The novel amyloid-beta peptide aptamer inhibits intracellular amyloid-beta peptide toxicity.

Amyloid ß peptide binding alcohol dehydrogenase (ABAD) decoy peptide (DP) can competitively antagonize binding of amyloid ß peptide to ABAD and inhibit the cytotoxic effects of amyloid ß peptide. Based on peptide aptamers, the present study inserted ABAD-DP into the disulfide bond of human thioredoxin (TRX) using molecular cloning technique to construct a fusion gene that can express the TRX1-ABAD-DP-TRX2 aptamer. Moreover, adeno-associated virus was used to allow its stable expression. Immunofluorescent staining revealed the co-expression of the transduced fusion gene TRX1-ABAD-DP-TRX2 and amyloid ß peptide in NIH-3T3 cells, indicating that the TRX1-ABAD-DP-TRX2 aptamer can bind amyloid ß peptide within cells. In addition, cell morphology and MTT results suggested that TRX1-ABAD-DP-TRX2 attenuated amyloid ß peptide-induced SH-SY5Y cell injury and improved cell viability. These findings confirmed the possibility of constructing TRX-based peptide aptamer using ABAD-DP. Moreover, TRX1-ABAD-DP-TRX2 inhibited the cytotoxic effect of amyloid ß peptide.