谷氨酸诱导海马神经元凋亡涉及线粒体释放细胞色素C

目的：建立体外谷氨酸诱导神经元兴奋损伤模型，探索其凋亡发生是否通过线粒体信号转导途径介导的细胞色素C（Cyt C）释放而实现，为今后干预性使用神经保护剂提供依据。方法:分离及培养新生Wistar大鼠海马神经元，选用合适谷氨酸浓度建立神经元损伤模型；利用LDH测定及流式细胞仪Annexin V/PI双染色法检测谷氨酸暴露后不同时点神经元凋亡及坏死的动态改变；采用Western blotting法检测caspase-3活性及线粒体内和胞浆内Cyt C水平动态变化。结果:谷氨酸诱导神经元损伤呈明显浓度及时间依赖性，50 μmol/L浓度可使LDH释放量明显增加 (18.4%,P<0.05)，暴露后6 h凋亡率显著增加；凋亡发生前，神经元caspase-3活性已明显增高（3 h），6 h达高峰；线粒体Cyt C释放发生在caspase-3增高前，30 min时胞浆内Cyt C水平即明显增加（P<0.05），3 h胞浆内Cyt C水平超过线粒体内，而线粒体内Cyt C水平进行性减少。结论:50 μmol/L谷氨酸可诱导海马神经元凋亡，凋亡机制可能是通过损伤线粒体膜，使Cyt C易位释放入胞浆激活caspase级联反应而致。     

氧化应激诱导HepG2肝癌细胞凋亡的研究(英)

目的：直接暴露细胞于活性氧能诱导发生凋亡，本文研究氧化应激诱导HepG2肝癌细胞的死亡及其机制。方法：暴露细胞于2 mmol/L过氧化氢产生氧化应激，用DNA凝胶电泳检测细胞凋亡，用荧光染色法检测细胞线粒体膜电位变化，Western blotting检测细胞浆中细胞色素c变化，fluorometric assay kit检测caspase活性变化。结果：氧化应激作用于HepG2细胞后12 h开始发生凋亡；氧化应激作用后4 h，细胞线粒体膜电位明显下降；胞浆中细胞色素c浓度呈时间依赖性增高；氧化应激作用8 h、12 h后细胞内caspase-3、caspase-9活性分别升高6.7及3.6倍，但caspase-8活性无变化。结论：氧化应激能诱导HepG2肝癌细胞发生凋亡，其途径与线粒体通路及caspase激活有关。     

Et-DHA通过激活线粒体途径和T细胞granzyme B诱导HepG2细胞凋亡

 目的：本研究探讨了二十二碳六烯酸乙酯（Et-DHA）对人肝癌HepG2细胞凋亡的影响。方法：HepG2细胞用于检测Et-DHA的抑癌活性,MTT法检测Et-DHA对HepG2细胞的直接抑制作用,Hoechst 33258荧光染色观察细胞的形态特征,ELISA法检测Et-DHA处理后HepG2细胞的活性氧簇（ROS）释放量、总超氧化物歧化酶（SOD）和caspase-9活性,Western blotting法检测胞质和线粒体中Bax、Bak、Bid、Bcl-2、Smac和细胞色素C(Cyt C),以及胞质中cleaved caspase-8、cleaved caspase-9和cleaved caspase-3的水平;T细胞与HepG2细胞共培养,进一步观察Et-DHA处理后T细胞的增殖对HepG2细胞活性的影响,并检测了颗粒酶（granzyme）B的水平。结果：Et-DHA显著抑制HepG2细胞的生长（P＜0.05）,这种抑制作用具浓度效应和时程效应;Et-DHA处理后HepG2细胞的ROS释放量增加,但总SOD活性无明显变化,caspase-9活性显著上升（P＜0.05）;线粒体上的促凋亡蛋白Bax、Bak和Bid水平增加,而抑凋亡蛋白Bcl-2以及线粒体中Cyt C和Smac的水平降低,胞质中的Cyt C、Smac、cleaved caspase-8、cleaved caspase-9、cleaved caspase-3以及cleaved Bid水平呈剂量性升高。另外 T细胞和HepG2细胞共培养组在Et-DHA的诱导下,HepG2细胞的凋亡程度与Et-DHA单独作用时相比进一步增加。在Et-DHA刺激下,T细胞内granzyme B上调,释放到HepG2 细胞内的granzyme B明显增多。结论:Et-DHA可能主要通过线粒体内源性途径以及caspase-8途径,激活caspase-3,诱导HepG2细胞凋亡,以及通过间接活化T细胞,促使 granzyme B增多,从而增强对HepG2细胞的毒性作用。     

