A comparative proteome analysis of hippocampal tissue from schizophrenic and Alzheimer's disease individuals

The proteins expressed by a genome have been termed the proteome.(1,2) Comp arative proteome analysis of brain tissue offers a novel means to identify biologically significant gene products that underlie psychopathology. In th is study we collected post mortem hippocampal tissue from the brains of sev en schizophrenic, seven Alzheimer's disease (AD) and seven control individu als. Hippocampal proteomes were visualised by two-dimensional gel electroph oresis of homogenised tissue. A mean of 549 (s.d. 35) proteins were success fully matched between each disease group and the control group. In comparis on with the control hippocampal proteome, eight proteins in the schizophren ic hippocampal proteome were found to be decreased and eight increased in c oncentration, whereas, in the AD hippocampal proteome, 35 proteins were dec reased and 73 were increased in concentration (P < 0.05). One protein, whic h was decreased in concentration in both diseases, was characterised as dia zepam binding inhibitor (DBI) by N-terminal sequence analysis. DBI can regu late the action of the GABA(A) receptor.(3,4) Protein changes involved 6% o f the assessed AD hippocampal proteome, whereas, in schizophrenia protein c hanges involved less than 1% of the assessed hippocampal proteome. We concl ude that schizophrenia has a subtle neuropathological presentation and comp arative proteome analysis is a viable means by which to investigate disease s of the brain at the molecular level.