Polyamines and acetylated polyamines differentially impact tau fibrillization and acetylspermidine increases tau oligomerization. a–c Thioflavin T assay using recombinant 4R0N (P301L) tau and treatment of polyamines (putrescine, spermidine, spermine) or acetylated polyamines (acetylputrescine, acetylspermidine, acetylspermine) followed by quantification of area under the curve (AUC) compared to tau + vehicle controls. Data is represented as triplicate average and tables reflect AUC change from tau + vehicle control (% tau, % change). d, e Characterization and validation of split GFP-Tau individual plasmids (pmGFP10C-Tau, pmGFP11C-Tau) and monoclonal cell line (N2a-ssGT). f, g Representative images (at 24 h) and quantification of tau oligomerization following treatment with acetylspermidine. Simple main effects analysis showed that 30 μM acetylspermidine increased tau oligomerization (F(1, 78) = 7.140, p = .009. No effect of time (F(2,78) = .719, p = .490) or interaction of variables (F(2, 78) = .144, p = .866) was detected. 2 × 3 Factorial analysis of variance (ANOVA), followed by post hoc comparisons using Fishers PLSD. *p < .05, the asterisk inidcates the main effect of drug. Data is represented by means ± S.E.M.