Global Profiles of Acetylated Proteins in Brains of Scrapie Agents 139A- and ME7-Infected Mice Collected at Mid-Early, Mid-Late, and Terminal Stages

Objective To describe the global profiles of acetylated proteins in the brains of scrapie agents 139Aand ME7-infected mice collected at mid-early,mid-late,and terminal stages.Methods The acetylated proteins from the cortex regions of scrapie agent(139A-and ME7)-infected mice collected at mid-early(80 days postinfection,dpi),mid-late(120 dpi),and terminal(180 dpi) stages were extracted,and the global profiles of brain acetylated proteins were assayed with proteomic mass spectrometry.The proteins in the infected mice showing 1.5-fold higher or lower levels than that of agematched normal controls were considered as differentially expressed acetylated peptides(DEAPs).Results A total of 118,42,and 51 DEAPs were found in the brains of 139A-80,139A-120,and 139A-180dpi mice,respectively.Meanwhile,390,227,and 75 DEAPs were detected in the brains of ME7-80,ME7-120,and ME7-180 dpi mice,respectively.The overwhelming majority of DEAPs in the mid-early stage were down-regulated,and more portions of DEAPs in the mid-late and late stages were up-regulated.Approximately 22.1%(328/1,485) of acetylated peptides mapped to 74 different proteins were mitochondrial associated.Kyoto Encyclopedia of Genes and Genomes pathway analysis identified 39(80dpi),13(120 dpi),and 10(180 dpi) significantly changed pathways in 139A-infected mice.Meanwhile,55,25,and 18 significantly changed pathways were observed in the 80,120,and 180 dpi samples of139A-and ME7-infected mice(P < 0.05),respectively.Six pathways were commonly involved in all tested samples.Moreover,many steps in the citrate cycle(tricarboxylic acid cycle) were affected,represented by down-regulated acetylation for relevant enzymes in the mid-early stage and upregulated acetylation in the mid-late and late stages.Conclusion Our data here illustrated the changes in the global profiles for brain acetylated proteins during prion infection,showing remarkably inhibited acetylation in the early stage and relatively enhanced acetylation in the late stage.