脱氢表雄酮对狼疮性BXSB小鼠脾脏淋巴细胞凋亡的影响

目的 研究脱氢表雄酮(DHEA)对BXSB狼疮性小鼠脾脏淋巴细胞凋亡的影响,并探讨其作用机理.方法 运用流式细胞术、免疫双荧光染色法检测脾脏淋巴细胞凋亡.结果 当DHEA的浓度为10-8mol/L时,淋巴细胞凋亡率降低,与对照组比较有差异有统计学意义(P＜0.05),细胞坏死率差异无统计学意义(P＞0.05);DHEA与西药组或中药组联合应用对淋巴细胞凋亡抑制作用更加显著,差异有统计学意义(P＜0.01).结论 脱氢表雄酮可明显抑制BXSB小鼠脾脏淋巴细胞凋亡率.     

CD4+ CD25+调节性T细胞AICD机制的研究

目的探讨CD4^＋CD25^＋调节性T细胞活化诱导的细胞死亡（AICD）发生的机制。方法CD4^＋CD25^＋T细胞以磁性细胞分离器（MACS）从BALB／c小鼠或DO11．10小鼠的静息T细胞分离纯化。体外细胞增殖抑制实验证实其免疫调节作用。CD4^＋CD25^＋T细胞的AICD以CD3／CD28单克隆抗体活化或以特异性OVA323-339肽、抗原提呈细胞活化等两种方法获得。CD4^＋CD25^＋T细胞凋亡相关基因的表达通过实时定量PCR检测。流式细胞仪检测细胞的凋亡率。进一步观察FasL中和抗体、TRAIL中和抗体及caspase抑制剂zVAD-fmk对CD4^＋CD25^＋T细胞凋亡的影响。结果MACS成功分离CD4^＋CD25^＋T细胞，纯度可达98％，该细胞可特异性表达Foxp3基因，能明显抑制效应性T细胞的体外增殖。CD3／CD28抗体以及OVA特异性抗原活化8d的CD4^＋CD25^＋调节性T细胞AICD达39％～45％。活化前后的CD4^＋CD25^＋调节性T细胞死亡受体家族表达发生明显变化；FasL、TRAIL中和抗体及zVAD-fmk可明显抑制CD4^＋CD25^＋调节性T细胞的凋亡。结论FasL／Fas及其他凋亡相关分子可能参与了CD4^＋CD25^＋调节性T细胞的凋亡。     

胃癌患者外周血CD4+CD25+调节性T细胞的检测及临床意义

目的研究胃癌患者外周血CD4+CD25+调节性T细胞频数的变化,并探讨该群细胞频数的变化与肿瘤的病理类型及临床分期的相关性.方法应用流式细胞仪分析胃癌患者和健康对照组外周血中单个核细胞(pBMCs)的CD4+CD25+调节性T细胞频数,并探讨该种细胞频数的变化与胃癌的相关性.结果32例胃癌患者CD4+CD25+T细胞占CD4+T细胞19.40%±8.76%,高于25例健康对照组的10.68%±3.57%(P＜0.01).分化较好的胃癌患者CD4+CD25+T细胞占CD4+T细胞16.79%±4.21%,低分化胃癌患者CD4+CD25+T细胞占CD4+T细胞20.02%±10.42%,两者之间差异显著(P＞0.05).Ⅲ、Ⅳ期的胃癌患者CD4+CD25+T细胞占CD4+T细胞22.43%±8.36%,明显高于Ⅰ、Ⅱ期的胃癌患者(CD4+CD25+T细胞占CD4+T细胞的15.27%±6.85%,P＜0.05).结论CD4+CD25+T细胞在胃癌患者中比例升高,可能是产生肿瘤免疫抑制的重要机制,CD4+CD25+T细胞的高表达可作为胃癌患者肿瘤进展的重要标志.     

