LOX-1 Regulation in Anti-atherosclerosis of Active Compounds of Herbal Medicine: Current Knowledge and the New Insight / 中国结合医学杂志

Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) have recently been identified to be closely related to the occurrence and development of atherosclerosis (AS). A growing body of evidence has suggested Chinese medicine takes unique advantages in preventing and treating AS. In this review, the related research progress of AS and LOX-1 has been summarized. And the anti-AS effects of 10 active components of herbal medicine through LOX-1 regulation have been further reviewed. As a potential biomarker and target for intervention in AS, LOX-1 targeted therapy might provide a promising and novel approach to atherosclerotic prevention and treatment.

Oxidized low-density lipoprotein stimulates dendritic cells maturation via LOX-1-mediated MAPK/NF-κB pathway

Dendritic cells (DCs) play a crucial role as central orchestrators of immune system response in atherosclerosis initiation and progression. Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is involved in the immune maturation of DCs, but the underlying mechanisms remain unclear. We isolated mouse bone marrow progenitors and stimulated them with granulocyte-macrophage colony-stimulating factor and interleukin (IL)-4 to induce immature DCs. We then treated DCs with oxidized low-density lipoprotein (oxLDL) to induce maturation. LOX-1 siRNA was used to investigate the modulation of LOX-1 on the development of DCs and the underlying signal pathways. CD11c-positive DCs were successfully derived from mouse bone marrow progenitors. OxLDL promoted the expressions of DCs maturation markers and pro-inflammatory cytokines. OxLDL also upregulated LOX-1 expression and activated MAPK/NF-κB pathways. LOX-1 siRNA could attenuate the expression of MAPK/NF-κB pathways and inflammatory cytokines. In conclusion, oxLDL induced the maturation of DCs via LOX-1-mediated MAPK/NF-κB pathway, which contributed to the initiation and progression of atherosclerosis.

Study on visfatin-induced inflammation and necroptosis via LOX-1 in human umbilical vein endothelial cells / 生物医学工程学杂志

The aim of the study is to identify the effects and underlying mechanisms of visfatin on inflammation and necroptosis in vascular endothelial cells. Human umbilical vein endothelial cells (HUVECs) were stimulated with visfatin or pretreated with Polyinosinic acid (LOX-1 inhibitor). By using the Western blot, RT-PCR, immunocytochemistry, enzyme-linked immunosorbent assay (ELISA), MTT and flow cytometry technique, the occurrence of inflammation and necroptosis in HUVECs were evaluated. Our results showed that 100 ng/mL visfatin significantly increased the mRNA and protein expression of monocyte chemotactic protein 1 (MCP-1) and LOX-1 after 24 hours' treatment in HUVECs. However, pretreatment with Polyinosinic acid could significantly reduce the expression of MCP-1 compared with visfatin group. Additionally, 100 ng/mL visfatin could induce the production of necrotic features and increase the mRNA expression of BMF (one of the markers of necroptosis), while pretreating with Polyinosinic acid markedly downregulated the mRNA expression of BMF gene and promoted the cell proliferation. These results indicate that visfatin might induce inflammation and necroptosis via LOX-1 in HUVECs, suggesting that visfatin plays a central role in the development of atherosclerosis.

