Global profiles of a cetylated proteins in the brains of scrapie agents 139A- and ME7-infected mice collected at mid-early, mid-late and terminal stage

Abstract

BackgroundAcetylation is a reversible post-translational modification in eukaryotic and prokaryotic cells, actively participating in the regulation for biological functions and in the pathogenesis of diseases.MethodsThe acetylated proteins from the cortex regions of scrapie agents 139A- and ME7-infected mice collected at mid-early (80 days post-infection, dpi), mid-late (120 dpi) and terminal stage (180 dpi) were extracted. The global profiles of the brain acetylated proteins were assayed with proteomic mass spectrometry. The acetylated peptides whose levels were >1.5-fold higher or lower than that of age-matched normal controls were considered as differentially expressed acetylated peptides (DEAPs).ResultsA total of 1,485 acetylated peptides were identified. 118, 42 and 51 DEAPs were in the brains of 139A-80 dpi, 120 dpi and 180 dpi, while 390, 227 and 75 DEAPs were in those of ME7-80 dpi, 120 dpi and 180 dpi, respectively. Overwhelming majority of the DEAPs in mid-early stage was down-regulated, while more portions of DEAPs in mid-late and late stage were up-regulated. Approximately 22.1% (328/1485) acetylated peptides were mitochondrial associated, which were mapped to 74 different proteins. Among them, 44 (59.5%) proteins showed differentially expressed at least at one tested time-point. KEEG pathways analysis identified 39, 13, 10 and 55, 25, 18 pathways in the samples of 80, 120 and 180 dpi of 139A- and ME7-infected mice as significantly changed (P<0.05), respectively. Six pathways were commonly involved in all tested samples, including carbon metabolism, metabolic pathways, biosynthesis of amino acids, glycolysis/gluconeogenesis, pyruvate metabolism and citrate cycle (TCA cycle). Moreover, dozens of steps in TAC cycle were affected via down-regulated acetylation for the relevant enzymes in the mid-early stage, while many steps were affected in the mid-late stage via up-regulated acetylation. In the late stage, the affected steps focused on up-regulated acetylation for succinate dehydrogenase, fumarate hydratase and malate dehydrogenase.ConclusionCollectively, Our data here illustrated a picture of global acetylation for brain proteins during prion infection, showing remarkably inhibiting acetylation in the early stage and relatively enhanced acetylation in the late stage.

Aberrant SENP1-SUMO-Sirt3 Signaling Causes the Disturbances of Mitochondrial Deacetylation and Oxidative Phosphorylation in Prion-Infected Animal and Cell Models

“…Our previous study of acetylated proteomics has revealed abnormal alterations of several enzymes of oxidative phosphorylation in the brain tissues of scrapie-infected experimental mice, showing a down-regulation in the early stage (80 dpi) and an up-regulation in the late stage (180 dpi) . To obtain more direct evidence, the statuses of five enzymes and their acetylated forms involved in oxidation phosphorylation in the brains of 139A- and ME7-infected mice at the terminal stage were accessed by Western blots, controlled with the age-matched normal mice.…”

“…Our previous study has revealed aberrant alterations in the global profiles of the brain acetylated proteins by proteomics during prion infection in scrapie mouse models, showing remarkably inhibited acetylation in the early stage and relatively enhanced acetylation in the late stage . Two major components in the sirtuin family, Sirt3 and Sirt1, are markedly dysregulated in the brains of prion-infected animal and cell models. , In this report, we have identified that along with the reductions of the level and activity of Sirt3, the acetylated forms of several key enzymes in oxidative phosphorylation increase in the brains infected with scrapie agents at the terminal stage and in the prion-infected cell model.…”

“…Over 20% acetylated peptides mapped to 74 different proteins are mitochondrially associated in the brains of prion-infected mouse models. 18 In Sirt3 knockout cells, several enzymes in the TCA cycle are found to be increasingly acetylated. 27 Overexpression of Sirt3 reverses, at least partially, the change of acetylation of CS and its activity in the MPP + -treated PD cell model.…”

“…Sirt3 mediates the acetylation process for a crowd of mitochondrial proteins, including the enzymes involved in cell oxidative phosphorylation. Over 20% acetylated peptides mapped to 74 different proteins are mitochondrially associated in the brains of prion-infected mouse models . In Sirt3 knockout cells, several enzymes in the TCA cycle are found to be increasingly acetylated .…”

“…the brain tissues of scrapie-infected experimental mice, showing a down-regulation in the early stage (80 dpi) and an up-regulation in the late stage (180 dpi). 18 To obtain more direct evidence, the statuses of five enzymes and their acetylated forms involved in oxidation phosphorylation in the brains of 139A-and ME7-infected mice at the terminal stage were accessed by Western blots, controlled with the agematched normal mice. As shown in Figure 1A−E, the levels of all tested proteins, including AceCS2, GDH, LCAD, CS, and IDH2, were comparable between scrapie-infected mice and normal controls, while those of their acetylated forms increased in those two scrapie-infected mouse models with statistically significant differences in the quantitative assays.…”