Fig. 8: Tau strains maintained their potencies during in vivo propagation.

a Representative IHC staining with AT8 on brain sections from 6hTau mice unilaterally inoculated with 0.2 μg tau strain extracted either from primary human diseased brains (P0) or strain_P0 injected 6hTau mice (P1). The total protein in P0 and P1 lysates were also adjusted the same using non-injected 6hTau brain lysates. The DG region of ventral hippocampus showed neuronal tau pathologies in all the cases. The astrocytic and oligodendrocytic tau pathologies induced by PSP and CBD strains are, respectively, shown in the hippocampal CA regions and the fimbria white matter region. Quantification in b neuronal; c astrocytic, and d oligodendrocytic tau pathologies in the ipsilateral sides (i) of 6hTau mice injected with strain_P0/P1 shown in a. Two-tailed t-tests were performed with significant difference where p ≤ 0.05. Data are presented as mean ± s.e.m. and each dot represents a mouse. Hpx hippocampus, DG dentate gyrus, CA cornu ammonis, Fim fimbria, WM white matter. Quantifications were from ipsilateral (i) sides. e Representative ICC staining with anti-mouse tau antibody R2295M on primary mouse neurons treated with AD_P0/P1 or PSP_P0/P1 at three dosages (10, 20, and 40 ng) per well. Control (Ctrl) brain lysate was extracted in the same way as strain_P1 from non-injected old 6hTau mouse brains. The amount of Ctrl lysate was matched to the total protein of AD_P1 40 ng, which contains the highest total protein. AD_P0/P1 all induced tau aggregate in the neuropil, while PSP_P0/P1 also induced obvious tau aggregate in somas. Scale bar, 50 μm. Relative quantification in f AD strains and g PSP strains. The normalization was made to DAPI counts and then, respectively, to AD_P0 40 ng dose for AD strains, or PSP_P0 40 ng dose for PSP strains. Data are presented as mean ± s.e.m. and each dot represents a batch repeat. One-way ANOVA with multiple comparisons were performed. Significant differences were considered when p ≤ 0.05. Source data is available as a Source Data file.