Mild MPP+ exposure-induced glucose starvation enhances autophagosome synthesis and impairs its degradation
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Parkinson’s disease (PD) is a prevalent neurodegenerative disorder, mainly characterised by the progressive loss of dopaminergic neurons. MPP+ has been widely used as a PD-related neurotoxin, and their reports suggested the several hypotheses for neuronal cell death. However, most of these hypotheses come from the studies about the acute MPP+ exposure. We previously revealed that mild MPP+ exposure (10 and 200 μM), which induces gradual cell death, impairs autophagosome degradation at 48 h. In the present study, we further investigated the specific events of mild MPP+ exposure and revealed that mild MPP+ exposure causes the cell death through glucose starvation, but not acute toxic model (2.5 and 5 mM). At 36 h after mild MPP+ exposure, autophagosome synthesis was enhanced owing to glucose starvation and continued to enhance until 48 h, despite impaired autophagosome degradation. Inhibition of autophagosome synthesis reduced mild MPP+-induced cell death. In conclusion, we clarified that glucose starvation-enhanced autophagosome synthesis occurs at an earlier stage than impaired autophagosome degradation and is important in mild MPP+ toxicity.
This work was supported by Japan Society for the Promotion of Science (JSPS) Grants-in-Aid for Scientific Research (B) Grant Number 24406004 (to Y.K.), The Pharmacological Research Foundation, Tokyo, Japan (to Y.K.), and Suzuken Memorial Foundation (to Y.K.).
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Graduate School of Biomedical & Health Sciences