Regulation of Apolipoprotein A-I Gene Expression in Human Macrophages by Oxidized Low-Density Lipoprotein

Author(s):  
Ekaterina V. Nekrasova ◽  
Ekaterina E. Larionova ◽  
Katerina Danko ◽  
Darya O. Kuzmina ◽  
Vladimir S. Shavva ◽  
...  
2009 ◽  
Vol 296 (6) ◽  
pp. C1329-C1337 ◽  
Author(s):  
Mark D. Mattaliano ◽  
Christine Huard ◽  
Wei Cao ◽  
Andrew A. Hill ◽  
Wenyan Zhong ◽  
...  

Oxidized low-density lipoprotein (OxLDL) has been implicated as a proatherogenic factor with a pathological role in the induction of endothelial dysfunction. Endothelial cells bind and uptake OxLDL primarily through the scavenger receptor lectin-like oxidized-low-density lipoprotein receptor-1 (LOX-1), which is believed to mediate critical effects of OxLDL in endothelial cells. To examine the biological events following LOX-1 activation by OxLDL, we used cDNA microarray analysis to globally analyze gene expression changes induced by OxLDL treatment of human aortic endothelial cell line (HAECT) cells overexpressing LOX-1. Consistent with reported functions of OxLDL, in control HAECT cells, OxLDL elicited gene changes in the oxidative stress pathway and other signaling pathways related to OxLDL. With OxLDL treatment, LOX-1-dependent gene expression changes associated with inflammation, cell adhesion, and signal transduction were observed. The transcripts of a number of cytokines and chemokines were induced, which included interleukin-8, CXCL2, CXCL3, and colony-stimulating factor-3. The secretion of these cytokines was confirmed by enzyme-linked immunosorbent assay analysis. In addition, our data revealed a novel link between LOX-1 and a number of genes, including Delta/notch-like epidermal growth factor repeat containing, stanniocalcin-1, cAMP response element modulator, and dual specificity phosphatase 1. Promoter analysis on the genes that changed as a result of LOX-1 activation by OxLDL allowed us to identify early growth response 1 and cAMP response element-binding protein as potential novel transcription factors that function downstream of LOX-1. Our study has enabled us to elucidate the gene expression changes following OxLDL activation of LOX-1 in endothelial cells and discover novel downstream targets for LOX-1.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 246-246
Author(s):  
Mingyi Chen ◽  
Xin Lin ◽  
Hannah Archibald ◽  
Ted Wun ◽  
Ralph Green

Abstract Abstract 246 Introduction: Inflammation and abnormal adhesion of sickle red blood cells (RBCs), leukocytes and platelets to the vascular endothelium are postulated to play a central role in the pathogenesis of vaculopathy associated with sickle cell disease (SCD). Dysfunctional endothelial cells in the SCD vaso-occlusive process display vasoconstriction, proinflammatory and prothrombotic changes. Sickle RBCs may damage or activate the endothelium via enhanced expression of cell surface adhesion molecules such as vascular cell adhesion molecule (VCAM), intercellular adhesion molecules (ICAM), platelet endothelial cellular adhesion marker (PECAM), E- selectin, and P-selectin. In addition, SCD modulates high levels of circulating soluble adhesion molecules especially during the sickle cell crisis. Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is an endothelial cell receptor for oxidized low-density lipoprotein. The enhanced expression of LOX-1 in endothelial cells has been identified in a variety of pathologic conditions including atherosclerosis, diabetic vasculopathy, hyperlipidemia and inflammation. The purpose of this study is to investigate changes in the expression of LOX-1 and its potential role in the pathogenesis of SCD vasculopathy. Methods: Using real time quantitative PCR, we analyzed LOX-1 gene expression in cultured human coronary endothelial cells (HCEC) following static incubation with sickle RBCs. We also measured circulating soluble LOX-1 (sLOX-1) concentrations by sandwich ELISA assay in SCD patient plasma. The statistical analysis was performed using Student's t-test. Results: LOX-1 gene expression in HCEC was significantly increased by incubation with sickle RBCs compared with normal RBCs. Upregulation was detected after 1 hour of incubation, and reached a peak after 6 hours. We studied 48 SCD (hemoglobin SS) patients (26 female, 22 male); vs 17 healthy (hemoglobin AA) control subjects (12 female, 5 male). The SCD cohort comprised pediatric and adult patients in steady-state (33 patients) and vaso-occlusive crisis (VOC; 15 patients). The concentration of circulating sLOX-1 protein in plasma of SCD patients (mean: 3.05±2.53 ng/mL; range 0.30 – 11.30 ng/mL) was significantly higher (p=0.0046) than in control healthy subjects (mean: 1.27±0.81 ng/mL). In the 15 SCD patients with VOC, sLOX-1 concentrations were higher, (mean: 3.65±2.40 ng/mL). Conclusions: Our study reveals that LOX-1 gene expression in endothelial cells is upregulated by incubation with SCD erythrocytes. Baseline circulating sLOX-1 levels are elevated in SCD patients compared with healthy controls. sLOX-1 levels are further elevated in VOC. Enhanced LOX-1 expression in endothelial cells may play a role in the pathophysiology of SCD vasculopathy. Studies of sLOX-1 in SCD may provide new insights into risk stratification, and may lead to novel therapeutic strategies for sickle cell patients with acute vascular complications. Disclosures: Green: Emisphere - Consultancy: Consultancy; Teva Pharmaceuticals - expert testimony: Consultancy.