Prevention and Treatment of Atherosclerosis by Three Different Chinese Medical Compounds: a Mechanism Study / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To study the effect of Buyang Huanwu Decoction (BHD), Xuefu Zhuyu Decoction (XZD), and Sijunzi Decoction (SD) contained serums on expressions of Toll-like receptor 4 (TLR4)/nuclear factor (NF)-κB signals, lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), tumor necrosis factor-α (TNF-α), vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), and to explore possible anti-atherosclerotic mechanisms.</p><p><b>METHODS</b>Twenty New Zealand rabbits were divided into 4 groups at random, i.e., the normal control group, the BHD group (6.7 g/kg), the XZD group (3.6 g/kg), and the SD group (1.6 g/kg), 5 in each group. All medication lasted for 7 successive days. Two h after the final medication, about 50 mL blood was withdrawn from rabbit heart for preparing serums. Human umbilical vein endothelial cell ECV304 were cultured in vitro for 18 h and randomly divided into the blank control group, the model group, the Western medicine (WM) control group, the BHD group, the XZD group, and the SD group at random. ECV304, except in the blank control group, were stimulated with lipopolysaccharide (LPS) for 2 h. Those in the WM control group and CM groups were treated respectively with corresponding CM contained serum for 24 h. Finally gene and protein expressions of TLR4, myeloid differentiation factor 88 (MyD88), tumor necrosis factor receptor-associated factor-6 (TRAF-6), NF-κB, LOX-1, TNF-α, ICAM-1, and VCAM-1 were detected by fluorescent quantitative PCR and Western blot.</p><p><b>RESULTS</b>Compared with the blank control group, mRNA expressions of TLR4, MyD88, TRAF-6, NF-KB, LOX-1 , TNF-cx, ICAM-1, and VCAM-1 increased significantly; protein expressions of TLR4, NF-κB, LOX-1, TNF-α, ICAM-1, and VCAM-1 also increased significantly in the model group (P < 0.01). Compared with the model group, mRNA and protein expressions of each index could be significantly inhibited in the BHD group, the XZD group, and the WM control group (P < 0.05). Besides, mRNA and protein expressions of each index could be significantly elevated more in the BHD group and the XZD group than in the WM control group (P < 0.05). No statistical difference existed in each index between the SD group and the rest groups (P > 0.05).</p><p><b>CONCLUSIONS</b>The mechanism of BHD and XZD for fighting against atherosclerosis might be associated with inhibiting TLR4/NF-κB signal transduction pathway and expressions of its downstream inflammatory factors such as LOX-1, TNF-α, ICAM-1, and VCAM-1. But SD showed no associated effect on atherosclerosis.</p>

Effect of Antrodia cinnamomea on gene expression related to aortal endothelial injury in rats with hyperlipidemia / 中国中药杂志

<p><b>OBJECTIVE</b>To investigate the effect of Antrodia cinnamomea on gene expression related to aortal endothelial injury of rats with hyperlipidemia.</p><p><b>METHOD</b>Fifty SD rats were randomly divided into five groups: the normal control group (NG), the model group (MG), the antrodia cinnamomea groups of low, middle and high doses (AC-LG, AC-MG, AC-HG, 250, 500, 1 000 mg x kg(-1)). The rats were fed with high-fat diets to establish the hyperlipidemia model. After the drug administration for 10 weeks, their serum lipid, SOD, MDA and ox-LDL, LOX-1, P38 MAPK and NF-kappaB mRNA and protein expression were respectively determined, and the aortal endothelial injury was observed under electron microscope.</p><p><b>RESULT</b>In the model group, the contents of TC, TG and LDL-C significant increased (P < 0.01), whereas the content of HDL-C significant decreased (P < 0.01). Compared with the model group, both the AC-M group and the AC-H group showed reduction in endothelial injury and significant decrease in the content of TC, TG and LDL-C (P < 0.05 or P < 0.01). The content of HDL-C increased, but with no significant difference. SOD activity in serum remarkably increased (P < 0.05 or P < 0.01), MDA and ox-LDL levels dramatically decreased (P < 0.05 or P < 0.01).</p><p><b>CONCLUSION</b>A. cinnamomea can alleviate endothelial lipid injury by inhibiting the expressions of LOX-1, P38MAPK and NF-kappaB in aorta and better protect aortal endothelial cells from oxidative lipid injury.</p>

Ox-LDL increases OX40L in endothelial cells through a LOX-1-dependent mechanism

Oxidative low-density lipoprotein (Ox-LDL) is a key risk factor for the development of atherosclerosis, and it can stimulate the expression of a variety of inflammatory signals. As a new and highly sensitive inflammation index, OX40L may be a key to understanding the mechanisms that regulate interactions between cells within the vessel wall and inflammatory mediators during the development of atherosclerosis. To investigate whether Ox-LDL regulates OX40L expression through an oxidized LDL-1 receptor (LOX-1)-mediated mechanism, we investigated the effect of different concentrations of Ox-LDL (50, 100, 150 µg/mL) on endothelial cell proliferation and apoptosis. Stimulation with Ox-LDL increased OX40L protein 1.44-fold and mRNA 4.0-fold in endothelial cells, and these effects were inhibited by blocking LOX-1. These results indicate that LOX-1 plays an important role in the chronic inflammatory process in blood vessel walls. Inhibiting LOX-1 may reduce blood vessel inflammation and provide a therapeutic option to limit atherosclerosis progression.

