几种抗氧化剂对细胞间粘附分子-1表达的影响

目的 探讨抗氧化剂调节内皮细胞表面的粘附分子ICAM-1表达的分子生物学机制。方法 内皮细胞表面的粘附分子表达用细胞ELISA方法测定,内皮细胞NF-kB的活性用电泳迁移率分析测定。结果 PDTC,DCI和chrysin能明显抑制ICAM-1的表达。Probucol仅在低浓度时对ICAM-1有轻微抑制作用。电泳迁移率分析结果,只有PDTC对NF-kB的活性有抑制作用,其它三种抗氧化药无效。结论 这几种抗氧化药抑制内皮细胞表面粘附分子的表达与它们对核转录因子NF-kB的作用并无必然的联系。     

ERK1/2信号通路在内皮微粒诱导人脐静脉内皮细胞ICAM-1表达中的作用

目的:探讨细胞外信号调节激酶1/2（ERK1/2）信号通路在内皮微粒（EMPs）诱导人脐静脉内皮细胞（HUVECs）表达细胞间黏附分子-1（ICAM-1）中的作用。方法:体外培养HUVECs,选取生长良好的第4～5代细胞,分为EMPs不同浓度作用组、EMPs不同时间作用组及ERKl/2特异性抑制剂组。应用蛋白免疫印迹法（Western blot）检测ICAM-1和磷酸化ERK1/2蛋白的表达。用实时荧光定量PCR（qRT-PCR）检测ICAM-1 mRNA的表达。结果:EMPs作用HUVECs后,ICAM-1 mRNA和其蛋白以及磷酸化ERK1/2蛋白的表达显著高于对照组,且呈浓度和时间依赖性的关系（均P<0.01）;而ERKl/2特异性抑制剂PD98059对ICAM-1 mRNA和其蛋白以及磷酸化ERK1/2蛋白的表达,均有明显的抑制作用（均P<0.01）。结论:EMPs可诱导HUVECs中ICAM-1表达,其机制可能与激活ERK1/2信号通路有关。     

Chlamydophila pneumoniae induces ICAM-1 expression in human aortic endothelial cells via protein kinase C-dependent activation of nuclear factor-kappaB

Chlamydophila pneumoniae has an epidemiological link with atherosclerosis and acute cardiovascular events. One mechanism that may explain such a link is the increased expression of intracellular adhesion molecule-1 (ICAM-1) in C pneumoniae-infected endothelial cells. Upregulation of ICAM-1 by C pneumoniae is well recognized and has been extensively studied, but the signaling pathways involved are not yet defined. Because upregulation of ICAM-1 by cytokines and other stimuli has been shown to be mediated by either mitogen-activated protein kinase, protein kinase C (PKC), or nuclear factor-kappaB (NF-kappaB) pathways, we examined whether these pathways were involved in the ICAM-1 upregulation induced by C pneumoniae. Our data show a time-dependent phosphorylation of p44/p42 and SAPK/JNK pathways in C pneumoniae-infected cells. However, inhibition of the classic mitogen-activated protein kinase pathway using the PD98059 and U0126 inhibitors and inhibition of SAPK/JNK pathway did not suppress C pneumoniae-induced ICAM-1 expression. C pneumoniae also activates the NF-kappaB pathway at 30 minutes after infection. Treatment of human aortic endothelial cells (HAECs) with the NF-kappaB inhibitors BAY117085 and caffeic acid phenethyl ester led to a concentration-dependent inhibition of C pneumoniae-induced ICAM-1 upregulation. Finally, C pneumoniae-infected HAECs show membrane translocation of total PKC 30 minutes after cell infection. Calphostin C, a general PKC inhibitor, blocked both C pneumoniae-induced ICAM-1 expression and C pneumoniae-induced NF-kappaB translocation. In conclusion, we demonstrated that C pneumoniae-induced ICAM-1 expression in HAECs requires NF-kappaB and PKC activation and that NF-kappaB activation is PKC dependent.     