2008 ◽  
Vol 7 (8) ◽  
pp. 3572-3582 ◽  
Author(s):  
Annabelle Dupont ◽  
Maggy Chwastyniak ◽  
Olivia Beseme ◽  
Anne-Laure Guihot ◽  
Hervé Drobecq ◽  
...  

2012 ◽  
Vol 302 (1) ◽  
pp. C165-C177 ◽  
Author(s):  
Aluganti N. Chandrakala ◽  
Devraj Sukul ◽  
Krithika Selvarajan ◽  
Chittoor Sai-Sudhakar ◽  
Benjamin Sun ◽  
...  

Brain natriuretic peptide (BNP) and monocyte chemotactic protein-1 (MCP-1) are biomarkers of heart failure (HF). The aim of the present study was to determine the role of oxidized low-density lipoprotein (Ox-LDL) in the induction of these biomarkers and the signaling pathways involved in vitro. Incubation of HL-1 cardiomyocytes and human myocytes with Ox-LDL induced the expression of BNP and MCP-1 genes, while native LDL had no effect. When peroxides associated with Ox-LDL were reduced to hydroxides, the ability to induce BNP and MCP-1 gene expression was abolished. Furthermore, exposure of HL-1 cells to ischemic conditions alone had no effect on BNP gene expression, while ischemia followed by reperfusion resulted in increased expression of BNP gene. Inhibitors of ERK and JNK inhibited the induction of BNP. Signaling array results suggested that the induction of both MAPK and NF-κB pathways is involved in the induction of BNP by Ox-LDL. These results suggest that Ox-LDL or peroxidized lipids formed in oxidatively stressed myocytes during ischemia-reperfusion injury may play a role in the induction of BNP and MCP-1.


Blood ◽  
2003 ◽  
Vol 101 (12) ◽  
pp. 4847-4849 ◽  
Author(s):  
Vladimir A. Shatrov ◽  
Vadim V. Sumbayev ◽  
Jie Zhou ◽  
Bernhard Brüne

Abstract Oxidized low-density lipoprotein (oxLDL) and macrophages play a central role in atherosclerosis. Here, we obtained evidence that oxLDL induced hypoxia-inducible factor-1α (HIF-1α) protein accumulation in human macrophages (Mono-Mac-6) under normoxia. HIF-1α accumulation was attenuated by pretreatment with the antioxidant N-acetyl-L-cysteine (NAC), the nitric oxide (NO) donor S-nitrosoglutathione (GSNO), and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitors such as diphenyleniodonium (DPI) or 4-(2-aminoethyl)-benzenesulfonyl fluoride (AEBSF), thus implicating the contribution of oxLDL-generated reactive oxygen species (ROS). Whereas oxLDL did not modulate HIF-1α mRNA levels, experiments with cycloheximide pointed to a translational mechanism in oxLDL action. HIF-1–dependent luciferase reporter gene analysis underscored HIF-1 transactivation. Our results indicate that oxLDL induced HIF-1α accumulation and HIF-1–dependent reporter gene activation in human macrophages via a redox-mediated pathway. This finding may suggest a role of HIF-1 in atherosclerosis and oxLDL-induced pathogenesis.


2009 ◽  
Vol 87 (3) ◽  
pp. 493-498 ◽  
Author(s):  
Paula Martín-Fuentes ◽  
Fernando Civeira ◽  
María Solanas-Barca ◽  
Angel Luis García-Otín ◽  
Estíbaliz Jarauta ◽  
...  

To examine if overexpression of certain chemokines and proinflammatory cytokines in response to oxidized low-density lipoprotein could be involved in the onset and development of tendon xanthomas (TX), we quantified IL-1β, TNF-α, and IL-8 and compared gene expression of PPAR-γ, NF-κBIA, IL-8, IL-1β, CXCL3, tryptase, and TNF-α in macrophages of familial hypercholesterolemia subjects with and without TX stimulated with oxidized low-density lipoprotein at 1, 3, 6, and 18 h of incubation. We propose that chemokines belonging to the CXC family could play an important role in the etiology of TX, with CXCL3 being a possible biological marker of onset and development of TX.


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