Effects of electroacupuncture on the expression of oxidized low-density lipoprotein and its receptors in rats with coronary atherosclerotic heart disease / 中国针灸

<p><b>OBJECTIVE</b>To explore action mechanism of electroacupuncture for coronary atherosclerotic heart disease (CHD) in order to provide experimental support for clinical acupoint selection.</p><p><b>METHODS</b>Among sixty clean-grade healthy male Wistar rats, twenty-four cases were randomly selected as a normal control group and an electroacupuncture (EA) preconditioning group, 12 cases in each one. Then rats in the EA preconditioning group and the rest 36 rats were fed with high fat diet for 12 weeks to duplicate the CHD model. When the models were successfully established, the rats were randomly divided into a model control group, an EA group and a medication group, 12 cases in each one. EA was applied with Hwa-to SDZ-IV apparatus in the EA preconditioning group at "Neiguan" (PC 6) and "Xinshu" (BL 15), 1 mA in current intensity, 2 Hz in frequency, 30 min per times, once every other day for 14 weeks. When model was established, the same acupoint and method was used in the EA group for 2 weeks while intragastric administration of atorvastatin mixed suspension, 0.25 mg/kg, once a day, was applied in the medication group for 2 weeks. The content of oxidized low-density lipoprotein (oxLDL) in the serum was tested by double antibody enzyme-linked immunosorbent assay (ELISA) while content of lectin-like oxidized low density lipoprotein receptor-1 (LOX-1) in coronary arterial tissue was test by western blot method. Expression of LOX-1 mRNA was tested by fluorogenic quantitative polymerase chain reaction (PCR).</p><p><b>RESULTS</b>After model was duplicated successfully, the content of oxLDL in the serum and the expression of LOX-1 and its mRNA in coronary arterial tissue in the model control group were increased significantly compared with those in the normal control group (all P < 0.01). Compared with the model control group, the content of oxLDL in the serum and the expression of LOX-1 and its mRNA in coronary arterial tissue in the EA preconditioning group, EA group and medication group were significantly reduced (all P < 0.01).</p><p><b>CONCLUSION</b>The electroacupuncture at "Neiguan" (PC 6) and "Xinshu" (BL 15) could effectively reduce the content of oxLDL in the serum and expression of LOX-1 and its mRAN in coronary arterial tissue in CHD rats. The oxidative modificatory low-density lipoprotein and its specific receptor system could be one of the ways to prevention and treatment of acupuncture for CHD.</p>

Beneficial effect of Lisosan G on cultured human microvascular endothelial cells exposed to oxidised low density lipoprotein.

Background & objectives: Nutritional compounds which display anti-inflammatory and antioxidant effects have specific applications in preventing oxidative stress and endothelial dysfunction. In this study we evaluated the effect of Lisosan G (powder of Triticum sativum grains) on human microvascular endothelial cells (HMEC-1) exposed to oxidized low density lipoprotein (ox-LDL). Methods: The protective effects of Lisosan G were evaluated on human microvascular endothelial cells exposed to ox-LDL. Intercellular adhesion molecular-1 (ICAM-1), endothelin-1 (ET-1), and interleukin-6 (IL-6) concentrations and the expression of the respective genes were evaluated in response to incubation with ox-LDL, after co-incubation with ox-LDL and Lisosan G or exposed to Lisosan G alone. The analysis of LOX-1 gene was performed with RT-PCR semi quantitative method. The degree of oxidation induced in relation to control, was established by measurement of malondialdehyde (MDA) production. Results: The incubation with ox-LDL induced a significant increase in ICAM-1, IL-6 and ET-1 levels compared to the basal condition (P<0.01, P<0.05, and P<0.01, respectively), while in presence of Lisosan G, ICAM-1 levels showed a significant reduction both compared to the cultures treated with ox-LDL and control (P<0.01). IL-6 levels did not show any difference; ET-1 levels showed a partial reduction after co-treatment with Lisosan G, and also with Lisosan G alone, reduced the concentration below control (P<0.01). The modulation of these markers was confirmed by RT-PCR analysis. An association between MDA formation and the three markers production was observed. Semi-quantitative analysis of LOX-1 gene expression showed a significant up-regulation only after ox-LDL exposure. Interpretation & conclusions: The results demonstrate that Lisosan G may have an important role in the prevention of microcirculatory dysfunction.

