Effect of Leptospira interrogans outer membrane proteins LipL32 on HUVEC

Leptospira cause disease through a toxin-mediated process by inducing vascular injury, particularly a small-vessel vasculitis. Breakdown of vessel endothelial cell integrity may increase vessel permeability which is correlated with the changes of tight junction and/or apoptosis in vessel endothelial cells. The specific toxin responsible remains unidentified. In this study, we amplified outer membrane protein LipL32 from the genome of Leptospira interrogans serovar Lai, and it was subcloned in pET32a(+) vector to express thioredoxin(Trx)–LipL32 fusion protein in Escherichia coli BL21(DE3). The protein was expressed and purified, and Trx–LipL32 was administered to culture with human umbilical vein endothelial cells (HUVEC) to elucidate the role of leptospiral outer membrane proteins in vessel endothelial cell. The purified recombinant protein was capable to increase the permeability of HUVECs. And the protein was able to decrease the expression of ZO-1 and induce F-actin in HUVECs display thickening and clustering. Moreover, apoptosis of HUVEC was significantly accelerated. But the fusion partner had no effect in these regards. It is possible that LipL32 is involved in the vessel lesions.     

Cell-derived microparticles contain caspase 3 in vitro and in vivo.

BACKGROUND: Microparticles (MP) from endothelial cells (endothelial microparticles; EMP) circulate in disease states, but the processes such as apoptosis or cell activation underlying their release are unclear. OBJECTIVES: We investigated whether adherent (viable) or detached (apoptotic) endothelial cells are the possible source of EMP in vitro, i.e. under control and interleukin (IL)-1alpha activation conditions, and in vivo. METHODS: Adherent and detached endothelial cells, and EMP, were isolated from human umbilical vein endothelial cell cultures (n = 6), treated without or with IL-1alpha (5 ng mL(-1); 24 h). Cell fractions were analyzed by flow cytometry for annexin V binding, propidium iodide (PI) and caspase 3 staining (n = 3). Caspase 3 in EMP was studied using Western blot (n = 6) and flow cytometry (n = 6). Plasma from healthy subjects and systemic lupus erythematosus patients (both n = 3) were analyzed for caspase 3-containing (E)MP. RESULTS: Detached but not adherent cells double-stained for annexin V and PI, confirming the apoptotic conditions of the detached cells and the viable nature of the adherent cells. Caspase 3 was solely present in the detached cells and procaspase 3 in the adherent cells. Caspase 3 was present in EMP from both control and IL-1alpha-treated cultures. Counts of EMP and detached cells, but not adherent cells, highly correlated (r = 0.959, P < 0.0001). In vivo circulating MP from nucleated (endothelial cells, monocytes) and anucleated cells (platelets, erythrocytes) contained caspase 3. CONCLUSIONS: EMP contain caspase 3 and may be mainly derived from detached (apoptotic) endothelial cells in vitro. The presence of caspase 3 in MP from anucleated cell types, however, suggests that its presence may not necessarily be related to apoptosis in vivo but may be associated with caspase 3 activation unrelated to apoptosis.     

Biological activity of bevacizumab,a humanized anti-VEGF antibody <Emphasis Type="Italic">in vitro</Emphasis>

Bevacizumab (Avastin, Genentech) is a humanized monoclonal antibody targeting vascular endothelial growth factor (VEGF), a critical angiogenic factor involved in both physiological and pathological conditions. It has been recently approved by the US FDA as a first-line therapy for widespread metastatic colorectal cancer. This report is a detailed biological characterization of bevacizumab in a variety of in vitro models. It is shown that bevacizumab potently neutralizes VEGF and blocks its signal transduction through both the VEGFR-1 and VEGFR-2 receptors, as demonstrated by the inhibition of VEGF-induced cell proliferation, survival, permeability, nitric oxide production, as well as migration and tissue factor production. Although bevacizumab retains the ability to bind to human Fc receptors and complement protein C1q, it does not demonstrate cell or complement-mediated cytotoxicity in either VEGF producing or targeting cells. Thus the mechanism of anti-tumor activity of bevacizumab is most likely due to its anti-angiogenesis effect through binding and neutralization of secreted VEGF.     

17β-雌二醇对氧化型低密度脂蛋白由钙介导细胞骨架损伤的抑制作用

目的　通过观察 1 7β 雌二醇 (1 7β E2 )与氧化低密度脂蛋白 (OX LDL)作用于血管内皮细胞后细胞内微丝肌动蛋白的变化以及同细胞内钙离子变化间的关系 ,以探讨雌激素的血管保护作用机制。方法　采用ECV 30 4脐静脉内皮细胞株体外培养 ,分为空白对照组 ,OX LDL(2 0 0 μg/ml)组 ,4× 1 0 - 7mol/LE2 作用组 ,E2 保护组 ,采用激光扫描共聚焦显微镜分别观察OX LDL作用后 1 2h时的胞内钙离子的变化及OX LDL作用 2 4h时的细胞骨架微丝的改变。结果　OX LDL作用 1 2h后细胞内钙离子浓度明显升高 ,而细胞骨架微丝也在 2 4h后发生明显的破坏。雌激素预处理后可明显抑制OX LDL作用导致后细胞内钙离子浓度的升高 ,并且明显地防止细胞骨架微丝损伤的发生。结论　 1 7β E2 可能通过抑制OX LDL导致的细胞内钙离子升高从而防止细胞骨架微丝损伤的发生 ,这可能是雌激素产生血管保护作用的机制之一。     

