The renal cell carcinoma lysis by a specific cytotoxic T cell clone is independent of the Fas/Fas-L cytotoxic pathway

The expression of Fas antigen at the surface of renal cell carcinoma and the susceptibility to Fas-mediated lysis by a tumor specific CTL clone were investigated. Renal cell carcinoma cell lines expressed Fas antigen and were susceptible to apoptosis mediated by antibodies to Fas/APO1. Using RT-PCR, we further showed that these cell lines expressed mRNA for Fas deleted transmembrane region, corresponding to a soluble form of Fas/APO-1. To investigate the role of the Fas/FasL pathway in the cytotoxic response against RCC cells, we analyzed the induction of Fas-L on a tumor specific T cell clone (CTL 8C2), previously generated against one RCC cell line. Fas-L expression on CTL 8C2 was detected by RT-PCR after stimulation with autologous tumor cells. However, the cytotoxic activity of CTL 8C2 was completely abolished when EGTA was added, suggesting that the cytolysis was mainly mediated by a Ca++-dependent pathway, perforin/granzyme-based.     

兔股动脉粥样硬化斑块模型中TF及TFPI的变化

目的： 观察兔股动脉粥样硬化斑块发展过程中斑块内组织因子（TF）及组织因子途经抑制物-1（TFPI-1）、组织因子途经抑制物-2（TFPI-2）的变化。方法： 新西兰雄兔通过高脂饲养合并股动脉球囊损伤建立动脉粥样硬化斑块模型。在建模8周、10周和12周，分别截取球囊损伤处股动脉标本，检测斑块组织内TF、TFPI-1和TFPI-2的蛋白表达；并测定斑块内TF、TFPI-1和TFPI-2的mRNA水平。结果： 自8周、10周到12周，血管斑块中TF、TFPI-1和TFPI-2的观测区域内阳性染色面积均逐渐增加。自8周、10周到12周，血管斑块中TF的mRNA水平和TFPI-1的mRNA水平均逐渐增加；TFPI-2mRNA表现为前期无明显变化，12周时显著下调。结论： 在兔股动脉粥样硬化斑块的形成过程中，随着斑块内TF基因及蛋白表达的增加,TFPI-1和TFPI-2反应性表达增加，但其表达水平未能完全抑制斑块的进展。     

Molecular biomarkers monitoring human skeletal muscle fibres and microvasculature following long-term bed rest with and without countermeasures

The cellular mechanisms of human skeletal muscle adaptation to disuse are largely unknown. The aim of this study was to determine the morphological and biochemical changes of the lower limb soleus and vastus lateralis muscles following 60 days of head-down tilt bed rest in women with and without exercise countermeasure using molecular biomarkers monitoring functional cell compartments. Muscle biopsies were taken before (pre) and after bed rest (post) from a bed rest-only and a bed rest exercise group (n = 8, each). NOS1 and NOS3/PECAM, markers of myofibre 'activity' and capillary density, and MuRF1 (E3 ubiquitin-ligase), a marker of proteolysis, were documented by confocal immunofluorescence and immunoblot analyses. Morphometrical parameters (myofibre cross-sectional area, type I/II distribution) were largely preserved in muscles from the exercise group with a robust trend for type II hypertrophy in vastus lateralis. In the bed rest-only group, the relative NOS1 immunostaining intensity was decreased at type I and II myofibre membranes, while the bed rest plus exercise group compensated for this loss particularly in soleus. In the microvascular network, NOS3 expression and the capillary-to-fibre ratio were both increased in the exercise group. Elevated MuRF1 immunosignals found in subgroups of atrophic myofibres probably reflected accelerated proteolysis. Immunoblots revealed overexpression of the MuRF1 protein in the soleus of the bed rest-only group (> 35% vs. pre). We conclude that exercise countermeasure during bed rest affected both NOS/NO signalling and proteolysis in female skeletal muscle. Maintenance of NO signalling mechanisms and normal protein turnover by exercise countermeasure may be crucial steps to attenuate human skeletal muscle atrophy and to maintain cell function following chronic disuse.     

ERK1/2－STAT3通路在H2O2预处理导致的适应性细胞保护中的作用

目的：探讨ERK1/2-STAT3通路在H₂O₂预处理导致的适应性细胞保护中的作用。方法：在PC12细胞建立H₂O₂预处理对抗氧化应激（300 μmol/L H₂O₂）损伤细胞的模型。应用Hoechst33258核染色法观察细胞调亡的形态学改变；应用碘化丙啶(PI)染色流式细胞术检测细胞凋亡率；免疫印记法(Western blotting) 测定p-ERK1/2和p-STAT3的表达水平。结果：100 μmol/L H₂O₂预处理PC12细胞90 min可明显抑制300 μmol/L H₂O₂作用12 h引起的细胞凋亡，并激活ERK1/2和STAT3；ERK1/2抑制剂UO126和JAK2抑制剂AG-490（10 μmol/L）均可明显地阻断H₂O₂预处理引起的细胞保护作用；UO126（10 μmol/L）亦能明显地抑制H₂O₂预处理对STAT3的上调作用。结论：H₂O₂预处理能激活PC12细胞的ERK1/2-STAT3信号转导旁路，这可能是预处理的细胞保护机制之一。     

Hydrophobic domains determine localization of IncC and IncG full-length proteins of C. trachomatis during their expression in cultured HeLa cells