Effects of miR-590-5p on ox-LDL-induced endothelial cells apoptosis and LOX-1 expression / 中南大学学报(医学版)

OBJECTIVE@#To investigate the effect of miR-590-5p on the expression of lectin-like oxidized low density lipoprotein receptor 1 (LOX-1) in apoptotic human umbilical vein endothelial cells (HUVECs) induced by ox-LDL, and to explore the role of miR-590-5p in modulating HUVECs apoptosis.@*METHODS@#HUVECs were exposed to ox-LDL (50 μg/mL) for 0 to 48 h. Apoptosis was detected by Annexin V-FITC stain and was distinguished from necrosis by propidium iodide (PI) staining. The relative expression level of miR-590-5p in HUVECs was analyzed using real-time quantitative PCR (RT-qPCR). HUVECs were transfected with miR-590-5p mimics or miRNA mimics control followed by 50 μg/mL ox-LDL stimulation for 48 h. LOX-1 mRNA and protein were measured by RT-qPCR and Western blot, and apoptosis in HUVECs was analyzed by flow ctyometry after Annexin V-FITC/PI double stain.@*RESULTS@#Incubation of HUVECs with 50 μg/mL ox-LDL for 0 to 48 h resulted in a time-dependent induction of apoptotic cell death and down-regulation of miR-590-5p. Transfection of miR-590-5p mimics suppressed LOX-1 expression at both mRNA and protein levels, leading to a reduction of ox-LDL-induced apoptosis in HUVECs.@*CONCLUSION@#MiR-590-5p protects endothelial cells from ox-LDL induced apoptosis by inhibiting the expression of LOX-1.

Lentivirus-mediated LOX-1-RNA interference attenuates oxidative stress-induced apoptosis in myocardial cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To construct a lectin-like oxidized low-density lipoprotein receptor (LOX-1) RNA interference (RNAi) lentivirus and explore the role of LOX-1 in H(2)O(2)-induced apoptosis of rat myocardial cells.</p><p><b>METHODS</b>LOX-1 shRNA sequence was synthesized and cloned into pLentiLox3.7 (pLL3.7) lentiviral vector to construct the lentiviral vector pLL3.7-LOX1. The lentiviral vectors (pLL3.7 and pLL3.7-LOX1) and the packaging vectors dR8.9 and VSVG were co-transfected into 293FT cells for packaging the lentivirus. H9C2 myocardial cells were infected by the lentiviruses to observe the inhibitory rate of LOX-1 on H(2)O(2)-induced apoptosis of H9C2 cells by RT-PCR, CCK-8, and Hochest33258 staining.</p><p><b>RESULTS</b>Double restriction enzyme digestion and DNA sequencing confirmed correct insertion of the sequence. Suppression of LOX-1 by the lentivirus attenuated H(2)O(2)-induced cell viability reduction and apoptosis in the myocardial cells (P<0.01).</p><p><b>CONCLUSION</b>LOX-1 activation may play an important role in H(2)O(2)-induced apoptosis of rat myocardial cells.</p>

Effects of yiqi huoxue compound contained drug serum on the expressions of toll-like receptor 4 and downstream signal transduction pathway, and LOX-1, TNF-alpha, ICAM-1 in the human vein endothelial cells / 中国中西医结合杂志

