Yellow fever virus strains Asibi and 17D-204 infect human umbilical cord endothelial cells and induce novel changes in gene expression

Yellow fever (YF) is a zoonotic infection with more than 200,000 cases reported annually. Relatively little is known about YF pathogenesis in humans. In this study, we demonstrate that human vascular endothelial cells are susceptible to infection with wild-type and vaccine strains of the YFV and that these infections lead to a differential cellular response to infection. The infection of endothelial cells with either virus resulted in a significant induction of interferon-inducible genes p 78 and Cig 5 while wild-type virus induced a much more pronounced IL 6 and Bc l2 response than did the vaccine strain. Both viruses induced RANTES gene expression, but only the wild-type virus had corresponding increases in RANTES protein expression. The results demonstrate that the wild-type and vaccine strains of YFV elicit significantly different responses to infection in endothelial cells, despite being nearly identical genetically. These differences may account for the attenuated phenotype of the YFV vaccine strain, though the mechanism remains unclear. These data also point to a role for vascular endothelial cells in YF hemorrhagic fever and also suggest that IL 6 may play a role in increased viral pathogenesis, perhaps by influencing coagulation via release of coagulation co-factors such as fibrin or fibrinogen.     

肺炎衣原体对血管内皮细胞的感染及其对ICAM-1表达的影响

目的:观察肺炎衣原体对人脐静脉内皮细胞(HUVECs)的感染及其对细胞分泌和表达细胞间粘附分子1(ICAM-1)的影响,探讨C.pneumoniae感染在动脉粥样硬化形成中的作用及其可能机制。方法:用人喉表皮癌(HEP-2)细胞培养C.pneumoniae,以C.pneumoniae感染HUVE细胞,经透射电镜及PCR检测有无感染。用流式细胞仪检测感染前后HUVE细胞表面ICAM-1蛋白的表达的变化,用荧光定量RT-PCR检测ICAM-1mRNA的变化。结果:C.pneumoniae能感染体外培养的HUVE细胞;感染后12h,细胞表面ICAM-1蛋白的表达即增加,其峰值约在感染后24h;荧光定量RT-PCR结果显示其增加在mRNA水平。结论:C.pneumoniae能感染体外培养的人脐静脉内皮细胞并增加ICAM-1的表达,提示C.pneumoniae感染可能是动脉粥样硬化的始动因子之一,其致动脉粥样硬化机制可能与感染后血管内皮细胞粘附分子表达的增加有关。     

A peptide inhibitor of vascular adhesion protein-1 (VAP-1) blocks leukocyte-endothelium interactions under shear stress

Vascular adhesion protein-1 (VAP-1) is an endothelial adhesion molecule mediating leukocyte interactions with blood vessels during leukocyte extravasation. Molecularly VAP-1 is a cell-surface-expressed ecto-enzyme belonging to the group of semicarbazide-sensitive amine oxidases (SSAO; EC 2.4.6.3), which deaminate primary amines. Here we asked whether peptides displaying a suitable free amine group could be a substrate or inhibitor of SSAO and thus regulate VAP-1-mediated leukocyte adhesion. On the basis of a molecular model of VAP-1, we designed synthetic peptides that fit to the substrate channel of VAP-1. One of these lysine-containing peptides effectively inhibits VAP-1-dependent lymphocyte rolling and firm adhesion to primary endothelial cells under physiologically relevant shear conditions. The same peptide inhibits the SSAO activity of endothelial and recombinant VAP-1 in a selective and long-lasting manner. We also show that all enzymatically active VAP-1 is displayed on the cell surface. Our results suggest that, in addition to soluble amines, specific cell-surface-bound molecules containing free NH(2) groups in a suitable position may modulate the enzymatic activity of SSAO. Moreover, the inhibitory peptide diminishes leukocyte interactions with endothelial cells under conditions of shear, and thus it may be useful to treat inflammatory conditions.     

叶酸拮抗同型半胱氨酸诱导的内皮细胞凋亡的作用机制

目的： 明确同型半胱氨酸（Hcy）对内皮细胞凋亡的影响以及叶酸的拮抗作用，阐明Bax和Bcl-2在同型半胱氨酸诱导内皮细胞凋亡及叶酸拮抗中的作用。方法: 用不同浓度的Hcy处理内皮细胞后，应用末端转移标记技术（TUNEL）以及Annexin V/PI染色加流式细胞术了解细胞凋亡状态，免疫组化方法检测Bax、Bcl-2的表达。结果: Hcy能促进细胞凋亡，叶酸具有拮抗作用。Hcy能促进细胞Bax、Bcl-2的表达，上调Bax/Bcl-2比值，叶酸能减少细胞表达Bax及Bcl-2，下调Bax/Bcl-2比值。结论: Bax、Bcl-2参与了Hcy诱导内皮细胞凋亡以及叶酸拮抗作用的过程。     

