诱发口腔鳞癌细胞凋亡嵌合基因表达载体的构建

目的：获取含凋亡基因fas表达调控元 件cdc25A片段和fas开放阅读框架的cdc25A -fas嵌合基因，构建和鉴定真核表达载体pAdTrack-CMV-cdc25A -fas和pAdTrack-cdc25A-fas，为将口腔鳞癌细胞固有的 促细胞增殖信号转变为促细胞凋亡信号的研究奠定基础。方法:根据fa s基因、cdc25A已知序列设计合成引物，采用PCR技术从pBLF58-1质 粒中扩增得到嵌合基因cdc25A-fas；然后定向克隆至真核表达载 体pAdTrack-CMV和pAdTrack，分别转化大肠杆菌E.coli DH5α感受态细胞；卡那霉素筛 选阳性克隆；进行PCR、酶切鉴定和序列分析。结果：PCR扩增得到特异 的 1 603 bp的cdc25A-fas片段；筛选并鉴定得到含pAdTrac k-CMV-cdc25A-fas和pAdTrack-cdc25A- fas的大肠杆菌E.coli DH5α阳性克隆。结论:成功构建了真核表 达载体pAdTrack-CMV-cdc25A-fas和pAdTrack-cdc25 A-fas,为下一步研究其在肿瘤基因治疗中的作用奠定基础。     

新生儿缺氧缺血性脑病患儿血清sFas/sFasL水平的变化

目的观察缺氧缺血性脑病(HIE)新生儿血清可溶性Fas(sFas)和可溶性Fas配体(sFasL)的动态变化及其与头颅CT改变程度的相关性。方法选择HIE新生儿48例,按临床分度及头颅CT分度分为轻、中、重度3组。应用双抗体夹心酶联免疫吸附法(ELISA)测定其血清sFas、sFasL含量。结果1.HIE患儿急性期、恢复早期血清sFas、sFasL水平均明显高于对照组(P均<0.01);二者急性期均显著高于恢复早期(P均<0.01)。2.轻、中、重度HIE患儿急性期血清sFas与sFasL水平均明显高于对照组(P<0.05,0.01)。3.HIE患儿急性期血清sFas与sFasL水平呈密切正相关(r=0.51 P<0.01)。结论HIE患儿血清sFass、FasL水平增高与其病程和病情密切相关,血清sFasL和sFas水平可作为判断HIE病情的实验室指标之一。     

Different roles of PD-L1 and FasL in immunomodulation mediated by human placenta-derived mesenchymal stem cells

Mesenchymal stem cells (MSCs) derived from either bone marrow (BMSCs) or placenta (PMSCs) have the capacity to suppress immune responses to mitogenic and allogeneic stimulations. Both cell contact and soluble factor dependent mechanisms have been proposed to explain this immunosuppression. This study explored the roles of some of cell surface molecules expressed on human PMSCs (hPMSCs) in hPMSC mediated immunomodulation. hPMSCs strongly suppressed mitogen and allogeneic peripheral mononuclear cells (PBMCs) induced T cell activation and proliferation. hPMSCs constituently expressed programmed death-ligand 1 (PD-L1) and Fas ligand (FasL) molecules. Neutralising antibodies to-PD-L1 and FasL significantly reduced the suppressive effect of hPMSCs on T cell proliferation. However, only anti-PD-L1 antibody partially restored early T cell activation suppressed by hPMSCs. Anti-FasL antibody but not anti-PD-L1 antibody reduced apoptosis of activated T cell indicating that FasL molecule plays a role in inducing apoptosis of activated T cells, although overall hPMSCs diminished T cell apoptosis. Different effects of PD-L1 and FasL molecules on T cell activation and activated T cell apoptosis suggest that these two molecules influence T cell response at different stages. hPMSCs significantly prevented activated T cells from going into S phase. Both antibodies to PD-L1 and FasL had significant effect on reversing the effect of hPMSCs on cell cycles. hPMSCs reduced INF-γ but increased IL-10 production by mitogen activated T cells. Both antibodies partially abolished the effect of hPMSCs on INF-γ and IL-10 production. These data demonstrated that PD-L1 and FasL molecules play significant roles in immunomodulation mediated by hPMSCs. This study provides a rational basis for modulation of negative costimulators on hPMSCs to increase their immunosuppressive properties in their therapeutic applications.     

