Nrf2-mediated neuroprotection by MANF against 6-OHDA-induced cell damage via PI3K/AKT/GSK3β pathway

Oxidative stress and apoptosis are thought to be broadly involved in the pathogenesis of Parkinson's disease. We previously reported that Mesencephalic astrocyte-derived neurotrophic factor (MANF) possesses anti-oxidation and anti-apoptotic effects against 6-OHDA-induced neurotoxicity, but the specific molecular mechanism remains unclear. In this study, we showed that MANF up-regulates the expression of nuclear factor erythroid 2-related factor (Nrf2) and promotes its translocation into the nucleus. The anti-oxidation and anti-apoptotic effects of MANF could be partially blocked by inhibitor or shRNA-mediated knockdown of Nrf2. Furthermore, MANF activated phospoinositide-3-kinase (PI3K)/Akt signaling and suppressed glycogen synthase kinase (GSK3 beta) activation. PI3K inhibitor (LY49002) abolished effects of MANF on AKT phosphorylation, GSK3 beta inactivation, Nrf2 nuclear translocation and subsequently abrogated MANF-mediates cytoprotection. Collectively, our findings indicated that MANF-mediated protection against 6-OHDA-induced cytotoxicity by potentiating the Nrf2-related survival mechanism through the PI3K/Akt/GSK3 beta pathway.