Differential Effects of AT1 Receptor Inhibition on Superoxide Generation and Endoplasmic Reticulum Stress in Human Coronary Artery Endothelial Cells

Presentation Number: MON 522
Date of Presentation: April 3rd, 2017

Marilu MARGARITA Jurado*1, Michael John Haas2, Luisa M. Onstead-Haas3 and Arshag D Mooradian2
1University of Florida Jacksonville College of Medicine, Jacksonville, FL, JACKSONVILLE, 2University of Florida, Jacksonville, Jacksonville, FL, 3University of Florida, Jacksonville, FL

Abstract

Differential effects of AT1 Receptor Inhibition on Superoxide Generation and Endoplasmic Reticulum Stress in Human Coronary Artery Endothelial Cells. Marilu Jurado-Flores, Luisa Onstead-Haas, Arshag D. Mooradian, and Michael J. Haas. Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Florida Jacksonville College of Medicine, Jacksonville, FL 32209.

Background. AT1 receptor inhibition has been shown to suppress glucose-induced superoxide (SO) generation in the kidney and other tissues both in vitro and in vivo. However, glucose has been shown to also induce endoplasmic reticulum (ER) stress in several cell types including coronary artery endothelial cells (HCAEC).

Methods. SO generation and ER stress were measured in HCAEC treated with high-dextrose or tunicamycin (TM) by MCLA chemiluminescence and the ES-TRAP assay, respectively. AT1 receptor expression was knocked out via a specific siRNA and results compared to cells transfected with a non-specific control siRNA. AT1 receptor expression was measured by Western blot.

Results. Exposure of HCAEC to high-dextrose induced SO generation and ER stress. Inhibition of AT1 receptor expression with an AT1-specific siRNA, but not a control siRNA, inhibited both of these responses, as did treatment with the AT1 receptor antagonists losartan and candesartan. As expected, treatment of HCAEC with TM induced ER stress, however inhibition of AT1 expression via siRNA or addition of losartan or candesartan had no effect on ER stress. Although lisinopril, captopril, and spironolactone inhibited high-dextrose-induced SO generation, however only spironolactone inhibited both high-dextrose-induced and TM-induced ER stress.

Conclusions. Inhibition of AT1 expression and/or activity prevented high-dextrose-induced SO generation and ER stress but had no effect on TM-induced ER stress in HCAEC.

 

Nothing to Disclose: MMJ, MJH, LMO, ADM