链球菌组蛋白样蛋白对小鼠腹腔巨噬细胞产生IL-1的影响

目的　研究链球菌HlpA对小鼠腹腔巨噬细胞 (MΦ)产生IL 1的作用。方法　用RINm5F细胞产氮量测定IL 1活性。结果　链球菌HlpA(0～ 10 0 μg mL)在体外以剂量和时间依赖方式促进MΦ产生IL 1(P <0 .0 0 1)。LTA和HlpA的混合物对IL 1的产生呈协同增强作用 (P <0 .0 0 1) ;肝素则起抑制作用 (P <0 .0 0 1)。结论　纯化的链球菌HlpA在体外刺激小鼠腹腔MΦ产生IL 1;HlpA和LTA对MΦ的IL 1产生呈协同增强作用。     

NADPH氧化酶在TNF-α诱导HUVEC HO-1表达中的作用

目的探讨NADPH氧化酶来源的活性氧(ROS)在TNF-α诱导人脐静脉内皮细胞(HUVEC)血红素氧化酶1(HO-1)表达中的作用。方法用小分子RNA干扰(siRNA)技术消除HUVEC的NADPH氧化酶p47phox亚基,用分子探针2,7-DCF测定细胞内ROS的产生量以及用RT-PCR测定HO-1 mRNA的表达。结果TNF-α(200 U/mL)作用24 h后,HUVEC中ROS的产生量增加了138%,细胞内HO-1 mRNA表达较对照组增加146.5%;转染p47phoxsiRNA后,细胞内NADPH氧化酶p47phox亚基的mRNA表达消失,ROS的产生量降低至对照组水平,而HO-1 mRNA的表达水平降低约54%。结论TNF-α刺激后,HUVEC内产生的ROS主要来源于NADPH氧化酶的活化,但ROS仅部分介导了TNF-α对HO-1基因表达的诱导作用。     

链球菌蛋白对RAW264.7小鼠巨噬细胞免疫学活性的调节作用

目的:探讨链球菌蛋白对RAW264.7小鼠巨噬细胞免疫活性调节及其相关作用机制.方法:不同浓度的链球菌蛋白与RAW264.7小鼠巨噬细胞共同作用后,采用MTT 法检测细胞的增殖活化;吞噬中性红试验观察巨噬细胞的吞噬功能;生物化学法检测巨噬细胞上清液中TNF-α和IL-6 的含量;RT-PCR法检测细胞中TNF-α、IL-6和Toll样受体(Toll-like receptors,TLRs)的mRNA表达情况;流式细胞术检测细胞表面TLR2和TLR4的表达强度.结果:链球菌蛋白对巨噬细胞的生长增殖和吞噬功能有较强的刺激作用(P<0.05),促进TNF-α和IL-6的表达和分泌(P<0.05),并可上调巨噬细胞表面模式识别受体TLR2和TLR4的表达(P<0.05).结论:链球菌蛋白通过刺激RAW264.7小鼠巨噬细胞的增殖,增强细胞吞噬活性以及诱导细胞因子的产生等发挥其免疫调节作用.     

葡萄糖胺对TNF-α诱导的血管内皮细胞VCAM-1表达的影响

目的探讨葡萄糖胺对肿瘤坏死因子-α(tumornecrosis factor-α,TNF-α)诱导的人脐带血管内皮细胞(HUVEC)血管细胞黏附分子(vascular cell adhesion molecule,VCAM-1)表达的影响。方法实时逆转录聚合酶链式反应(Real time RT-PCR)和免疫印迹法(Western blot)分别测定葡萄糖胺对VCAM-1的表达情况;Western blot法测定HUVEC核因子-κB(nuclear factor,NF-κB)磷酸化程度。结果葡萄糖胺抑制TNF-α诱导的VCAM-1在HUVEC的表达;NF-κB抑制剂BMS-345541抑制TNF-α诱导的VCAM-1的表达;葡萄糖胺抑制TNF-α诱导的NF-κB的磷酸化。结论葡萄糖胺抑制TNF-α诱导的VCAM-1的表达与抑制NF-κB的活化相关。     

