MAPT and Alzheimer disease: In addition to the increase in abundance of tau protein in AD brain-derived microglial EVs, we found that levels of neuron-specific and synapse-enriched proteins were either exclusively detected (CEND1 and SNAP25) or significantly upregulated (SYT-1, SYT-11, STX1B, and Thy1) in the AD group (Figures 2A,B).