C. Western blottau levels from concentrated media from ex-vivo organotypic slice cultures of Cspa+/+ or Cspa-/- mice. DnaJC5 was detected by DnaJC5 antibody (Synaptic Systems). Quantification of extracellular tau levels are mean ± SEM, n=3, **p<0.01 one-way analysis of variance with Tukey's multiple comparison post-hoc analysis. 