低氧诱导大鼠肺泡巨噬细胞产生TNF-α的机制

目的：研究低氧诱导肺泡巨噬细胞低氧诱导因子-1α(HIF-1α)的表达及HIF-1α对肺泡巨噬细胞产生肿瘤坏死因子-α(TNF-α)的影响。方法：应用HIF-1α诱骗法(HIF-1α decoy)抑制低氧(3％O2，5％CO2，92％N2)培养的肺泡巨噬细胞中HIF-1α的作用，并用免疫组织化学、Western blot、半定量RT-PCR、酶联免疫吸附法(ELISA)分别检测HIF-1α蛋白、mRNA的表达和TNF-α的产生。结果：HIF-1α在常氧对照组肺泡巨噬细胞核中表达呈阴性，在低氧组和HIF-1α decoy组表达呈阳性；低氧组和HIF-1α decoy组中HIF-1α蛋白的含量显著高于常氧对照组(P<0.05)。HIF-1α mRNA的含量在低氧组和HIF-1α decoy组明显高于常氧对照组(P<0.05)；培养的巨噬细胞上清液中TNF-α的含量在低氧组(115±17 ng／L)明显高于常氧对照组(69±13 ng／L，P<0.05)和HIF-1α decoy组(81±15 ng／L，P<0.05)。结论： 低氧可明显诱导肺泡巨噬细胞HIF-1α的表达和活性增强，后者能促进TNF-α的产生，提示在可导致肺部低氧的炎症性疾病如COPD中HIF-1α可能发挥重要作用。     

2型糖尿病患者血清IGF-1、TNF-α与视网膜病变的关系

目的:探讨胰岛素样生长因子-1(IGF-1)与肿瘤坏死因子-α(TNF-α)在2型糖尿病(DM)视网膜病变(DR)发病中的作用。方法:应用酶联免疫吸附方法(ELISA)对127例2型糖尿病患者及36例健康人血清中的IGF-1和TNF-α进行测定。结果:(1)DM组血清IGF-1的含量低于对照组(P<0.01),而TNF-α的含量高于对照组(P<0.01)。(2)BDR组的IGF-1、TNF-α的含量高于NDR组(P<0.05)。(3)PDR组的IGF-1、TNF-α的含量高于NDR组(P<0.01)。(4)DR的严重程度与IGF-1、TNF-α水平呈正相关(P<0.01)。结论;TNF-α的过度表达及IGF-1的降低在DM的发病机制中起重要作用,而糖尿病合并视网膜病变时,血中IGF-1和TNF-α水平升高,IGF-1和TNF-α可能参与了DR的发生和发展。     

菟丝子黄酮通过调控ZBED3-AS1影响成骨细胞凋亡

目的:探讨菟丝子黄酮(TFCC)对长链非编码RNA含BED型锌指蛋白3反义RNA 1(ZBED3-AS1)表达和成骨细胞凋亡的影响,旨在阐明TFCC调控成骨细胞凋亡的分子机制。方法:将成骨样细胞株UMR-106分为对照组、肿瘤坏死因子α(TNF-α)组、TNF-α+TFCC组、TNF-α+pcDNA3.1组、TNF-α+pcDNA3.1-ZBED3-AS1组、TNF-α+TFCC-5+si-NC组、TNF-α+TFCC-5+si-ZBED3-AS1组、TNF-α+TFCC-5+pcDNA3.1组和TNF-α+TFCC-5+pcDNA3.1-ZBED3-AS1组。采用CCK-8法和集落形成实验检测细胞增殖;流式细胞术检测细胞凋亡;Western blot检测caspase-3和p21的表达;RT-qPCR检测ZBED3-AS1的表达。结果:TNF-α处理后UMR-106细胞的活力和集落形成能力降低,凋亡率升高,p21和caspase-3表达升高,ZBED3-AS1表达降低(P<0.05)。TFCC(1、10和100μg/L)干预或过表达ZBED3-AS1后,UMR-106细胞的活力和集落形成能力升高,凋亡率降低,ZBED3-AS1表达增加,从而减轻TNF-α处理对UMR-106细胞增殖和凋亡的影响(P<0.05)。抑制ZBED3-AS1表达减轻了TFCC对TNF-α作用下UMR-106细胞增殖和凋亡的影响(P<0.05)。过表达ZBED3-AS1增强了TFCC对TNF-α作用下UMR-106细胞增殖和凋亡的影响(P<0.05)。结论:TFCC通过上调ZBED3-AS1表达可促进成骨细胞增殖,抑制TNF-α诱导的成骨细胞凋亡。     

