Hepatic insulin-degrading enzyme regulates glucose and insulin homeostasis in diet-induced obese mice

© 2020 The Authors.The insulin-degrading enzyme (IDE) is a metalloendopeptidase with a high affinity for insulin. Human genetic polymorphisms in Ide have been linked to increased risk for T2DM. In mice, hepatic Ide ablation causes glucose intolerance and insulin resistance when mice are fed a regular diet. [Objective]: These studies were undertaken to further investigate its regulatory role in glucose homeostasis and insulin sensitivity in diet-induced obesity. [Methods]: To this end, we have compared the metabolic effects of loss versus gain of IDE function in mice fed a high-fat diet (HFD). [Results]: We demonstrate that loss of IDE function in liver (L-IDE-KO mouse) exacerbates hyperinsulinemia and insulin resistance without changes in insulin clearance but in parallel to an increase in pancreatic β-cell function. Insulin resistance was associated with increased FoxO1 activation and a ~2-fold increase of GLUT2 protein levels in the liver of HFD-fed mice in response to an intraperitoneal injection of insulin. Conversely, gain of IDE function (adenoviral delivery) improves glucose tolerance and insulin sensitivity, in parallel to a reciprocal ~2-fold reduction in hepatic GLUT2 protein levels. Furthermore, in response to insulin, IDE co-immunoprecipitates with the insulin receptor in liver lysates of mice with adenoviral-mediated liver overexpression of IDE. [Conclusions]: We conclude that IDE regulates hepatic insulin action and whole-body glucose metabolism in diet-induced obesity via insulin receptor levels.This work was supported by grants from the Ministerio de Economía, Industria y Competitividad: SAF2016-77871-C2-1-R to IC; SAF2016-77871-C2-2-R to GP; This work was supported by grants from the Ministerio de Ciencia e Innovación PID2019-110496RB-C21 to IC; PID2019-110496RB-C22 to GP. European Foundation for the Study of Diabetes (European Diabetes Research Programme on New Targets for Type 2 Diabetes supported by MSD-2017) to IC and GP. The project leading to these results has received funding from “la Caixa” Foundation, under agreement LCF/PR/PR18/51130007 to GP. This work was suppoted by grant from NIH GM115617 to ML