TTR and Alzheimer disease: Although increased levels of TTR protein have been previously reported in hippocampal cells from AD-like transgenic mouse models (Li et al., 2011; Stein and Johnson, 2002), no difference in the level of TTR was observed in CA1 hippocampal cells between 12 months-old WT and Tau22 mouse brains (Supplementary Figures S6D,E).