阿托伐他汀下调肿瘤坏死因子-α诱导的人脐静脉内皮细胞CD40配体的表达

研究阿托伐他汀(atorvastatin,AT)对TNF-α诱导的人脐静脉内皮细胞(human umbilical vein endothelial cell,HUVEC)CD40L表达的影响。体外培养的HUVEC株,第2~3代用于实验。实验分5组:对照组;TNF组:培养基中加TNF-α40ng/ml;AT1组、AT2组、AT3组:加TNF-α40ng/ml基础上分别加小剂量、中剂量、大剂量含AT血清,孵育时间6h、12h和24h。采用流式细胞术测定CD40L蛋白表达水平,免疫组化染色观察细胞CD40L蛋白表达情况。HUVEC孵育24hTNF组CD40L表达量明显高于对照组(P0.05);AT2组和AT3组明显低于TNF组(P0.05);HUVEC孵育12h和24hAT3组组CD40L表达量明显低于TNF-α组(P0.05);免疫组化染色显示不同剂量含AT血清预处理后,细胞阳性颗粒降低,CD40L表达下调。中剂量及大剂量含AT血清预处理能够明显下调HUVEC孵育24hTNF-α诱导的CD40L表达,AT下调TNF诱导的HUVEC CD40L表达呈孵育时程依赖性及剂量依赖性。     

TNF-α和IFN-γ对肾小管上皮细胞趋化因子表达的影响

目的探讨细胞因子TNF-α和IFN-γ对肾小管上皮细胞趋化因子CXCL9、CXCL10和CXCL11表达的影响。方法分别以TNF-α以及IFN-γ和TNF-α联合作用肾小管上皮细胞HK-2不同时间后,用Real-time PCR和ELISA分别检测CXCL9、CXCL10和CXCL11 mRNA和蛋白水平。用流式细胞术检测淋巴细胞表面CXCR3表达情况,通过趋化实验检测细胞培养上清对淋巴细胞的趋化作用。结果肾小管上皮细胞在TNF-α作用12 h后能够诱导趋化因子CXCL9、CXCL10和CXCL11mRNA表达上调,CXCL9 mRNA的表达在48 h达到高峰,而CXCL10和CXCL11 mRNA表达高峰在12 h;CXCL9、CXCL10和CXCL11蛋白的基础分泌水平均较低,在TNF-α作用12 h后,分泌水平也逐渐升高,CXCL9、CXCL10在48 h时分泌达到高峰,CXCL11分泌高峰在72 h。与TNF-α单独作用组和IFN-γ单独作用组相比,TNF-α和IFN-γ联合作用使肾小管上皮细胞趋化因子CXCL9、CXCL10和CXCL11 mRNA表达和蛋白分泌明显增强(P<0.05)。与新鲜分离的淋巴细胞相比,活化的淋巴细胞表面的CXCR3表达明显升高(P<0.05)。TNF-α以及IFN-γ和TNF-α联合作用HK-2细胞培养上清对活化的淋巴细胞具有明显的趋化作用(P<0.05)且能被抗CXCR3抗体所阻断(P<0.05)。结论细胞因子TNF-α能诱导肾小管上皮细胞趋化因子CXCL9、CXCL10和CXCL11表达,且与IFN-γ联合作用对趋化因子的表达具有协同作用。     