细胞松弛素B对内皮细胞损伤修复的影响

目的观察细胞松弛素B对内皮细胞损伤修复过程中微丝骨架系统的形态结构变化,研究阻断微丝功能对内皮细胞损伤修复的影响。方法以培养单层内皮细胞损伤模型,采用免疫荧光染色和3H-TdR掺入法,研究微丝功能对创面愈合及细胞增殖的影响。结果内皮细胞在损伤修复过程中伴随微丝特殊而有序的变化。用细胞松弛素B破坏微丝,可不同程度抑制创面的愈合及细胞增殖,并呈一定的时间-剂量依赖关系。结论微丝功能在促进内皮细胞修复过程中起重要作用,可通过直接或间接效应影响DNA合成,从而影响修复过程。     

Cytotoxic effects of ingested Staphylococcus aureus on bovine endothelial cells: Role of S. aureus α-hemolysin

Previously we observed that Staphylococcus aureus phagocytized by cultured bovine endothelial cells do not proliferate intracellularly, but are cytotoxic to bovine endothelial cells. To investigate S. aureus virulence factors which may be produced intracellularly and cause lysis of endothelial cells, we tested S. aureus mutants defective in production of one or more potential virulence factors and corresponding parent strains for cytotoxicity to endothelial cell monolayers subsequent to being ingested. Following incubation of endothelial cell monolayers with S. aureus for 3.5 h, cultures were supplemented with lysostaphin to destroy extracellular but not intracellular S. aureus. At subsequent times, viability of endothelial cells was assayed by retention of ³H-adenine and the number of intracellular S. aureus was measured. The cytotoxic activity of S. aureus culture supernatants was also characterized. The results indicate that S. aureus α-hemolysin is cytotoxic to bovine endothelial cells and plays an important role in the damage suffered by bovine endothelial cell monolayers following ingestion of S. aureus. Ingestion of α-hemolysin-producing S. aureus by endothelial cells in vivo might be expected to result in destruction of endothelium followed by development of platelet-fibrin vegetations. This possible sequence of events is compatible with the frequently fulminant course of S. aureus endocarditis.     

AN AUTOPSY CASE OF PRIMARY ANGIOSARCOMA OF THE PERICARDIUM MIMICKING MALIGNANT MESOTHELIOMA

The pathology of a rare case of primary diffuse angiosarcoma of the pericardium is reported. Grossly, the heart was entirely encased by the pericardial tumor, and the myocardium was only superficially invaded by the tumor. The tumor tissue extended directly to the mediastinum, where the great vessels were embedded in the tumor. A few minute distant metastases were found only in the bilateral lungs and pulmonary hilar lymph nodes. Microscopically, the tumor tissue was composed of malignant cells forming vascular channels admixed with solid areas. Histo- and immunohistochemically, no mesothelial characteristics were evident. Factor VHI-related antigen and Ulex'europaeus I lectin were positive, implying that the tumor was of vascular origin. Grossly, and in part microscopically, this case resembled malignant diffuse mesothelioma, indicating that pericardial angiosarcoma may sometimes mimick malignant mesothelioma. ACTA PATHOL JPN 38: 1345-1351, 1988.     

卡巴胆碱抑制肿瘤坏死因子所致微血管内皮细胞通透性增高

目的探讨卡巴胆碱对肿瘤坏死因子-α（tumor necrosis factor-α，TNF-α）诱导的增加微血管通透性的作用。方法采用FITC标记白蛋白漏出法、考马斯亮蓝染色法观察卡巴胆碱对TNF-α诱导微血管内皮细胞通透性，细胞形态和细胞骨架变化的影响。结果与对照组比较，TNF-α明显增加微血管内皮细胞通透性（P〈0．05），诱导细胞皱缩，细胞间隙增大和细胞骨架排列紊乱。给予卡巴胆碱可以明显抑制TNF-α诱导微血管内皮细胞通透性增加，并呈剂量依赖性，同时可以使细胞间隙明显减小，细胞骨架排列有序。结论卡巴胆碱可能通过抑制TNF-α对细胞骨架的损伤，进而抑制微血管通透性增加。     

外源性凝血途径和内皮细胞损伤与动脉粥样硬化之间的关系研究

目的探讨外源性凝血途径在动脉粥样硬化(AS)发病中的作用。方法均采用ELISA法测定心肌梗死、脑梗死、脑出血病人及正常对照组血浆TF、FⅦa的含量及不同时期这些物质浓度的变化、同时通过测定内皮细胞损伤的分子标记物vWF、内皮素 -1(ET -1)、总组织因子途径抑制物(TFPI)、组织因子(TF)探讨外源性凝血途径的活化与水平状况及内皮细胞损伤之间的关系。结果心肌梗死、脑梗死、脑出血病人TF、TFPT、ET -1、vWF、FⅦa,血中的浓度较正常对照组高 (P<0.01) ,有非常显著意义。结论外源性凝血途径与内皮细胞损伤和AS有密切相关。