溶血磷脂酰胆碱诱导内皮细胞表达血管内皮生长因子及丹酚酸B的抑制作用

研究溶血磷脂酰胆碱对内皮细胞中血管内皮生长因子表达的影响以及丹酚酸B的保护作用。在人脐静脉内皮细胞株ECV30 4培养基中加入溶血磷脂酰胆碱或溶血磷脂酰胆碱 +丹酚酸B ,用酶联免疫吸附试验检测各组内皮细胞培养上清液中血管内皮生长因子蛋白含量 ;用原位杂交检测血管内皮生长因子mRNA的表达。结果显示 ,培养的ECV30 4中未见血管内皮生长因子mRNA的表达 ,溶血磷脂酰胆碱刺激后可见血管内皮生长因子mRNA的高表达 ,加入丹酚酸B后阳性反应明显低于溶血磷脂酰胆碱组。酶联免疫吸附试验结果显示 ,溶血磷脂酰胆碱可使ECV30 4细胞条件培养基中血管内皮生长因子蛋白表达明显增加 ,丹酚酸B可明显降低其含量。以上结果提示 ,溶血磷脂酰胆碱能诱导ECV30 4表达高水平的血管内皮生长因子 ,丹酚酸B可明显降低其含量     

乙酰肝素酶在胃癌组织中的表达及临床意义

癌细胞侵袭和转移的一个重要机制是降解基底膜和细胞外基质结构.硫酸乙酰肝素降解性糖苷内切酶的激活与肿瘤细胞转移有关,这在鼠B16-Fl0黑色素瘤细胞在血管内皮细胞细胞外基质上的培养试验中被证实[1].Takaoka等[2]采用逆转录聚合酶链反应(RT-PCR)和免疫组化方法在临床标本和细胞中证明乙酰肝素酶的表达与胃癌的侵袭性和预后不良有关.     

Syndecan-1和乙酰肝素酶在胃癌淋巴结转移中的相互作用

胃癌的侵袭和转移涉及多个步骤，其中穿越由细胞外基质和基底膜组成的屏障是必不可少的一步。该屏障主要由两种成分构成：一是结构蛋白，二是糖氨聚糖，后者的主要成分是硫酸乙酰肝素蛋白多糖(HSPG)。乙酰肝素酶(HPA)基因编码的蛋白质是惟一降解HSPG硫酸肝素(HS)侧链的核苷内切酶。我们先前的研究显示，HPA mRNA表达与胃癌淋巴结转移有关，且可能通过与CD44v6和基质金属蛋白酶(MMP)-7的协同作用参与胃癌的侵袭转移。     

硫酸乙酰肝素蛋白聚糖在脂蛋白代谢中的作用

硫酸乙酰肝素蛋白聚糖(HSPGs)是一种广泛存在于体内多种细胞表面以及细胞外基质的蛋白聚糖(PGs)。PGs由核心蛋白和糖胺聚糖(GAGs)两部分组成。PGs的大部分生物学功能是通过GAGs实现的〔1〕。肝细胞表面表达的HSPGs主要包括多配体PGs-1,-2和-4(syndecan-1,-2 and-4)和磷脂酰肌醇聚糖-1和-4(glypican-1and-4)〔2〕。此外,还有分泌型的PGs,包括基底膜聚糖(perle-can)、集聚蛋白(agrin)、丝甘蛋白聚糖(serglycin)和胶原XⅧ     

同型半胱氨酸对血管内皮细胞合成蛋白聚糖的影响

为探讨同型半胱氨酸对血管内皮细胞合成蛋白聚糖的影响，采用400umol／L同型半胱氨酸作用于培养的人脐静脉内皮细胞，以^35S-Na2SO4为示踪物标记细胞合成的蛋白聚糖，通过离子交换层析，凝胶过滤层析分离蛋白聚糖。结果发现，实验组培养液中总蛋白聚糖降低，硫酸乙酰肝素蛋白聚糖及硫酸软骨素-硫酸皮肤素蛋白聚糖含量也降低，但其百分含量未见改变。细胞层中蛋白聚糖未见明显变化。     

