Tyrosine nitrosylation is detectable in vitro and in vivo and strongly reduced in GFAP-cre:TrkBflox/flox EAE mice. (A) Stainings for nitrotyrosine, β-tubulin, and DAPI in neuronal cultures exposed to ACM from nontreated (NT; left) and BDNF (middle)- or IL1-treated (right) astrocytes. (B and C) iNOS and nitrotyrosine expression in EAE mice. Double immunofluorescence for GFAP and iNOS (B) or nitrotyrosine (C) in spinal cord of TrkBflox/flox and GFAP-cre:TrkBflox/flox mice at day 18 after immunization with MOG_35–55 peptide. Insets show enlarged images of iNOS- or nitrotyrosine-positive astrocytes. Graphs show relative quantification. Four mice/group from two independent EAE experiments were analyzed. Red lines indicate mean values for each group. *, P < 0.05. (D) Protein nitrotyrosilation in MS lesions. (left) Double immunofluorescence and confocal microscopy for TrkB-ECD and nitrotyrosine. (right) Nitrotyrosine localization on GFAP- or β-tubulin–positive cells. Representative images of three analyzed MS lesions; one z-stack images. Bars: (A and D) 10 µm; (B and C) 50 µm.