The Effects of Endogenous Non-Peptide Molecule Isatin and Hydrogen Peroxide on Proteomic Profiling of Rat Brain Amyloid-β Binding Proteins: Relevance to Alzheimer’s Disease?

Abstract

The amyloid-β peptide is considered as a key player in the development and progression of Alzheimer’s disease (AD). Although good evidence exists that amyloid-β 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 µM hydrogen peroxide significantly influenced the profile of amyloid-β binding proteins and 0.1 mM isatin decreased the number of identified amyloid-β 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-β 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-β oligomers described in the literature for some isatin derivatives.

The effect of isatin on protein-protein interactions between cytochrome b5 and cytochromes P450

“…Одним из субстратов цитохромов P450 системы является индол, который окисляется до изатина рядом СYP (СYP2A6, СYP2C19 и СYP2E1) [16]. Изатин (2,3-диоксоиндол)эндогенный индол, обладающий широким спектром биологических и фармакологических активностей, которые реализуются при взаимодействии с многочисленными внутриклеточными изатинсвязывающими белками [17][18][19][20].…”

Direct Molecular Fishing of New Protein Partners for Human Thromboxane Synthase

“…Isatin is an endogenous bioregulator with a wide range of biological and pharmacological activities which are implemented when it interacts with many intracellular isatin-binding proteins [19-22, 39-41]. Since CYP2E1 turned out to be one of the proteins that interact with TBXAS1, we assumed that isatin can affect TBXAS1 • CYP2E1 complex formation.…”

Isatin, an endogenous nonpeptide biofactor: A review of its molecular targets, mechanisms of actions, and their biomedical implications

“…Certain evidence exists that isatin influences various protein‐protein interactions. For example, it has a significant impact on proteomic profiles of amyloid‐binding proteins .…”

“…Proteomic profiling of rat brain homogenates, performed using amyloid‐beta as an affinity ligand, resulted in identification of about 90 individual intracellular proteins bound to amyloid‐beta . About one third of the amyloid‐β binding proteins underwent oxidative modification or differential expression in patients with Alzheimer's disease (AD).…”

“…For Molecular targets sensitive to physiologically relevant concentrations of isatin (modified from [13,27,39] Increased oxidation in AD brain example, it has a significant impact on proteomic profiles of amyloid-binding proteins [91]. Proteomic profiling of rat brain homogenates, performed using amyloid-beta as an affinity ligand, resulted in identification of about 90 individual intracellular proteins bound to amyloid-beta [91]. About one third of the amyloid-b binding proteins underwent oxidative modification or differential expression in patients with Alzheimer's disease (AD).…”