Adhesion of B-Cell Chronic Lymphocytic Leukemia Cells to Marrow Stromal Cells is Mediated by α4β1 but not β2αL Integrin: MSC also Prevent Apoptosis of B-CLL Cells

Interactions between MSC and B-CLL cells were investigated to better understand the role of adhesion proteins in the biology of B-CLL. The role of β₁ and β₂ integrins and CD44 in adherence of B-chronic lymphocytic leukemia (CLL) cells to bone marrow stromal cell (MSC) monolayers and the ability of MSC to prevent apoptosis of CLL cells was investigated. Peripheral blood mononuclear cells, from 8 patients with CD5-positive B-CLL, were effectively depleted of CD3-positive cells with an immunomagnetic column. Purity of B-CLL cells, as judged by coexpression of CD19 and CD5 on two-color fluor-ocytometry, was 92±4% (mean±SD) (n = 8). ⁵¹Cr-labelled B-CLL cells, were incubated with isotype murine monoclonal antibodies or blocking MoAb's against the following adhesion proteins: integrins β₁, α₄, and α_L (chain of LFA-1), CD44 and CD106 (VCAM-1). The B-CLL cell adherence to marrow stromal cell (MSC) monolayers at 2hrs was 29±12% (mean±1SD). MoAb's against CD106, α₄, and β₁ caused a significant inhibition of heterotypic adherence in 2/8, 3/8 and 4/8 experiments. Despite universal expression of α_L on B-CLL cells, MoAb against α_L did not influence adhesion of B-CLL cells in any of the eight experiments. MoAb's against CD44 caused an increase in B-CLL cell adherence to MSC in 1/8 experiments. No correlation between basal adhesion and intensity of α₄ expression was noted. The absence of this correlation can be explained by the highly variable expression of α₄ on the B-CLL cells from a limited number of patients. Notably, the intensity of α₄ and β₁ expression, on the B-CLL cells correlated with the degree of inhibition by anti-α₄ and anti-β₁ MoAb. A significant positive correlation was noted between baseline adhesion and intensity of β₁ expression. Thus, α₄β₁ and its ligand VCAM-1 are important for adhesion of B-CLL cells to MSC. However, other ligands of α₄ and other as yet undescribed adhesion proteins may also play a role in B-CLL cell adhesion to MSC.

In addition, when B-CLL cells were cocultured in direct contact with MSC monolayers, the proportion of B-CLL cells undergoing apoptosis decreased significantly.     

Inflammation in nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) describes a range of disorders characterized by excess accumulation of triglyceride within the liver. While simple steatosis may be clinically stable, nonalcoholic steatohepatitis (NASH) can be progressive. Inflammation is believed to be the driving force behind NASH and the progression to fibrosis and subsequent cirrhosis. This article will review and interpret the current literature in an attempt to expand our understanding of the environmental and genetic causes of inflammation and its effects in NAFLD.     

Characterization of a probiotic-derived soluble protein which reveals a mechanism of preventive and treatment effects of probiotics on intestinal inflammatory diseases

The beneficial effects of probiotics have been demonstrated in many diseases, such as inflammatory bowel disease. The known mechanisms for probiotic action include blocking pathogenic bacterial effects, enhancing the innate immunity and decreasing pathogen-induced inflammation, and promoting intestinal epithelial cell survival, barrier function, and protective responses. We purified and cloned a Lactobacillus rhamnosus GG (LGG)-derived soluble protein, p40. This protein ameliorated cytokine-induced apoptosis in intestinal epithelial cells through activation of the EGF receptor and its down-stream target, Akt. By using special hydrogel beads to protect p40 from degradation, we showed that p40 reduced intestinal epithelial apoptosis and preserved barrier function in the colon epithelium in an EGF receptor-dependent manner, thereby preventing and treating intestinal inflammation in mouse models of colitis. Further works regarding structural analysis of p40, regulation of EGF receptor activation and immunoregulatory effects by p40 are discussed. These results may provide insights into the clinical application of probiotics for intestinal inflammatory disorders.     

蕲艾提取液药物血清对大鼠肝星状细胞凋亡的影响

目的：研究蕲艾提取液药物血清对大鼠肝星状细胞（HSC）凋亡的影响。方法：传代培养的HSC—T6与蕲艾提取液药物血清共同培养24小时后,采用Annexin V／PI对双染结合流式细胞仪检测细胞凋亡。结果：蕲艾提取液药物血清组早期细胞凋亡率显著高于空白对照组及生理盐水血清组（P〈0．01）,并且随着血清浓度的增加,HSC—T6早期细胞凋亡率逐渐增高,呈剂量依赖关系。结论：蕲艾提取液药物血清促进HSC凋亡,这可能是蕲艾提取液药物血清抗肝纤维化作用机制之一。     

青藤碱对胶原诱导性关节炎大鼠滑膜细胞凋亡的影响

目的研究青藤碱对Ⅱ型胶原蛋白诱导性大鼠关节模型(CIA)滑膜细胞凋亡的影响。方法原位细胞凋亡检测试剂盒检测各组原代大鼠滑膜细胞凋亡的水平。结果青藤碱组CIA大鼠滑膜细胞的凋亡数明显增加。结论青藤碱治疗类风湿性关节炎的机制可能与诱导滑膜细胞凋亡有关。     

