies to demonstrate DJ-1 mode of action and its consequence on brain characteristics. We expect to generate data that will not be achievable using single models and thereby contribute significantly to the overall understanding of PD. Specifically we will solve the DJ-1 protein complex structure, define DJ-1 mode of action, identify/characterize novel DJ-1 associated pro teins, identify/characterize DJ-1 post-translational modifications, establish zebrafish as a PD model, and map/characterize the brain proteome/ metabolome in response to oxidative stress and PD. The project is highly interdisciplinary with several elemen ts. To overcome potential R&D challenges we have estabslihed an 11 partner national and international network which will contribute expertise within the different elements. The anticipated value and applications of the project are: i) Extend our understa nding of PD onset, mechanism and progression, ii) Demonstrate the value of combining complementary models to understand disease, and iii) Generate findings for new PD biomarker design and disease management