Rebamipide reduces indomethacin-induced gastric injury in mice via down-regulation of ICAM-1 expression

Non-steroidal anti-inflammatory drugs (NSAIDs) induced gastric mucosal injury occurs through subsequent events following free radical production derived from activated neutrophils. In this study, we hypothesized that rebamipide, a novel anti-ulcer agent, exerts a protective effect on NSAID-induced gastric injury through its antioxidant properties. The protective effect of rebamipide in a mouse model of indomethacin-induced gastric injury and mechanisms for this effect were investigated. Pre-treatment with rebamipide significantly inhibited indomethacin-induced gastric mucosal injury in mice. Gastric thiobarbituric acid reactive substances (TBARS) levels and myeloperoxidase (MPO) activity substantially increased 3 hr after indomethacin administration. These increases were significantly inhibited by pre-treatment with rebamipide. Furthermore, rebamipide pre-treatment notably decreased intercellular adhesion molecule-1 (ICAM-1) expression that was up-regulated in gastric tissue treated with indomethacin. Therefore, rebamipide may reduce indomethacin-induced gastric mucosal injuries through its antioxidant effect, which inhibits the neutrophil activation step following up-regulation of ICAM-1 expression on endothelial cells.     

Angiopoietin-1 reduces VEGF-stimulated leukocyte adhesion to endothelial cells by reducing ICAM-1, VCAM-1, and E-selectin expression

Vascular endothelial growth factor (VEGF) and angiopoietin-1 (Ang1) are potent vasculogenic and angiogenic factors that hold promise as a means to produce therapeutic vascularization and angiogenesis. However, VEGF also acts as a proinflammatory cytokine by inducing adhesion molecules that bind leukocytes to endothelial cells, an initial and essential step toward inflammation. In the present study, we used human umbilical vascular endothelial cells (HUVECs) to examine the effect of Ang1 on VEGF-induced expression of three adhesion molecules: intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin. Interestingly, Ang1 suppressed VEGF-induced expression of these adhesion molecules. Furthermore, Ang1 reduced VEGF-induced leukocyte adhesion to HUVECs. These results demonstrate that Ang1 counteracts VEGF-induced inflammation by reducing VEGF-induced endothelial adhesiveness.     

Perfusion with sickle erythrocytes up-regulates ICAM-1 and VCAM-1 gene expression in cultured human endothelial cells

Sickle cell anemia is characterized by periodic vasoocclusive crises. Increased adhesion of sickle erythrocytes to vascular endothelium is a possible contributing factor to vasoocclusion. This study determined the effect of sickle erythrocyte perfusion at a venous shear stress level (1 dyne/cm(2)) on endothelial cell (EC) monolayers. Sickle erythrocytes up-regulated intercellular adhesion molecule-1 (ICAM-1) gene expression in cultured human endothelial cells. This was accompanied by increased cell surface expression of ICAM-1 and also elevated release of soluble ICAM-1 molecules. Expression of vascular cell adhesion molecule-1 (VCAM-1) messenger RNA (mRNA) was also strikingly elevated in cultured ECs after exposure to sickle cell perfusion, although increases in membrane-bound and soluble VCAM-1 levels were small. The presence of cytokine interleukin-1beta in the perfusion system enhanced the production of ICAM-1 and VCAM-1 mRNA, cell surface expression, and the concentrations of circulating forms. This is the first demonstration that sickle erythrocytes have direct effects on gene regulation in cultured human ECs under well-defined flow environments. The results suggest that perfusion with sickle erythrocytes increases the expression of cell adhesion molecules on ECs and stimulates the release of soluble cell adhesion molecules, which may serve as indicators of injury and/or activation of endothelial cells. The interactions between sickle red blood flow, inflammatory cytokines, and vascular adhesion events may render sickle cell disease patients vulnerable to vasoocclusive crises.     