白果内酯调控LEF1-AS1/miR-23b-3p分子轴缓解肺炎链球菌诱导的肺泡上皮细胞损伤

目的探讨白果内酯对肺炎链球菌诱导的肺泡上皮细胞损伤的保护作用及其对lncRNA LEF1-AS1/miR-23b-3p分子轴的调控作用。方法用肺炎链球菌诱导肺泡上皮细胞建立细胞损伤模型(感染组);分别转染si-NC、si-LEF1-AS1后,用肺炎链球菌感染细胞(感染+si-NC组和感染+si-LEF1-AS1组);pcDNA、pcDNA-LEF1-AS1分别转染至肺泡上皮细胞后用白果内酯与肺炎链球菌共同处理细胞(感染+白果内酯+pcDNA组和感染+白果内酯+pcDNA-LEF1-AS1组)。ELISA法检测TNF-α、IL-1β、IL-6的水平;流式细胞术检测细胞凋亡率;q RT-PCR法检测LEF1-AS1、miR-23b-3p的表达量;双荧光素酶报告基因实验检测LEF1-AS1与miR-23b-3p的靶向关系;Western blot检测Bcl-2、Bax蛋白表达量。结果白果内酯能够降低肺炎链球菌诱导的肺泡上皮细胞中TNF-α、IL-1β、IL-6的水平和LEF1-AS1的表达量(P<0.05),并可降低凋亡率和Bax蛋白水平(P<0.05),还可促进miR-23b-...     

Synergistic Effect of Histamine and TNF-α on Monocyte Adhesion to Vascular Endothelial Cells

The histamine level is high during allergic attacks, and patients with allergy may have chronic inflammatory conditions at which tumor necrosis factor (TNF)-α is extensively released by macrophages. Here, in vitro static and microfluidic flow assays were conducted to investigate the combined influence of histamine and TNF-α on adhesion of monocytic THP-1 cells to human umbilical vein endothelial cells (HUVEC). In a static assay, histamine stimulation of TNF-α-activated HUVEC elevated the number of attached THP-1 cells. In a flow assay, the number of crawling and firmly adherent THP-1 cells was higher on TNF-α + histamine activated HUVEC than on HUVEC activated by TNF-α alone. This synergistic effect of histamine and TNF-α is caused by the increased endothelial surface expression of intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and E-selectin. Since the exposure of TNF-α-activated endothelium to histamine favors monocyte recruitment, it may be a serious risk factor for atherosclerosis and other inflammatory disorders.     

Streptococcal histone induces murine macrophages To produce interleukin-1 and tumor necrosis factor alpha

The histone-like protein (HlpA) is highly conserved among streptococci. After lysis of streptococci in infected tissues, HlpA can enter the bloodstream and bind to proteoglycans in the glomerular capillaries of kidneys, where it can react with antibodies or stimulate host cell receptors. Deposits of streptococcal antigens in tissues have been associated with localized acute inflammation. In this study, we measured the ability of purified HlpA (5 to 100 microg/ml), from Streptococcus mitis, to induce the production of proinflammatory cytokines by cultured, murine peritoneal macrophages. The release of tumor necrosis factor alpha (TNF-alpha) and interleukin-1 (IL-1) was time and concentration dependent and was not diminished by the presence of polymyxin B. Exposure of macrophages to a mixture of HlpA and lipoteichoic acid resulted in a synergistic response in the production of both TNF-alpha and IL-1. Stimulation with a mixture of HlpA and heparin resulted in reduced cytokine production (50% less IL-1 and 76% less TNF-alpha) compared to that by cells incubated with HlpA alone. The inclusion of antibodies specific to HlpA in macrophage cultures during stimulation with HlpA did not affect the quantity of TNF-alpha or IL-1 produced. These observations suggest that streptococcal histone may contribute to tissue injury at infection sites by promoting monocytes/macrophages to synthesize and release cytokines that initiate and exacerbate inflammation. Streptococcus pyogenes, which can infect tissues in enormous numbers, may release sufficient amounts of HlpA to reach the kidneys and cause acute poststreptococcal glomerulonephritis.     