沉默FoxM1通过促进线粒体释放细胞色素C诱导口腔鳞癌细胞凋亡

目的:研究沉默叉头框蛋白M1 (FoxM1)基因对口腔鳞癌细胞凋亡影响及机制。方法:口腔鳞癌SCC9细胞感染FoxM1-shRNA慢病毒或阴性对照慢病毒,用RT-qPCR和Western blot测定沉默效果。MTT法测定细胞活力变化,平板克隆实验测定细胞克隆形成能力变化,流式细胞术测定细胞凋亡变化,Western blot测定细胞中cleaved caspase-3和cleaved caspase-9蛋白水平变化,JC-1法测定细胞线粒体膜电位变化,Western blot测定细胞线粒体和胞浆中细胞色素C(cytochrome C)蛋白水平的变化。结果:FoxM1-shRNA慢病毒感染成功下调口腔鳞癌细胞中FoxM1的表达(P0.05),阴性对照慢病毒对细胞中FoxM1表达水平没有影响。沉默FoxM1的口腔鳞癌细胞活力降低(P0.05),细胞克隆形成能力也降低(P0.05),细胞凋亡率及cleaved caspase-3和cleaved caspase-9蛋白水平均升高(P0.05),线粒体膜电位降低(P0.05),胞浆中cytochrome C蛋白水平升高(P0.05),线粒体中cytochrome C蛋白水平降低(P0.05)。结论:沉默FoxM1可以通过降低口腔鳞癌细胞线粒体膜电位、促进线粒体释放cytochrome C而诱导细胞凋亡。     

TRAIL诱导Hela细胞凋亡的线粒体信号通路

 目的 探讨 TRAIL 诱导人宫颈癌 Hela 细胞凋亡的线粒体通路。 方法 琼脂糖凝胶电泳判断细胞凋亡;激光共聚焦、Western blot、荧光免疫和 caspase-3 活性检测测定细胞线粒体膜电位 (∆Ψm) 、Bcl-2 蛋白、细胞色素 c (Cyt c) 和凋亡诱导因子 (AIF) 蛋白在细胞中的定位以及 caspase-3 活性。结果 TRAIL 能诱导 Hela 细胞凋亡,有凋亡细胞特有的 DNA 梯状条带。同时,TRAIL具有时间依赖性致 ∆Ψm 和 Bcl-2 蛋白含量明显下降,线粒体 Cyt c 蛋白释放,AIF 蛋白向细胞质、细胞核转移,caspase-3 活性增强。结论 TRAIL 诱导 Hela 细胞凋亡途径之一是通过线粒体信号通路进行的。     

去甲斑蝥素通过半胱氨酸天冬氨酸酶诱导HeLa细胞凋亡

目的：研究去甲斑蝥素（NCTD）通过半胱氨酸天冬氨酸酶（caspase）途径诱导人宫颈癌HeLa细胞凋亡的机制。方法： 采用MTT法、形态学观察、DNA凝胶电泳、乳酸脱氢酶（LDH）检测及Western blot检测法。结果： 去甲斑蝥素能显著诱导HeLa细胞发生凋亡，caspase-家族、caspase-3、-8、-10抑制剂可以部分地抑制NCTD诱导的细胞死亡。细胞凋亡时caspase-3、-8、-9酶活力升高，而且caspase-3的作用底物-caspase-3 激活的DNA酶抑制物（ICAD）蛋白表达下降。结论： 去甲斑蝥素通过激活caspase途径诱导HeLa细胞凋亡。     

