ABSTRACT
While Aß and Tau cellular distribution has been largely studied, the comparative internalization and subcellular accumulation of Tau and Aß isolated from human brain extracts in endothelial and neuronal cells has not yet been unveiled. We have previously demonstrated that controlled enrichment of Aß from human brain extracts constitutes a valuable tool to monitor cellular internalization in vitro and in vivo. Herein, we establish an alternative method to strongly enrich Aß and Tau aggregates from human AD brains, which has allowed us to study and compare the cellular internalization, distribution and toxicity of both proteins within brain barrier endothelial (bEnd.3) and neuronal (Neuro2A) cells. Our findings demonstrate the suitability of human enriched brain extracts to monitor the intracellular distribution of human Aß and Tau, which, once internalized, show dissimilar sorting to different organelles within the cell and differential toxicity, exhibiting higher toxic effects on neuronal cells than on endothelial cells. While tau is strongly concentrated preferentially in mitochondria, Aß is distributed predominantly within the endolysosomal system in endothelial cells, whereas the endoplasmic reticulum was its preferential location in neurons. Altogether, our findings display a picture of the interactions that human Aß and Tau might establish in these cells.