PDTC可改变TNF-α诱导的eNOS基因表达下调

目的探讨肿瘤坏死因子-α（TNF-α）对人脐静脉内皮细胞（HUVEC）中内皮型一氧化氮合酶基因（eNOS）表达的作用以及PDTC对此作用的改变。方法将培养的内皮细胞分为3组：1组为无任何处理的HUVEC,2组为子痫前期（PE）患者血清作用的HUVEC,3组为用正常晚孕妇女血清作用的HUVEC。用逆转录-聚合酶链反应检测三组细胞中eNOS mRNA的表达。酶联免疫吸附实验（ELISA）检测PE患者和正常孕妇血清中TNF-α含量。用1ng/ml、3ng/ml、5ng/ml 3种浓度的TNF-α分别作用三组细胞6h,以及用浓度为3ng/ml的TNF-α作用三组细胞分别长达6h、12h、24h,逆转录-聚合酶链反应（RT-PCR）检测eNOS mRNA的表达;将二硫代氨基甲酸吡硌烷（PDTC,5mmol/ml）与TNF-α（3ng/ml）同时作用以及TNF-α（3ng/ml）单独作用三组细胞6h,RT-PCR检测eNOS基因mRNA的表达。结果三组细胞中都有eNOS表达,2组表达量显著低于1组和3组（P〈0.01）。ELISA结果显示,PE患者血清中TNF-α含量显著高于正常晚孕妇女（P〈0.01）。TNF-α作用HUVEC细胞后eNOS表达显著低表达,并成时间和剂量依赖关系（P〈0.01）。PDTC和TNF-α同时作用的HUVEC和TNF-α单独作用的HUVEC相比,其eNOS表达显著增高（P〈0.01）。结论可下调eNOS在HUVEC中的表达,PDTC可改变TNF-α诱导的eNOSN表达的下调。     

干扰素和肿瘤坏死因子对人脐静脉内皮细胞表达HLA-Ⅱ类抗原的影响

采用cell-ELISA法对IFN-α、γ及rTNFα单独或协同影响人脐静脉内皮细胞（HUVEC）表达HLA-Ⅱ类抗原作了定量观察。结果表明,IFNγ直接刺激 HUVEC可依浓度和时间依赖的方式提高其 HLA-Ⅱ类抗原表达量,而rTNFα、IFNα单独处理HUVEC无效。当rTNFα和IFNγ同时诱导时,对HUVEC表达HLA-DR、DP、DQ均表现抑制作用。但是,当先用IFNγ诱导HUVEC 24h后,再加入rTNFα则发现DR、DP、DQ的表达升高,起促进作用。     

Interleukin-8 differentially modulates interleukin-4- and interleukin-2-induced human B cell growth

The effect of interleukin-8 (IL)-8 on human B cell growth, as determined by thymidine uptake and viable cell numbers was studied. IL-8 inhibited IL-4-induced growth of B cells costimulated with anti-μ antibodies (Ab) or Staphylococcus aureus Cowan strain I (SAC) in a dose-dependent fashion. In contrast, IL-8 did not inhibit IL-2-induced growth of B cells. The IL-8-mediated inhibition was specific, since it was blocked by anti-IL-8 mAb but not by control IgG1. Moreover, anti-tumor necrosis factor-α (anti-TNF-α) Ab blocked IL-8-mediated inhibition. On the other hand, TNF-α, but not other cytokines including IL-1β, IL-3, IL-5, IL-6, interferon-α (IFN-α) or IFN-γ, inhibited IL-4-mediated growth, and inhibition by TNF-α was blocked by anti-TNF-α Ab but not by control IgG. IL-4 had no effect on TNF-α binding by B cells while it decreased TNF-α production by B cells. IL-8 had no effect in binding of IL-4, IL-2 or TNF-α by B cells, however, it enhanced TNF-α production by B cells. These results indicate that IL-8 inhibited IL-4-induced human B cell growth by enhancement of endogenous TNF-α production.     