T细胞在激活诱导凋亡中的信号途径

淋巴细胞AICD是免疫系统维持稳定的一种重要机制。现在已知的可引发AICD的途径包括CD3/TCR途径、CD2途径、CD47途径、CD30途径。它们最终将信号传递至两条凋亡途径,引起细胞死亡。第一条是死亡受体信号传导途径,其中主要包括Fas/PasL途径、Apo-TRAIL等TNF受体超家族起始的途径。另外,Bcl-2家族构成的线粒体途径可能参与一定的调节作用。     

恶性肿瘤患者CD4+CD25+/CD4+CD25high调节性T细胞的研究

目的：探讨恶性肿瘤患者外周血CD4^＋CD25^＋/CD4^＋CD25^high调节性T细胞（Regulatory T cell，Treg）水平的特点及其临床意义。方法：采用流式细胞术检测Treg水平，并进行分层分析。结果：62例恶性肿瘤患者外周血中CD4^＋CD25^＋/CD4^＋CD25^high Treg占T细胞的百分比分别为19.61%±8.17%和4.20%±1.90%，高于正常对照组（分别为P〈0.05和P〈0.001），它们与NK细胞呈负相关（r分别为-0.2361和-0.306）。随疾病进展，CD4^＋ CD25^＋Treg水平升高，肿瘤进展期（IV期）与前3期比较有极显著差异（P〈0.001）。CD4^＋CD25^high Treg占CD4＋T细胞的百分比率逐渐升高，中期（Ⅲ期）患者与早期患者、正常对照组比较有极显著差异（P〈0.001）；晚期患者与中期患者比较有极显著差异（P〈0.001）。结论：恶性肿瘤患者外周血CD4^＋CD25^＋/CD4^＋CD25^high Treg水平的升高，与恶性肿瘤免疫功能低下及肿瘤的发生发展密切相关。     

白血病中Fas/FasL系统诱导的细胞凋亡作用

Fas FasL系统是研究最深入的介导细胞凋亡的途径 ,当Fas与FasL结合时 ,可直接引起Fas+ 细胞的凋亡。但是在白血病的发病过程中 ,尽管高表达Fas,似乎仍存在着血细胞的凋亡不足。许多研究表明 ,白血病细胞对Fas FasL途径介导的凋亡不敏感或存在抵抗也是导致白血病耐药的原因之一 ,白血病的Fas抗性与多种因素有关 ,对它们的研究可为白血病的治疗提供新的方法     

三氧化二砷诱导Jurkat细胞凋亡过程中线粒体的变化

目的： 研究三氧化二砷（As₂O₃）诱导Jurkat细胞凋亡过程中线粒体的变化特点。方法: 以As₂O₃诱导Jurkat细胞凋亡为模型，利用Annexin V-FITC/PI双染流式细胞术研究细胞凋亡和坏死，DiOC₆(3)/PI染色流式细胞术检测线粒体膜电势（△ψm），壬基酚丫啶橙(NAO)/PI染色流式细胞术检测线粒体质量，利用2,7-二氯二氢荧光素乙酰乙酸(DCFH-DA)染色流式细胞术检测细胞内活性氧的变化。 结果: 在4×10^-6mol/L As₂O₃诱导下，Jurkat细胞在48 h凋亡比率为(18.98±1.40)%， 对照组为(5.17±0.80)%，组间差异显著（P<0.01）；As₂O₃组坏死比率为(8.56±0.70)%，对照组为(1.53±0.55)%，组间差异显著（P<0.01）。As₂O₃组在48 h时点的线粒体膜电势低于对照组（P<0.05）， 线粒体膜电势下降的Jurkat细胞比率分别为（23.07±3.62)%和（6.63±1.46)%。 同时Jurkat细胞As₂O₃组线粒体质量显著低于对照组（P<0.01），线粒体质量下降的细胞比率分别为（25.90±1.80)%和（6.37±1.04)%。As₂O₃组自由基产生明显高于对照组（P<0.01）， DCFDA平均荧光强度分别为24.41±0.75和17.06±0.48。结论: As₂O₃诱导Jurkat细胞凋亡过程中，线粒体膜电势和质量均下降，细胞内氧自由基水平升高。     

