OR05-5 AZP-3404, a 9-Amino Acid Peptide Analog of Insulin-Like Growth Factor-Binding Protein 2, Reverses Insulin Resistance in Leptin-Deficient ob/ob Mice

• Published in: Journal of the Endocrine Society Vol. 3; no. Supplement_1
• Main Authors: Milano, Stephane, Delale, Thomas, Abribat, Thierry, Culler, Michael, van der Lely, Aart, Clemmons, David
• Format: Journal Article
• Language: English
• Published: Washington, DC Endocrine Society 30-04-2019
• Subjects: Diabetes Mellitus and Glucose Metabolism
• ISSN: 2472-1972; 2472-1972
• DOI: 10.1210/js.2019-OR05-5

Insulin-like growth factor-binding protein-2 (IGFBP-2), one of six highly-conserved binding proteins that modulate circulating IGF1, has significant regulatory actions on carbohydrate, lipid and bone metabolism that are independent of its IGF-1 binding role. The metabolic activity of IGFBP-2 has been localized to a short peptide sequence within its unique heparin-binding domain, HBD-1, that is able to reproduce the metabolic actions of the full IGFBP-2 on bone and fat. Through structure-activity studies of this sequence, an acylated 9-amino acid peptide, AZP-3404, with enhanced stability and pharmacokinetics, has been developed that retains the activity of IGFBP-2 on fat and bone metabolism. As IGFBP-2 treatment has also been demonstrated to improve glucose homeostasis in animal models of severe insulin resistance, including the leptin-deficient ob/ob mouse, the present study was undertaken to determine whether AZP-3404 is able to reverse insulin resistance and improve glucose homeostasis in the ob/ob mouse. Male B6.Cg-Lepob/J mice were implanted with HD-XG telemetric devices (Data Sciences International), which allows continuous, wireless monitoring of carotid blood glucose under awake, unrestrained conditions. Animals were randomly assigned to groups (n=8) receiving either saline or AZP-3404 at 1 or 3 mg/kg, b.i.d. for four weeks. The mean daily blood glucose level prior to study initiation was 507 ± 102 mg/dL. Treatment with AZP-3404 dose-dependently decreased the average daily glucose concentration, such that by day 27, glucose levels were reduced by 64 ± 29 and 100 ± 16 mg/dL in the 1 and 3 mg/kg AZP-3404-treated groups, respectively, while slightly increased by 14 ± 29 mg/dL in the vehicle-treated group. On days 7, 14, 21 and 28, following a 24-hour fast, the mice were given an intraperitoneal glucose tolerance test (IPGTT: 1g glucose/kg) to evaluate the impact of AZP-3404 on glucose disposal which is impaired in ob/ob mice. By day 28, the fasting glucose level was reduced by 8% and 20% in the 1 and 3 mg/kg AZP-3404-treated groups, respectively, as compared with fasting levels on day 7. The IPGTTs revealed a progressive, dose-dependent reduction in glucose excursion that reached a decrease of 40% after 4 weeks of treatment with 3mg/kg AZP-3404. In related studies, we have observed that AZP-3404, both alone and in an additive manner with insulin, stimulates glucose transport in mouse C2C12 differentiated myotubes through activation of AMP-activated protein kinase (AMPK). These findings suggest that AZP- 3404 stimulates glucose uptake by muscle tissue in ob/ob mice thereby improving glucose homeostasis. The results from these studies confirm that AZP-3404 retains the ability of IGFBP-2 to restore glucose homeostasis and support the development of AZP-3404 as a novel therapeutic approach for syndromes of severe insulin resistance.