<p><b>OBJECTIVE</b>To investigate the effects of Yiqi Huoxue Compound (YHC) contained drug serum on the expressions of TLR4 and its downstream signal transduction pathway and LOX-1, TNF-alpha, ICAM-1 in human umbilical vein endothelial cells (HUVECs), and to study its possible anti-atherosclerosis (AS) mechanism. METHODS Twenty New Zealand rabbits were divided into 4 groups in random, i. e., the normal control group, the high concentration group, the middle concentration group, and the low concentration group, 5 in each group. Normal saline was given to rabbits in the normal control group by gastrogavage. High, middle, and low concentration of YHC was respectively given to rabbits in the rest 3 groups by gastrogavage for 7 successive days. The blood was withdrawn from the heart 2 h after the last gastrogavage. The serum was isolated after centrifuge. HUVECs was in vitro cultured and then randomly divided into 6 groups, i. e., the normal control group, the model group, the Western medicine control group, the high, middle, and low YHC groups. HUVECs were stimulated with LPS for 2 h, and then treated with high, middle, and low YHC contained serum. HUVECs were collected 24 h later. The gene expressions of TLR4, MyD88, TRAF-6, TRAM, TRIF, NF-kappaB, LOX-1, TNF-alpha, and ICAM-1 were detected using fluorescent quantitative PCR. The protein expressions of TLR4, MyD88, TRAF-6, and LOX-1 were determined using Western blot method.</p><p><b>RESULTS</b>After HUVECs were stimulated by LPS, the expressions of TLR4, MyD88, TRAF-6, TRAM, TRIF, NF-kappaB, LOX-1, TNF-alpha, and ICAM-1 were enhanced, showing statistical difference when compared with the vehicle control group (P < 0.01). YHC contained serum significantly decreased the higher expressions of TLR4, MyD88, TRAF-6, NF-kappaB, LOX-1, TNF-alpha, and ICAM-1, showing statistical difference when compared with the model group (P < 0.05).</p><p><b>CONCLUSIONS</b>YHC could inhibit the TLR signal transduction pathway and the expressions of LOX-1, TNF-alpha, and ICAM-1. These might be one of the mechanisms for treating various immune inflammatory diseases and preventing AS.</p>

Aspirin and pravastatin reduce lectin-like oxidized low density lipoprotein receptor-1 expression, adhesion molecules and oxidative stress in human coronary artery endothelial cells / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Oxidative stress and inflammation are important steps in the pathogenesis of atherosclerosis. We postulated that therapeutic concentrations of aspirin and pravastatin, especially in combination, may suppress oxidative stress and inflammation in endothelial cells, and this concept was examined in human coronary artery endothelial cells (HCAECs).</p><p><b>METHODS</b>Human coronary artery endothelial cells were cultured and treated with oxidized-low density lipoprotein (ox-LDL, 60 microg/ml for 24 hours) alone, or pre-treated with aspirin (1, 2 or 5 mmol/L), pravastatin (1, 5 or 10 micromol/L) or their combination (1 mmol/L aspirin and 5 micromol/L pravastatin), followed by ox-LDL treatment. After respective treatment, superoxide anion production, p38 mitogen activated protein kinase and transcription factor NF-kappaB activation, protein expression of lectin-like ox-LDL receptor-1 (LOX-1) and adhesion molecules, and monocyte adhesion were measured.</p><p><b>RESULTS</b>Ox-LDL treatment greatly elicited its receptor LOX-1 expression, superoxide anion production and inflammatory response, which were minimally affected by low concentration of aspirin (1 mmol/L) or pravastatin (5 micromol/L), but were markedly decreased by their combination. Activation of p38 mitogen activated protein kinase and NF-kappaB, the expression of intercellular adhesion molecule-1 and monocyte chemotactic protein-1, which were only mildly affected by aspirin or pravastatin alone, were significantly attenuated by their combination. As a consequence, monocyte adhesion to endothelial cells was markedly attenuated by the combination of the two agents. Well-known anti-oxidants alpha-tocopherol and gamma-tocopherol had similar inhibitory effects on ox-LDL-mediated oxidative stress and LOX-1 expression as well as monocyte adhesion as did the combination of aspirin and pravastatin.</p><p><b>CONCLUSIONS</b>These studies point to a positive interaction between aspirin and pravastatin with regard to endothelial biology. Anti-oxidant and subsequent anti-inflammatory effect may be one of the potential underling mechanisms.</p>

Value of serum soluble lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) and LOX-1 mRNA in peripheral mononuclear cells in early diagnosis of acute coronary syndrome / 南方医科大学学报

<p><b>OBJECTIVE</b>To assess the value of serum soluble lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) levels and LOX-1 mRNA expression in peripheral blood mononuclear cells in early diagnosis of acute coronary syndrome (ACS).</p><p><b>METHODS</b>Enzyme-linked immunosorbent assay was used to detect the levels of plasma ox-LDL and LOX-1 in 95 patients with ACS, 60 with stable angina pectoris (SAP) and 40 normal control subjects. The expression of LOX-1 mRNA in peripheral blood mononuclear cells was detected by RT-PCR in the 3 groups.</p><p><b>RESULTS</b>The levels of ox-LDL, LOX-1 and LOX-1 mRNA in the peripheral blood mononuclear cells were significantly higher in ACS patients than in SAP patients and normal control subjects (P<0.05). In ACS group, the level of plasma ox-LDL was significantly correlated to serum LOX-1 and LOX-1 mRNA expression in peripheral mononuclear cells.</p><p><b>CONCLUSION</b>The level of plasma soluble LOX-1 and LOX-1 mRNA in peripheral mononuclear cells are significantly increased in ACS, and when combined, they provide a useful means for detecting ACS in the prophase.</p>

