Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0004153 (atherosclerosis)
 77,401 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A critical event in the early stages of atherosclerosis is the focal accumulation of lipid-laden foam cells derived from macrophages. In various cholesterol-fed animal models of atherosclerosis, localized attachment of circulating monocytes to arterial endothelial cells appeared to precede the formation of foam cells. It is suggested that monocyte recruitment into early lesions depends on the endothelial adhesiveness for monocytes and lymphocytes. In vivo and in vitro experiments have identified molecules, such as ICAM-1, VCAM-1, and P-selectin, that can support the adhesion of monocytes and lymphocytes. Moreover, oxidized LDL, lysophosphatidyl-choline, and oxidized fatty acids induce the expression not only of these adhesion molecules but also of scavenger receptors, such as CD-36, SR-A, and LOX-1. Recently, we isolated and characterized the novel receptors for oxidized LDL, namely, LOX-1 and SR-PSOX. Expression of LOX-1 is found on endothelial cells, smooth muscle cells, and macrophages, whereas SR-PSOX is expressed on macrophages. In this paper the significance of oxidized LDL and its receptors, LOX-1 and SR-PSOX, in terms of atherogenesis is discussed.
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PMID:Role of oxidized LDL in atherosclerosis. 1179 67

Recent progress in the study of atherosclerosis revealed that the proatherogenic property of LDL is attributable to oxidized LDL. Macrophages recruited to vascular wall phagocytose oxidized LDL and transformed into foam cells, which is a hallmark of atheroma. Endothelial cells also binds oxidized LDL and changes its phenotype to the status of "endothelial dysfunction." We successfully cloned the endothelial receptor for oxidized LDL, designated LOX-1. LOX-1-mediated action of oxidized LDL induces the decrease in NO release and the increased expression of adhesion molecules, which are typical changes in endothelial dysfunction. The expression of LOX-1 is quite inducible. Proinflammatory cytokines, etc. induce the expression of LOX-1 in vitro; and proatherogenic conditions, e.g., hypertension, hyperlipidemia, and diabetes, induce the expression of LOX-1 in vivo. This manner of expression suggests the importance of LOX-1 in pathological settings. LOX-1 binds not only oxidized LDL, but also binds apoptotic cells and activated platelets through the interaction with anionic phospholipids. This property might bridge atherosclerosis and thrombosis. A novel system to detect LOX-1 ligand in plasma detected the increased level of LOX-1 ligand in hypercholesterolemic rabbits compared with normal ones. This system might be useful to predict the status of endothelial function and the risk of ischemic heart disease.
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PMID:[Molecular identification of LOX-1 and analysis of its pathophysiological role]. 1191 16

Oxidatively modified low-density lipoprotein (ox-LDL) leads to endothelial activation, dysfunction and injury. Recently, a novel lectin-like receptor for ox-LDL (LOX-1) has been identified, primarily in the endothelial cells, and it allows uptake of ox-LDL into endothelial cells. This receptor is transcriptionally upregulated by tumor necrosis factor-alpha, angiotensin II, shear stress and ox-LDL itself. The expression of this receptor activates a variety of intracellular processes that lead to expression of adhesion molecules and endothelial activation. This receptor is highly expressed in the blood vessels of animals and humans with hypertension, diabetes mellitus and atherosclerosis. Expression of this receptor may also be relevant in intra-arterial thrombogenesis and myocardial ischemia-reperfusion injury. Identification and regulation of this receptor and understanding of signal transduction pathways may lead to new therapies of diseases characterized by endothelial dysfunction.
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PMID:Identification, regulation and function of a novel lectin-like oxidized low-density lipoprotein receptor. 1198 3

One of the critical events in the early stage of atherosclerosis is the focal accumulation of lipid-laden foam cells derived from macrophages. In various cholesterol-fed animal models of atherosclerosis, it was found that localized attachment of circulating monocytes to arterial endothelial cells appears to precede the formation of foam cells. It has been suggested that monocyte recruitment into early lesions is depend upon the endothelial adhesiveness for monocytes and lymphocytes. In vivo and in vitro experiments have identified molecules, such as ICAM-1, VCAM-1 and P-selecin, those can support the adhesion of monocytes and lymphocytes. Moreover oxidized LDL, lysophosphatidylcholine and oxidized fatty acids induce the expression of not only these adhesion molecules but also scavenger receptors, such as CD-36, SR-A and LOX-1. Recently we isolated and characterized the novel receptors for oxidized LDL, named LOX-1 and SR-PSOX. The expression of LOX-1 is found on endothelial cells, smooth muscle cells and macrophages. Whereas SR-PSOX expresses on macrophages. We address in this paper on the significance of hyperlipidemia, especially oxidized LDL and its receptors in terms of atherosclerosis.
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PMID:[Hyperlipidemia and atherosclerosis]. 1202 85

