A DPP-IV-resistant triple-acting agonist of GIP, GLP-1 and glucagon receptors with potent glucose-lowering and insulinotropic actions in high-fat-fed mice

Abstract

Aims/hypothesis We designed a chemically modified, enzyme-resistant peptide with triple-acting properties based on human glucagon with amino acid substitutions aligned to strategic positions in the sequence of glucose-dependent insulinotropic polypeptide (GIP). Methods Y 1 -dA 2 -I 12 -N 17 -V 18 -I 27 -G 28,29 -glucagon (termed YAG-glucagon) was incubated with dipeptidylpeptidase IV (DPP-IV) to assess stability, BRIN-BD11 cells to evaluate insulin secretion, and receptor-transfected cells to examine cAMP production. Acute glucose-lowering and insulinotropic properties of YAG-glucagon were assessed in National Institutes of Health (NIH) Swiss mice, while longer-term actions on glucose homeostasis, insulin secretion, food intake and body weight were examined in high-fat-fed mice. Results YAG-glucagon was resistant to DPP-IV, increased in vitro insulin secretion (1.5-3-fold; p<0.001) and stimulated cAMP production in GIP receptor-, glucagon-like peptide-1 (GLP-1) receptor-and glucagon receptortransfected cells. Plasma glucose levels were significantly reduced (by 51%; p<0.01) and insulin concentrations increased (1.2-fold; p<0.01) after acute injection of YAGglucagon in NIH Swiss mice. Acute actions were countered by established GIP, GLP-1 and glucagon antagonists. In high-fat-fed mice, twice-daily administration of YAGglucagon for 14 days reduced plasma glucose (40% reduction; p<0.01) and increased plasma insulin concentrations (1.8-fold; p<0.05). Glycaemic responses were markedly improved (19-48% reduction; p<0.05) and insulin secretion enhanced (1.5-fold; p<0.05) after a glucose load, which were independent of changes in insulin sensitivity, food intake and body weight.

A Novel Glucagon-like Peptide-1 (GLP-1)/Glucagon Hybrid Peptide with Triple-acting Agonist Activity at Glucose-dependent Insulinotropic Polypeptide, GLP-1, and Glucagon Receptors and Therapeutic Potential in High Fat-fed Mice

“…Moreover, recent data relating to a modified glucagon/GIP peptide hybrid clearly show that this molecule was capable of activating GLP-1 Rs (17). Further studies in GIP, GLP-1, and double incretin R knock-out mice confirmed our initial in vitro findings, with [DA 2 ]GLP-1/GcG displaying prominent insulin secretory actions in all three models, corroborating triple agonist properties.…”

“…In Vitro cAMP Production-Effects of [DA 2 ]GLP-1/GcG, GLP-1, GIP, and glucagon on cAMP production were assessed in Chinese hamster lung cells transfected with either the human GIP-or GLP-1-R, as well as human embryonic kidney (HEK293) cells transfected with the human glucagon R (17). Cells were seeded (200,000 cells/well) into 96-well plates (Nunc) and washed with Hanks' balanced salt solution buffer before incubation with test peptides (10 Ϫ6 -10 Ϫ12 mol/liter) in the presence of 200 mol/liter 3-isobutyl-1-methylxanthine for 20 min at 37°C.…”

Incretin-based therapy for type 2 diabetes mellitus is promising for treating neurodegenerative diseases

“…YAG-glucagon is Y(1)-dA(2)-I(12)-N(17)-V(18)-I(27)-G(28,29)-glucagon. YAG-glucagon is a DPP-IV-resistant triple agonist of GIP, GLP-1, and GCGr and exhibits potent glucose-lowering and insulinotropic actions in HFD mice (Bhat et al, 2013b). Besides, the first 11 N-terminal residues of OXM were substituted with the sequence of stable d-Ala 2 GIP molecules to generate a novel GIP-OXM peptide (d-Ala 2 GIP-OXM).…”

Sequential induction of beta cell rest and stimulation using stable GIP inhibitor and GLP-1 mimetic peptides improves metabolic control in C57BL/KsJ db/db mice

“…Importantly, benefits where chiefly apparent when GIP(6-30)Cex-K 40 [Pal] was administered during the light cycle, coupled with liraglutide injection during the dark cycle. Thus, although the current trend is to develop dual or triple agonist for diabetes [29][30][31][32], treatment modalities that incorporate sustained periods of beta cell rest combined with suitable intervals of beta cell stimulation appear to have significant therapeutic potential for diabetes. As such, appropriate combined, but non-simultaneous, administration of a GIP receptor inhibitor and GLP-1 receptor mimetic should be further investigated for therapeutic efficacy in other animal models of diabetes and type 2 diabetes in humans.…”