Fig. 3.

Challenging OHSCs with exogenous tau assemblies induces seeded tau aggregation. a Timeline of organotypic hippocampal slice culture preparation and treatment. OHSCs were prepared from P7 pups. After 7 days in vitro (DIV), tau assemblies were added to the media and incubated for 3 days. A complete media change was carried out at the end of the seeding period (pink). At other times (green) 50% media changes were performed twice weekly until fixation at 28 days in vitro (DIV). b OHSCs derived from P301S tau transgenic mice were challenged with either 100 nM recombinant tau assemblies, 100 nM monomeric tau, 5 µL (~ 300 nM) of mouse brain origin sarkosyl insoluble (SI) tau or buffer only. WT OHSCs were challenged with 100 nM recombinant tau assemblies or buffer only. Scale bars, 50 µm. c Quantification of seeding levels in WT and P301S tau transgenic OHSCs, following addition of 100 nM recombinant tau assemblies or buffer only. d Levels of AT8 immunostaining following challenge of OHSCs with monomeric tau (Mono) or heparin assembled tau (Seed). e, f Levels of sarkosyl insoluble tau present in transgenic P301S (e) or WT (f) OHSCs with and without the addition of 100 nM recombinant tau assemblies. Data derived from Western blot, normalised to input levels of tau and loading control. g Levels of human tau (HT7) present in WT OHSCs after 3 days of exposure to 300 nM recombinant tau assemblies applied beneath the membrane. c and d, statistical significance determined by Kruskal–Wallis test by ranks and Dunn’s multiple comparisons test. e–g statistical significance determined by unpaired t-test. For panels c–f, data points represent individual fields of view from multiple slices derived from N = 3 mice per condition. ****P < 0.0001; **P < 0.01; *P < 0.05; ns, not significant)