Synthesis and evaluation of ferrocenoyl pentapeptide (Fc-KLVFF) as an inhibitor of Alzheimer’s Aβ1–42 fibril formation in vitro

Aggregation and fibril formation of β-amyloid peptides (Aβ) is the key event in the pathogenesis of Alzheimer’s disease. Many efforts have been made on the development of effective inhibitors to prevent Aβ fibril formation or disassemble the preformed Aβ fibrils. Peptide inhibitors with sequences homologous to the hydrophobic segments of Aβ can alter the aggregation pathway of Aβ, together with decrease of the cell toxicity. In this study, the conjugate of ferrocenoyl (Fc) with pentapeptide KLVFF (Fc-KLVFF), was synthesized by HBTU/HOBt protocol in solution. The inhibitory effect of Fc-KLVFF on Aβ1–42 fibril formation was evaluated by thioflavin T fluorescence assay, and confirmed by atomic force microscopy (AFM) and transmission electron microscopy (TEM) analyses. Fc-KLVFF shows high inhibitory effect towards the fibril formation of Aβ1–42. Additionally, the attachment of ferrocenoyl moiety onto peptides allows us to investigate the interaction between the inhibitor and Aβ1–42 in real-time by electrochemical method. As expected, tethering of ferrocenoyl moiety onto pentapeptide shows improved lipophilicity and significant resistance towards proteolytic degradation compared to its parent peptide.

The conjugate of ferrocene and pentapeptide peptide KLVFF, Fc-KLVFF (5) exhibits significant inhibitory effect toward the fibril formation of Aβ1–42, and shows greatly improved the enzymatic stability.Figure optionsDownload as PowerPoint slide