腺苷对人静脉内皮细胞增殖的影响

目的探讨腺苷对人脐静脉内皮细胞（human umbilical vein endothelial cell，HUVEC）增殖的影响。方法MTT法观察腺苷的最佳作用浓度及最佳作用时问。结果4％FBS浓度下，腺苷具有明显的促HUVEC增殖作用，为最佳浓度。在10-^4 mol／L腺苷终浓度对细胞增殖有明显的促进作用，为最佳腺苷浓度。腺苷的促生艮作用在24h即出现，在48h已达到较高水平。结论在血供基本被阻断或血流基本正常的情况下，腺苷可能对细胞增殖尤影响；但在m流减少的情况下，腺苷的应用可以促进内皮细胞增殖，可能对血管新生有启动作用。     

Influence of carboxylic acid functionalization on the cytotoxic effects induced by single wall carbon nanotubes on human endothelial cells (HUVEC)

A vast variety of nanomaterials have been developed in the recent years, being carbon nanotubes (CNTs) the ones that have attracted more attention, due to its unique properties which make them suitable for numerous applications. Consequently, it is predicted that tons of CNTs will be produced worldwide every year, being its exposure of toxicological concern. Nanomaterials, once into the body, can translocate from the uptake sites to the blood circulation or the lymphatic system, resulting in distribution throughout the body. Thus, the vascular endothelium can be in contact with them and can suffer from their toxic effects. In this regard, the aim of this work was to investigate the cytotoxicity of single-walled carbon nanotubes (SWCNTs) on human endothelial cells evaluating the influence of acid carboxylic functionalization and also the exposure time (24 and 48 h). Biomarkers assessed were neutral red uptake, protein content, a tetrazolium salt metabolization and cell viability by means of the Trypan blue exclusion test. Cells were exposed to concentrations between 0 and 800 μg/mL SWCNTs for 24 and 48 h. Results have shown that both SWCNTs and carboxylic acid functionalized single-walled carbon nanotubes (COOH-SWCNTs) induce toxic effects in HUVEC cells in a concentration- and time-dependent way. Moreover, the carboxylic acid functionalization results in a higher toxicity compared to the SWCNTs.     

疡愈涂剂对人白细胞与血管内皮细胞黏附影响的分子机制

目的研究疡愈涂剂(YangYuTuJi,YYTJ)对白细胞与血管内皮细胞黏附影响的分子机制,探讨其促进皮肤创伤愈合的机制。方法用虎红染色法观察YYTJ高(132.5mg/L)、中(66.3mg/L)、低(33.2mg/L)浓度对中性粒细胞(polymorphonuclear,PMN)、人单核细胞(THP-1)与肿瘤坏死因子(tumor necrosis factor,TNF)诱导的人脐静脉内皮细胞(human umbilical vein endothelial cells,HUVEC)黏附的影响,用荧光免疫细胞化学法观察YYTJ对HUVEC表面细胞间黏附分子-1(inter cell ularadhesion molecule-1,ICAM-1)、血管细胞黏附分子-1(vascular cell adhesion molecule-1,VCAM-1)和CD44表达的影响。结果 YYTJ和TNF共同作用HUVEC12h后,高浓度YYTJ能明显抑制HUVEC与PMN以及THP-1黏附(P<0.05),能明显抑制HUVEC表面ICAM-1和CD44表达(P<0.05)。中浓度YYTJ能明显抑制HUVEC表面VCAM-1和CD44表达(P<0.05,P<0.01)。低浓度YYTJ能明显降低HUVEC表面CD44表达(P<0.05)。结论疡愈涂剂通过降低TNF诱导的HUVEC表面黏附分子的表达,抑制白细胞与血管内皮细胞的黏附,从而抑制过度的炎性反应。     

风轮菜活性部位体外抗氧化作用的实验研究

目的研究风轮菜活性部位(CCE)的体外抗氧化活性,为将其开发为新的抗氧化药物提供实验依据。方法通过体外实验测定CCE对超氧阴离子(O-2)、羟基自由基(.OH)及有机自由基DPPH.的清除作用以及对亚铁离子-维生素C(Fe2+-VitC)诱导的小鼠肝脂质过氧化的影响。建立高浓度葡萄糖损伤人脐静脉内皮细胞(HUVECs)的体外模型,测定CCE对细胞超氧化物歧化酶(SOD)和乳酸脱氢酶(LDH)活性的影响。结果CCE能有效清除O-2、.OH和DPPH自由基,其中.OH的清除力最强,对Fe2+-VitC诱导的肝匀浆脂质过氧化反应有明显的抑制作用,且呈浓度依赖性。此外,CCE能明显提高高糖刺激下内皮细胞中的SOD水平,降低LDH活性。结论CCE具有显著的体外抗氧化活性。