Fig. 3

Aβ oligomers promote tau seeding in primary hippocampal neurons and human neuroblastoma cells. a 500 nM tau seeds were added to primary hippocampal neurons from PS19 mice with (top panels) or without (bottom panels) 24 h pretreatment of 200 nM Aβ oligomers. Immunostaining with tau antibodies HT7 (left) or AT8 (right) was performed 24 h after the addition of tau seeds. Nuclei were stained with DAPI (blue). The scale bar denotes 20 μm. Tau inclusions are highlighted by white arrows. b A schematic representation of the assays used to measure Aβ promotion of tau seeding in neuroblastoma SH-SY5Y cells. Cells were treated with Aβ oligomers at 24 h and tau seeds at 48 h and then lysed at 72 h. ELISA was used to measure tau concentration in the lysates, then seeding was measured in the tau-biosensor cells, and the seeding capacity of the supernatant was measured by FRET-based flow cytometry. c Quantification of tau seeding in SH-SY5Y cells with or without pretreatment with Aβ oligomers. The representative western blot above the bar graph shows that a similar amount of total tau in the SH-SY5Y cell lysates was used in each case. Data are mean ± SD (n = 6, ****p < 0.0001, one-way ANOVA)