Disconnect between signalling potency and in vivo efficacy of pharmacokinetically optimised biased glucagon-like peptide-1 receptor agonists
Maria Lucey, Philip Pickford, Stavroula Bitsi, James Minnion, Jan Ungewiss, Katja Schoeneberg, Guy A. Rutter, Stephen R. Bloom, Alejandra Tomás, Ben Jones
Abstract
The objective of this study was to determine how pharmacokinetically advantageous acylation impacts on glucagon-like peptide-1 receptor (GLP-1R) signal bias, trafficking, anti-hyperglycaemic efficacy, and appetite suppression. In vitro signalling responses were measured using biochemical and biosensor assays. GLP-1R trafficking was determined by confocal microscopy and diffusion-enhanced resonance energy transfer. Pharmacokinetics, glucoregulatory effects, and appetite suppression were measured in acute, sub-chronic, and chronic settings in mice. A C-terminally acylated ligand, [F1,G40,K41.C16 diacid]exendin-4, was identified that showed undetectable β-arrestin recruitment and GLP-1R internalisation. Depending on the cellular system used, this molecule was up to 1000-fold less potent than the comparator [D3,G40,K41.C16 diacid]exendin-4 for cyclic AMP signalling, yet was considerably more effective in vivo, particularly for glucose regulation. C-terminal acylation of biased GLP-1R agonists increases their degree of signal bias in favour of cAMP production and improves their therapeutic potential.