Parkinson's disease-associated Pink1 loss disrupts vesicle trafficking in ensheathing glia causing dopaminergic neuron synapse loss

Parkinsons disease (PD) is commonly associated with the loss of dopaminergic neurons in the substantia nigra, but many other cell types are affected even before neuron loss occurs. Recent studies have linked oligodendrocytes to early stages of PD, though their precise role is still unclear. Pink1 is mutated in familial PD and through unbiased single-cell sequencing of the entire brain of Drosophila Pink1 models, we observed significant gene deregulation in ensheathing glia (EG); cells that share functional similarities with oligodendrocytes. We found that the loss of Pink1 leads to the activation of EG, similar to the reactive response of EG seen upon nerve injury. Using cell-type specific transcriptomics, we identified deregulated genes in EG as potential functional modifiers. Specifically, downregulating two trafficking factors, Rab7 and Vps13, also mutated in PD, or the direct regulators of Rab7, Mon1 and Ccz1, specifically in EG was sufficient to rescue neuronal function and protect against dopaminergic synapse loss. Our findings demonstrate that Pink1 loss in neurons triggers an injury response in EG, and that Pink1 loss in EG in turn disrupts neuronal function. Vesicle trafficking components, which regulate membrane interactions between organelles within EG, play a crucial role in maintaining neuronal health and preventing dopaminergic synapse loss. Our work highlights the essential role of glial support cells in the pathogenesis of PD and identifies vesicle trafficking within these cells as a key point of convergence in disease progression.