Identification of a peptide inhibitor disrupting the PCSK9-LDLR interaction <i>via</i> pharmacophore-based virtual screening, molecular dynamics simulations and <i>in vitro/vivo</i> evaluation

The PCSK9-LDLR interaction, driving elevated LDL-C, is a key driver of ASCVD pathogenesis. Identifying peptides disrupting this interaction offers an alternative ASCVD therapy. Herein, <i>via</i> structure-based virtual screening with Pep2-8 as a control, we identified TPP-4, a high-affinity peptide inhibitor targeting PCSK9. Compared to Pep2-8, TPP-4 showed lower binding free energy (approximately -9.8 kcal/mol) and <i>K</i>_d values (<i>K</i>_d = 0.08 ± 0.01 μM), interacting with PCSK9's LDLR-binding domain through multiple interactions. CD spectroscopy also provided indirect evidence for these key interactions. Additionally, it stably bound to the LDLR binding domain of PCSK9 during 100 ns MD simulations. It showed good serum stability, negligible HepG2 cytotoxicity, and restored surface LDLR (EC₅₀ = 1.12 ± 0.05 μM). In mice, TPP-4 upregulated hepatic LDLR and reduced plasma total cholesterol levels. In conclusion, these data demonstrate that TPP-4 could be a high-affinity and potent candidate peptide for ASCVD treatment.