Effect of IL-10 on LOX-1 expression of peripheral blood monocytes in patients with acute coronary syndrome / 中南大学学报(医学版)

OBJECTIVE@#To determine the expression of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) of peripheral blood monocytes in patients with acute coronary syndromes (ACS),and to further explore the effect of anti-inflammatory factor interleukin-10 (IL-10) on the expression of LOX-1.@*METHODS@#Twenty-eight healthy controls and 28 ACS patients were enrolled in the study. The levels of IL-10 and tumor necrosis factor (TNF-alpha) were determined by enzyme-linked immunosorbnent assay(ELISA). The monocytes of peripheral blood in patients and controls were isolated and incubated with exogenous IL-10 (20 microg/L). The expression of LOX-1 protein and mRNA in the monocytes was examined by Western blot and reverse transcriptase PCR (RT-PCR).@*RESULTS@#Compared with the healthy controls, the levels of serum IL-10 and TNF-alpha were significantly elevated in ACS patients (P<0.01). The expression of LOX-1 protein and mRNA was markedly upregulated in the isolated monocytes from ACS patients, which could be downregulated by IL-10 (20 microg/L, 3 h) (P<0.01).@*CONCLUSION@#The effect of anti-inflammatory factor IL-10 on the atherosclerosis may be a new mechanism resulting in plaque stabilization via the decreased LOX-1 expression of peripheral monocytes in ACS patients.

The expression and down stream effect of lectin like-oxidized low density lipoprotein 1 (LOX-1) in hyperglycemic state.

The lesions of atherosclerosis represent a series of highly specific cellular and molecular responses. Low density lipoprotein (LDL), which may be modified by oxidation, glycation, aggregation, association with proteoglycans, or incorporation into immune complexes, is a major cause of injury to the endothelium and vascular smooth muscle cells (VSMC).The major major cell types involved in atherogenesis, macrophages and VSMC, are activated by pro-inflammatory stimuli including modified LDL. Modified LDL induces inflammatory responses in macrophages, migration and proliferation of SMC, and triggers foam cell formation. Scavenger receptors, including LOX-1, play a key role in foam cell formation by mediating the uptake of modified LDL. LOX-1 expression is detected in endothelial cells of early atherosclerosis lesions of human carotid arteries. Advanced lesions showed LOX-1 expression not only in endothelial cells but also in macrophages and more frequently in VSMC, and may be involved in foam cell transformation in macrophages and VSMC. The metabolic abnormalities that characterize diabetes, particularly hyperglycemia, free fatty acids, and insulin resistance, provoke molecular mechanisms that alter the function and structure of blood vessels. These include increased oxidative stress, intracellular signal transduction disturbances, and activation of the receptor for advanced glycation end products (R-AGE). Data showed that LOX-1 expression is enhanced by proatherogenic factors relevant to human diabetes, including high glucose, oxLDL, advance glycation end products, and C-reactive protein. LOX-1 expression increased also through oxygen species (ROS), endothelin-1 (ET-1), tumor necrosis factor-alpha (TNF-alpha), shear stress, activation of protein kinase-C (PKC), angiotensin-II (ANG-II), and through inflammatory pathways.

