Correlation of Aβ‐pE(3) and ptau in human and mouse brain

Abstract

AbstractBackgroundSenile plaques frequently contain pyroglutamate amyloid β (Aβ‐pE(3)), a N‐terminally truncated Aβ species that is more closely linked to Alzheimer’s Disease (AD) compared to other Aβ species. Tau protein is highly phosphorylated at several residues in AD, specifically tau protein phosphorylated (ptau) at Ser202/Thr205 is known to be increased in AD. First studies suggest that the two pathologies of plaques and tau phosphorylation might be linked to each other.MethodTo evaluate if Aβ‐pE(3) and ptau Ser202/Thr205 levels correlate in human and transgenic AD mouse models we analyzed human cortical and hippocampal brain tissue of different Braak stages as well as murine brain tissue of two transgenic mouse models for levels of Aβ‐pE(3) and ptau Ser202/Thr205 and correlated the data.ResultOur results show that Aβ‐pE(3) formation increases already at early Braak stages while ptau Ser202/Thr205 mostly increases at later stages. Further analyses revealed strong correlations between the two pathologies in the temporal, frontal, cingulate and occipital cortex. However, correlation in the hippocampus was weaker. Evaluation of murine transgenic brain tissue demonstrated a slow but steady increase of Aβ‐pE(3) from 6 to 12 months of age in the cortex and hippocampus of APPSL mice and a very early and strong Aβ‐pE(3) increase in 5xFAD mice. ptau Ser202/Thr205 levels increased at the age of 9 months in APPSL mice and already at 6 months in 5xFAD mice.ConclusionOur results show that Aβ‐pE(3) and ptau Ser202/Thr205 levels strongly correlate in human as well as murine brain tissues, suggesting that tau phosphorylation might be amplified by Aβ‐pE(3).