Carpachromene Ameliorates Insulin Resistance in HepG2 Cells via Modulating IR/IRS1/PI3k/Akt/GSK3/FoxO1 Pathway.

Rania Alaaeldin,Iman A M Abdel-Rahman,Nancy Youssef,Ahmed E Allam,Qing-Li Zhao,Heba Ali Hassan,Sayed F Abdelwahab,Moustafa Fathy

doi:10.3390/molecules26247629

Abstract

Insulin resistance contributes to several disorders including type 2 diabetes and cardiovascular diseases. Carpachromene is a natural active compound that inhibits α-glucosidase enzyme. The aim of the present study is to investigate the potential activity of carpachromene on glucose consumption, metabolism and insulin signalling in a HepG2 cells insulin resistant model. A HepG2 insulin resistant cell model (HepG2/IRM) was established. Cell viability assay of HepG2/IRM cells was performed after carpachromene/metformin treatment. Glucose concentration and glycogen content were determined. Western blot analysis of insulin receptor, IRS1, IRS2, PI3k, Akt, GSK3, FoxO1 proteins after carpachromene treatment was performed. Phosphoenolpyruvate carboxykinase (PEPCK) and hexokinase (HK) enzymes activity was also estimated. Viability of HepG2/IRM cells was over 90% after carpachromene treatment at concentrations 6.3, 10, and 20 µg/mL. Treatment of HepG2/IRM cells with carpachromene decreased glucose concentration in a concentration- and time-dependant manner. In addition, carpachromene increased glycogen content of HepG2/IRM cells. Moreover, carpachromene treatment of HepG2/IRM cells significantly increased the expression of phosphorylated/total ratios of IR, IRS1, PI3K, Akt, GSK3, and FoxO1 proteins. Furthermore, PEPCK enzyme activity was significantly decreased, and HK enzyme activity was significantly increased after carpachromene treatment. The present study examined, for the first time, the potential antidiabetic activity of carpachromene on a biochemical and molecular basis. It increased the expression ratio of insulin receptor and IRS1 which further phosphorylated/activated PI3K/Akt pathway and phosphorylated/inhibited GSK3 and FoxO1 proteins. Our findings revealed that carpachromene showed central molecular regulation of glucose metabolism and insulin signalling via IR/IRS1/ PI3K/Akt/GSK3/FoxO1 pathway.

Highlights

Insulin resistance is a condition that arises from the defect in insulin-mediated actions on glucose and lipid metabolism, which occurs mainly in liver, muscles, and adipose tissues.This contributes to numerous human diseases including type 2 diabetes mellitus and cardiovascular diseases [1,2]
We investigated, for the first time, the potential activity of carpachromene, which was shown to inhibit α-glucosidase enzyme activity [23], on glucose consumption, metabolism, and insulin signaling in a HepG2 cells insulin resistant model
To obtain the insulin resistant model of HepG2 cells (HepG2/Insulin Resistant Model (IRM)), we examined the effect of different concentrations of insulin (0.005, 0.05, 0.5, 5, 50 μmol) on glucose concentration for different time intervals 12, 24, 36, 48, as shown in Table 1 and Figure 1

Summary

Introduction

Insulin resistance is a condition that arises from the defect in insulin-mediated actions on glucose and lipid metabolism, which occurs mainly in liver, muscles, and adipose tissues. This contributes to numerous human diseases including type 2 diabetes mellitus and cardiovascular diseases [1,2]. It initiates a downstream signaling cascade to phosphorylate the tyrosine residues of the insulin receptor substrate (IRS) family for their activation. IRS-1 (IRS1) and -2 (IRS2) are implicated in most of the metabolic actions mediated via insulin receptors [4]. Insulin receptor activation and the consecutive phosphorylation/activation of signaling proteins, primarily

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