Effects of oxidized low-density lipoprotein on endothelial progenitor cells survival and activity mediated by lectin-like oxidized low density lipoprotein receptor / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate whether oxidized low-density lipoprotein (oxLDL) affects the survival and activity of endothelial progenitor cell (EPC) and whether the effects are mediated by lectin-like oxidized low-density lipoprotein receptor (LOX-1).</p><p><b>METHODS</b>CD34+ cells isolated from human umbilical blood were cultured in endothelial cell growth medium-2 (EGM-2). After 14 days of culture, some EPCs were stimulated with 10, 25, 50 microg/ml of oxLDL for 48 hours; some were preincubated with LOX-1 mAb, a blocking antibody of LOX-1, for 24 hours, then exposed to 50 microg/ml oxLDL for 48 hours; others without any further treatment were used as control. The survival of EPC and the ability of adhesion, migration, and tube formation were examined. The levels of LOX-1 protein and mRNA expression were also assayed.</p><p><b>RESULTS</b>Incubation with oxLDL at concentrations of 25 microg/ml or higher resulted in a dose-dependent increase of EPC apoptosis [25 microg/ml: (15.8 +/- 1.1.0%, 50 microg/ml: (18.8 +/- 2.0)% versus control: (9.0 +/- 1.2)%; P < 0.05]. Treated with oxLDL led to a significantly reduced migratry rate [25 microg/ml: (5.7 +/- 1.0)%, 50 microg/ml: (5.1 +/- 0.8)% versus control: (9.5 +/- 0.8)%; P < 0.05]. EPC treated with oxLDL showed a dose-dependent reduction of adhesion to fibronectin (25 Kg/ml: 33 +/- 2, 50 microg/ml: 30 +/- 3 versus control: 37 +/- 5; P < 0.05). Treatment with oxLDL impaired the in vitro vasculogenesis ability of EPCs. The total length of the tube structures in each photograph was decreased [25 microg/ml: (2.9 +/- 0.5) mm, 50 microg/ml: (1.8 +/- 0.5) mm versus control: (5.0 +/- 0.6) mm; P < 0.05]. The tube structure was severely disrupted, resulting in an incomplete and sparse tube network. However, all the detrimental effects on EPC were attenuated by pretreatment of EPC with LOX-1 mAb. In addition, Western blot analysis revealed that oxLDL increased LOX-1 protein expression from 100% to (172 +/- 8)% at a dose of 50 microg/ml. Furthermore, oxLDL caused an increase in LOX-1 mRNA expression from 100% to (174 +/- 39)% at a dose of 50 microig/ml.</p><p><b>CONCLUSION</b>OxLDL can directly inhibit EPC survival and activity and these effects are mediated by its receptor, LOX-1.</p>

Lectin-like oxidized low-density lipoprotein receptor-1: protein, ligands, expression and pathophysiological significance / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To review the recent research progress in lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) including its protein, ligands, expression and pathophysiological significance. Data sources Information included in this article was identified by searching of PUBMED (1997 - 2006) online resources using the key term LOX-1.</p><p><b>STUDY SELECTION</b>Mainly original milestone articles and critical reviews written by major pioneer investigators of the field were selected.</p><p><b>RESULTS</b>The key issues related to the LOX-1 protein as well as ligands for LOX-1. Factors regulating the expression of LOX-1 were summarized. The pathophysiological functions of LOX-1 in several diseases were discussed.</p><p><b>CONCLUSIONS</b>Identification of LOX-1 and a definition of its biological role in pathophysiologic states provide deeper insight into the pathogenesis of some cardiovascular diseases especially in atherosclerosis and provide a potential selective therapeutic approach. LOX-1 is unlocking and drugs targeting LOX-1 might be a promising direction to explore.</p>

Intervention of Tongxinluo capsule against vascular lesion of atherosclerosis and its effect on lectin-like oxidized low density lipoprotein receptor-1 expression in rabbits / 中国结合医学杂志

<p><b>OBJECTIVE</b>To investigate the prevention by Tongxinluo capsule (TXL) of vascular lesions and its effect on the levels of protein and gene expression of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) of vascular wall in rabbits with atherosclerosis (AS), and to explore its possible mechanism against AS.</p><p><b>METHODS</b>AS models were established by feeding New Zealand white rabbits with high-cholesterol diet, and 24 immature rabbits were randomly divided into the control group, model group and treated group (treated with TXL capsule). The indexes of total cholesterol (TC) and low density lipoprotein (LDL) levels were measured at the 16th week. The intima thickness and the plaque area of abdominal aorta were quantitatively analyzed by pathological morphological analysis, the expression of macrophage and smooth muscle cell (SMC) in intima were detected by immunohistochemical method and histologic segments were stained by Hematoxilin-Eosin (HE) to identify the degree of atherosclerotic lesion in the model group and the prevention by TXL. The LOX-1 gene and protein expression in abdominal aorta was detected by semi-quantitative RT-PCR and immunohistochemistry, respectively.</p><p><b>RESULTS</b>In the model group, the levels of TC and LDL were significantly elevated, aortic intima thickened extensively, the intima area enhanced, and macrophages expression increased; the levels of LOX-1 gene and protein expression was up-regulated in endothelium and neo-intima of the abdominal aorta. The treatment with TXL reduced blood lipids, attenuated arterial intimal proliferation, markedly inhibited the expression of macrophage and excessively expressed the level of LOX-1.</p><p><b>CONCLUSION</b>TXL has an inhibitory effect on blood lipids, and it can prevent the occurrence of vascular lesion and cure its development, and its protection against AS was possibly associated with a crucial endothelial protective action through lowering the expression of LOX-1 in vascular walls.</p>

