The Protective Effect of Minocycline in a Paraquat-Induced Parkinson's Disease Model inDrosophilais Modified in Altered Genetic Backgrounds

Abstract

Epidemiological studies link the herbicide paraquat to increased incidence of Parkinson's disease (PD). We previously reported thatDrosophilaexposed to paraquat recapitulate PD symptoms, including region-specific degeneration of dopaminergic neurons. Minocycline, a tetracycline derivative, exerts ameliorative effects in neurodegenerative disease models, includingDrosophila. We investigated whether our environmental toxin-based PD model could contribute to an understanding of cellular and genetic mechanisms of minocycline action and whether we could assess potential interference with these drug effects in altered genetic backgrounds. Cofeeding of minocycline with paraquat prolonged survival, rescued mobility defects, blocked generation of reactive oxygen species, and extended dopaminergic neuron survival, as has been reported previously for a genetic model of PD inDrosophila. We then extended this study to identify potential interactions of minocycline with genes regulating dopamine homeostasis that might modify protection against paraquat and found that deficits in GTP cyclohydrolase adversely affect minocycline rescue. We further performed genetic studies to identify signaling pathways that are necessary for minocycline protection against paraquat toxicity and found that mutations in theDrosophilagenes that encode c-Jun N-terminal kinase (JNK) and Akt/Protein kinase B block minocycline rescue.