独蒜兰乙酸乙酯萃取物通过内源性线粒体通路诱导白血病K562细胞和HL-60细胞凋亡

目的:探讨独蒜兰乙酸乙酯萃取物对人慢性粒细胞白血病K562细胞和急性髓性白血病HL-60细胞增殖及凋亡的影响以及诱导凋亡的途径。方法:采用XTT法、台盼蓝拒染法、Annexin V-FITC/PI双染法、PI染色法、4',6-二脒基-2-苯基吲哚(DAPI)染色和Western blot法研究不同浓度独蒜兰乙酸乙酯萃取物对上述2种白血病细胞增殖、凋亡、细胞周期和凋亡相关蛋白表达等方面的影响。结果:独蒜兰正丁醇萃取物对K562细胞活力几乎没有抑制作用,而乙酸乙酯萃取物能显著抑制K562和HL-60细胞的活力和增殖。乙酸乙酯萃取物对于HL-60细胞作用24 h的半数抑制浓度(IC_(50))为(42.14±2.54)mg/L,对于K562细胞的IC_(50)为(51.28±3.12)mg/L。Annexin V-FITC/PI和DAPI染色结果显示,乙酸乙酯萃取物呈剂量依赖性诱导2种细胞凋亡,且50 mg/L的乙酸乙酯萃取物作用后K562细胞的凋亡率为33.1%,而HL-60细胞的凋亡率为63.1%,说明HL-60细胞对乙酸乙酯萃取物更加敏感,伴有典型的细胞核凋亡形态学改变。PI染色结果显示HL-60细胞和K562细胞都被阻滞于G_2期。Western blot结果显示,随着药物浓度的升高,细胞凋亡抑制蛋白Bcl-2的表达降低,而促凋亡蛋白Bax、cleaved caspase-3和活化的多腺苷二磷酸核糖聚合酶的表达逐渐升高,内源性线粒体凋亡的特征胞浆中细胞色素C和凋亡诱导因子表达也逐渐升高。结论:独蒜兰乙酸乙酯萃取物能显著抑制K562和HL-60细胞增殖,并通过触发内源性线粒体凋亡通路诱导这2种细胞凋亡。     

线粒体与细胞凋亡

凋亡是机体细胞的一种程序性死亡。线粒体作为细胞能量代谢的场所,不仅能诱导细胞凋亡,还是细胞凋亡的执行者。线粒体内的细胞色素C和细胞凋亡诱导因子参与凋亡的诱导,同时Caspase3、7、9还参与线粒体/细胞色素C诱导的细胞凋亡机制,线粒体内的Bc l-2和Bc l-X1也参与细胞凋亡的调节。对线粒体生命代谢活动的了解及运用对我们认识机体发生、发育及衰老有重要意义。     

抗人DR5单克隆抗体诱导Jurkat和U937细胞凋亡的线粒体信号通路

目的:探讨抗人死亡受体5(Death receptor 5,DR5)单克隆抗体mDRA-6诱导Jurkat和U937细胞凋亡的线粒体信号通路。方法:MTT法检测mDRA-6对Jurkat和U937细胞生长增殖的影响,以及caspase-9、3抑制剂对mDRA-6抑制Jur-kat和U937细胞生长增殖的影响;琼脂糖凝胶电泳检测Jurkat和U937细胞DNA片段化降解;Western blot检测mDRA-6对Jurkat和U937细胞bax、bcl-2、bcl-xl、Cyt c及caspase-9、3的激活改变。结果:mDRA-6呈时间、浓度依赖性地抑制Jurkat和U937细胞的生长增殖,10 mg/L的mDRA-6作用6、8和10小时,Jurkat细胞增殖抑制率分别达59.38%、72.56%和76.28%,U937细胞增殖抑制率分别达38.67%、47.54%和50.59%。琼脂糖凝胶电泳显示,10 mg/L的mDRA-6作用6小时,Jurkat和U937细胞均呈现凋亡细胞特有的DNA梯形条带;Western blot检测结果发现,随着mDRA-6作用时间延长,Jurkat和U937细胞内促凋亡分子bax增多,抗凋亡分子bcl-2及bcl-xl减少,Cyt c释放明显增多,同时caspase-9、caspase-3也显示明显的激活表现。预先使用caspase-9抑制剂孵育细胞1小时,mDRA-6所致Jurkat和U937细胞生长抑制率分别降低了24.36%(t=5.44,P﹤0.01)和20.82%(t=4.29,P﹤0.01),mDRA-6所致Jurkat和U937细胞凋亡率分别降低了32.89%和23.97%。结论:线粒体信号通路激活是抗人死亡受体5(Death receptor 5,DR5)单克隆抗体mDRA-6诱导Jurkat和U937细胞凋亡的途径之一。     

