Fig. 5

Rate of mouse tau aggregation and conformation of newly formed aggregates. A The experimental workflow for pellets containing sarkosyl-insoluble mouse tau obtained from cell lyses for analyses by conformation-dependent immunoassay (CDI) and western blots. B Kinetics of evolution of sarkosyl-insoluble mouse tau conformers in neuronal cultures: CDI data from cell lysis of cortical neurons inoculated by AD-tau 1–6 and mouse tau (Ctrl) samples at 7DIV for 1 h (starting point), 3, 7, and 14 days. N-fold relative sarkosyl-insoluble a total tau levels, c 3R-tau levels, and e 4R-tau levels in cell lysis inoculated with AD-tau 1–6 and mouse tau (control) to non-treated cultures (medium) show different kinetics of insoluble tau formation for individual AD-tau inoculates. The conformation of insoluble b total tau, d 3R-tau, and f 4R-tau in cultures expressed as D/N ratio from CDI data of native sarkosyl-insoluble cell lysis samples (native, N) and Gdn HCl-treated samples (denatured, D) show mostly increasing of mouse tau misfolding and the variability dependence on human AD-tau inoculates. All CDI graphs are means ± SEM (n = 6; three independent experiments with two values for CDI measurement. C Correlation of tau conformation in the original samples of human AD-tau (x-axis) with sarkosyl-insoluble tau newly formed in cortical neurons inoculated for three days with AD-tau (y-axis) expressed as D/N ratios from CDI shows linear regression with statistical significance (p = 0.003, n = 6; three independent experiments with two values from each CDI measurement). D Western blots of sarkosyl-insoluble fractions of cell lyse of primary neurons inoculated with AD-tau at 7DIV and a treated for 1 h and b 14 days before cell lyses developed by specific mouse tau antibody (clone RTM47) show various degrees of increase of high-molecular-weight (HMW) mouse tau conformers after 14 days of inoculation period compared to 1 h treatment. c Semi-quantification of the density of HMW tau signal (> 50 kDa) normalized to PonceauS staining by one-way ANOVA shows a statistically significant difference between the starting point and 14 days after inoculation (*** p < 0.001). All data are expressed as mean ± SEM combined from three independent experiments