Title:The effects of endogenous non-peptide molecule isatin and hydrogen peroxide on proteomic profiling of rat brain amyloid-beta binding proteins: relevance to Alzheimer's disease?
Authors:Medvedev AE; Buneeva OA; Kopylov AT; Gnedenko OV; Medvedeva MV; Kozin SA; Ivanov AS; Zgoda VG; Makarov AA
Publication:Int J Mol Sci. 2014 Dec 29;16(1):476-95. doi: 10.3390/ijms16010476.
The amyloid-beta peptide is considered as a key player in the development and progression of Alzheimer's disease (AD). Although good evidence exists that amyloid-beta accumulates inside cells, intracellular brain amyloid-binding proteins remain poorly characterized. Proteomic profiling of rat brain homogenates, performed in this study, resulted in identification of 89 individual intracellular amyloid-binding proteins, and approximately 25% of them were proteins that we had previously identified as specifically binding to isatin, an endogenous neuroprotector molecule. A significant proportion of the amyloid-binding proteins (more than 30%) are differentially expressed or altered/oxidatively modified in AD patients. Incubation of brain homogenates with 70 microM hydrogen peroxide significantly influenced the profile of amyloid-beta binding proteins and 0.1 mM isatin decreased the number of identified amyloid-beta binding proteins both in control and hydrogen peroxide treated brain homogenates. The effects of hydrogen peroxide and isatin have been confirmed in optical biosensor experiments with purified glyceraldehyde-3-phosphate dehydrogenase, one of the known crucial amyloid-beta binding proteins (also identified in this study). Data obtained suggest that isatin protects crucial intracellular protein targets against amyloid binding, and possibly favors intracellular degradation of this protein via preventing formation of amyloid-beta oligomers described in the literature for some isatin derivatives.