顺铂通过p66Shc-线粒体信号通路诱导人肾小管上皮细胞凋亡

 目的：探讨p66Shc-线粒体信号通路在顺铂诱导的人肾小管上皮细胞凋亡中的作用。方法：体外培养人肾小管上皮细胞,Western blotting法检测顺铂对p66Shc及磷酸化p66Shc(Ser36)蛋白表达的影响,然后将细胞分为对照组、顺铂组及顺铂+p66ShcS36A（第36位Ser突变为Ala的p66Shc）组,用激光共聚焦显微镜观察p66Shc对顺铂诱导的细胞活性氧簇、线粒体活性氧簇及细胞凋亡的影响,Western blotting法检测线粒体凋亡信号通路相关蛋白的表达。结果：顺铂促进p66Shc蛋白磷酸化,对p66Shc蛋白表达无影响;顺铂诱导细胞凋亡,细胞及线粒体活性氧簇产生增加,细胞色素C释放,caspase-9表达增加,p66ShcS36A可以抑制顺铂诱导的细胞氧化损伤及凋亡。结论：顺铂通过p66Shc-线粒体信号通路诱导人肾小管上皮细胞凋亡。     

Cyt-C 依赖的线粒体途径在T42诱导肝癌HepG2细胞凋亡中的作用

目的 检测重组肿瘤抑素42肽(T42)诱导肝癌HepG2细胞凋亡及与线粒体凋亡途径的关系,探讨T42诱导肿瘤细胞凋亡的可能机制.方法 吖啶橙/溴化乙锭(AO/EB)荧光染色观察细胞凋亡的形态学变化;流式细胞仪检测凋亡率;JC-1荧光染色检测线粒体膜电位的变化;Western印迹检测细胞色素C(Cyt-C)的分布.结果 18 μmol/LT42作用下,HepG2细胞出现明显凋亡形态学变化,凋亡率为22.4%,与对照组比较差异有统计学意义(t=7.75,P＜0.05);T42降低了HepG2细胞线粒体膜电势,明显减少了线粒体Cyt-C.结论 T42通过降低线粒体膜电势,促进Cyt-C由线粒体膜释放到胞浆中,激活 caspase-3途径诱导人肝癌细胞系HepG2细胞凋亡.

Abstract：

Objective The aim of the present article is to detect the apoptosis of hepatocarcinoma cells HepG2 induced by recombinant tumor endostatin 42 peptide (T42) ,with an emphasis on the signaling pathways involved. Methods Observed the morphological changes associated with the apoptosis of HepG2 cells by using AO/EB. Apoptosis rate were dentified by using flow cytometry. Mitochondrial membrane potential was evaluated by using JC-1 fluorescent staining. The distribution of cytochrome C(Cytc ) was estimated by using western blot. Results Compared with the control group, there was significant difference in apoptosis rate of cells HepG2 under 18μmol /L of T42. (22.4% vs 3.70% ,t =7.75, P＜0.05). Mitochondrial membrane potential was decreased by T42, and cytochrome c was reduced significantly compared with the control group. Conclusions The result demonstrated that the T42 enhanced the apoptosis of HepG2 cells and its potential mechanism was related to the decreased of mitochondrial membrane potential, an increase in Cytochrome C released into the cytosol, and reduced activation of Caspase-3 channels.     