Increased lectin-like oxidized low density lipoprotein receptor-1 expression in the autologous vein grafts and vein graft atherosclerosis / 中华心血管病杂志

<p><b>OBJECTIVE</b>To study the changes of lectin-like oxidized low density lipoprotein receptor-1 (LOX-1) expression in the autologous vein grafts and vein graft atherosclerotic lesions.</p><p><b>METHODS</b>Thirty New Zealand white rabbits were randomly assigned to normal control group (rabbits fed with normal diet, n = 10), vein graft group (autologous external jugular vein grafting to common carotid artery and fed with normal diet, n = 10) or vein graft plus high-lipid diet group (autologous vein graft and fed with high-lipid diet, n = 10) for 12 weeks. LOX-1 expressions in the grafts were examined by immunohistochemistry and semi-quantitative reverse transcription-PCR. The relationships between serum total cholesterol level, intimal thickness and LOX-1 expression were also investigated.</p><p><b>RESULTS</b>LOX-1 expression was low in the endothelium of external jugular veins in the normal control group and significantly increased in the endothelium and neointima of vein grafts in the vein graft group (0.31 +/- 0.14 vs. 0.09 +/- 0.04, P < 0.01) and which was further increased in the endothelium and atherosclerotic lesions in the vein graft plus high-lipid diet group (0.93 +/- 0.34 vs. 0.31 +/- 0.14, P < 0.01). LOX-1 expression in the atherosclerotic lesions was located both in endothelial cells and foam cells and the expression was most prominent in endothelial cells. LOX-1 expression and intimal thickness were positively related to serum total cholesterol level (P = 0.00 and 0.02) and the partial correlation coefficient was 0.78 and 0.42, respectively.</p><p><b>CONCLUSIONS</b>LOX-1 expression is increased in endothelium and neointima of autologous vein grafts of rabbits. Hypercholesterolemia upregulates LOX-1 expression in vein graft atherosclerosis. Thus, LOX-1 might play an important role in the pathogenesis of vein graft atherosclerosis.</p>

Tyrosine kinase dependent lectin-like oxidized LDL receptor-1 upregulation by thrombin and factor Xa in vascular smooth muscle cells / 中华心血管病杂志

<p><b>OBJECTIVE</b>Thrombin and factor Xa are key players in the process of arterial thrombi formation and lectin-like oxidized low density lipoprotein receptor-1 (LOX-1) is a cell surface endocytosis receptor for atherogenic oxidized LDL (ox-LDL). Here we investigate whether thrombin and factor Xa can induce LOX-1 protein expressions in cell-associated forms and soluble forms in cultured bovine aortic smooth muscle cells (BSMCs).</p><p><b>METHODS</b>BSMCs were treated with thrombin or factor Xa in the presence or absence of AG1478, an epidermal growth factor (EGF) receptor-associated tyrosine kinase inhibitor. Total cell lysates and concentrated culture medium were then analyzed by Western blot using a mouse anti-LOX-1 monoclonal antibody.</p><p><b>RESULTS</b>LOX-1 protein levels in cell lysates and culture medium were significantly increased by thrombin and factor Xa in a concentration- and time-dependent manner. Upregulation of LOX-1 protein expressions in cell lysates and concentrated culture medium was observed at concentrations above 2.0 and 3.0 U/ml of thrombin and 50 and 100 nmol/L of factor Xa, respectively. Increased LOX-1 protein expressions in cell lysates and cell culture medium were detectable as early as 4 h and peaked at 12 h after treatment with thrombin or factor Xa. LOX-1 expression induced by thrombin and factor Xa could be blocked by pretreatment with AG1478.</p><p><b>CONCLUSIONS</b>Thrombin and factor Xa can act as LOX-1 inducers via tyrosine kinase activation.</p>