内质网应激与细胞凋亡

内质网(ER)是细胞内重要的细胞器,参与多种细胞进程,这些进程对于维持细胞存活和发挥细胞的正常生理功能具有重要的作用。然而在多种生理病理条件下,内质网稳态会发生变化而失衡,从而诱发内质网应激(ERS),此时机体通过激活未折叠蛋白反应(UPR)来恢复内质网的正常功能。当持续的ERS状态无法恢复时,ERS就会触发细胞凋亡程序,通过不同的凋亡途径引起细胞凋亡。     

脑缺血/再灌注损伤后内质网应激对神经元转归的影响

内质网本身在细胞生理及组成结构方面起至关重要的作用,当内质网出现功能障碍时,未折叠蛋白反应(UPR)试图增加未折叠蛋白的折叠能力而减轻内质网应激(ERS)的压力。当无法缓解时,细胞便通过内质网凋亡途径走向凋亡。而脑缺血/再灌注损伤(CIRI)会导致内环境紊乱,引起ERS反应,进而通过ERS途径引起神经元凋亡。现对内质网的结构、功能、ERS机制、ERS后产生的UPR机制以及凋亡机制予以阐述,并提出了对CIRI后ERS状态下神经元转归的应对措施。     

胰岛素生长因子与内质网应激关系的研究进展

内质网应激(ERS)是脑缺血/再灌注、病毒性肝炎、乳腺癌等众多疾病发生的重要病理过程,同时是一个多因素、多步骤协同的复杂病理生理过程。近来的研究报道,胰岛素生长因子(IGFs)能通过ERS的多条路径的联系恢复内质网稳态,促进细胞存活,但在内质网持续应激时则启动内质网相关凋亡途径,诱导细胞凋亡。该文以IGFs为切入点,探讨IGFs和ERS的相互关系,并对之进行综述。     

阿托伐他汀对同型半胱氨酸诱导内皮细胞内质网应激的抑制作用

目的： 观察阿托伐他汀对同型半胱氨酸（Hcy）诱导的人脐静脉内皮细胞内质网应激（endoplasmic reticulum stress,ERS）以及凋亡的影响。方法: 不同浓度的Hcy或联合阿托伐他汀处理人脐静脉内皮细胞后,流式细胞术检测细胞凋亡率,实时定量PCR和蛋白质印迹法测定ERS相关分子BiP、CHOP及p-eIF2α、p- PERK的表达变化。结果: Hcy呈浓度依赖性地诱导内皮细胞ERS相关分子BiP、CHOP及p-eIF2α、p-PERK的表达,阿托伐他汀可明显抑制Hcy诱导的内皮细胞ERS相关分子的表达,减少内皮细胞凋亡。结论： 阿托伐他汀可通过下调ERS相关信号通路,抑制Hcy诱导的人脐静脉内皮细胞凋亡。     

心力衰竭中内质网应激相关诱导因子的研究进展

内质网合成及加工蛋白的功能异常可引起未折叠蛋白的聚集,从而引起内质网应激(ERS)和未折叠蛋白反应。适度的ERS使心肌细胞发生代偿性肥大,但过强和持续的ERS可使心肌细胞由代偿转向凋亡,从而致心力衰竭。该文综述了各种ERS诱导因子在心力衰竭发生、发展中的作用,阐明ERS在心力衰竭病理形成过程中发挥着重要的作用,也为心力衰竭的治疗开启了新思路。     

内质网应激在胰岛损伤中作用的研究进展

内质网应激(endoplasmic reticulum stress,ERS)是由未折叠与错误折叠蛋白质在内质网腔中积聚引起的一种特殊的细胞内应激。细胞在氧化应激、炎症、钙离子紊乱等多种刺激因素下,内质网稳态被破坏,继而诱发ERS。适应性的ERS通过未折叠蛋白质反应以及保护性自噬恢复内质网稳态,发挥细胞保护作用;严重和持续的ERS将会诱导凋亡、焦亡、自噬等不同类型的细胞死亡。胰岛对氧化应激等介导的损伤非常敏感,不同程度的ERS可与氧化应激、炎症等途径协同作用调节胰岛功能。因此,有效调控ERS可能为糖尿病及其并发症的防治提供新的思路。     

内质网应激与吸入麻醉药引起的认知功能障碍的研究进展

内质网(ER)广泛存在于真核细胞中,其内环境的稳定是实现ER功能的基本条件,ER内未折叠或错折叠蛋白积聚和钙平衡失调均可导致内质网应激(ERS),而长期、严重的ERS则会诱导细胞凋亡及死亡。ERS在神经退行性疾病病理机制中的作用已成为近年来的热点,国内外关于ERS与临床疾病的相关     