Cerivastatin does not prevent oxidative injury of human aortic endothelial cells

The anti-atherogenic properties of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) have been well established in several circulatory beds. Increasing evidence suggests that statins may help attenuate ischemia-reperfusion injury, a beneficial effect that may be related to the antioxidant capabilities of statins; however, this remains controversial. We performed this study to determine whether the HMG-CoA reductase inhibitor cerivastatin can prevent oxidative stress-induced injury in cultured human aortic endothelial cells (HAEC). The HAEC were subjected to oxidative stress in the absence and presence of increasing concentrations of cerivastatin (50 nM-1,000 nM). Oxidative stress was induced by increasing concentrations of hydrogen peroxide or endogenous superoxide anions generated by the inhibition of superoxide dismutase using diethylthiocarbamate (10 mM). Cell viability and mitochondrial activity were measured by mitochondria-dependent 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) conversion. Cell morphology was also examined using light microscopy. Exposing HAEC to cerivastatin for 24 hours had no effect on cell viability using both cell morphology and MTT conversion: the HAEC incubated in 100 nM cerivastatin had 90% +/- 2.2% viability of the control. As expected, hydrogen peroxide produced a concentration-dependent decrease in cell viability. Varying concentrations of cerivastatin pretreatment for < or = 18 hours showed no protection of HAEC against hydrogen peroxide-induced injury. As a positive control, the prototype antioxidant N-acetyl-L-cysteine was cytoprotective even with the highest hydrogen peroxide concentration. Neither cerivastatin nor N-acetyl-L-cysteine protected HAEC against diethylthiocarbamate-induced oxidative injury at any concentration. In this study, cerivastatin did not protect cultured HAEC against oxidative stress induced by hydrogen peroxide or diethylthiocarbamate.     

Role of the JNK pathway in thrombin-induced ICAM-1 expression in endothelial cells

OBJECTIVE: Thrombin induces leukocyte adherence to endothelial cells via increased expression of intercellular adhesion molecule-1 (ICAM-1). Although ICAM-1 expression is regulated by NF-kappaB, recent studies have suggested that additional signaling mechanisms may also be involved. The goal of this study was to determine whether mitogen-activated protein (MAP) kinases, including extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK), and p38 MAP kinase (p38), mediate thrombin-induced ICAM-1 expression in endothelial cells. METHODS: Western blot analysis using anti-ICAM-1 antibody and luciferase assays were performed in cultured endothelial cells after addition of signal transduction inhibitors or transfection of various gene constructs. JNK kinase activity was determined by a kinase assay using c-Jun as a substrate or by Western blot analysis with anti-phospho-JNK antibody. RESULTS: Treatment of endothelial cells with the JNK-specific inhibitors, SP600125 or JNK inhibitory peptide 1 (JNKI1), resulted in a significant decrease in thrombin-induced ICAM-1 expression as demonstrated by Western blot analysis (67 +/- 3% and 72 +/- 7%, respectively). In contrast, inhibitors of MEK and p38 had only minimal effect. The combination of SP600125 and the NF-kappaB inhibitor, BAY11-7082, resulted in complete inhibition of thrombin-induced ICAM-1 expression. The Galpha(q) inhibitor, YM-254890, inhibited thrombin-induced JNK activation and ICAM-1 expression. Dominant-negative Ras and Rac1, but not Rho, inhibited thrombin-induced JNK activation and ICAM-1 promoter activity. Finally, thrombin-induced JNK activation and ICAM-1 promoter activity were inhibited by betaARK1ct (a Gbetagamma subunit scavenger) and Csk. CONCLUSIONS: These data suggest that, in concert with NF-kappaB, JNK regulates thrombin-induced ICAM-1 expression by a mechanism that is dependent on Galpha(q), Gbetagamma, Ras, Rac1 and the Src kinase family.     

氧化型低密度脂蛋白对血管内皮细胞ICAM-1 mRNA表达的影响

目的 探讨氧化型低密度脂蛋白(ox-LDL)对人血管内皮细胞表达细胞间粘附分子-1(ICAM-1)的影响。方法 采用血管内皮细胞株EAhy926培养，观察150mg／L的氧化型低密度脂蛋白作用在不同时程(0～36h)及不同终浓度(0～300mg／L)的氧化型低密度脂蛋白作用24h对细胞间粘附分子-1mRNA表达的影响。RT-PCR测定ICAM-1基因表达水平。结果 氧化型低密度脂蛋白可诱导培养血管内皮细胞表达细胞间粘附分子-1mRNA，并呈时间和剂量依赖性增加。结论 ox-LDL可以促进EAhy926细胞间粘附分子-1表达，ICAM-1可能参与氧化型低密度脂蛋白所致的动脉粥样硬化进程。     