Alloreactive CD4+ T lymphocytes can exert cytotoxicity to chronic myeloid leukaemia cells processing and presenting exogenous antigen

Existing evidence supports that CD4⁺ T lymphocytes play a role in the graft-versus-leukaemia (GVL) reaction after allogeneic bone marrow transplantation (BMT) for chronic myeloid leukaemia (CML), not only as initiators of the immune response but also as effectors of GVL. In BMT between HLA-identical pairs this CD4-mediated GVL would require CML cells to process and present antigens through MHC class II molecules. To investigate whether CML cells are capable of processing and presenting antigens, and suitable targets for CD4⁺ T-cell-mediated cytotoxicity, we generated HLA-DR1-restricted CD4⁺ cytotoxic T-cell clones that specifically recognized tuberculous purified protein derivative (PPD). We have shown that CML cells and B lymphoblastoid cell line (B-LCL) cells but not PHA-blasts from patients with CML processed exogenous antigen, PPD, and induced proliferative and cytotoxic CD4⁺ T-cell responses. Antigen presentation was blocked by antibodies to HLA-DR but not to MHC class I and by treatment with chloroquine and brefeldin. This indicates that CML cells use a classic MHC class II antigen processing pathway to present PPD antigens to CD4⁺ T cells. Cytotoxicity to CML was shown by antibody blocking studies to be mediated mainly through fas antigen. These findings indicate that donor CD4⁺ T cells alone are sufficient to mediate GVL effects following allogeneic BMT for CML.     

银杏叶提取物预处理对大鼠肝移植细胞凋亡及bcl-2和fas mRNA表达的影响

目的:探讨银杏叶提取物(EGb)预处理对大鼠肝移植的保护作用及其可能的机制.方法:将大鼠随机分为EGb预处理组(EGb组,供受体各18只),生理盐水对照组(NS组,供受体各18只),假手术组(S0组,18只).SO组不进行肝移植.EGb组和NS组采用Kamada's袖套法制备大鼠原位肝移植模型.切取供肝前1 h,EGb组经阴茎背静脉注射EGb 40 mg/kg 生理盐水共2 ml;NS组注射生理盐水2 ml.分别于供肝再灌注后2 h、6 h、24 h处死动物,检测血清ALT、AST;取肝组织行病理组织学检查,TUNEL法检测细胞凋亡,RT-PCR检测bcl-2及fas mRNA的表达.结果:供肝再灌注后各时点,NS组血清ALT、AST水平、细胞凋亡指数、bcl-2及fas mRNA的表达均较SO组升高(P均＜0.05).与NS组比较,EGb组大鼠血清ALT、AST水平、细胞凋亡指数及fas mRNA的表达均降低,bcl-2 mRNA表达量升高(P均＜0.05),肝组织病理改变较轻.但EGb组各指标均高于SO组(P均＜0.05).结论:EGb预处理可以减轻移植肝的缺血再灌注损伤,对供肝有保护作用.该作用可能与减少肝细胞凋亡有关.     

fas/apo-1、bcl-2蛋白在急性髓系白血病细胞的表达特点及意义

用免疫印迹（Western blot）、碱性磷酸酶抗碱性磷酸酶法（APAAP）分析19例急性髓系白血病（AML）骨髓细胞fas/apo-1、bcl-2蛋白表达水平的变化。结果表明绝大部分AML骨髓过表达bcl-2蛋白,部分病例表达fas/apo-1,两者表达呈一定的负相关性。分析结果显示bcl-2蛋白过表达所致的凋亡抑制状态是化疗耐药的主要机制之一,而fas/apo-1的表达是预后较好的特征。     

