Aegeline inspired synthesis of novel ß3-AR agonist improves insulin sensitivity in vitro and in vivo models of insulin resistance.

BACKGROUND AND PURPOSE: In our drug discovery program of natural product, earlier we have reported Aegeline that is N-acylated-1-amino-2- alcohol, which was isolated from the leaves of Aeglemarmelos showed anti-hyperlipidemic activity for which the QSAR studies predicted the compound to be the ß3-AR agonist, but the mechanism of its action was not elucidated. In our present study, we have evaluated the ß3-AR activity of novel N-acyl-1-amino-3-arylopropanol synthetic mimics of aegeline and its beneficial effect in insulin resistance. In this study, we have proposed the novel pharmacophore model using reported molecules for antihyperlipidemic activity. The reported pharmacophore features were also compared with the newly developed pharmacophore model for the observed biological activity. EXPERIMENTAL APPROACH: Based on 3D pharmacophore modeling of known ß3AR agonist, we screened 20 synthetic derivatives of Aegeline from the literature. From these, the top scoring compound 10C was used for further studies. The in-slico result was further validated in HEK293T cells co-trransfected with human ß3-AR and CRE-Luciferase reporter plasmid for ß3-AR activity.The most active compound was selected and ß3-AR activity was further validated in white and brown adipocytes differentiated from human mesenchymal stem cells (hMSCs). Insulin resistance model developed in hMSC derived adipocytes was used to study the insulin sensitizing property. 8 week HFD fed C57BL6 mice was given 50 mg/Kg of the selected compound and metabolic phenotyping was done to evaluate its anti-diabetic effect. RESULTS: As predicted by in-silico 3D pharmacophore modeling, the compound 10C was found to be the most active and specific ß3-AR agonist with EC50 value of 447 nM. The compound 10C activated ß3AR pathway, induced lipolysis, fatty acid oxidation and increased oxygen consumption rate (OCR) in human adipocytes. Compound 10C induced expression of brown adipocytes specific markers and reverted chronic insulin induced insulin resistance in white adipocytes. The compound 10C also improved insulin sensitivity and glucose tolerance in 8 week HFD fed C57BL6 mice. CONCLUSION: This study enlightens the use of in vitro insulin resistance model close to human physiology to elucidates the insulin sensitizing activity of the compound 10C and edifies the use of ß3AR agonist as therapeutic interventions for insulin resistance and type 2 diabetes.