脱氢表雄酮对人脐静脉内皮细胞CD40/CD40L表达的影响

目的:探讨脱氢表雄酮(DHEA)对干扰素-γ(I NF-γ)刺激下的人脐静脉内皮细胞(HUVECs)CD40/CD40L表达的影响。方法:原代培养人脐静脉内皮细胞,给予I NF-γ刺激和不同浓度DHEA干预。采用流式细胞术检测CD40/CD40L在细胞表面的表达,通过反转录-聚合酶链反应(RT-PCR)检测CD40/CD40L mRNA的表达。结果:I NF-γ刺激HUVECs表达CD40/CD40L,DHEA下调I NF-γ诱导的HUVECs表面CD40/CD40L的表达,同时对I NF-γ刺激下的CD40/CD40L mRNA的表达有抑制作用,并且呈剂量依赖性。结论:DHEA能减轻I NF-γ刺激下的人脐静脉内皮细胞CD40/CD40L的表达。     

急性淋巴细胞白血病患者CD4+CD25+调节性T细胞水平变化

目的 观察急性淋巴细胞白血病(ALL)患者外周血中CD4+ CD25+调节性T细胞(Treg)的变化,探讨其临床意义.方法 收集47例ALL初诊患者组、13例经化疗完全缓解组、9例未缓解组及20例健康对照组抗凝血,采用流式细胞仪检测CD4+ CD25+ Treg的水平.结果 CD4+ CD25+ Treg比例在ALL初...     

幽门螺杆菌致T细胞凋亡：Fas/FasL介导的T细胞无反应性

目的 评价幽门杆菌（Hp）致T细胞死亡的方式和机制,探讨这种作用与Hp感染致宿主产生免疫耐受的关系。方法 应用AnnexinV染色流式细胞术检测Hp致T细胞死亡的方式;应用细胞毒实验（JAM技术）和FasIgG抗体、caspase8抑制剂组断实验评价T细胞凋亡与Fas/FasL作用的关系,并通过流式细胞术直接检测Hp对T细胞FasL表达的上调作用及其与T细胞产生凋亡的时效关系。结果 AnnexinV染色和JAM技术证实H致T慢以凋亡方式进行的。这种细胞凋亡能被抗Fas抗体和caspase8抑制剂阻断,因而是Fas依赖,TH2细胞较TH1样T细胞对这种作用更敏感。由于Hp能直接上调T细胞的FasL且其发生时间与凋亡出现时间吻合,证实Hp是通过凋节T细胞之间Fas/FasL相互作用而致其凋亡的。Hp能通过调节Fas/FasL作用而负调节T细胞的生长,这可能是Hp感染致宿主发生T细胞耐受的机制之一。     

2型登革病毒诱导ED25细胞凋亡及死亡受体的表达变化

目的： 观察2型登革病毒（dengue virus type 2，DV2）感染ED25（人肝静脉内皮细胞）诱导细胞凋亡及胞膜死亡受体TRAILR、TNFR、Fas表达水平的改变，并探讨其意义。方法: 用 DV2感染ED25细胞，流式细胞技术检测ED25细胞感染前、后凋亡变化及胞膜死亡受体TRAILR1-4、TNFR1-2、Fas的表达。结果: 病毒感染后ED25细胞凋亡增加，感染前细胞凋亡数约5.7%±1.2%，而感染后细胞凋亡数约27.3%±1.6%，P<0.05；病毒感染后细胞Fas表达百分比增加，感染前为44.3%±2.2%,而感染后为63.0%±2.3%，P<0.05;而TRAILR1-4、TNFR1-2表达水平甚低，感染前后无明显改变。结论: 2型登革病毒感染可以诱导肝静脉内皮细胞ED25细胞凋亡，其中死亡受体Fas表达增高，提示DV2可能通过调节Fas/FasL的表达诱导细胞凋亡，有利于进一步研究登革病毒感染引起肝脏器官损伤。     