Calcium channel blockade has been shown to inhibit experimental atherosclerosis, and early clinical trials suggest that it also reduces atherosclerosis in humans. However, the mechanisms underlying the direct protective effect of calcium channel blockade on endothelial cell injury are not fully understood. The apoptosis of endothelial cells induced by oxidized low-density lipoproteins (oxLDL) may provide a mechanistic clue to the "response-to-injury" hypothesis of atherogenesis. Here we report that the calcium channel blocker, nifedipine, prevents the apoptosis of human umbilical venous endothelial cells (HUVECs) induced by oxLDL via downregulation of the endothelial receptor for oxidized LDL (LOX-1) and inhibition of CPP32-like protease activity. The incubation of HUVEC with oxLDL increased LOX-1 mRNA levels and CPP32-like protease activity, and induced apoptosis. Preincubation of HUVEC with nifedipine before incubation with oxLDL significantly suppressed the increase in LOX-1 mRNA levels and CPP32-like protease activity, preventing apoptosis in a dose-dependent manner. These results suggest that nifedipine blocks the suicide pathway leading to the apoptosis of endothelial cells by decreasing LOX-1 mRNA levels and CPP32-like protease activity. Thus, nifedipine seems to play a protective role against the "response-to-injury" hypothesis of atherogenesis.
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PMID:Nifedipine prevents apoptosis of endothelial cells induced by oxidized low-density lipoproteins. 1207 88

LOX-1, a receptor for oxidized low-density lipoprotein (ox-LDL), plays a critical role in endothelial dysfunction and atherosclerosis. LOX-1 activation also plays an important role in monocyte adhesion to endothelial cells. A number of studies show that 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) reduce total LDL cholesterol and exert a cardioprotective effect. We examined the modulation of LOX-1 expression and its function by two different statins, simvastatin and atorvastatin, in human coronary artery endothelial cells (HCAECs). We observed that ox-LDL (40 microg/ml) treatment up-regulated the expression of E- and P-selectins, VCAM-1 and ICAM-1 in HCAECs. Ox-LDL mediated these effects via LOX-1, since antisense to LOX-1 mRNA decreased LOX-1 expression and subsequent adhesion molecule expression. Pretreatment of HCAECs with simvastatin or atorvastatin (1 and 10 microM) reduced ox-LDL-induced expression of LOX-1 as well as adhesion molecules (all P < 0.05). A high concentration of statins (10 microM) was more potent than the low concentration (1 microM) (P < 0.05). Both statins reduced ox-LDL-mediated activation of the redox-sensitive nuclear factor-kappaB (NF-kappaB) but not AP-1. These observations indicate that LOX-1 activation plays an important role in ox-LDL-induced expression of adhesion molecules. Inhibition of expression of LOX-1 and adhesion molecules and activation of NF-kappaB may be another mechanism of beneficial effects of statins in vascular diseases.
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PMID:Statins modulate oxidized low-density lipoprotein-mediated adhesion molecule expression in human coronary artery endothelial cells: role of LOX-1. 1213 Jul 21

Lectin-like oxidized low-density lipoprotein (LDL) receptor-1 (LOX-1) was initially identified as the major receptor for oxidized LDL (OxLDL) in endothelial cells. Its inducible expression in macrophages and smooth muscle cell was also observed. LOX-1 is a Type II membrane protein with a typical C-type lectin structure at the extracellular C-terminus. It can be cleaved by an unknown protease at the extracellular juxtamembrane region to release the soluble form of LOX-1. The extracellular domains of LOX-1 are post-translationally modified by N-linked glycosylation. Mutagenesis studies revealed that the lectin domain of LOX-1 is the functional domain that recognizes the LOX-1 ligand. The C-terminal end residues and several conserved positively charged residues spanning the lectin domain are essential for OxLDL binding. LOX-1 activation by OxLDL causes endothelial changes that are characterized by activation of nuclear factor-kappaB through an increased reactive oxygen species, subsequent induction of adhesion molecules, and endothelial apoptosis. In vitro, expression of LOX-1 is induced by many inflammatory cytokines, oxidative stress, hemodynamic stimuli, and OxLDL. In vivo, the expression is enhanced in pro-atherogenic settings including, hypertension, hyperlipidemia, and diabetes, and, indeed, is accumulated in the atherosclerotic and glomerulosclerotic lesions. LOX-1 binds multiple classes of ligands that are implicated in the pathogenesis of atherosclerosis. Besides OxLDL, LOX-1 can recognize apoptotic/aged cells, activated platelets, and bacteria, implying versatile physiological functions. Taken together, all these findings support the possible contribution of LOX-1 to the pathogenesis of vascular disorders, particularly atherosclerosis. Development of antagonists for LOX-1 might be a good therapeutic approach to vascular diseases.
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PMID:LOX-1, the receptor for oxidized low-density lipoprotein identified from endothelial cells: implications in endothelial dysfunction and atherosclerosis. 1216 30

