Overexpressing the endosomal activator in neurons not only caused those organelles to swell, but also bungled synaptic transmission, goaded hyperphosphorylation of tau, and destroyed cholinergic neurons.
By tracing the transcriptomes of neurons that wither early and late in the course of Alzheimer’s disease, researchers peg subpopulations of excitatory neurons in entorhinal cortex as selectively vulnerable to tau. Reactive astrocytes aid and abet.
In cultured cells, lysosomal activity was necessary to enable tau seeds to break out of internalized exosomes and trigger the aggregation of tau in the cytosol.