MAPT and Alzheimer disease: Similarly, an apparent reduction of tau electrophoretic mobility was observed in 3xTg-AD mice, and this change was accompanied by a significant increase in the total p-S202/Thr205 tau concentration, particularly at 6 and 9–12 months, between the two strains (F1,22 = 19.91 p < 0.01) (Fig. 4A), To analyze the relationship between Dkk-1 levels and tau phosphorylation, we performed an index that revealed a significant (R = 0.54) correlation between Dkk-1 and tau phosphorylation in the transgenic mice but not in the WT mice (Fig. 4B, ).