Lovastatin-stimulated superinduction of E-selectin,ICAM-1 and VCAM-1 in TNF-alpha activated human vascular endothelial cells

Inhibitors of HMG-CoA reductase (statins) reveal important pharmacological effects in addition to reducing the plasma LDL cholesterol level. In the pathogenesis of arteriosclerosis, transendothelial migration of various leukocytes including monocytes is a crucial step. We, therefore, investigated the expression of E-selectin, intercellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in vascular endothelial cells as influenced by lovastatin. Human umbilical vein endothelial cells (HUVECs) express significant amounts of selectins and cell adhesion molecules (CAMs) within a few hours after stimulation with TNF-alpha. This effect is potentiated by 100-200% when the cells are pretreated with 0.1-2.5 microM lovastatin. The lovastatin-mediated increase in the cytoplasm and at the cell surface is dose-dependent and significant at lovastatin concentrations comparable to plasma levels in patients under lovastatin treatment. The lovastatin-potentiated increase of E-selectin and CAMs is correlated with a corresponding increase of selectin- and CAM-specific mRNA. We conclude that, in vivo, statin treatment could trigger an enhanced recruitment of macrophages that might support the cholesteryl ester efflux from the arteriosclerotic plaque.     

Simvastatin reduces Chlamydophila pneumoniae-mediated histone modifications and gene expression in cultured human endothelial cells

Inflammatory activation of the endothelium by Chlamydophila pneumoniae infection has been implicated in the development of chronic vascular lesions and coronary heart disease by seroepidemiological and animal studies. We tested the hypothesis that C. pneumoniae induced inflammatory gene expression is regulated by Rho-GTPase-related histone modifications. C. pneumoniae infection induced the liberation of proinflammatory interleukin-6, interleukin-8, granulocyte colony-stimulating factor, macrophage inflammatory protein-1beta, granulocyte/macrophage colony-stimulating factor, and interferon-gamma by human endothelial cells. Cytokine secretion was reduced by simvastatin and the specific Rac1 inhibitor NSC23766 but was synergistically enhanced by inhibitors of histone deacetylases trichostatin A and suberoylanilide hydroxamic acid. Infection of endothelial cells with viable C. pneumoniae, but not exposure to heat-inactivated C. pneumoniae or infection with C. trachomatis, induced acetylation of histone H4 and phosphorylation and acetylation of histone H3. Pretreatment of C. pneumoniae-infected cells with simvastatin or NSC23766 reduced global histone modifications as well as specific modifications at the il8 gene promoter, as shown by chromatin immunoprecipitation. Reduced recruitment of nuclear factor kappaB p65/RelA as well as of RNA polymerase II was observed in statin-treated cells. Taken together, Rac1-mediated histone modifications seem to play an important role in C. pneumoniae-induced cytokine production by human endothelial cells.     

p38信号通路在内皮细胞微粒诱导人脐静脉内皮细胞表达细胞间黏附分子-1中的作用

目的观察p38信号通路（P38MAPK）在内皮细胞微粒（EMPs）诱导人脐静脉内皮细胞（HU—VECs）表达细胞间黏附分子-1（ICAM-1）中的作用。方法将体外培养的HUVECs随机分组：①EMPs不同时点观察组：用EMPs（终浓度105／m1）分别刺激细胞0、3、6、12、24h;②EMPs不同剂量作用组：分别用终浓度为0、10^2、10^3、10^4、10^5／ml的EMPs刺激细胞24h;③EMPs＋p38MAPK特异性抑制剂SB203580组：在EMPs（终浓度10^5／ml）刺激前,与终浓度为5μmol／L的SB203580共同孵育30min。用蛋白免疫印迹法（Western blot）测定p38MAPK磷酸化表达,实时荧光定量PCR测定ICAM—1mRNA的表达。结果EMPs可激活p38MAPK,使磷酸化p38MAPK蛋白表达量及ICAM—1mRNA表达量增加,且呈剂量和时间依赖性。p38MAPK特异性拈抗剂SB203580可显著抑制EMPs的此作用。结论p38信号通路可能部分参与了对EMPs诱导HUVECs表达ICAM-1的调控。     