SHIP1调控STAT3信号通路对白血病Jurkat细胞活力和凋亡的影响

目的:探讨含SH2结构域的肌醇5-磷酸酶1(SHIP1)通过调控信号转导及转录激活因子3(STAT3)信号通路对人白血病细胞活力和凋亡的影响。方法:以白血病Jurkat细胞为研究对象,将转染空载体和SHIP1过表达载体的细胞分别记为阴性对照(NC)组和SHIP1组,同时以不作处理的细胞为空白对照(control)组,用real-time PCR和Western blot检测转染效果,MTT法检测细胞活力,流式细胞术检测细胞凋亡,Western blot检测细胞中活化的caspase-3(cleaved caspase-3)、STAT3和磷酸化STAT3(p-STAT3)的蛋白水平。同时,用STAT3信号通路抑制剂AG490作用于control组和SHIP1组细胞,分别记为control+AG490组和SHIP1+AG490组,再观测上述指标的变化。结果:分别与control组和NC组比较,SHIP1组SHIP1的mRNA表达水平和蛋白水平均显著升高(P0.05);细胞存活率显著降低(P0.05);细胞凋亡率显著升高(P0.05);cleaved caspase-3蛋白水平显著升高(P0.05);p-STAT3蛋白水平显著降低(P0.05)。分别与control组和control+AG490组比较,SHIP1+AG490组的细胞存活率显著降低(P0.05);cleaved caspase-3蛋白水平显著升高(P0.05);p-STAT3蛋白水平显著降低(P0.05);细胞凋亡率显著升高(P0.05)。结论:SHIP1能够通过抑制STAT3信号通路抑制人白血病细胞生长,促进白血病细胞凋亡。     

Avian encephalomyelitis virus nonstructural protein 2C induces apoptosis by activating cytochrome c/caspase-9 pathway

The nonstructural protein 2C is highly conserved among picornaviruses and plays an important role in the assembly of mature virions, membrane association, and viral RNA synthesis. The investigation of other potential functions of nonstructural protein 2C from avian encephalomyelitis virus (AEV) resulted in identifying for the first time that the protein 2C is involved in apoptosis. Expression of the protein 2C on chick embryo brain (CEB) and Cos-7 cells produced TUNEL-positive cells characterized by a cleavage of cellular DNA and the formation of membrane-enclosed apoptotic bodies. Analysis of the protein 2C showed that the N-terminal domain containing 35 amino acid (aa) residues (between 46 and 80 aa) is associated with apoptotic function. Transfection of the deletion mutant lacking this 35 aa's into CEB and Cos-7 cells failed to induce apoptosis. Furthermore, the protein 2C induced apoptosis in the transfected CEB and Cos-7 cells through activation of caspase-9 rather than caspase-8 followed by activation of caspase-3 pathway. Analysis of the Western blots of caspase-3 and caspase-9 showed the characteristics of active caspase-3 and -9 in the 2C-transfected CEB and Cos-7 cells as seen in the AEV-infected CEB cells while they were in the form of procaspase-3 and procaspase-9 in the 2C mutant-transfected cells. To further elucidate the mechanism of the 2C-induced apoptosis, the 2C-transfected CEB and Cos-7 cells were fractionated into mitochondria and cytosol and subjected for Western blotting, located cytochrome c in the mitochondria as well as the cytosol fractions, while it was only sequestered in the mitochondrial fraction in the mutant 2C-transfected cells. The protein 2C was located in the mitochondria and cytosol of the transfected/infected CEB and transfected Cos-7 cells, but the mutant lost its ability to localize to the mitochondria. Altogether, the results demonstrate that the protein 2C localized to the mitochondria of the transfected cells triggered the efflux of cytochrome c into the cytosol in turn activating the upstream caspase-9 and then the downstream caspase-3, thus leading to apoptosis in the cells.     

Hydrogen peroxide induces apoptosis through the mitochondrial pathway in rat Schwann cells

Oxidative stress is one of the several mechanisms that induces apoptosis in cells. It has been shown that hydrogen peroxide (H₂O₂) induces apoptosis in several kinds of cells; however, the role of H₂O₂ in the apoptosis of Schwann cells (SCs) is currently unclear. The objective of this study was to determine whether H₂O₂ is capable of inducing apoptosis in SCs and whether or not such an effect is associated with the activation of mitochondrial pathway. We demonstrated that H₂O₂ induces apoptosis in SCs, and is associated with increased release of cytochrome c from mitochondria and the activation of caspase-3 and -9 by up-regulation of Bax and down-regulation of Bcl-2. These results suggest a potential role for H₂O₂ in SC injury by triggering apoptosis via the mitochondrial pathway under oxidative stress.     