重组腺相关病毒介导人血管内皮生长因子165基因在培养大鼠心肌细胞中的表达

目的探讨2型腺相关病毒载体介导的人血管内皮生长因子165基因在离体心肌细胞中的表达及表达产物的生物活性。方法构建携带人血管内皮生长因子的2型腺相关病毒载体(rAAV-2/hVEGF165),感染大鼠原代心肌细胞,采用逆转录聚合酶链反应、免疫印迹法和酶联免疫吸附测定等方法检测心肌细胞人血管内皮生长因子165的表达,应用MTT法检测转染后细胞上清液中血管内皮生长因子165的生物学活性。结果逆转录聚合酶链反应检测结果发现感染的心肌细胞可表达人血管内皮生长因子165 mRNA;免疫印迹法检测结果表明感染的心肌细胞中有人血管内皮生长因子165,酶联免疫吸附测定法检测到血管内皮生长因子蛋白分泌水平为546.5±15.6pg/L,未转染组未检测到血管内皮生长因子蛋白的分泌;还发现感染的心肌细胞上清具有明显的促人内皮细胞增殖作用。结论2型腺相关病毒载体介导的人血管内皮生长因子165可有效转染大鼠心肌细胞,且表达产物具有促内皮细胞增殖作用。     

汉滩病毒感染EA.hy926细胞上调固有免疫相关分子表达的研究

目的　探讨汉滩病毒（hantaan virus, HTNV）感染EA.hy926细胞诱导抗病毒固有免疫相关分子的表达,为建立HTNV感染的细胞模型提供依据。方法　将HTNV感染EA.hy926细胞,利用间接免疫荧光和实时荧光定量PCR技术于不同感染时间段,检测EA.hy926细胞中模式识别受体、细胞因子及抗病毒相关分子的mRNA表达水平。结果　HTNV感染EA.hy926细胞后,随着感染时间的持续,核蛋白mRNA相对表达倍数显著上调,且不同感染时间段差异具有统计学意义（P＜0.05）;与未处理组相比,HTNV感染EA.hy926后,Toll样受体3、RIG-I和MDA5模式识别受体mRNA相对表达倍数均显著上调（P均＜0.05）,IL-6、IL-10、IFN-β和CCL5细胞因子mRNA相对表达倍数均显著上调（P均＜0.05）,ISG15、MxA、OAS1、IFITM1和IFITM3抗病毒相关分子mRNA相对表达倍数均显著上调（P均＜0.05）。结论　HTNV感染EA.hy926细胞后,可上调抗病毒固有免疫相关分子的表达,该细胞可以作为体外HTNV感染的细胞模型。     

乙酰肝素酶在肺癌侵袭转移及治疗中作用的研究进展

乙酰肝素酶是一种β-D-葡萄糖醛酸内切酶,为体内惟一能够降解硫酸乙酰肝素蛋白多糖的酶,可以在特定部位裂解硫酸乙酰肝素蛋白多糖,破坏细胞外基质及基底膜,并参与恶性肿瘤新生血管的形成,与恶性肿瘤的侵袭转移密切相关,乙酰肝素酶由此成为抗肿瘤作用的新靶点,其抑制剂有望成为临床抗肿瘤治疗的新途径.本文就乙酰肝素酶在肺癌侵袭转移及治疗中作用的研究作一综述.     

乙型肝炎病毒感染对原发性肝细胞癌血管内皮生长因子、环氧合酶-2蛋白表达的影响

目的:探讨乙型肝炎病毒(HBV)感染对肝细胞癌(HCC)中血管内皮生长因子(VEGF)、环氧合酶-2(COX-2)蛋白表达水平的影响和肿瘤血管形成的临床病理意义.方法:利用血清学指标检测40例HCC的HBV感染情况,采用快速免疫组化法检测HCC中VEGF、COX-2的蛋白表达,用抗CD34单克隆抗体显示血管内皮细胞,根据CD34阳性的血管内皮细胞计数测定肿瘤微血管密度(MVD).结果:HBV感染组中VEGF、COX-2蛋白以及MVD的阳性表达率均高于非HBV感染组,差异有显著性意义(P<0.05).VEGF和COX-2表达呈正相关(r=0.618,P<0.01).结论:HBV可能通过上调VEGF、COX-2等血管形成因子表达,共同促进了肿瘤血管的生成,从而促进HCC的生长、浸润和转移.     