瘦素对缺氧复氧L02肝细胞凋亡及Fas/FasL表达的影响

目的： 观察瘦素(leptin)对缺氧复氧人正常肝细胞（L02）凋亡的影响。方法: 将L02细胞分别分为正常对照组、单纯缺氧12 h复氧组(IR组)和缺氧12 h复氧加不同浓度的瘦素（分别为100 μg/L、200 μg/L、400 μg/L、800 μg/L 和1 600 μg/L）干预组, 以流式细胞仪分析、DNA缺口末端标记 (TUNEL) 试验、荧光定量 PCR 等方法观察leptin 对L02肝细胞凋亡、Fas/FasL mRNA表达的影响。结果: （1）与正常对照组相比,IR组细胞凋亡率和TUNEL细胞阳性率增加（P<0.01）,加用不同浓度瘦素干预组的细胞凋亡率和TUNEL细胞阳性率与IR组相比明显下降（P<0.05）;（2）与正常对照组相比,IR组 L02 细胞中Fas/FasL mRNA表达明显上调(P<0.01);加用不同浓度瘦素干预组与IR组相比,Fas/FasL mRNA表达下降,以400 μg/L瘦素作用明显,结果有显著差异（P<0.05）。结论: 瘦素能减轻缺氧复氧培养L02肝细胞的凋亡,其机制可能与其下调细胞中Fas/FasL mRNA的表达有关。     

Fas/FasL介导的caspase-3活化与急性胰腺炎腺泡细胞凋亡的关系

目的： 研究凋亡调控基因及蛋白Fas、FasL和caspase-3在大鼠急性胰腺炎（AP）组织中的表达及其相互关系。方法：经胰胆管逆行注射不同浓度的牛磺胆酸钠建立不同炎症程度的AP模型,采用RT-PCR、Western blotting技术检测大鼠胰腺炎组织Fas、FasL和caspase-3蛋白及mRNA的表达, TUNEL法检测胰腺炎组织腺泡细胞凋亡。结果：在正常胰腺组织内即可见Fas、FasL、caspase-3蛋白和mRNA的表达;建立AP模型后,随胰腺炎症程度的加重,Fas、FasL、caspase-3蛋白和mRNA的表达逐渐下降,腺泡细胞凋亡率亦逐渐下降,且caspase-3 表达水平在各个组间的变化趋势与Fas/FasL系统的变化趋势相一致。结论：Fas/FasL系统介导的凋亡途径参与了急性胰腺炎腺泡细胞凋亡的调节。     

钩端螺旋体脂多糖诱导J774A.1细胞凋亡及相关信号通路调控作用的研究

目的 了解问号钩端螺旋体脂多糖(L-LPS)体外诱导小鼠单核-巨噬样细胞株(J774A.1)凋亡及Toll样受体(TLR)和相关信号通路调控细胞凋亡的作用.方法 酚水法从问号钩体黄疸出血群赖型赖株中提取L-LPS.流式细胞术测定L-LPS诱导J774A.1细胞凋亡及FasL中和抗体阻断细胞凋亡的作用.实时荧光定量RT-PCR(qPCR)及流式细胞术检测L-LPS作用前后J774A.1细胞Fas/FasLmRNAs和蛋白表达水平变化.TLR2或TLR4抗体封闭试验、信号通路阻断试验及流式细胞术,检测TLR2、TLR4及p38丝裂原活化蛋白激酶(MAPK)、c-Jun氨基末端激酶(JNK)和胞外信号调节激酶(ERK)通路对L-LPS诱导细胞凋亡的调控作用.结果 100 ng/ml L-LPS作用J774A.1细胞4、12和24 h的凋亡率分别为56.50%、69.28%和24.35%,FasL中和抗体封闭后,细胞凋亡率分别下降至11.21%、21.58%和12.70%(P＜0.05).L-LPS作用4、12和24 h的J774A.1细胞FasL和Fas mRNAs水平分别为正常细胞的1.34、2.12、2.10及2.45、3.87、3.12倍(P＜0.05),FasL和Fas蛋白表达率分别从L-LPS作用前的4.82%和15.32%上调至18.61%、60.13%、42.75%(P＜0.05)和76.34%、85.70%和77.92%(P＜0.05).TLR2抗体封闭后L-LPS诱导J774A.1细胞的凋亡率(11.54%)明显低于未封闭细胞(66.56%,P＜0.05),但TLR4抗体封闭细胞的凋亡率仍高达55.27%(P＞0.05).p38MAPK与JNK通路阻断后L-LPS诱导J774A.1细胞凋亡率(20.54%和47.98%)明显低于未阻断细胞(62.17%,P＜0.05),ERK通路阻断后细胞凋亡率仍高达61.72%(P＞0.05).结论 L-LPS经TLR2识别后通过p38MAPK和JNK通路上调J774A.1细胞Fas和FasL表达,从而参与L-LPS诱导细胞凋亡过程.     