IL-1beta acts in synergy with endogenous IL-1beta in A375-S2 human melanoma cell apoptosis through mitochondrial pathway

Interleukin-1beta (IL-1beta) is a pivotal proinflammatory cytokine. To investigate the mechanism of IL-1beta-induced cell death in human malignant melanoma A375-S2 cells, MTT assay, photomicroscopical observation, DNA agarose gel electrophoresis, radioimmunoassay and Western blot analysis were carried out. IL-1beta did not only induce nuclear condensation and DNA fragmentation, but also increased degradation of two substrates of caspase-3, poly ADP-ribose polymerase (PARP) and inhibitor of caspase-activated DNase (ICAD). Simultaneously, release of precursor of IL-1beta (pro-IL-1beta) and endogenous IL-1beta production were involved in the apoptotic process. IL-1beta enhanced the ratio of Bax/Bcl-2 and Bax/Bcl-xL expression and up-regulated apoptosis inducing factor (AIF) expression, which required the activation of downstream caspases. These results suggest that IL-1beta induces endogenous IL-1beta production, enhances cleavage of caspase downstream substrates and promotes mitochondria mediated apoptosis in A375-S2 cells.     

丹参酮ⅡA通过JNK通路诱导人骨肉瘤HOS细胞凋亡

目的:探究丹参酮ⅡA对人骨肉瘤HOS细胞增殖和凋亡的影响及机制。方法:采用CCK-8实验考察丹参酮ⅡA对HOS细胞活力的影响,并确定给药剂量。集落形成实验与细胞迁移实验研究丹参酮ⅡA对肿瘤细胞增殖与迁移能力的影响。Hoechst 33258染色、透射电镜与流式细胞技术检测丹参酮ⅡA对肿瘤细胞凋亡的影响。Western blot进一步检测细胞凋亡与JNK通路相关蛋白的变化;并通过JNK抑制剂验证肿瘤细胞中上述通路与凋亡的关系。结果:一定剂量的丹参酮ⅡA能抑制HOS细胞的增殖与迁移能力,且效应呈浓度依赖与作用时间依赖性,并能诱导凋亡发生。Western blot进一步表明,随着药物浓度增加,cleaved caspase-3与Bax蛋白水平上升,Bcl-2蛋白表达下降,JNK通路相关蛋白表达上升,这些变化可被JNK抑制剂SP600125缓解。CCK-8实验结果显示,抑制JNK通路可减少药物导致的细胞活力抑制。结论:丹参酮ⅡA可通过JNK通路诱导人骨肉瘤HOS细胞发生凋亡,具有显著抑制肿瘤细胞增殖的作用。     

Effects of bacterial N-acyl homoserine lactones on human Jurkat T lymphocytes-OdDHL induces apoptosis via the mitochondrial pathway

Diverse Gram-negative bacteria communicate with each other by using diffusible N-acyl-homoserine lactone (AHL) signaling molecules to coordinate gene expression with cell population density. This mechanism termed ‘quorum sensing’ is involved in the regulation of physiological functions as well as multiple virulence determinants. It becomes more and more evident, that bacteria communicate not only with each other but also with their host. Up to now, little is known about this interkingdom communication. The AHL quorum sensing molecule N-3-(oxododecanoyl)-l-homoserine lactone (OdDHL) from Pseudomonas aeruginosa has been shown to influence the immune system of the host. The role and potential influence of other AHL molecules from other bacteria have so far not been determined. In this paper, we investigated the role of 7 different AHLs on apoptosis of human Jurkat T lymphocytes. We found, that among all homoserine lactones tested, only OdDHL rapidly induced apoptosis which was accompanied by the breakdown of the mitochondrial transmembrane potential (ΔΨ_m). Since overexpression of anti-apoptotic Bcl-2 completely abrogated the apoptotic effect, we presume that OdDHL induces apoptosis by activation of the intrinsic mitochondrial apoptosis pathway. The reason that bacteria induce apoptosis is largely unknown. We suspect that through apoptosis an anti-inflammatory response is triggered.