肝细胞凋亡的基因调控

细胞凋亡是生物界普遍存在的一种基本生理活动,大量研究表明,细胞凋亡过程与许多细胞因子及基因密切相关。本文综述了与肝细胞凋亡有关的p53基因、C-myc基因、Fas基因、Bax基因和Bcl-2基因等。     

细胞凋亡的基因调控研究进展

细胞凋亡的调控是细胞生理死亡和肿瘤等疾病发生的重要机制。分别对线虫和哺乳类动物细胞凋亡的基因调控研究进展进行了综述 ,阐述了bcl 2基因家族、c myc基因、p5 3基因、白细胞介素Ⅰβ转化酶基因家族、Fas/FasL基因对细胞凋亡的调控作用。     

细胞凋亡与NF-κB激活的信号传导研究

细胞凋亡是细胞受基因调控的主动死亡方式,对于生物体的正常发育及生理功能的维持具有重要意义。NF-κB是一类在动物细胞中广泛表达的转录因子,其主要生理功能之一是通过诱导凋亡抑制基因的转录,拮抗细胞凋亡的发生。NF-κB的活化调控是细胞生死抉择过程的关键机制之一。现已证明细胞凋亡及NF-κB活化的异常会导致多种人类疾病。本项目从凋亡的执行机制和调控机制两方面入手,对细胞凋亡的机理进行了研究。建立了基于爪蟾卵细胞提取物的非细胞凋亡诱导体系,并利用这一体系,发现爪蟾细胞凋亡特异核酸酶XAD及其特异性的抑制因子IXAD;首次证明磷酸肌酸和核质素在凋亡过程中的作用。克隆了3个新的凋亡诱导基因。在细胞凋亡的调节机制方面,克隆了7个分别作用于NF-κB活化信号通路不同步骤的新的调节基因,发现5个已知蛋白调节不同NF-κB活化途径的新功能。此外,在国际上较早开展了植物细胞凋亡的研究,首次报道体外培养植物细胞凋亡过程中有细胞色素C的释放。     

血管内皮细胞凋亡过程中几种癌基因表达的研究

为了研究细胞凋亡的分子调控机制 ,用光学显微技术、DNA凝胶电泳和Northernblot方法 ,研究了去除生长因子 (FGF和血清 )和蛇毒诱导的两个血管内皮细胞凋亡系统中 p53、c H ras、c myc和bcl 2基因的表达 .发现去除生长因子诱导的细胞凋亡过程中 ,p53基因表达显著增加 ,c H ras和c myc基因表达无变化 ;蛇毒诱导细胞凋亡过程中 ,p53基因表达显著增加 ,c H ras和c myc基因表达无变化 .在正常生长和凋亡细胞中均未检测到bcl 2基因的明显表达 .实验结果表明 :p53基因参与上述两种细胞凋亡诱导系统的分子调控 ;c H ras基因只参与去除生长因子诱导的细胞凋亡过程 ,而不参与蛇毒诱导的细胞凋亡过程 ;这两种细胞凋亡诱导系统均与c myc基因表达无关 ;未见bcl 2基因明显参与血管内皮细胞的凋亡过程 .     

细胞凋亡的分子机理

细胞凋亡是由一些基因编码和细胞主动自杀过程,又称程序性细胞死亡,它在机体的生长、分化与病理中具有积极意义。综述了核酸内切酶及凋亡相关基因在细胞凋亡中的作用,重点讨论了Caspase家族的研究进展。     

病毒感染与细胞凋亡

阐述了细胞凋亡的概念，与细胞凋亡相关的病毒和基因，病毒调控细胞凋亡的机制和研究病毒感染与细胞凋亡关系的意义，以增进人们对病毒和细胞之间关系的理解。     

细胞凋亡与肿瘤治疗

细胞凋亡是基因调控的主动过程。许多癌基因与抑癌基因参与细胞凋亡过程。本文综述了肿瘤细胞凋亡的相关主细胞凋亡在肿瘤治疗中的作用。     

HCAP1基因对Raji细胞凋亡及凋亡相关蛋白Bax/Bcl - 2的作用

目的：研究外源HCAP1基因产物对Burkitt淋巴瘤细胞系Raji细胞凋亡及凋亡相关蛋白Bax／Bcl-2的作用。方法：用脂质体介导的基因转移方法，把外源HCAP1基因转染到Raji细胞中，用流式细胞术和Hochest 33258荧光染色检测细胞凋亡；用Western blot检测外源HCAP1基因对凋亡相关蛋白Bax和Bcl-2蛋白表达的调节。结果：外源HCAPl基因导入Raji细胞24、48和96h后，细胞凋亡率增加。Western blot显示Bax／Bel-2蛋白表达比值明显增高。结论：转染外源性HCAP1基因可诱导Raji细胞凋亡，使Bax／Bcl-2蛋白表达比例上调可能是HCAP1诱导凋亡的机制之一。     

