Combining proteomics, peptidomics and MALDI imaging for the investigation of the pathophysiology of experimental Parkinson's disease

抄録

Treatment of mice with MPTP is one of several models used to mimic Parkinson's disease (PD) in humans. First, we have developed a peptidomic approach to study a large number of neuropeptides and employed it to an investigation of the endogenous neuropeptide content of PD. Secondly, two-dimensional fluorescence difference gel electrophoresis (DIGE) was used to pinpoint significant differences in protein abundance. Finally, direct molecular imaging of the biological samples using MALDI-MS was shown to be a powerful tool for investigating the spatial distribution of peptides and proteins directly on tissue samples. The 2D DIGE analysis demonstrated significant changes in a number of striatal proteins following dopamine depletion using an animal model of PD. The peptidomics approach was developed using only mg quantities of brain tissue. The comparisons of neuropeptides revealed several differences in relative abundance both between the different animal groups and the different brain regions. The compared peptides comprise precursor families of both known secretory pathway proteins, including granin-like neuroendocrine peptide, CART, POMC, prosomatostatin, proenkephalin, and precursors with neuropeptides identified as novel. Further, our results show that MALDI imaging directly on tissue slices provides unique information regarding the peptide and protein expression in experimental models of PD. For example, dopamine depleted mice showed an increase in the expression of cytochrome C and cytochrome C oxidase, and that increased expression is most intense in the cortex. The present study demonstrates that protein profiles obtained from specific brain regions using DIGE and MALDI imaging combined with data from a peptidomic approach allow for the study of complex biochemical processes such as those occurring in experimental PD.