抗Fas抗体诱导人肾小球系膜细胞凋亡

研究抗Ｆａｓ抗体对人肾小球系膜细胞的致凋亡作用，探讨Ｆａｓ－ＦａｓＬ在肾脏损务中的作用。方法：常规方法分离，培养人肾小球系膜细胞，并传代鉴定，用不同浓度的抗Ｆａｓ抗体刺激４－６代Ｍｃｓ１６ｈ后，荧光染色观察Ｍｃｓ凋亡变化，二苯胺法和ＤＮＡ凝胶电泳方法定量和定性分析ＭｃｓＤＮＡ片段化变化。     

FasL/Fas pathway is involved in dengue virus induced apoptosis of the vascular endothelial cells

The hallmark of the dengue hemorrhagic fever/dengue shock syndrome is hematologic abnormality. The pathogenesis of dengue hemorrhagic fever/dengue shock syndrome remains unknown. Our work showed that the dengue virus serotype‐2 induced apoptosis in human umbilical vein endothelial cells. Fas (CD95), Tumor Necrosis Factor receptors, and Tumor Necrosis Factor‐related apoptosis‐inducing ligand receptors are the most common death receptors, which can induce apoptosis. Compared with the untreated human umbilical vein endothelial cells, Fas expression was increased both in the mRNA level and on the surface of infected human umbilical vein endothelial cells. FasL was expressed at similar levels on human umbilical vein endothelial cells over a course of dengue virus serotype‐2 infection, but the expression in mRNA level was increased in infected human umbilical vein endothelial cells. It is possible that there is soluble FasL secreted from human umbilical vein endothelial cells in the supernatant. Tumor Necrosis Factor‐related apoptosis‐inducing ligand receptor 1 and Tumor Necrosis Factor receptors 1–2 were constantly very low, whereas Tumor Necrosis Factor‐related apoptosis‐inducing ligand receptors 2–4 decreased after dengue virus serotype‐2 infection. This result suggested that dengue virus serotype‐2 may inhibit Tumor Necrosis Factor‐related apoptosis‐inducing ligand receptors‐induced apoptosis. The apoptotic rates in human umbilical vein endothelial cells were decreased upon the addition of caspase family inhibitors. In addition, activated caspase 8 and caspase 3 were also observed by Western blot following dengue virus serotype‐2 infection. Thus, it is shown that the Fas/FasL pathway may participate in dengue virus‐induced apoptosis of vascular endothelial cells in vitro. J. Med. Virol. 82:1392–1399, 2010. © 2010 Wiley‐Liss, Inc.     

Increased Fas-mediated apoptosis in polymorphonuclear cells from HIV-infected patients

Neutrophils represent an important line of innate host defence against invading microorganisms and their functional detriment during HIV infection, including accelerated spontaneous cell death, has been shown to contribute to AIDS development. Neutrophils are susceptible to apoptosis via Fas and an interaction between Fas and FasL was suggested originally as a mechanism to explain constitutive neutrophil apoptosis. We have explored some intracellular pathways leading to PMN apoptosis from 28 HIV-infected patients and 24 healthy volunteers. As previously reported, accelerated spontaneous apoptosis was observed in HIV+ patients, but this did not correlate with viral load. Furthermore, an increase in the level of spontaneous apoptosis was detected in neutrophils from HIV-infected patients following inhibition of ERK, suggesting an impairment of this kinase pathway during the early stages of infection which may contribute to PMN dysfunction. An elevated susceptibility to undergo apoptosis was observed following cross-linking of Fas, which correlated both with viral load and co-expression of Fas/FasL surface molecules. Different mechanisms for spontaneous and Fas-induced apoptosis are proposed which together contribute to the neutropenia and secondary infections observed during the progression to AIDS.     