罗格列酮对胰岛素抵抗大鼠主动脉内皮功能的影响及其机制的研究

目的:观察罗格列酮对胰岛素抵抗大鼠主动脉内皮依赖性血管舒张和一氧化氮(NO)含量、内皮型一氧化氮合酶(eNOS)、磷脂酰肌醇-3激酶及蛋白激酶B表达的影响。方法:4~6周龄雄性SD大鼠予高糖高脂喂养8周,建立胰岛素抵抗模型,分为对照组和治疗组,每组各15只,治疗组用罗格列酮[3mg/(kg.d)]干预8周,另取15只正常大鼠为正常组。实验终止时用葡萄糖输注率评价胰岛素抵抗,观察大鼠离体主动脉对乙酰胆碱依赖性血管舒张反应,Griess重氮化反应法检测主动脉NO含量,逆转录聚合酶链反应方法检测磷脂酰肌醇-3激酶、蛋白激酶B和eNOS mRNA表达,电镜观察主动脉超微结构。结果:对照组葡萄糖输注率、主动脉内皮依赖性舒张功能、NO浓度、磷脂酰肌醇-3激酶、蛋白激酶B、eNOS mRNA表达较正常组均显著降低(P<0.01),治疗组上述指标均显著升高(P<0.01)。透射电镜检查可见对照组主动脉内皮细胞和内皮下结构的病理改变,治疗组胸主动脉超微结构接近正常。结论:胰岛素抵抗大鼠存在内皮依赖性舒张功能紊乱和主动脉NO浓度、磷脂酰肌醇-3激酶、蛋白激酶B、eNOS mRNA表达下降,用罗格列酮治疗可改善其内皮功能,增强NO产生和磷脂酰肌醇-3激酶、蛋白激酶B、eNOS mRNA表达。     

Intracerebral chondroitinase ABC and heparan sulfate proteoglycan glypican improve outcome from chronic stroke in rats

Physical and chemical constraints imposed by the periinfarct glial scar may contribute to the limited clinical improvement often observed after ischemic brain injury. To investigate the role of some of these mediators in outcome from cerebral ischemia, we treated rats with the growth-inhibitory chondroitin sulfate proteoglycan neurocan, the growth-stimulating heparan sulfate proteoglycan glypican, or the chondroitin sulfate proteoglycan-degrading enzyme chondroitinase ABC. Neurocan, glypican, or chondroitinase ABC was infused directly into the infarct cavity for 7 d, beginning 7 d after middle cerebral artery occlusion. Glypican and chondroitinase ABC reduced glial fibrillary acidic protein immunoreactivity and increased microtubule-associated protein-2 immunoreactivity in the periinfarct region, and glypican- and chondroitinase ABC-treated rats showed behavioral improvement compared with neurocan- or saline-treated rats. Glypican and chondroitinase ABC also increased neurite extension in cortical neuron cultures. Glypican increased fibroblast growth factor-2 expression and chondroitinase ABC increased brain-derived neurotrophic factor expression in these cultures, whereas no such effects were seen following neurocan treatment. Thus, treatment with glypican or enzymatic disruption of neurocan with chondroitinase ABC improves gross anatomical, histological, and functional outcome in the chronic phase of experimental stroke in rats. Changes in growth factor expression and neuritogenesis may help to mediate these effects.     

Heparanase, tissue factor, and cancer

Heparanase is an endo-beta- D-glucuronidase that is capable of cleaving heparan sulfate side chains of heparan sulfate proteoglycans on cell surfaces and the extracellular matrix, activity that is strongly implicated in tumor metastasis and angiogenesis. Evidence was provided that heparanase overexpression in human leukemia, glioma, and breast carcinoma cells results in a marked increase in tissue factor (TF) levels. Likewise, TF was induced by exogenous addition of recombinant heparanase to tumor cells and primary endothelial cells, induction that was mediated by p38 phosphorylation and correlated with enhanced procoagulant activity. TF induction was further confirmed in heparanase-overexpressing transgenic mice and correlated with heparanase expression levels in leukemia patients. Heparanase was also found to be involved in the regulation of tissue factor pathway inhibitor (TFPI). It was shown that heparanase overexpression or exogenous addition induces two- to threefold increase of TFPI expression. Similarly, heparanase stimulated accumulation of TFPI in the cell culture medium. Extracellular accumulation exceeded, however, the observed increase in TFPI at the protein level and appeared to be independent of heparan sulfate and heparanase enzymatic activity. Instead, a physical interaction between heparanase and TFPI was demonstrated, suggesting a mechanism by which secreted heparanase interacts with TFPI on the cell surface, leading to dissociation of TFPI from the cell membrane and increased coagulation activity, thus further supporting the local prothrombotic function of heparanase. As heparins are strong inhibitors of heparanase, in view of the effect of heparanase on TF/TFPI pathway, the role of heparins' anticoagulant activity may potentially be expanded.     