TNF-α与香烟烟雾在诱导气道上皮细胞株黏蛋白表达的相互作用

目的 探讨肿瘤坏死因子TNF-α与香烟提取物共同诱导气道黏液高分泌的相互关系及作用特点。方法 培养的人气道上皮细胞BEAS-2B,转染核转录因子（NF）-κB"decoy"寡核苷酸（ODNs）,并以乱序NF-κB ODNs为对照转染组,各组均分别予以TNF-α、10%香烟提取物（CSE）单独刺激及共同刺激,以Western blot、ELISA及RT-PCR法检测各组刺激前后磷酸化表皮生长因子受体（p-EGFR）、黏蛋白（MUC5AC）蛋白及mRNA水平。结果 转染乱序NF-κB ODNs的细胞予以TNF-α、10% CSE刺激后,各组细胞中p-EGFR蛋白水平较对照组升高,伴随MUC5AC蛋白含量及基因转录水平的提高(P<0.05);共孵育组中较单独刺激组升高更为显著（P<0.05）。转染NF-κB"decoy"ODNs组再予以TNF-α刺激,细胞中MUC5AC蛋白含量及mRNA水平与未转染组相比升高不明显,而单用CSE刺激组中的MUC5AC、p-EGFR水平仍有明显升高（P<0.05）;共孵育组显示出与CSE单独刺激组相似的结果。结论 TNF-α、CSE能协同促进气道上皮细胞中黏蛋白合成,转录因子NF-κB主要参与TNF-α所致的MUC5AC表达,而在CSE诱导的效应过程中作用不明显。     

沉默 HOXA11-AS 靶向 miR-766-3p 对 ox-LDL 诱导的血管内皮细胞损伤的影响

目的 探讨长链非编码 RNA (lncRNA) 同源异形盒基因 A11 反义 RNA (HOXA11-AS) 靶向微小 RNA-766-3p (miR-766-3p) 对氧化低密度脂蛋白 ( ox-LDL) 诱导的血管内皮细胞损伤的影响。 方法 以 100 μg / mL 的 ox-LDL 处理人脐静脉血管内皮细胞 (human umbilical vein endothelial cell, HUVEC) 24 h 建立 细胞损伤模型。 将 HUVEC 分为对照 (con) 组、 ox-LDL 组、 ox-LDL + si-NC 组、 ox-LDL + si-HOXA11-AS 组、 ox-LDL + miR-NC 组、 ox-LDL + miR-766-3p 组、 ox-LDL + si-HOXA11-AS + anti-miR-NC 组、 ox-LDL + si-HOXA11-AS + anti-miR-766-3p 组。 RT-qPCR 检测 HOXA11-AS 和 miR-766-3p 表达。 流式细胞术分析细胞凋亡。 试剂盒检测 LDH 释放量、 胞内 SOD 活性。 ELISA 法检测培养液中 TNF-α、 IL-1β 水平。 双荧光素酶报告实 验确定 HOXA11-AS 和 miR-766-3p 的靶向关系。 结果 与 con 组比较, ox-LDL 组 HUVEC 细胞凋亡率、 LDH 释放量、 HOXA11-AS 表达量以及培养液中 TNF-α、 IL-1β 水平显著升高 (P< 0. 05), SOD 活性、 miR-766-3p 表达量显著降低 (P< 0. 05)。 与 ox-LDL + si-NC 组比较, ox-LDL + si-HOXA11-AS 组 HUVEC 细胞凋亡率、 LDH 释放量以及培养液中 TNF-α、 IL-1β 水平显著降低 (P< 0. 05), SOD 活性显著升高 (P< 0. 05)。 与 ox-LDL + miR-NC 组比较, ox-LDL + miR-766-3p 组 HUVEC 细胞凋亡率、 LDH 释放量以及培养液中 TNF-α、 IL-1β 水平显著降低 (P< 0. 05), SOD 活性显著升高 (P< 0. 05)。 miR-766-3p 是 HOXA11-AS 的直接靶点。 与 ox-LDL + si-HOXA11-AS + anti-miR-NC 组比较, ox-LDL + si-HOXA11-AS + anti-miR-766-3p 组 HUVEC 细胞凋亡 率、 LDH 释放量以及培养液中 TNF-α、 IL-1β 水平显著升高 (P< 0. 05), SOD 活性显著降低 (P< 0. 05)。 结论 沉默 HOXA11-AS 通过靶向上调 miR-766-3p 表达能够抑制 ox-LDL 诱导的血管内皮细胞凋亡、 氧化应 激和炎性反应。     

