Design of Potent and Proteolytically Stable Biaryl-Stapled GLP-1R/GIPR Peptide Dual Agonists

Abstract

Recent clinical trials have revealed that the chimeric peptide hormones simultaneously activating glucagon-like peptide-1 receptor (GLP-1R) and glucose-dependent insulinotropic polypeptide receptor (GIPR) demonstrate superior efficacy in glycemic control and body weight reduction, better than those activating the GLP-1R alone. However, the linear peptide-based GLP-1R/GIPR dual agonists are susceptible to proteolytic cleavage by common digestive enzymes present in the gastrointestinal tract and thus not suitable for oral administration. Here, we report the design and synthesis of biaryl-stapled peptides, with and without fatty diacid attachment, that showed potent GLP-1R/GIPR dual agonist activities. Compared to a linear peptide dual agonist and semaglutide, the biaryl-stapled peptides displayed drastically improved proteolytic stability against the common digestive enzymes. Furthermore, two stapled peptides showed excellent efficacy in an oral glucose tolerance test in mice, owing to their potent receptor activity in vitro and good pharmacokinetics exposure upon subcutaneous injection. By exploring a more comprehensive set of biaryl staplers, we expect that this stapling method could facilitate the design of the stapled peptide-based dual agonists suitable for oral administration.

Stapled peptides: targeting protein-protein interactions in drug development

“…Significantly, the increased half-life owing to the insertion of the staple is not only limited to the extracellular environment where most proteases are located but also recorded in the intracellular environment (Figure 9B). Kuster et al [148] attempted to target the "dimer-of-dimers" interface of the carboxy-terminal binding protein (CtBP) interacting protein (CtIP) via an innovative stapled peptide-based approach, in which they found that the helical content upon hydrocarbon stapling showed a sharp increase and a higher ability to resist protease hydrolysis as only a slight effect on the steady state level of CtIP was observed in the cycloheximide (CHX) chase experiment. Mourtada et al [87] discovered Mag(i + 4)1,15(A9K) as a selective candidate drug for StAMP via the design algorithm and proved that the stapled peptide is an attractive strategy for AMP-based antibiotic development due to the enhancement of the α-helical structure with biological activity can twist the amide bonds and make stapled peptide becoming a poor substrate for proteases.…”

“…Indeed, the insertion of staples forces the peptide into α-helical conformation, which enhances the helicity of the peptide and also increases its hydrophobicity by exposing non-polar side chains to the environment outside. Many studies have proven that α-helical stapled peptides show tremendous potential for improving cell permeability, providing a pathway for intracellular proteins as drug targets [148,[152][153][154][155][156][157][158].…”

“…In addition, Limaye et al [81] employed the positively charged Lys (K) residues to replace the solvent-exposed residues at different positions of peptides, resulting in peptide libraries with different net positive charges, among which WAHMIS-2 with the highest positive charge exhibits higher cell penetration ability compared to others. Kuster et al [148] found that the overall positive charge of SP [18][19][20][21][22][23][24][25][26][27][28] , which is more positively charged by the removal of E29, combined with the extended hydrophobic interface, resulted in a higher intracellular uptake rate of the peptide compared to its longer corresponding peptide SP [18][19][20][21][22][23][24][25][26][27][28][29][30][31] , indicating that positive NC seems to have the ability to enhance cell uptake and biological activity. Wu et al [110] reported a peptide library comprising a series of functionalized dialkynyl linkers equipped with double CuAAC staple.…”