Lipoprotein modulation of subendothelial heparan sulfate proteoglycans (perlecan) and atherogenicity

Heparan sulfate proteoglycans (HSPGs) are key constituents of subendothelial extracellular matrix that play an important role in the assembly and structure of the basement membrane, regulation of basement membrane permeability, growth factor activity and cellular adhesion. Vascular HSPGs decrease during inflammation, atherosclerosis and diabetes. Recent studies showed that HSPGs are negatively regulated by atherogenic molecules and positively regulated by antiatherogenic agents. Extracellular matrix HSPG, perlecan, appears to be a key target of regulation by these agents. At least two levels of regulation appear to control perlecan HSPG in matrix; a change in core protein expression or a change in heparan sulfate metabolism. Atherogenic levels of low-density lipoprotein (LDL), oxidized LDL and lysolecithin decrease not only perlecan core protein synthesis but also enhance heparan sulfate degradation by stimulating endothelial secretion of heparanase. ApoE and apoE-HDL, in contrast, increase perlecan core protein as well as sulfation of heparan sulfate. Increased perlecan in endothelial cells was associated with increased antithrombin-binding and antiproliferative heparan sulfates. Moreover, modulation of perlecan appears to have a direct effect on smooth muscle cell growth. Thus, lipoprotein modulation of vascular perlecan may play a key role in the modulation of atherogenesis.     

Immunohistochemical study of proteoglycans in D-galactosamine-induced acute liver injury in rats

In this study, we carried out an immunohistochemical investigation of time-dependent alterations in the distribution of proteoglycans, and the proliferation profiles of hepatocytes and fat-storing cells (FSCs) in the livers of rats intoxicated withd-galactosamine (GalN). The proliferative cells were analyzed by proliferative cell nuclear antigen (PCNA) staining. In untreated rats, heparan sulfate, dermatan sulfate, and chondroitin/chondroitin sulfate were detected within the portal spaces and the central veins, and, with the exception of chondroitin, also within the reticular fibers. After administration of GalN, the number of PCNA-positive cells (FSCs and hepatocytes) and FSCs increased, reaching maximal on the 2nd and 3rd days, respectively. Heparan sulfate showed complicated changes. Dermatan sulfate decreased in portal spaces from the 2nd to the 3rd day, and in reticular fibers from 12 h to the 6th day. Chondroitin/chondroitin sulfate staining was observed from 2 h to the 6th day in the sinusoidal endothelia, which suggests that the sinusoidal endothelia may produce chondroitin/chondroitin sulfate transiently during liver damage as part of the mechanism of regeneration. Heparan sulfate and chondroitin/chondroitin sulfate were detected in necrotic regions, but dermatan sulfate was not. These observations suggest that heparan sulfate and chondroitin/chondroitin sulfate are involved in cell proliferation or morphogenesis and that the dermatan sulfate plays a role in the differentiation or functional maintenance of cells in liver regeneration.     

Varied low density lipoprotein binding property of proteoglycans synthesized by vascular smooth muscle cells cultured on extracellular matrix

Earlier we showed that the extracellular matrix (ECM) secreted by vascular cells modulated proteoglycan synthesis by vascular smooth muscle cells in culture and altered the proteoglycan characteristics. In this study, we tested the hypothesis that these ECM-mediated alterations increased the affinity of the proteoglycans for plasma low density lipoprotein (LDL). Newly synthesized proteoglycans were isolated from smooth muscle cells cultured on the ECMs secreted by vascular endothelial cells, smooth muscle cells, or THP-1 macrophages and their binding affinity for LDL determined. Proteoglycans from all cultures contained sub-fractions that bound LDL with low and high affinity. However, compared with the cells plated on the endothelial cell ECM, the cells plated on the smooth muscle cell ECM and macrophage ECM synthesized significantly more high affinity proteoglycans. Removal of collagen, elastin, and chondroitin sulfates from the smooth muscle cell ECM and chondroitin sulfates from the macrophage ECM increased the production of high affinity proteoglycans by 15-22%. However, neutralization of fibronectin from both ECMs decreased the high affinity proteoglycans by 20%. Removal of matrix-bound growth factors had no effect on the synthesis of high affinity proteoglycans. Compared with the low affinity proteoglycans, the high affinity proteoglycans were larger, more sulfated and contained higher proportions of chondritin sulfate, dermatan sulfate, and N-sulfated heparan sulfate chains. These results suggest that the ECM-mediated alterations in vascular smooth muscle cell proteoglycans may lead to increased deposition of LDL in the arterial wall.     