细胞凋亡基因Fas／FasL的免疫学作用

本文简介了有关细胞凋亡相关基因Fas/FasL的基因与蛋白结构,信号传导途径以及它在细胞凋亡中的作用,并讨论了它在免疫学上的功能以及与自身免疫性疾病的关系。     

Nucleostemin siRNA对结肠癌细胞株HT-29细胞凋亡的影响

利用RNA干扰技术沉默结肠癌细胞株HT-29细胞中Nucleostemin(NS)基因的表达,并分析其对HT-29细胞凋亡的影响,进一步利用半定量RT-PCR和Western blotting技术检测细胞凋亡相关基因caspase-3/9 mRNAs和蛋白的表达.结果表明,NS基因的沉默能明显提高caspase-3/9的活性(P0.05),并诱导细胞发生凋亡,此外,HT-29细胞中NS基因沉默后,caspase-3/9mRNAs和蛋白的表达均明显升高,提示NS基因沉默介导的细胞凋亡与caspase-3/9基因表达的升高密切相关.     

Essential role of the mitochondrial apoptosis-inducing factor in programmed cell death

Programmed cell death is a fundamental requirement for embryogenesis, organ metamorphosis and tissue homeostasis. In mammals, release of mitochondrial cytochrome c leads to the cytosolic assembly of the apoptosome-a caspase activation complex involving Apaf1 and caspase-9 that induces hallmarks of apoptosis. There are, however, mitochondrially regulated cell death pathways that are independent of Apaf1/caspase-9. We have previously cloned a molecule associated with programmed cell death called apoptosis-inducing factor (AIF). Like cytochrome c, AIF is localized to mitochondria and released in response to death stimuli. Here we show that genetic inactivation of AIF renders embryonic stem cells resistant to cell death after serum deprivation. Moreover, AIF is essential for programmed cell death during cavitation of embryoid bodies-the very first wave of cell death indispensable for mouse morphogenesis. AIF-dependent cell death displays structural features of apoptosis, and can be genetically uncoupled from Apaf1 and caspase-9 expression. Our data provide genetic evidence for a caspase-independent pathway of programmed cell death that controls early morphogenesis.     

细胞的程序死亡研究进展

本文主要讲述了细胞程序死亡(PCD)的基本概述,细胞程序死亡的诱导因素以及近年来细胞程序死亡方面的有关机理。     

中华大蟾蜍尾部程序性死亡的形态学和相关酶的研究

为了研究两栖类变态过程中程序性死亡的分子机制,本文利用尾部离体培养、DNA含量分析、组织切片和形态学分析等方法,观察和分析了中华大蟾蜍变态过程中尾部程序性死亡的形态学变化;同时研究了磷脂酰胆碱特异性磷脂酶C的抑制剂对蝌蚪尾部程序性死亡的影响.发现这一特异性抑制剂明显阻止了中华大蟾蜍变态中尾部的萎缩,表明该酶在其尾部的程序性死亡中发挥重要作用.本文的这一发现为深入研究发育过程中程序性死亡的分子机制奠定了基础.     

植物细胞程序性死亡的调控及检测

植物细胞程序性死亡（prognammed cell death,PCD）普遍存在于植物体发育过程中，是由基因调控的、主动的细胞死亡过程．本文对植物细胞程序性死亡的基本特征、调控及其检测方法进行了综述．     

棉铃虫单粒包埋型核型多角体病毒诱发草地贪夜蛾细胞株Sf的程序性死亡

棉铃虫单粒包埋型核型多角体病毒（ＨａＳＮＰＶ）能够诱发草地贪夜蛾Ｓｆ细胞株发生早期死亡现象．依据死亡过程的细胞形态变化，ＤＮＡ降解的梯状电泳特征以及对不同抑制剂敏感性的差异，可以初步断定该死亡现象为程序性死亡．早期死亡伴随着病毒ＤＮＡ复制与子代病毒生成的中止．同时发现野生型ＡＣＭＮＰＶ的共感染能够有效地抑制早期死亡的发生，并对抑制作用的可能性机制进行了探讨．     

Loss of cyclophilin D reveals a critical role for mitochondrial permeability transition in cell death

