Abstract 3757: Targeted Inactivation of Receptor for Advanced Glycation Products Reduced Oxidative LDL-Induced Inflammation and Atherosclerosis in Non-Diabetic LDL Receptor−/− Mice

Abstract

Receptor for advanced glycation products (RAGE) is a multiligand receptor on vascular cells and plays an important role in the progression of diabetic complications. To define if RAGE modulates atherosclerosis under non-diabetic conditions, we examined the effect of RAGE deficiency in non-diabetic mice with hyperlipidemia. RAGE knockout mice (RAGE−/−) were bred with low-density lipoprotein receptor knockout (LDLr−/−) mice to generate the double knockout (DKO) mice. The mice were fed with western diet for 12 weeks, and aortic atherosclerotic lesions were analyzed histologically. Although there was no difference in body weight, fasting blood glucose and serum AGE levels between DKO and LDLr−/− mice, DKO mice exhibited a significant decrease in the size and macrophage content in atherosclerosis lesions compared with LDLr−/− mice. Expressions of endothelial adhesion molecules such as VCAM-1 and ICAM-1 in the aorta were lower in DKO mice than those in LDLr−/− mice. Chemiluminescence and fluorescence-based assays revealed that DKO mice showed lower oxidative stress in the vessel wall than LDLr−/− mice. Complementary in vitro studies revealed that peritoneal macrophages isolated from RAGE−/− mice exhibited a decrease in oxidative LDL (oxLDL)-induced ERK activation and proliferation when compared to RAGE+/+ macrophages. In contrast, overxpression of RAGE in COS7 cells resulted in the augmented ERK activation in response to oxLDL, which is abolished by the co-incubation with anti-RAGE blocking antibodies. The results indicated that oxLDL activated RAGE and increased oxidative stress via NADH/NADPH oxidase pathway. OxLDL may serve as a new ligand for RAGE. RAGE inactivation inhibits atherosclerosis by reducing pro-inflammatory and oxidative stress under the hyperlipidmic, non-diabetic condition.