小鼠卵巢内质网应激模型的建立及诱导凋亡的研究

目的通过观察内质网应激(ERS)诱导剂衣霉素(TM)及ERS抑制剂牛磺熊去氧胆酸钠(TUDCA)对ERS相关标识性蛋白表达水平的影响,建立小鼠卵巢ERS模型。方法取4周龄昆明白小鼠卵巢,进行半卵巢培养。实验分组:新鲜对照组,不同浓度TM诱导组(1、5、10、20、30μg·mL-1),TUDCA+TM组、不同浓度TUDCA(1、2、5、10mM)+TM组。通过免疫组织化学技术观测培养1h卵巢内内质网应激伴侣蛋白GRP78、培养3h后ERS凋亡相关蛋白CHOP的表达水平;TUNEL法检测培养3、6、12、24、36、48h后卵巢细胞凋亡情况。结果与新鲜组相比,TM诱导1h后卵巢发生内质网应激反应,TM浓度为5-10μg·mL-1时GRP78表达水平达到最高(P<0.05),之后随TM浓度增加缓慢递减;TM诱导3h后卵巢内ERS凋亡相关蛋白CHOP表达水平在TM 10μg·mL-1处达到最高(P<0.05),凋亡细胞数随着培养时间的延长增加。TUDCA抑制ERS实验显示,随着TUDCA浓度的增大,10μg·mL-1TM诱导的GRP78蛋白表达呈递减趋势,其中TUDCA 10mM组GRP78表达水平基本恢复到新鲜组水平。结论 TM可诱导小鼠卵巢ERS,5μg·mL-1为诱导ERS保护作用浓度,而10μg·mL-1以上则产生ERS途径介导的凋亡。TUDCA可抑制TM诱导的卵巢ERS。     

中医药基于内质网应激防治糖尿病肾病研究进展

糖尿病肾病（diabetic nephropathy,DN）是糖尿病最常见的微血管并发症,发病率逐年增高,是导致终末期肾脏病的主要原因。内质网稳态对维持机体正常功能具有重要意义。研究表明,内质网稳态失衡可诱发内质网应激（endoplasmic reticulum stress,ERS）,激活未折叠蛋白反应（unfolded protein response,UPR）介导的3条细胞适应性应答通路以恢复内质网稳态,适度的ERS对细胞具有保护作用,而ERS持续存在超过内质网自身调节平衡时会激活细胞凋亡信号通路,引起肾脏足细胞损伤、肾小管功能障碍,加速糖尿病肾病的进展。因此,ERS信号通路及其关键因子已成为防治DN的重要靶点。中医药可通过多成分、多靶点协同作用延缓糖尿病肾病的进展。文章基于内质网应激途径对中医药防治糖尿病肾病的现状进行综述,总结其主要的作用机制及相关靶点、调控通路,以期为糖尿病肾病的治疗研究提供参考。     

内质网应激在对比剂诱导肾小管上皮细胞凋亡中的作用

目的:探讨内质网应激(ERS)在对比剂诱导的肾小管上皮细胞凋亡中的作用及N-乙酰半胱氨酸(NAC)的保护作用。方法:将不同浓度(50,100,150mgI/ml)碘普罗胺分别加入体外培养的大鼠肾小管上皮细胞(NRK-52E)中孵育1h;10mmol/L NAC预处理细胞1h后,加入100mgI/ml碘普罗胺共孵育1h。Hoechst-33342染色法检测肾小管上皮细胞凋亡率;荧光探针检测细胞内活性氧(ROS)的产生;Western印迹法检测细胞内内质网功能调节蛋白GRP78、内质网源性转录因子CHOP表达水平。结果:对比剂呈浓度依赖性诱导NRK-52E细胞凋亡,且呈浓度依赖性诱导NRK-52E细胞内ROS生成及GRP78、CHOP蛋白表达上调(P<0.05);经NAC预处理后,细胞内ROS生成及细胞凋亡率明显下降(P<0.05),且GRP78、CHOP蛋白表达下调(P<0.05)。结论:碘普罗胺能诱导肾小管上皮细胞凋亡,其机制可能与细胞内ROS生成增加,诱发ERS,上调GRP78、CHOP蛋白表达有关。抗氧化剂NAC通过降低NRK-52E细胞内ROS介导的ERS,减少肾小管上皮细胞凋亡。     

Endoplasmic Reticulum Stress Induced by Tunicamycin and Antagonistic Effect of Tiantai No.1(天泰1号) on Mesenchymal Stem Cells