Several species of scavenger receptors have so far been identified. However, it remains unclear which receptors are more crucial for the foam cell formation and progression. In the present study, we compared five major scavenger receptors (SR-A, CD36, CLA-1, CD68, and LOX-1) in their levels of expression at the different stages of foam cells derived from THP-1 cells. The expression of all scavenger receptors examined was up-regulated by the stimulation with TPA for 48 hours, despite the expressions of SR-A, CD36 and LOX-1 being very low before the treatment with TPA. Four to 7 days after the removal of TPA, the levels of CD36, CLA-1 and CD68 were increased significantly. In contrast, the expression of SR-A was suppressed significantly, and no change was observed in that of LOX-1. Furthermore, when the transformed macrophages were incubated with oxidized LDL, in which the uptake of [3H] cholesteryl oleoyl ether-labeled OxLDL was linear up to 7 days after the addition of OxLDL, the expression of CD36, CLA-1 and CD68 were greatly enhanced. This enhancement was more prominent than that without oxidized LDL, and the enhancement was sustained throughout the experimental period. On the other hand, SR-A was not up-regulated, and LOX-1 was down-regulated. We thus propose that CD36, CLA-1 and CD68, but not SR-A and LOX-1, may play crucial roles in the progression of macrophages to foam cells, which is a key step for the initiation of atherosclerosis.
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PMID:Synergically increased expression of CD36, CLA-1 and CD68, but not of SR-A and LOX-1, with the progression to foam cells from macrophages. 1223 39

We are always exposed to oxidative stress, when oxygen is used for production of energy for our daily activity. Mild to moderate oxidative stress affects intracellular signal transduction, accelerating the protective system for oxidation; thereby inflammatory cytokines are produced leading to increased levels of acute phase proteins. Vascular endothelial cells protect the vessels from oxidative stress, however, when they are damaged by shear stress to the vascular wall, oxidation spreads into the subendothelial matrix, leading to oxidation of low-density lipoproteins(LDL) accumulated there. Oxidized LDL is easily and abundantly taken up into macrophages via the scavenger receptors such as LOX-1, which leads to the formation of atherosclerosis. Markers for oxidative stress in vivo are being sought for prevention and treatment of cardiovascular diseases. There are a number of parameters as candidates, and among them, we chose biopyrrins, oxidative products of bilirubin, and have studied their role in coronary heart diseases. Urinary excretions of biopyrrins are significantly elevated in patients with coronary arterial stenosis and with ischemic changes on electrocardiogram. Similar finding have been obtained in patients with vasospastic angina. These findings suggest that markers for oxidative stress will be a good laboratory test for evaluation of coronary heart diseases.
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PMID:[Cardiovascular diseases and oxidative stress]. 1269 Jun 30

Experimental studies have shown that oxidized low-density lipoprotein (ox-LDL) up-regulates its receptor LOX-1. Both ox-LDL and LOX-1 are expressed in atherosclerotic plaques. Native LDL concentrations are elevated in atherosclerosis, suggesting a reduction in LDL-receptors. We hypothesized that ox-LDL via LOX-1 could influence the expression of LDL-receptors. This study was designed to examine the interaction between ox-LDL, LOX-1, and LDL-receptors in human coronary artery endothelial cells (HCAECs). HCAECs were incubated with ox-LDL (10-80 microg/ml) for 3-24h. Ox-LDL decreased the expression of LDL-receptor in a concentration- and time-dependent fashion. The effects of ox-LDL were mediated by its endothelial receptor LOX-1, since pretreatment of HCAECs with a blocking antibody to LOX-1 (JTX92, 10 microg/ml) prevented the effect of ox-LDL on LDL-receptor expression. The role of LOX-1 was further confirmed by the use of an antisense to LOX-1 mRNA, which also blocked the effect of ox-LDL in LDL-receptor expression. In other experiments, ox-LDL as expected induced superoxide anion generation; and pretreatment of HCAECs with the anti-oxidants trolox and alpha-tocopherol (each 10 microM) inhibited the formation of superoxide anions as well as the down-regulation of LDL-receptor in response to ox-LDL. These studies provide the first evidence that ox-LDL via LOX-1 modulates LDL-receptor expression in HCAECs. The generation of free radicals elicited by ox-LDL may be a key step in this process.
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PMID:Oxidized LDL through LOX-1 modulates LDL-receptor expression in human coronary artery endothelial cells. 1287 12


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