Hormone Analogues with Unique Signaling Profiles from Replacement of α-Residue Triads with β/γ Diads

Prolonged Activation of the GLP-1 Receptor via Covalent Capture

The incretin gut hormone glucagon-like peptide-1 (GLP-1) has become a household name because of its ability to induce glucose-dependent insulin release with accompanying weight loss in patients. Indeed, derivatives of the peptide exert numerous pleiotropic actions that favorably affect other metabolic functions, and consequently, such compounds are being considered as treatments for a variety of ailments. The ability of native GLP-1 to function as a clinical drug is severely limited because of its short half-life in vivo. All of the beneficial effects of GLP-1 come from its agonism at the cognate receptor, GLP-1R. In our quest for long-lived activation of the receptor, we hypothesized that an agonist that had the ability to covalently cross-link with GLP-1R would prove useful. We here report the structure-guided design of peptide analogues containing an electrophilic warhead that could be covalently captured by a resident native nucleophile on the receptor. The compounds were evaluated using washout experiments, and resistance to such washing serves as an index of prolonged activation and covalent capture, which we use to tabulate longevity and robust long-lived GLP-1R agonism. The addition of SulF (cross-linkable warhead), an N-terminal trifluoroethyl group (for protease protection), and a C18 diacid lipid (protractor) all contributed to the increased wash resistance of GLP-1. The most effective compound based on the wash resistance metric, C2K26DAC18_K34SulF, has all three elements outlined and may serve as a blueprint and a proof-of-concept scaffold for the design of clinically useful molecules.

Systematical mutational analysis of teriparatide on anti-osteoporosis activity by alanine scanning

Osteoporosis is a progressive systemic skeletal disease that decreases bone density and bone quality, making them fragile and easy to break. In spite of effective anti-osteoporosis potency, teriparatide, the first anabolic medications approved for the treatment of osteoporosis, was proven to exhibit various side effects. And the relevant structure-activity relationship (SAR) of teriparatide was in need. In this work, we performed a systematical alanine scanning against teriparatide and synthesized 34 teriparatide derivatives. Their biological activities were evaluated and the importance of each residue for anti-osteoporosis activity was also revealed. A remarkable decrease in activity was observed for alanine replacement of the residue Gly12, His14, Ser17, Arg20 and Leu24, showcasing the important role of these residues in teriparatide on anti-osteoporosis activity. On contrary, when Gly13 and Gln30 were mutated to Ala, the peptide derivatives exhibited the significantly increased activities, demonstrating that these two residues could be readily replaced. Our research expanded the peptide library of teriparatide analogues and presented a potential opportunity for designing the more powerful anti-osteoporosis peptide agents.