Plasmid vectors encoding hydrophilic (IncB, IncC, IncE, IncG) and hydrophobic (IncC, IncG) domains of C. trachomatis incorporation membrane proteins and reporter green fluorescing proteins were constructed. After transfection of HeLa cells with these plasmid constructs, localization of the complex proteins was determined by laser confocal microscopy. Tropism of hydrophobic domains to compartments constituting the exocytotic pathway in the cell was demonstrated. Location of signal/sorting sequences responsible for specific localization was determined. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 145, No. 4, pp. 402–407, April, 2008     

脑缺血后TLR4作用与小胶质细胞的激活

脑缺血性损伤早期小胶质细胞即被激活。激活的小胶质细胞既有细胞毒性又有神经营养作用。小胶质细胞行使免疫功能的信号转导受体之一是TLR4（toll-like receptor 4）。TLR4在脑内主要表达在小胶质细胞，是一种模式识别受体（pattern recognition receptor，PRR）, 识别一些外源性和内源性的配体。最近的研究表明，TLR4信号通路在脑缺血再灌注损伤中起重要作用。TLR4通过激活小胶质细胞，大量表达炎症因子，加重脑缺血性损伤。     

高糖作用的肾小球系膜细胞SnoN/Ski蛋白表达及泛素化降解

目的: 观察高糖作用的大鼠肾小球系膜细胞内核转录共抑制因子SnoN/Ski及泛素连接酶Arkadia的表达变化,初步探讨SnoN/Ski泛素化降解在糖尿病肾病中的作用。方法: 将体外培养的大鼠肾小球系膜细胞分别设正常对照组 、高糖甲组(培养基含20 mmol/L葡萄糖)、高糖乙组(培养基含30 mmol/L葡萄糖)、高糖+MG132组(30 mmol/L葡萄糖培养基中预先加入0.5 μmol/L特异性泛素蛋白酶体抑制剂MG132)和甘露醇组。用蛋白免疫印迹技术和免疫荧光染色-激光共聚焦显微镜检测各组细胞SnoN/Ski及Arkadia蛋白的表达。结果: (1)正常系膜细胞中SnoN/Ski蛋白大量表达,Arkadia蛋白表达较弱。(2)高糖作用后SnoN/Ski蛋白表达减弱,Arkadia蛋白表达增强(P<0.05)。(3)与高糖组比较,高糖加入MG132后SnoN/Ski蛋白表达增加,Arkadia蛋白表达减弱(P<0.01)。(4)甘露醇组与正常组比较SnoN/Ski及Arkadia蛋白表达均无明显差异(P>0.05)。结论: (1)高糖可通过泛素蛋白酶体途径降解SnoN/Ski蛋白致其低表达。(2)E3连接酶Arkadia参与了高糖诱导的SnoN/Ski的泛素化降解 。     

TGFβ1，CTGF信号转导通路的变化在实验性小鼠肝纤维发生中的作用

 摘要：目的 探讨实验性肝纤维化小鼠肝组织中TGFβ1,CTGF信号转导通路的变化及意义。方法30只C57BL6/J小鼠随机分为正常对照组、肝纤维化模型组,采用10%的CCL4橄榄油腹腔注射诱导小鼠肝纤维化模型,对照组给予生理盐水灌胃,共造模8周。观察血清ALT、HA水平,HE染色、Masson染色观察肝组织炎症及纤维化程度,免疫组化法和RT-PCR法对肝组织α-SMA、TGFβ1、TGFβRⅡ、Smad3,Smad7,CTGF蛋白和mRNA水平进行检测,并与对照组肝组织进行比较。结果 模型组小鼠血清ALT及HA水平明显高于对照组;模型组小鼠肝组织α-SMA、TGFβ1、TGFβRII、Smad3、CTGF蛋白表达和TGFβ1、Smad3、CTGF mRNA表达明显高于对照组,而模型组肝组织Smad7蛋白和Smad7 mRNA表达较对照组小鼠显著降低。结论 TGFβ1和CTGF信号转导通路过度活化,Smad7表达和负调节TGFβ、CTGF信号转导通路的功能被抑制可能与肝纤维化的发生和发展密切相关。     

Mannan-binding lectin (MBL)-associated serine protease-1 (MASP-1), a serine protease associated with humoral pattern-recognition molecules: normal and acute-phase levels in serum and stoichiometry of lectin pathway components

The pattern-recognition molecules mannan-binding lectin (MBL) and the three ficolins circulate in blood in complexes with MBL-associated serine proteases (MASPs). When MBL or ficolin recognizes a microorganism, activation of the MASPs occurs leading to activation of the complement system, an important component of the innate immune system. Three proteins are produced from the MASP1 gene: MASP-1 and MASP-3 and MAp44. We present an assay specific for MASP-1, which is based on inhibition of the binding of anti-MASP-1-specific antibody to MASP-1 domains coated onto microtitre wells. MASP-1 was found in serum in large complexes eluting in a position corresponding to ～600 kDa after gel permeation chromatography in calcium-containing buffer and as monomers of ～75 kDa in dissociating buffer. The concentration of MASP-1 in donor sera (n = 105) was distributed log-normally with a median value of 11 μg/ml (range 4-30 μg/ml). Serum and citrate plasma levels were similar, while the values in ethylenediamine tetraacetic acid plasma were slightly lower and in heparin plasma were 1·5 times higher than in serum. MASP-1 was present at adult level at 1 year of age, while it was 60% at birth. In normal healthy individuals the level of MASP-1 was stable throughout a 2-month period. After induction of an acute-phase reaction by operation we found an initial short decrease, concomitant with an increase in C-reactive protein levels, followed by an increase, doubling the MASP-1 concentration after 2 days. The present data prepare the ground for studies on the associations of MASP-1 levels with disease.