Oxidative stress impairs autophagic flux in prion protein-deficient hippocampal cells

We previously reported that autophagy is upregulated in Prnp-deficient (Prnp0/0) hippocampal neuronal cells in comparison to cellular prion protein (PrPC)-expressing (Prnp+/+) control cells under conditions of serum deprivation. In this study, we determined whether a protective mechanism of PrPC is associated with autophagy using Prnp0/0 hippocampal neuronal cells under hydrogen peroxide (H2O2)-induced oxidative stress. We found that Prnp0/0 cells were more susceptible to oxidative stress than Prnp+/+ cells in a dose- and time-dependent manner. In addition, we observed enhanced autophagy by immunoblotting, which detected the conversion of microtubule-associated protein 1 light chain 3 β (LC3B)-I to LC3B-II, and we observed increased punctate LC3B immunostaining in H2O2-treated Prnp0/0 cells compared with H2O2-treated control cells. Interestingly, this enhanced autophagy was due to impaired autophagic flux in the H2O2-treated Prnp0/0 cells, while the H2O2-treated Prnp+/+ cells showed enhanced autophagic fl...