血管内皮生长因子增加内皮细胞通透性的基质金属蛋白酶-2机制

目的　研究血管内皮生长因子 (VEGF)增加血管内皮细胞对脂蛋白 (LDL)通透性与基质金属蛋白酶 2 (MMP 2 )的关系。方法　用异硫氰酸荧光素 (FITC)标记LDL ,荧光分光光度法测定FITC LDL的含量 ,在牛主动脉内皮细胞通透性模型上研究VEGF对FITC LDL通透率的影响 ;采用明胶酶谱法测定MMP 2活性。结果　VEGF剂量依赖性地增加血管内皮细胞对FITC LDL的通透性 ,MMP 2特异性抗体显著抑制VEGF的作用 ;VEGF还能剂量依赖性地升高MMP 2的活性。结论VEGF增加血管内皮细胞对FITC LDL的通透性的作用可能由MMP 2介导。     

Fluvastatin inhibits matrix metalloproteinase-1 expression in human vascular endothelial cells

Matrix metalloproteinase-1 (MMP-1), also called interstitial collagenase, may play an important role in the pathogenesis of atherosclerosis and atherosclerotic plaque rupture. We investigated the effects of fluvastatin on MMP-1 expression in human vascular endothelial cells (ECs). The addition of fluvastatin decreased the basal MMP-1 levels in the culture media of ECs in a time-dependent (0 to 48 hours) and dose-dependent (10(-)(8) to 10(-)(5) mol/L) manner. On the other hand, fluvastatin did not affect tissue inhibitor of metalloproteinase-1 levels. Collagenolytic activity in conditioned media of ECs was also dose-dependently reduced by fluvastatin. The effect of fluvastatin on MMP-1 expression was completely reversed in the presence of mevalonate or geranylgeranyl-pyrophosphate, but not in the presence of squalene. Inhibition of Rho by C3 exoenzyme also significantly decreased MMP-1 expression in ECs. Our findings revealed that fluvastatin decreases MMP-1 expression in human vascular ECs through inhibition of Rho.     

炎症细胞因子对人脐静脉内皮细胞分泌VEGF、ICAM-1的影响

目的：探讨炎症因子自细胞介素-1β（IL-1β）、肿瘤坏死因子-α（TNFα）对人脐静脉内皮细胞（HU—VEC）分泌血管内皮生长因子（VEGF）、细胞间粘附分子1（ICAM-1）的影响。方法：人脐静脉内皮细胞在37℃、5％CO2的条件下常规培养。实验采用4～5代细胞;按1×10^5／ml密度接种于5cm^2的培养皿中。24h后换液。生长接近80％融合时进行干预。按IL-1β组、TNF—α组、IL-1β＋TNF—α组、空白对照组进行刺激（IL—1β和TNFα干预浓度均为10ng／m1）,每组12个样本;在共同培养24h后收集细胞上清液。应用酶联免疫吸附测定（ELISA）法检测细胞上清液中VEGF、ICAM—1的浓度。结果：IL—1β组、TNF—α组、IL—1β＋TNF-α组的VEGF值（ng／ml）分别为（27．91±0．63）、（13．54±1．17）和（13．05±0．11）,均明显高于对照组（4．21±0．91）,P=0．000;IL—1β组、TNF-α组、IL-1β＋TNF—α组的ICAM-1值（ng／ml）分别为（2．88±0．98）、（2．96±0．03）和（2．30±0．20）．均明显高于空白对照组（0．25±0．01）。P=0．000。结论：炎症因子IL—1β、TNF—α均可促进人脐静脉内皮细胞分泌斑块不稳定相关标志物VEGF、ICAM-1,可能是炎症在急性冠脉综合征的发生、发展中起重要作用的机制之一。