Stabilizing Full-Length PYY for Native Y1R/Y2R Dual Agonism

Abstract Peptide agonists that engage multiple G protein-coupled receptors provide a framework for orchestrating discrete but complementary signaling pathways within a single molecular entity. Peptide YY (PYY) is an endogenous 36-residue multiagonist of the neuropeptide Y receptor (YR) family. Full-length PYY(1–36) activates both Y1R and Y2R, coupling Y1R-dependent pancreatic and glucoregulatory signaling with Y2R-dependent satiety pathways. This native dual agonism is rapidly uncoupled by the ubiquitous dipeptidyl peptidase-4 (DPP4), which removes the N-terminal dipeptide to yield PYY(3–36), a Y2R-selective ligand with markedly reduced Y1R activity. Thus, DPP4 hydrolysis alters the receptor pharmacology of PYY rather than merely shortening peptide lifetime. Here, we report chemically stabilized PYY analogues that are refractory to DPP4 while retaining potent agonism at both Y1R and Y2R. Preservation of this native dual agonism was not achieved by introducing 2-aminoisobutyric acid (Aib) at the penultimate N-terminal residue. Although Aib is widely used to protect GLP-1 and GIP receptor agonists from DPP4, it results in PYY derivatives with diminished receptor activity at the Y1R. N-terminal alkylation afforded a minimally perturbative strategy to block DPP4 recognition while maintaining the full-length PYY(1–36) functional pharmacophore. Structure–activity studies define N-terminal features required for dual-receptor potency and identify a lipidation site that retains receptor activity while producing an HSA-dependent potency shift consistent with albumin association. Together, these protease-stable PYY(1–36) analogues expand the chemical framework for preserving native multireceptor pharmacology in DPP4-sensitive peptides and for engineering long-acting therapeutic analogues.