<正>Objective:Changes of the internal and external cellular environments can induce calcium homeostasis disorder and unfolded protein aggregation in the endoplasmic reticulum(ER).This ER function disorder is called endoplasmic reticulum stress(ERS).Severe long-term ERS can trigger the ER apoptosis signaling pathway,resulting in cell apoptosis and organism injury.Recent researches revealed that ERS-induced cell death was involved in the neurocyte retrogradation in the progress of neuron degenerative diseases,such as Alzheimer's disease(AD),Parkinson's disease and so on.Therefore,the protection effect of the traditional Chinese drug——Tiantai No.1(天泰1号) on the ERS injury of AD was investigated at the molecular gene level in this study with a view to explore the gene pharmacodynamic actions and mechanisms of this drug.Methods: Primarily cultured marrow mesenchymal stem cells(MSCs) of rats were treated by tunicamycin(TM) in order to induce ERS.RT-PCR,fluorescence immunocytochemistry and Western blot techniques were used to determine the mRNA and protein expression levels of the protective stress protein-ER molecular chaperones GRP78 and GRP94(which would assist cells to resist cellular stress injury),and to determine the mRNA and protein expression levels of apoptosis promoting molecule Caspase-12 on the membrane of the ER,respectively. Results:Protein expression levels of GRP78 and GRP94 were significantly increased in the TM-induced MSCs, and the mRNA level of Caspase-12 was also remarkably increased in the TM-induced MSCs(P0.05).All these proved that the ERS model was successfully established by TM in MSC.Meanwhile,the mRNA and protein levels of GRP78 and GRP94 were all significantly increased compared with the model group(P0.05 or P0.01) after MSCs were treated with Tiantai No.1 while the mRNA and protein expression levels of Caspase-12 were significantly decreased compared with the model group(P0.05 or P0.01).This effect showed a dose dependent manner.Conclusion:Tiantai No.1 might attenuate the cell apoptosis induced by ERS injury,and thus protect the neurons against AD.     

Role of PERK/eIF2α/CHOP Endoplasmic Reticulum Stress Pathway in Oxidized Low-density Lipoprotein Mediated Induction of Endothelial Apoptosis

Objective PERK/eI F2α/CHOP is a major signaling pathway mediating endoplasmic reticulum(ER) stress related with atherosclerosis.Oxidized LDL(ox-LDL) also induces endothelial apoptosis and plays a vital role in the initiation and progression of atherosclerosis.The present study was conducted to explore the regulatory effect of ox-LDL on PERK/e IF2α/CHOP signaling pathway in vascular endothelial cells.Methods The effects of ox-LDL on PERK and p-e IF2α protein expression of primary human umbilical vein endothelial cells(HUVECs) were investigated by Western blot analysis.PERK gene silencing and selective eI F2α phosphatase inhibitor,salubrinal were used to inhibit the process of ox-LDL induced endothelial cell apoptosis,caspase-3 activity,and CHOP mR NA level.Results Ox-LDL treatment significantly increased the expression of PERK,PERK-mediated inactivation of e IF2α phosphorylation,and the expression of CHOP,as well as the caspase-3 activity and apoptosis.The effects of ox-LDL were markedly decreased by knocking down PERK with stable transduction of lentiviral sh RNA or by selective eI F2α phosphatase inhibitor,salubrinal.Conclusion This study provides the first evidence that ox-LDL induces apoptosis in vascular endothelial cells mediated largely via the PERK/eI F2α/CHOP ER-stress pathway.It adds new insights into the molecular mechanisms underlying the pathogenesis and progression of atherosclerosis.     

内质网应激与支气管哮喘

内质网应激是细胞对于内源性应激的一种适应性反应,由未折叠蛋白所诱导,其机制被称为未折叠蛋白反应(UPR)。哺乳动物UPR包含3个经典的分支通路,分别以胰腺内质网激酶(PERK)、需肌醇跨膜激酶/核酸内切酶1(IRE1)和活化转录因子6(ATF6)作为近端效应物,能够促进蛋白质折叠和转运,停止蛋白质的翻译合成,降解清除错误蛋白,并可启动凋亡程序诱导不能修复错误蛋白的细胞凋亡,从而维持内环境与组织细胞功能的稳态。支气管上皮内含多种蛋白质合成分泌旺盛的细胞类型,本身易出现内质网应激;支气管哮喘时,气道炎症状态等因素的存在被认为可以诱发UPR,并与气道炎症反应互为因果,交互作用。目前的研究认为,在支气管哮喘发病中,气道上皮细胞的钙稳态失调、透明质酸与黏蛋白的异常分泌、细胞因子对炎细胞的募集作用以及免疫调节状态的异常等环节与内质网应激存在密切的关系。本文即对内质网应激与哮喘的相关研究作一综述。     