CD-95在大鼠脊髓损伤中的表达和意义

目的探讨CD-95与脊髓损伤后细胞死亡的意义。方法150只SD大鼠重约250～300g,用Allen's打击法进行动物实验,打击力量为50g·cm。在大鼠实验性脊髓损伤后30min、1h、3h、6h、1d、2d、3d、1周、2周、4周使用多克隆抗体对CD-95免疫染色阳性细胞的存在和分布进行了研究,使用电镜对凋亡细胞进行研究。结果创伤后1h主要是灰质中的细胞可见CD-95的阳性表现。创伤后6h在白质中也可见蛋白的表达,并可见凋亡现象。伤后1～3d,灰质中减少,在白质中增加。阳性细胞开始减少,但白质中持续至伤后1～2周。伤后4周,损伤的脊髓组织中没有免疫染色阳性细胞的存在。结论阻断CD-95系统可能是对脊髓损伤治疗的一种新方法。     

转染外源性FasL的CD34+细胞诱导同种抗原特异性T细胞凋亡的实验研究

为探讨通过Fas/FasL途径选择性去除移植物中成熟T细胞的可能性 ,本研究借助反转录病毒途径 ,以FasL基因转染骨髓CD34+ 细胞 ,与经过富集的T细胞进行单向混合培养 (刺激细胞 /效应细胞比例为 5∶1) ,加入或不加入IFN γ ,IL 2 ,应用原位末端标记法 (TUNEL)和流式细胞术 (FCM)检测培养 5天后的细胞凋亡率 ,并比较两种细胞因子对移植物中CD34+ 细胞的影响。以转染外源FasL的CD34+ 细胞为刺激细胞 ,T细胞凋亡率为 (12 .1±1.5 ) %〔对照组为 (3.2± 1.1) % ,P <0 .0 1〕 ;经IFN γ或IL 2作用后 ,转染细胞诱导T细胞的凋亡率分别上升至(2 0 .1± 2 .3) % ,(17.6± 1.3) % (P <0 .0 1) ;且IL 2对CD34+ 细胞Fas抗原的表达无明显影响。上述结果表明 ,转染外源FasL的骨髓CD34+ 细胞可诱导同种抗原特异性T细胞凋亡 ,IFN γ和IL 2增强上述致细胞凋亡作用 ,且IL 2更有利于临床应用 ;提示该方案可选择性清除移植物中同种抗原特异性T细胞 ,可望为临床上防治移植物抗宿主病 (GVHD)提供新的途径     

p73基因在甲氨蝶呤诱导髓性白血病细胞系U937细胞凋亡过程中的表达

为了探讨甲氨蝶呤（MTX）诱导U937细胞凋亡过程中p73 mRNA的表达变化，用MTX诱导U937细胞凋亡，凋亡指标采用细胞形态学、DNA片段电泳、流式细胞术检测DNA含量及细胞周期的变化等方法；采用半定量反转录PCR（RT－PCR）检测p73 mRNA的表达变化。研究结果显示：MTX可诱导U937细胞凋亡。5μmol/L的MTX作用于U937细胞6小时，可见部分细胞体积缩小，染色质明显浓缩和核碎裂。DNA片段电泳，MTX处理组可见清晰的梯形条带。流式细胞仪检测发现MTX作用于U937细胞，6，8，10小时，细胞的凋亡率分别为5．15％，11．43％和14．7％，并使细胞阻滞在G2／M＋S期，而对照组细胞不发生凋亡。半定量RT－PCR结果显示在U937细胞凋亡前后，p73 mRNA的表达无明显变化。结论提示，在MTX诱导U937细胞凋亡过程中，p73的mRNA水平表达差异无显性。     

大鼠内毒素血症时外周血及肺泡内中性粒细胞死亡方式及呼吸爆发

本研究观察大鼠内毒素血症时肺组织中及外周血多形核中性粒细胞（PMN）凋亡，坏死及功能改变的差异。采用Wistar大鼠20只。腹腔注射LPS（O55B5，5mg/kg)造成内毒素血症，给予LPS后2，4，8，12小时（每组5只动物）取血及支气管肺泡灌洗，密度梯度法分离PMN，用流式细胞仪测定凋亡和坏死比例以及呼吸爆发功能的改变，同时采用5只大鼠作为正常对照。结果显示，内毒素血症时外周血和支气管肺泡灌洗液中PMN凋亡细胞比例相似。但与对照相比，外周血PMN坏死比例明显增加，呼吸爆发能力明显受抑，而支气管肺泡灌洗液PMN坏死比例显减少，呼吸爆发能力显增强。结论：在内毒素血症时，扣押于肺组织中的PMN在凋亡和坏死上表现出与比例显减少，呼吸爆发能力显增强，结论：在内毒素血症时，扣押于肺组织中的PMN在凋亡和坏死上表现出与外周血PMN不同的改变，其结果是组织中PMN存活增加，并持续处于活化状态，这与PMN造成组织损伤有关。