A GLP-1/glucagon (GCG)/CCK₂ receptors tri-agonist provides new therapy for obesity and diabetes

Background and purpose: Glucagon-like peptide-1 (GLP-1) and glucagon (GCG) receptor dual agonist have promising therapeutic effects in the treatment of obesity and diabetes. Moreover, GLP-1 and cholecystokinin 2 (CCK₂ ) dual agonists have been shown to restore pancreas function and improve glycaemic control in preclinical studies. We describe, for the first time, the beneficial effects of GLP-1/glucagon receptor and GLP-1/CCK₂ dual agonists, which can be integrated into one peptide, resulting in significant anti-diabetes and anti-obesity effectiveness.

Experimental approach: The in vitro potency of this novel peptide Xenopus (x) GLP-1/GCG/CCK₂ tri-agonist (xGLP/GCG/gastrin) against GLP-1, GCG, CCK₁ and CCK₂ receptors was determined on cells expressing the corresponding receptors by cAMP accumulation or ERK1/2 phosphorylation assays. The in vivo anti-diabetes and anti-obesity effects of this tri-agonist xGLP/GCG/gastrin were studied in both db/db and diet induced obesity (DIO) mice.

Key results: xGLP/GCG/gastrin was a potent and selective GLP-1, GCG and CCK₂ tri-agonist. In DIO mice, the metabolic benefits of xGLP-1/GCG/gastrin, such as reduction of body weight and hepatic lipid contents were significantly better than those of the peptide ZP3022 (GLP-1/CCK-2 dual agonist) and liraglutide. In a short-term study in db/db mice, xGLP/GCG/gastrin treatment had considerable effects, increasing islet numbers, islet areas and insulin content. In a long-term treatment study using db/db mice, xGLP-1/GCG/gastrin showed a significantly and sustained improvement in glucose tolerance and glucose control compared with that of liraglutide, ZP3022, cotadutide (GLP-1/GCG dual agonist) and xGLP/GCG-15.

Conclusions and implications: These results demonstrate the therapeutic potential of xGLP-1/GCG/gastrin for the treatment of obesity and diabetes.