Last modified: 2019-06-16
Abstract
Autophagy dysfunction is implicated in Parkinson’s disease (PD) pathogenesis, and autophagy induction has been shown to exert neuroprotective effects in several experimental PD models. Transcription factor EB (TFEB) is a key regulator of autophagy and lysosome biogenesis. TFEB over-expression has been reported to prevent alpha-synuclein over-expression-induced PD pathology. However, whether TFEB activation will also be protective against oxidative stress-induced PD models is unknown. 6-hydroxydopamine/ascorbic acid (6-OHDA/AA) is commonly used toxin to induce PD lesions both in vitro and in vivo by causing oxidative damage. In this study, we revealed that 6-OHDA/AA dramatically induced TFEB activation and autophagy both in vitro and in vivo, via calcineurin activation triggered by lysosomal calcium channel MCOLN1-mediated Ca2+ release. To explore the role of TFEB and autophagy activation in the 6-OHDA/AA-lesioned PD model, we boosted TFEB and autophagy both genetically or chemically and observed dramatic alleviation of neuronal cells death in SH-SY5Y cells, iPSC-derived and mice nigral dopaminergic neurons treated with 6-OHDA/AA. Above protective effects could be blocked by autophagy inhibitors like Chloroquine (CQ) or by knocking down autophagy related genes such as TFEB and ATG5. Finally, the neuroprotective mechanism of TFEB enhancers can be partially attributed to the enhancement of mitophagy to degrade damaged mitochondria for cell survival. Taken together, this study reveals that TFEB-mediated autophagy is a survival mechanism during oxidative stress and enhancement of this process is a neuroprotective strategy against oxidative stress-associated PD lesions.