AMG 837: A Novel GPR40/FFA1 Agonist that Enhances Insulin Secretion and Lowers Glucose Levels in Rodents

Agonists of GPR40 (FFA1) have been proposed as a means to treat type 2 diabetes. Through lead optimization of a high throughput screening hit, we have identified a novel GPR40 agonist called AMG 837. The objective of these studies was to understand the preclinical pharmacological properties of AMG 837. The activity of AMG 837 on GPR40 was characterized through GTPγS binding, inositol phosphate accumulation and Ca2+ flux assays. Activity of AMG 837 on insulin release was assessed on isolated primary mouse islets. To determine the anti-diabetic activity of AMG 837 in vivo, we tested AMG 837 using a glucose tolerance test in normal Sprague-Dawley rats and obese Zucker fatty rats. AMG 837 was a potent partial agonist in the calcium flux assay on the GPR40 receptor and potentiated glucose stimulated insulin secretion in vitro and in vivo. Acute administration of AMG 837 lowered glucose excursions and increased glucose stimulated insulin secretion during glucose tolerance tests in both normal and Zucker fatty rats. The improvement in glucose excursions persisted following daily dosing of AMG 837 for 21-days in Zucker fatty rats. Preclinical studies demonstrated that AMG 837 was a potent GPR40 partial agonist which lowered post-prandial glucose levels. These studies support the potential utility of AMG 837 for the treatment of type 2 diabetes

GDF15 deficiency promotes high fat diet-induced obesity in mice.

Pharmacological treatment of recombinant growth differentiation factor 15 (GDF15) proteins reduces body weight in obese rodents and primates. Paradoxically, circulating GDF15 levels are increased in obesity. To investigate the role of endogenous GDF15 in obesity development, we put GDF15 knockout mice and wildtype controls on high fat diet for the mice to develop diet-induced obesity. Compared to wildtype animals, GDF15 knockout mice were more prone to high fat diet-induced obesity. Male knockout mice showed worse glucose tolerance, lower locomotor activity and lower metabolic rate than wildtype mice. Additionally, GDF15 deficiency increased occurrences of high fat diet-induced skin lesions. Our data suggests that endogenous GDF15 has a protective role in obesity development and lack of GDF15 aggravates the progression of obesity and associated pathological conditions. Elevated GDF15 levels in obesity may have resulted from a response to overcome GDF15 resistance

Male GDF15 were more prone to high fat diet-induced obesity.

<p>(A) Body weight of male mice. (B) Body weight of female mice. (C) Average daily food intake. (D) Body composition of male mice. n = 12–21 for male mice. n = 11–22 for female mice. Data are shown as mean±SEM. *p<0.05, ***p<0.001 between WT and KO by ANOVA.</p

Metabolic rate and RER of female mice.

<p>(A) Oxygen consumption of female DIO mice: continuous 3-d recording and average value of each light cycle. (B) RER of female DIO mice: continuous 3-d recording and average value of each light cycle. (C) Heat production of female DIO mice: continuous 3-d recording and average value of each light cycle. n = 5–7. CLAMS recorded data are shown as mean. Analyzed average values are shown as mean±SEM.</p

Male GDF15 knockout DIO mice had lower metabolic rate than wildtype mice.

<p>(A) Oxygen consumption of male DIO mice: continuous 3-d recording and average value of each light cycle. (B) RER of male DIO mice: continuous 3-d recording and average value of each light cycle. (C) Heat production of male DIO mice: continuous 3-d recording and average value of each light cycle. n = 6. CLAMS recorded data are shown as mean. Analyzed average values are shown as mean±SEM. *p<0.05 between WT and KO by unpaired t-test.</p

Male GDF15 knockout DIO mice had higher glucose levels, insulin levels and worsened glucose tolerance.

<p>(A) 4hr fasting blood glucose levels of male mice. (B) 4hr fasting blood glucose levels of female mice. (C) 4hr fasting serum insulin levels of male mice. (D) 4hr fasting serum insulin levels of female mice. (E) Blood glucose levels of male mice during oral glucose tolerance test. (F) Blood glucose levels of female mice during oral glucose tolerance test. n = 12–21 for male mice. n = 11–22 for female mice. Data are shown as mean±SEM. *p<0.05, **p<0.01, ***p<0.001 between WT and KO by 2-Way ANOVA.</p

Male GDF15 knockout DIO mice had lower locomotor activity.

<p>(A) X-axis activity of male DIO mice: continuous 3-d recording and average value of each light cycle. (B) Z-axis activity of male DIO mice: continuous 3-d recording and average value of each light cycle. (C) Continuous 3-d recording of food intake of male DIO mice. (D) Cumulative food intake of male DIO mice. n = 6. Raw CLAMS recorded data are shown as mean. Analyzed average values are shown as mean±SEM. *p<0.05, **p<0.01 between WT and KO by 2-way ANOVA.</p

A Potent Class of GPR40 Full Agonists Engages the EnteroInsular Axis to Promote Glucose Control in Rodents

<div><p>Type 2 diabetes is characterized by impaired glucose homeostasis due to defects in insulin secretion, insulin resistance and the incretin response. GPR40 (FFAR1 or FFA1) is a G-protein-coupled receptor (GPCR), primarily expressed in insulin-producing pancreatic β-cells and incretin-producing enteroendocrine cells of the small intestine. Several GPR40 agonists, including AMG 837 and TAK-875, have been disclosed, but no GPR40 synthetic agonists have been reported that engage both the insulinogenic and incretinogenic axes. In this report we provide a molecular explanation and describe the discovery of a unique and potent class of GPR40 full agonists that engages the enteroinsular axis to promote dramatic improvement in glucose control in rodents. GPR40 full agonists AM-1638 and AM-6226 stimulate GLP-1 and GIP secretion from intestinal enteroendocrine cells and increase GSIS from pancreatic islets, leading to enhanced glucose control in the high fat fed, streptozotocin treated and NONcNZO10/LtJ mouse models of type 2 diabetes. The improvement in hyperglycemia by AM-1638 was reduced in the presence of the GLP-1 receptor antagonist Ex(9–39)NH₂.</p> </div