| [Objectives] The global analysis of cellular proteins has recently been termed proteomics and is a key area of research that is developing in the post-genome era. Proteomics offers scientists the possibility of identifying disease-associated protein markers to assist in diagnosis or prognosis and to select potential targets for specific drug therapy. To find related-proteins and to investigate molecular mechanisms of human brain aging and frontotemporal dementia, the proteomics was employed to study aged brains and brains of FTD patients.[Methods] The brains of subjects who died without clinical or pathologicalinvolvement of nervous system and brains of FTD patients were obtained at autopsy in Chinese PLA general hospital. The brain proteins extracted with mixture of urea, CHAPS, DTT, IPG buffer and protease inhibitors were run immobilized pH gradient (IPG) isoelectric focusing electrophoresis as the first dimension, and then run vertical SDS-PAGE as the second dimension. The gel was visualized by silver staining or colloidal coomassie blue staining and analysised with ImageMaster 2D Elite software. The proteins of interest were in-gel digested and identified using MALDI-TOF mass spectrometry or MALDI-TOF/TOF tandem mass spectrometry.Part I Preliminary proteomic study of human cerebellumsHuman brain proteins were isolated from cerebellum at the age of 94, 81 , 75 years and separated by two-dimensional gel electrophoresis. Eighty-eight prominent proteins with various functional characteristicsincluding intermediary metabolism enzymes, cytoskeleton proteins, antioxidant proteins, neuron-specific proteins and signaling proteins were identified. The database of human aged cerebellum was initially established.Part n Proteomic comparison between human adult and old cerebellumsTo investigate molecular mechanisms of human brain aging, cerebellum proteins were isolated from postmortem human adult and old brains and profiled by two-dimensional gel electrophoresis. With the help of ImageMaster 2D Elite software, five up-regulated protein spots in 2D gels of old brains were found compared with adult brains, which were identified as glutamate dehydrogenase precursor, creatine kinase precursor, glial fibrillary acidic protein, Mn-superoxide dismutase, alpha enolase. While eight down-regulated proteins hi old cerebellums were identified as carbonate dehydratase II, dihydropyrimidinase-related protein 2, pyruvate kinase, fructose-bisphosphate aldolase A, glutamine synthetase, carbonate dehydratase I, hemoglobin beta chain and hemoglobin alpha chain by MS.Part HI Proteomic comparison between cerebellums and frontal lobesProteins were isolated from human cerebellums and frontal lobes and separated by two-dimensional gel electrophoresis. Three up-regulated protein spots in 2D gels of cerebellums were found compared with frontal lobes, which were identified as antioxidant protein 2, creatine kinase precursor, fructose-bisphosphate aldolase C. Two down-regulated proteins in cerebellums were identified as pyruvate kinase Ml isozyme and glial fibrillary acidic protein. 30 common proteins, whose expressions were notaltered between cerebellums and frontal lobes, were also identified.Part IV Proteomic study of frontotemporal dementiaComparative proteomic analysis of brain proteins was employed to study 5 FTD patients compared to 4 controls. In the case of FTD brains, 18 protein spots were differentially expressed compared with age-matched nondemented control brains. 12 up-regulated proteins in FTD brains were identified as glyceraldehyde 3-phosphate dehydrogenase, uracil DNA glycosylase, human superoxide dismutase, isocitrate dehydrogenase subunit, synaptotagmin I, thioredoxin peroxidase 1, glial fibrillary acidic protein, P25 alpha, enoyl coenzyme A hydratase short chain 1, pyridoxine-5'-phosphate oxidase, Mn-superoxide dismutase, alpha enolase. 6 down-regulated proteins in FID brains were identified as antioxidant protein 2, ferritin heavy chain, glutamate dehydrogenase precursor, peptidyl-prol...
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