Development of D‐enantiomeric peptides as tau aggregation inhibitors directed against the hexapeptide motif PHF6* of tau

Abstract

Background Two hexapeptide motifs within Tau, designated PHF6* (275VQIINK280) and PHF6 (306VQIVYK311), are known to drive Tau aggregation, making them attractive targets for the development of Tau aggregation inhibitors for therapeutic options. Method Employing mirror‐image phage display with a large peptide library, we have identified PHF6* fibril binding peptides consisting of D‐enantiomeric amino acids. D‐enantiomeric peptides are extremely protease stable and considerably less immunogenic than L‐peptides, and the suitability of D‐peptides for therapeutic purposes has already been demonstrated. The most promising D‐peptide and its ability to inhibit Tau aggregation was investigated using various biochemical and biophysical methods, and compared to the performance of PHF6‐ or other PHF6*‐binding peptides selected earlier by our and other groups. Result MMD3 and MMD3rev inhibited PHF6*, TauRDΔK280 and full‐length Tau fibrillization in vitro. Our data demonstrated that the peptides prevent the formation of Tau ß‐sheet‐rich fibrils by formation of large amorphous aggregates. The binding mode of MMD3 and MMD3rev to PHF6* fibrils was investigated by in silico modeling. Conclusion Our peptides were able to penetrate cells and might be interesting for therapeutic and diagnostic applications in AD research.