Fig. 1

A human iPSC-based disease model to study cell-to-cell propagation of tau pathology. a Schematic outline of the experimental set-up. Neurons were exposed to tau aggregates and cultured in tau-free medium for additional time, followed by a UV-burst. Astrocytes were co-cultured with the apoptotic neurons to allow ingestion of the cell corpses and neuronal debris. Finally, the phagocytic astrocytes were introduced to a second cell culture consisting of healthy neurons. In parallel experiments, astrocytes were directly exposed to tau aggregates and then co-cultured with either healthy astrocytes or healthy neurons. b TEM images of synthetic tau fibrils, their sonicated counterpart (Tau-F), synthetic tau oligomers (Tau-O) and human AD brain derived tau (BDTau-F)