Productive HIV-1 infection of human vascular endothelial cells requires cell proliferation and is stimulated by combined treatment with interleukin-1β plus tumor necrosis factor-α

Vascular endothelial cells (EC) play a key role in viral tropism in vivo. Since conflicting reports have been published on the capability of HIV to infect EC in vitro, we analyzed some factors potentially capable of influencing the susceptibility of human umbilical vein endothelial cells (HU-VEC) to HIV-1. Both primary cultures and differentiated immortalized HUVEC lines were used. HUVEC were negative for the expression of CD4, but weakly CD26- and galactosylceramide-positive. Although binding of HIV to EC was substantial, the virus was apparently incapable of replicating in nonproliferating cultures. In resting cultures, the content of cell-associated HIV disappeared 4–6 days after infection without production of p24 and infectious progency. In contrast, infection of proliferating EC cultures led to the transient release of p24 and infectious virus (102.5-103.5 SFU/ml) peaking 2–6 days postinfection. Antibody neutralization of cytokines that may be produced by EC (IL1, IL6, IL8, TNF, IFN-β) failed to modify virus adsorption and replication, whereas treatment with IL1-β plus TNF-α stimulated both virus binding and virus release. As seen by gag polymerase chain reaction (PCR) the viral genome persisted up to 15 days in untreated EC cultures, but over 20 days in cultures exposed to IL1-β plus TNF-α. This study shows that: (a) CD4-negative HUVEC are capable of binding substantial amounts of HIV-1; (b) binding is enhanced by proinflammatory cytokines; (c) the establishement of productive infection is favored by cell proliferation; and (d) exposure to IL1-β plus TNF-α enhances virus replication. © Wiley-Liss, Inc.     

Does TNF-α directly increase endothelial cell monolayer permeability?

The effects of dexamethasone (DEX) and ϖ methyl ester (l-NAME) on the tumour necrosis factor-α (TNF-α)-induced increase in permeability of human umbilical vein endothelial cell (HUVEC) monolayer to [¹²⁵I] labelled bovine serum albumin (BSA) were examined. Preincubation of HUVEC monolayers with DEX (1μM, 2 h) completely abolished the effect of TNF-α (5 ng/ml, 18 h). Administration of DEX 2 h after TNF-α also reduced the effect of TNF-α, whilel-NAME (5 ng/ml, 1 mM, 18 h) had no significant effect.

The observed inhibition of the TNF-α-induced permeability increase on preincubation with DEX would suggest a role for nitric oxide (NO) in mediating the permeability response. However, this is not confirmed by the experiments withl-NAME. The inhibition caused by DEX administered after TNF-α would suggest alternative mechanisms by which DEX may be acting in addition to inhibition of NO synthase induction.