RT Journal Article SR Electronic T1 Extracellular monomeric and aggregated tau efficiently enter human neurons through overlapping but distinct pathways JF bioRxiv FD Cold Spring Harbor Laboratory SP 168294 DO 10.1101/168294 A1 Wassmer, T. A1 Evans, L. A1 Fraser, G. A1 Smith, J. A1 Perkinton, M. A1 Billinton, A. A1 Livesey, F.J. YR 2017 UL http://biorxiv.org/content/early/2017/07/25/168294.abstract AB A current working model is that Alzheimer's disease actively spreads from diseased to healthy neurons, mediated by transfer of extracellular, abnormal, disease-specific forms of the microtubule-associated protein tau. It is currently unclear whether transfer of tau between neurons is a toxic gain-of-function process in dementia, or reflects a constitutive biological process. We report two mechanisms of entry of monomeric tau to neurons: a rapid early dynamin-dependent phase, and a second, slower actin-dependent phase, suggesting that monomeric tau enters neurons via rapid saturable clathrin-mediated endocytosis and also by bulk endocytosis. Aggregated tau entry is independent of actin polymerisation and largely dynamin dependent, consistent with clathrin-mediated endocytosis and distinct from macropinocytosis, the major route for aggregated tau entry reported for non-neuronal cells. Anti-tau antibodies abrogate tau entry into neurons, with tau carrying antibody with it into neurons, indicating that antibody binding is insufficient to prevent neuronal tau entry.