Surfen, a small molecule antagonist of heparan sulfate

In a search for small molecule antagonists of heparan sulfate, we examined the activity of bis-2-methyl-4-amino-quinolyl-6-carbamide, also known as surfen. Fluorescence-based titrations indicated that surfen bound to glycosaminoglycans, and the extent of binding increased according to charge density in the order heparin > dermatan sulfate > heparan sulfate > chondroitin sulfate. All charged groups in heparin (N-sulfates, O-sulfates, and carboxyl groups) contributed to binding, consistent with the idea that surfen interacted electrostatically. Surfen neutralized the anticoagulant activity of both unfractionated and low molecular weight heparins and inhibited enzymatic sulfation and degradation reactions in vitro. Addition of surfen to cultured cells blocked FGF2-binding and signaling that depended on cell surface heparan sulfate and prevented both FGF2- and VEGF₁₆₅-mediated sprouting of endothelial cells in Matrigel. Surfen also blocked heparan sulfate-mediated cell adhesion to the Hep-II domain of fibronectin and prevented infection by HSV-1 that depended on glycoprotein D interaction with heparan sulfate. These findings demonstrate the feasibility of identifying small molecule antagonists of heparan sulfate and raise the possibility of developing pharmacological agents to treat disorders that involve glycosaminoglycan–protein interactions.     

TLR4介导汉滩病毒引起血管内皮细胞分泌IL-6和TNF-α

目的检测汉滩病毒感染血管内皮细胞后IL-6,IL-8和TNF-α的分泌变化及其与TLR4的关系。方法用5LgTCID50/mL的HTNV76-1180.2mL感染EVC-304细胞(TLR4+)和EVC-304TS4(TLR4-)分别为实验组,以病毒未感染为阴性对照组,以LPS(2μg/mL)刺激作为阳性对照。48h后取细胞培养上清,用人IL-6,IL-8和TNF-α定量EIA试剂盒分别检测IL-6,IL-8和TNF-α在两个细胞系感染前后的分泌水平。结果IL-8在两个细胞系中感染前后的变化不明显,IL-6和TNF-α在EVC-304细胞系中,HTNV感染后升高,而在TLR4表达阴性的EVC-304细胞中,感染前后变化不明显。结论在TLR4表达阳性的EVC-304细胞中IL-6和TNF-α分泌增加,血管内皮细胞EVC-304在HTNV感染后的IL-6和TNF-α分泌可能是TLR4介导的。     

Phosphomannopentaose Sulfate (PI‐88): Heparan Sulfate Mimetic with Clinical Potential in Multiple Vascular Pathologies

The sulfated oligosaccharide PI‐88 is a potent antiangiogenic, antitumor and anti‐metastatic agent derived from yeast. It is primarily composed of sulfated phosphomannopentaose and phosphomannotetraose oligosaccharide units and is presently under evaluation in Phase II clinical trials for anticancer efficacy. PI‐88 inhibits the heparan sulfate‐degrading enzyme heparanase, exhibits antiangiogenic activity and has anticoagulant properties mediated by heparin cofactor II. It also inhibits vascular smooth muscle cell proliferation, kinase signalling and arterial intimal thickening following balloon injury. Many heparan sulfate‐binding growth factors require heparan sulfate as a co‐receptor in order to effectively deliver growth signals to cells. Thus, the antiangiogenic and antirestenotic activity of PI‐88 may be at least partially due to this highly sulfated oligosaccharide competing with the interaction of growth factors, such as FGF‐2 and VEGF, with cell surface heparan sulfate. This heparan sulfate mimetic has, therefore, multiple functions and therapeutic potential in a variety of vascular disorders.