缺血后处理对缺血/再灌注损伤大鼠肾脏Fas,Bcl-2和Bax表达的影响

目的:探讨缺血后处理对缺血/再灌注(I/R)损伤大鼠肾脏Fas,Bax和Bcl-2表达的影响.方法:将24只SD大鼠随机分为假手术(S)组、I/R组和缺血后处理(IPO)组,每组8只,分别建立动物模型.各组分别采用免疫组化和免疫印迹法检测肾脏Fas,Bcl-2和Bax蛋白的表达变化.结果:IPO组较I/R组Fas阳性染色指数和表达显著降低,分别为[(31.17±4.81)% vs (36.26±5.32)%.P<0.05)]和[(0.98±0.11)vs(1.28±0.19),P<0.05)];IPO组和I/R组Bcl-2阳性染色指数和表达分别为[(32.34±5.12)%vs(31.33±4.55)%.P0.05)]和[(1.03±0.17)vs(0.75±0.11),P<0.05)],Bax阳性染色指数和表达分别为[(25.60±3.79)%vs(29.67±4.34)%,P<0.05)]和[(0.59±0.08)vs(0.91±0.16),P<0.05)].结论:IPO可使Fas和Bax的表达减少,同时可使Bcl-2的表达增加,从而减少缺血再灌注损伤大鼠肾脏细胞的凋亡.     

Hypoxia,angiotensin-II,and norepinephrine mediated apoptosis is stimulus specific in canine failed cardiomyocytes: a role for p38 MAPK,Fas-L and cyclin D1

BACKGROUND: Apoptosis may contribute to the myocardial dysfunction associated with heart failure (HF). Activation of the p38 MAPK cascade can induce apoptosis in non-cardiac cells through increased expression of Fas-L, or through decreased expression of cyclin D(1). AIMS: We tested the hypothesis that hypoxia (HX), angiotensin-II (A-II) and norepinephrine (NEPI) can mediate apoptosis by activating p38 MAPK, and thus initiating stimulus specific changes in Fas-L and cyclin D(1) expression in failing cardiomyocytes. METHODS AND RESULTS: Cardiomyocytes isolated from ten dogs with HF induced by coronary microembolizations were subjected to HX or A-II or NEPI with and without a p38 MAPK inhibitor (SB 203580). TUNEL staining for DNA fragmentation and Western blots for p38 MAPK, Fas-L and cyclin D(1) detection were performed. HX-induced apoptosis was associated with increased Fas-L expression, A-II-induced apoptosis was associated with increased Fas-L and decreased cyclin D(1) expression, and NEPI-induced apoptosis was associated with decreased cyclin D(1) expression. Inhibition of p38 MAPK activity attenuated stress-induced apoptosis in all experiments and reversed changes in Fas-L and cyclin D(1) expression. CONCLUSIONS: HX, A-II and NEPI mediate apoptosis in failing cardiomyocytes via different effects on Fas-L and cyclin D(1) expression. Inhibition of p38 MAPK reversed these effects, suggesting that apoptosis induced by HX, A-II and NEPI involves activation of p38 MAPK upstream from Fas-L and cyclin D(1).     

基因转移FasL诱导人黑色素瘤细胞凋亡的体外研究

目的：探讨体外基因转移Fas配体(FasLigand, FasL)对恶性人黑色素瘤细胞凋亡的影响。方法：用携带人FasL cDNA的缺陷型重组腺病毒载体(AdFL)，在体外转导2株黑色素瘤细胞，并使其表达；通过流式细胞仪、RTPCR法进行 Fas/FasL表达检测，TUNEL法及荧光显微镜检测细胞凋亡状况。结果：流式细胞仪和 RTPCR检测两株黑色素瘤细胞表面均表达Fas，不表达FasL，而AdFL转导的两株黑色素瘤细胞均能表达FasL；AdFL能显著诱导两株黑色素瘤细胞在体外凋亡或抑制其生长。结论：重组腺病毒FasL在体外诱导人黑色素瘤细胞凋亡效果显著。