Mitochondria play a critical role in mediating both apoptotic and necrotic cell death. The mitochondrial permeability transition (mPT) leads to mitochondrial swelling, outer membrane rupture and the release of apoptotic mediators. The mPT pore is thought to consist of the adenine nucleotide translocator, a voltage-dependent anion channel, and cyclophilin D (the Ppif gene product), a prolyl isomerase located within the mitochondrial matrix. Here we generated mice lacking Ppif and mice overexpressing cyclophilin D in the heart. Ppif null mice are protected from ischaemia/reperfusion-induced cell death in vivo, whereas cyclophilin D-overexpressing mice show mitochondrial swelling and spontaneous cell death. Mitochondria isolated from the livers, hearts and brains of Ppif null mice are resistant to mitochondrial swelling and permeability transition in vitro. Moreover, primary hepatocytes and fibroblasts isolated from Ppif null mice are largely protected from Ca2+-overload and oxidative stress-induced cell death. However, Bcl-2 family member-induced cell death does not depend on cyclophilin D, and Ppif null fibroblasts are not protected from staurosporine or tumour-necrosis factor-alpha-induced death. Thus, cyclophilin D and the mitochondrial permeability transition are required for mediating Ca2+- and oxidative damage-induced cell death, but not Bcl-2 family member-regulated death.     

BCL—2和细胞程序性死亡的调控

细胞程序性死亡是一种自杀性细胞死亡,乃多细胞高等生物去除有害及多余细胞之途径,为生物体正常的生长发育及功能维持所必需。本文阐述了BCL—2基因与程序性细胞死亡调控之间的关系。     

Cyclophilin D-dependent mitochondrial permeability transition regulates some necrotic but not apoptotic cell death

Mitochondria play an important role in energy production, Ca2+ homeostasis and cell death. In recent years, the role of the mitochondria in apoptotic and necrotic cell death has attracted much attention. In apoptosis and necrosis, the mitochondrial permeability transition (mPT), which leads to disruption of the mitochondrial membranes and mitochondrial dysfunction, is considered to be one of the key events, although its exact role in cell death remains elusive. We therefore created mice lacking cyclophilin D (CypD), a protein considered to be involved in the mPT, to analyse its role in cell death. CypD-deficient mice were developmentally normal and showed no apparent anomalies, but CypD-deficient mitochondria did not undergo the cyclosporin A-sensitive mPT. CypD-deficient cells died normally in response to various apoptotic stimuli, but showed resistance to necrotic cell death induced by reactive oxygen species and Ca2+ overload. In addition, CypD-deficient mice showed a high level of resistance to ischaemia/reperfusion-induced cardiac injury. Our results indicate that the CypD-dependent mPT regulates some forms of necrotic death, but not apoptotic death.     

SO_2诱导拟南芥保卫细胞凋亡

以拟南芥叶片下表皮为材料,研究了SO_2体内衍生物-亚硫酸钠和亚硫酸氢钠混合液(3:1,mmol·L~(-1)/mmol·L~(-1))对气孔保卫细胞的致死效应.结果表明,浓度1.0～5.0 mmol·L~(-1)的SO_2衍生物处理表皮3 h可引起保卫细胞死亡,死细胞出现核固缩、核断裂、凋亡小体等典型的核凋亡特征,且胁迫组细胞内活性氧和钙离子水平升高.蛋白酶抑制剂Z-Asp-CH_2-DCB和TLCK能减少SO_2衍生物诱导的细胞凋亡;过氧化氢酶(CAT)、抗坏血酸(AsA),及Ca~(2+)螯合剂乙二醇双四乙酸(EGTA)和Ca~(2+)通道抑制剂LaCl_3均可使SO_2衍生物诱发的细胞死亡率降低.0.1 mmol·L~(-1)的AsA或EGTA能降低胁迫组胞内的活性氧和Ca~(2+)水平,与死亡率降低相伴发生.以上结果表明,一定浓度的SO_2可诱导拟南芥保卫细胞凋亡,胁迫可能通过诱导活性氧产生、胞外钙内流,造成胞内Ca~(2+)浓度升高,引发细胞程序性死亡.     

Engulfment genes cooperate with ced-3 to promote cell death in Caenorhabditis elegans.

Genetic studies have identified over a dozen genes that function in programmed cell death (apoptosis) in the nematode Caenorhabditis elegans. Although the ultimate effects on cell survival or engulfment of mutations in each cell death gene have been extensively described, much less is known about how these mutations affect the kinetics of death and engulfment, or the interactions between these two processes. We have used four-dimensional-Nomarski time-lapse video microscopy to follow in detail how cell death genes regulate the extent and kinetics of apoptotic cell death and removal in the early C. elegans embryo. Here we show that blocking engulfment enhances cell survival when cells are subjected to weak pro-apoptotic signals. Thus, genes that mediate corpse removal can also function to actively kill cells.