An oral GLP-1 and GIP dual receptor agonist improves metabolic disorders in high fat-fed mice

Abstract

Dual activation of the glucagon-like peptide 1 (GLP-1) receptor and the glucose-dependent insulinotropic polypeptide (GIP) receptor has potential as a novel strategy for treatment of diabesity. Here, we created a hybrid peptide which we named 19W, and show that it is more stable in presence of murine plasma than exendin-4 is. In vitro studies were performed to reveal that 19W could stimulate insulin secretion from INS-1 cells in a dose-dependent manner, just like the native peptide GIP and exendin-4 do. 19W effectively evoked dose-dependent cAMP production in cells targeting both GLP-1R and GIPR. In healthy C57BL/6J mice, the single administration of 19W significantly improved glucose tolerance. When administered in combination with sodium deoxycholate (SDC), its oral hypoglycemic activity was enhanced. Pharmacokinetics studies in Wistar rats revealed that 19W was absorbed following oral uptake, while SDC increased its bioavailability. A long-term (28 days) exposure study of twice-daily oral administration to high fat-fed (HFF) mice showed that 19W significantly reduced animal food intake, body weight, fasting blood glucose, total serum cholesterol (T-CHO), non-esterified free fatty acids (NEFA), and low-density lipoprotein cholesterol (LDL-C) levels. It also significantly improved glucose tolerance and the pancreatic β/α cell ratio, and decreased the area of liver fibrosis. These results clearly demonstrate the beneficial action of this novel oral GLP-1/GIP dual receptor agonist to reduce adiposity and hyperglycemia in diabetic mice and to ameliorate liver fibrosis associated with obesity. This dual-acting peptide can be considered a good candidate for novel oral therapy to treat obesity and diabetes.