Conclusion
In conclusion, the polypeptide YVRHLKYVRHLK designed in this study has a neuroprotective effect on PC12 cytotoxicity induced by Aβ1-42. Graphical Abstract.
Methods
In this study, we first found the crystal structure of the Aβ1-42 receptor protein from the RCSB PDB protein structure database and used the SYBYL X2.0 software for molecular docking, and then used the Peptide Ranker, Innovagen, DPL, and ToxinPred online websites to perform peptides. Predict the activity score, toxicity and water solubility, and then calculate the affinity constant KD value of polypeptide and Aβ through Surface Plasmon Resonance (SPR) experiment. Subsequently, the CCK-8 kit method was used to determine the toxicity of different concentrations of peptides (3.125, 6.25, 12.5, 25, 50, 100, 200 μM) to PC12 cells, and then the peptides and Aβ according to different concentration ratios (1:4, 1:2, 1:1, 1:0.5, 1:0.25, 0:4), this method is also used to detect the effect of peptides on Aβ-induced neurotoxicity. The thioflavin T (ThT) fluorescence method was used to detect the effects of peptides (50 μM) on Aβ (25 μM) aggregation inhibitory effect.
Results
The results showed that the CScore of YVRHLKYVRHLK peptide molecule docking was 10.0608, the predicted activity score was 0.20, and the KD value was 5.385 × 10-5. The ThT and CCK-8 kit method found that the peptide itself is less toxic to PC12 cells at a concentration of 50 μM, and it has a significant inhibitory effect on the formation of Aβ1-42 aggregates when incubated with Aβ1-42 at a ratio of 1:1 (p < 0.05) and can significantly reduce the PC12 cytotoxicity induced by Aβ1-42 (p < 0.05).