7,8-dihydroxyflavone protects PC12 cells against 6-hydroxydopamine-induced cell death through modulating PI3K/Akt and JNK pathways.

We have recently shown that 7,8-dihydroxyflavone (7,8-DHF) protects PC12 cells against 6-OHDA-induced cytotoxicity through its antioxidant activity. In the present study, we investigated the molecular mechanisms underlying the neuronal protective activity of 7,8-DHF. Western blot analysis showed that 6-OHDA (100μM, 24h) enhanced the phosphorylation of JNK and ERK1/2, but it markedly suppressed the expression of p-Akt, implying that 6-OHDA induces PC12 cell death through activating the pro-apoptotic MAPKs pathway but suppressing the survival PI3K/Akt pathway. More importantly, addition of 7,8-DHF fully prevented the activation of JNK and suppression of Akt induced by 6-OHDA. Interestingly, pretreatment with the PI3K-specific inhibitor LY294002 largely blocked 7,8-DHF function in protecting PC12 cells from 6-OHDA-induced cell death. In contrast, the MEK inhibitor PD98059 showed little effect on the protective activity of 7,8-DHF. These results suggest that 7,8-DHF might protect PC12 cells from 6-OHDA-induced cell death through activating PI3K/Akt pathway and inhibiting JNK pathway.