Effect of irreversibly glycated LDL in human vascular smooth muscle cells: lipid loading, oxidative and inflammatory stress.
The major complication of diabetes is accelerated atherosclerosis, the progression of which entails complex interactions between the modified low-density lipoproteins (LDL) and the cells of the arterial wall. Advanced glycation end product-modified-LDL (AGE-LDL) that occurs at high rate in diabetes contributes to diabetic atherosclerosis, but the underlying mechanisms are not fully understood. The aim of this study was to assess the direct effect of AGE-LDL on human vascular smooth muscle cells (hSMC) dysfunction. Cultured hSMC incubated (24 hrs) with human AGE-LDL, native LDL (nLDL) or oxidized LDL (oxLDL) were subjected to: (i) quantification of the expression of the receptors for modified LDL and AGE proteins (LRP1, CD36, RAGE) and estimation of lipid loading, (ii) determination of NADPH oxidase activity and reactive oxygen species (ROS) production and (iii) evaluation of the expression of monocyte chemoattractant protein-1 (MCP-1). The results show that exposure of hSMC to AGE-LDL (compared to nLDL) induced: (a) increased NADPH oxidase activity (30%) and ROS production (28%) by up-regulation of NOX1, NOX4, p22phox and p67phox expression, (b) accumulation of intracellular cholesteryl esters, (c) enhanced gene expression of LRP1 (160%) and CD36 (35%), and protein expression of LRP1, CD36 and RAGE, (d) increased MCP-1 gene expression (160%) and protein secretion (300%) and (e) augmented cell proliferation (30%). In conclusion, AGE-LDL activates hSMC (increasing CD36, LRP1, RAGE), inducing a pro-oxidant state (activation of NADPHox), lipid accumulation and a pro-inflammatory state (expression of MCP-1). These results may partly explain the contribution of AGE-LDL and hSMC to the accelerated atherosclerosis in diabetes.
Sima
Anca V
AV
Department of Lipoproteins and Atherosclerosis, Institute of Cellular Biology and Pathology 'Nicolae Simionescu', Bucharest, Romania. anca.sima@icbp.ro
Botez
Gabriela M
GM
Stancu
Camelia S
CS
Manea
Adrian
A
Raicu
Monica
M
Simionescu
Maya
M
D015703:Antigens, CD / Q000235:genetics; D001158:Arteries / Q000166:cytology; D050197:Atherosclerosis / Q000209:etiology; D018955:CD36 Antigens / Q000235:genetics; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000235:genetics; D048909:Diabetes Complications; D042783:Endothelial Cells / Q000737:chemistry / Q000166:cytology / Q000378:metabolism*; D015870:Gene Expression; D017127:Glycation End Products, Advanced / Q000378:metabolism*; D006801:Humans; D007249:Inflammation; D008077:Lipoproteins, LDL / Q000378:metabolism*; D026503:Low Density Lipoprotein Receptor-Related Protein-1 / Q000235:genetics; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000378:metabolism*; D000074624:NADPH Oxidase 1; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism; D018384:Oxidative Stress; D010750:Phosphoproteins / Q000235:genetics; D017382:Reactive Oxygen Species / Q000097:blood; D000067759:Receptor for Advanced Glycation End Products; D011971:Receptors, Immunologic / Q000235:genetics / Q000378:metabolism; D000093844:Glycated Proteins
D015703:Antigens, CD; D018955:CD36 Antigens; D018932:Chemokine CCL2; D017127:Glycation End Products, Advanced; D008077:Lipoproteins, LDL; D026503:Low Density Lipoprotein Receptor-Related Protein-1; D000074624:NADPH Oxidase 1; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases; D010750:Phosphoproteins; D017382:Reactive Oxygen Species; D000067759:Receptor for Advanced Glycation End Products; D011971:Receptors, Immunologic; C475476:LRP1 protein, human; C031797:glycated lipoproteins, LDL; D000093844:Glycated Proteins; C079789:neutrophil cytosol factor 67K; C402799:NOX1 protein, human; C498910:NOX4 protein, human; C086986:CYBA protein, human