Abstract
Parkinson's disease (PD) is thought to develop through a complex interplay of genetic and environmental factors. Epidemiological studies have linked exposure to certain pesticides such as paraquat with elevated PD risk, although how a person's genetic makeup influences disease risk upon exposure remains unknown. Here, we used a genome-wide approach to uncover genes that play a role in resistance to paraquat-induced dopaminergic (DA) neurodegeneration in Drosophila. We developed a paraquat exposure model displaying delayed-onset DA neurodegeneration to recapitulate this aspect of human disease. We reveal that genetic background is a strong determinant of paraquat-induced DA neurodegeneration susceptibility across a series of nearly 200 fly strains called the Drosophila Genetic Reference Panel. Through unbiased genome-wide analysis and follow-up validation, we identify 2 candidate paraquat resistance genes, luna and CG32264. In gene-level studies, decreased expression of luna or CG32264 is associated with paraquat-induced DA neuron loss while overexpression of either gene prevents neurodegeneration in vivo. The mammalian ortholog of CG32264 is Phactr2, which has previously been linked to idiopathic PD risk in several populations. Hence, our results reveal genes regulating paraquat-induced DA neuron loss that intersect with human PD risk variants, supporting the potential relevance of our findings to PD and underscoring a role for gene-environment interactions in pesticide-related DA neurodegeneration.
