Abstract P2152: Asperuloside Ameliorates Obesity-associated Endothelial Dysfunction Via Activating Nrf2/HO-1 Signaling Pathway

Abstract

Objectives: Asperuloside (ASP) is the major bioactive components in Eucommia species but its effects on vascular health and the underlying mechanism remain unknown. In this study we aim to investigate the protective vascular effect of ASP and we hypothesize that ASP ameliorates obesity associated endothelial dysfunction. Methods: After induction of obesity in C57BL/6 male mice fed with high fat diet for twelve weeks, they were treated daily with ASP (50 mg/kg) via oral gavage for seven weeks in vivo study. C57BL/6 mice aortae were used for ex vivo study and endothelial cells were used for in vitro study. Vascular function was determined by wire myograph. DHE and MitoSOX staining were used to detect ROS levels. QPCR, aortic en-face immunofluorescence staining and Western blotting were used to analyze mRNA and protein expressions. Small interfering (si)RNA of Nrf2 and HO-1, inhibitors of Nrf2 (ML385) and HO-1 (OB-24) were used to elucidate the mechanistic pathway of ASP ’s action. Findings: ASP significantly improved endothelial-dependent relaxations, suppressed oxidative stress, reduced VCAM-1 (~2 fold) and ICAM-1 (~2 fold) expression, increased both Nrf2 (~1.5 fold) and HO-1 (~1.5 fold) expression in obese mice aortae, IL-1β-treated aortae ex vivo and endothelial cells. However, ASP failed to prevent endothelial dysfunction in HO-1 inhibited aortae and HO-1-siRNA transfected endothelial cells, indicating that ASP improved endothelial function through upregulating HO-1. Nrf2 knockdown attenuated HO-1 upregulation by ASP, showing that ASP regulated Nrf2/HO-1 pathway. ASP increased nuclear Nrf2 and dual luciferase reporter assay illustrated that ASP increased ARE binding activity. Moreover, inhibition of Nrf2/ARE binding by ML385 blocked vascular protective effects and HO-1 upregulation by ASP, showing that ASP activated Nrf2/HO-1 signaling by stimulating Nrf2/ARE binding. Conclusions: This study for the first time shows that ASP rescues endothelial dysfunction and suppresses vascular oxidative stress associated with obesity and IL-1β via activating Nrf2/HO-1 pathway. These findings explore the pharmacological effects of ASP and contribute to the development of a novel treatment for endothelial dysfunction in cardiovascular diseases.