Coelomic cells show apoptosis via Fas/FasL system: a comparative study between healthy human pregnancies and missed miscarriages

BACKGROUND: The Fas/Fas ligand (FasL) system represents one of the mainapoptotic pathways controlling placental apoptosis throughoutgestation. In the current study, we have examined the Fas/FasLprotein expression and the apoptotic incidents of coelomic cells,amniotic cells and trophoblastic tissue in first trimester humanpregnancies and missed miscarriages (MM). METHODS: Protein expression was determined by immunofluoresence, westernblotting analysis, immunohistochemistry and indirectly by RT–PCR,whereas apoptotic cell death was assessed by in situ DNA fragmentationanalysis. RESULTS: Coelomic cells express Fas/FasL proteins, can undergo apoptosisand were the only cells in which apoptosis, Fas protein expressionand FasL protein expression were accordingly increased alongwith gestational age (P = 0.001, P = 0.008; P = 0.012, respectively).In contrast, amniotic cells and trophoblast showed a consistencyin the expression levels of Fas/FasL proteins in healthy pregnancies.MM were accompanied by increased Fas/FasL protein expressionin all examined samples (P < 0.001). The increase of Fas/FasLprotein expression was accompanied by proportional increaseof apoptotic incidents among the coelomic cell population (P= 0.023, P = 0.009, respectively), whereas amniotic cells andtrophoblast appeared to be resistant to Fas-induced apoptosis.The lowest expression of Fas/FasL proteins and the minimum occurrenceof apoptotic incidents were detected in the trophoblast. CONCLUSIONS: These data suggest that there is a different regulation andfunction of the Fas/FasL system in early human pregnancies.Aberration of the Fas-mediated apoptosis may represent one ofthe execution-step necessary for pregnancy loss in MM cases.     

First trimester trophoblast cells secrete Fas ligand which induces immune cell apoptosis

Since the invading trophoblast represents a semi-allograft, it should be rejected by the mother. It has, therefore, been postulated that during normal pregnancy the trophoblast evades the maternal immune system though the establishment of immune privilege by triggering the death of activated lymphocytes which may be sensitized to paternal alloantigens. Such peripheral tolerance may be directed through the Fas/Fas ligand (FasL) apoptotic pathway and mediated by FasL expressed by the trophoblast. However, in vivo studies show that membrane-associated expression of FasL may instead promote allograft rejection, rather than protection. The aim of this study was to determine if there is a role for FasL in trophoblast immune privilege. In this study, we demonstrate that isolated first trimester trophoblast cells lack membrane-associated FasL, but express a cytoplasmic form in association with a specialized secretory lysosomal pathway. Furthermore, this intracellular FasL is constitutively secreted by trophoblast cells via the release of microvesicles. Following disruption of these microvesicles, the whole 37 kDa secreted FasL is able to induce T-cell death by apoptosis through activation of the Fas pathway. Therefore, we propose that secretion of FasL may be one mechanism by which trophoblast cells promote a state of immune privilege and, therefore, protect themselves from maternal immune recognition.     

LPS-induced transient testicular dysfunction accompanied by apoptosis of testicular germ cells in mice

The aim of this study was to clarify effects of inflammation on spermatogenesis in LPS-administered mice. ICR mice were treated by intraperitoneal injection for 7 days with either physiological saline (control) or 0.1 mg lipopolysaccharide (LPS)/kg body weight/day. Control mice were killed at 24 h after the last injection and the LPS-treated group after 24 h or 1, 3, or 5 weeks. Sperm concentration and motility in the cauda epididymis were examined as well as immunohistochemical localization of Fas and FasL and germ cell apoptosis. Sperm concentration and motility markedly fluctuated in LPS-treated mice. Increase of apoptotic cells was common in all post-LPS treatment groups, with a peak at 24 h after LPS injection. In contrast to the lack of Fas immunoreactivity in control testes, LPS-treated groups demonstrated Fas in many germ cells, especially in spermatocytes and spermatids. Immunoreactivity for FasL, on the other hand, was positive for some Sertoli cells, Leydig cells, and germ cells in both control and LPS-treated groups at all time points. The results suggest that the Fas/FasL system mediates apoptosis of germ cells in LPS-treated mice testes. LPS-administered mice thus provide a good experimental model for the study of transient disruption of spermatogenesis.