GFAP and prion disease: To confirm that animals died of prion disease, histopathological analyses were done to check for spongiosis, by a Hematoxylin/Eosin (HE) staining (Supplementary Fig. S2a–d) and for astrogliosis, by GFAP immunolabelling (Supplementary Fig. S2e–h) on brain tissue sections of animals treated with DMSO or with A6 at 5 mg/kg.