The effect of β-amyloid on thioredoxin antioxidant system

Abstract

Beta-amyloid peptide (Aβ) contributes significantly to neurodegeneration during the development of Alzheimer’s disease (AD). Many studies showed that Aβ can cause oxidative damage. Thioredoxin (Trx) is a redox protein that can reverse cysteine oxidative modifications such as sulfenylation and nitrosylation. Thioredoxin-interacting protein (Txnip) is an endogenous Trx inhibitor. In the present study, using immunoblotting analysis, I found that Txnip protein levels and total sulfenylated protein levels were significantly increased in the hippocampus and frontal cortex of 9 and 12-month old App/Ps1 mice compared with wild-type mice. Aβ also directly increased Txnip protein levels, and cysteine sulfenylation and nitrosylation. Using CRISPR/Cas9 technology, we found that knocking out Txnip in HT22 cells blocked Aβ-induced protein sulfenylation and nitrosylation. Our findings suggest that Aβ may upregulate Txnip, subsequently inhibiting Trx activity and enhancing cysteine sulfenylation and nitrosylation. These results also indicate that Txnip may have a potential for AD treatment.