Overexpression of tau has previously been shown to result in release of highly phosphorylated tau17 from cells, often in association with exosomes7, 16 and it will be of great interest to next determine whether tau released from 3xTg-AD slices is aberrantly phosphorylated and/or cleaved relative to tau released from wild-type slices. This evidence concerns the gene MAPT and Alzheimer disease.