Figure 7

Aβ 1-42 promotes tau phosphorylation, cleavage and aggregation while Aβ 1-40 does not. 8 month old P301S mice (1N4R form with Prion promoter) were injected with saline into the left entorhinal cortex and Aβ1-42 (2ug) into the right entorhinal cortex or saline into the left entorhinal cortex and Aβ1-40 (2ug) into the right entorhinal cortex. 18 days after injection, the brain extracts were analyzed by western blot. A) Representative images of western blots of soluble tau (S1 fraction) detected with anti-tau antibodies and normalized to actin. B) Quantification of western blots in (A). C) Representative images of western blots of insoluble tau (P1 fraction), detected with anti-tau antibodies. D) Quantification of western blots in (C) Aβ1-42 injection significantly induced tau phosphorylation (PHF-1 and pS262 epitope) in the S1 and P1 brain fractions. 3-fold increase in Tau421 was found in the soluble fraction (A and B). Significant decrease in pS262 immunoreactivity was observed in S1 fraction from Aβ1-40 injected brain areas compared to control side. Histographs show mean +/− standard error, n =3. *p <0.05; **p <0.01; ***p <0.005.