A. SH-SY5Y cells were transfected with Tau or Tau K353R, followed by the treatment with vehicle or DOPEGAL (60 μM). Western blot analysis showing that DOPEGAL induced Tau oligomerization, phosphorylation, AEP activation, and Tau cleavage, which were blocked by Tau K353R mutation. B. LDH assay demonstrated that Tau but not Tau K353R overexpression mediated cell death, which was enhanced by DOPEGAL treatment. C. The activation of AEP was confirmed by enzymatic assay. All data in B&C were analyzed by one-way ANOVA and shown as mean ± SEM. n = 3 per group. D & F. Primary neurons were treated with DOPEGAL in the presence or absence of tau PFFs. Immunofluorescence shows insoluble tau phosphorylation (D) and quantification (F). E & G. Neuronal apoptosis induced by DOPEGAL and tau PFFs was assessed using TUNEL staining. Scale bar is 20 μm. All data in F & G are shown as mean ± SEM. n = 8 per group. One-way ANOVA. H. Immunofluorescence shows tau cleavage and Tau modification by DOPEGAL. Scale bar is 20 μm. I. Immunofluorescence shows Tau modification by DOPEGAL. Scale bar is 20 μm. The images of H & I are representatives of three independent experiments with similar results.