高糖诱导内质网应激对血管内皮细胞炎症反应的作用

【目的】 探讨高糖通过诱导内质网应激(ERS)引起人脐静脉内皮细胞(EAhy926)炎症反应的作用机制?【方法】人脐静脉内皮细胞给予正常浓度糖(5.5 mmol/L)或高浓度糖(25 mmol/L)干预0?2?4?8?12 h,或ERS诱导剂毒胡萝卜素(TG)0.5 μmol/L干预24 h?Western blot检测下列蛋白表达水平:细胞间黏附因子-1(ICAM-1)?肿瘤坏死因子-α(TNFα)等炎症因子;葡萄糖调节蛋白78(GRP78)?磷酸化真核细胞翻译起始因子2α(p-eIF2α)?活化转录因子4(ATF4)等ERS标志蛋白;以及磷酸化信息传递与转录活化因子3(p-STAT3)和总信息传递与转录活化因子3(t-STAT3)?【结果】炎症因子ICAM-1?TNFα, ERS标志蛋白GRP78?p-eIF2α?ATF4 以及p-STAT3等蛋白的表达均随高糖干预时间的延长而逐步增加,除GRP78在干预8 h后达到峰值(P < 0.05),其余蛋白均在干预12 h后达到峰值(P < 0.05)?给予ERS诱导剂TG干预细胞24 h, GRP78?p-eIF2α?ICAM-1?TNFα的表达水平均明显增加,分别是对照组的5.55倍?1.63倍?1.76倍?2.07倍(P < 0.05);此外,p-STAT3的表达水平也有所增加,为对照组的2.15倍(P < 0.05),但t-STAT3水平无明显变化(P > 0.05)?【结论】 高糖可诱导内皮细胞发生ERS与炎症反应,ERS诱导剂可诱发细胞的炎症反应,磷酸化的STAT3信号途径可能起到连接ERS与炎症反应的重要作用?     

Role of Endoplasmic Reticulum Stress in Silica-induced Apoptosis in RAW264.7 Cells

Objective We investigated the role of endoplasmic reticulum stress(ERS) in silica-induced apoptosis in alveolar macrophages in vitro. Methods RAW264.7 cells were incubated with 200 μg/mL silica for different time periods. Cell viability was assayed by the MTT assay. Cell apoptosis was evaluated by DAPI staining, flow cytometry analysis, and Western blot analysis of caspase-3. Morphological changes in the endoplasmic reticulum were observed by transmission electron microscopy. The expression of ERS markers binding protein(BiP) and CCAAT-enhancer-binding protein homologous protein(CHOP) was examined by Western blotting and real-time PCR. As an inhibitor of ERS, 4-phenylbutyric acid(4-PBA) was used in the experiments. Results Silica exposure induced nuclear condensation and caspase-3 expression in RAW264.7 cells. The number of apoptotic cells increased after silica exposure in a time-dependent manner. Silica treatment induced expansion of the endoplasmic reticulum. In addition, the expression of BiP and CHOP increased in silica-stimulated cells. Furthermore, 4-PBA treatment inhibited silica-induced endoplasmic reticulum expansion and the expression of Bi P and CHOP. Moreover, 4-PBA treatment attenuated nuclear condensation, reduced apoptotic cells, and downregulated caspase-3 expression in silica-stimulated cells. Conclusion Silica-induced ERS is involved in the apoptosis of alveolar macrophages.     

Endoplasmic reticulum stress-induced apoptosis in the development of reproduction

Proteins synthesized in the endoplasmic reticulum(ER) are properly folded with the assistance of ER chaperones. Accumulation of misfolded protein in the ER triggers an adaptive ER stress(ERS) response termed the unfolded protein response. Recent interest has focused on the possibility that the accumulation of misfolded proteins can also contribute to reproductive response, including preimplantation embryos, testicular germ cell, placenta, and unexplained intrauterine growth restriction(IUGR). The major ERS pathway constituents are present at all stages of preimplantation development and that the activation of ERS pathways can be induced at the 8-cell, morula and blastocyst stage. This review mainly introduced the research progress of ERS induced apoptosis of reproductive cells, providing a new direction for the research of reproductive disease therapy.     

TTF1-NP诱导人肝癌HepG-2细胞凋亡的内质网应激作用

目的:通过不同剂量长白山珍珠梅黄酮纳米粒(TTF1-NP)分别诱导不同种人肝癌细胞和人正常肝细胞凋亡,探讨TTF1-NP对不同细胞的作用及涉及的内质网应激作用机制。方法:以体外培养的不同种人肝癌细胞(Hep3B、HepG-2和PLC/PRF/5)和人肝细胞(Chang Liver)为模型,实验分为阴性对照组、阳性对照组(5-Fu)和TTF1-NP实验组,TTF1-NP处理浓度分别为50、100和200 μmol·L^-1。采用MTT法检测TTF1-NP对不同种细胞的生长抑制作用,选择最佳抑制效果细胞(HepG-2)为主要研究细胞株;利用流式细胞术检测细胞凋亡率;应用Western blotting和免疫细胞化学染色技术检测内质网应激关键蛋白表达情况;通过内质网应激抑制剂4-苯丁酸(4-PBA)作用,再次检测相关蛋白的表达情况。 结果:与阴性对照组比较,不同浓度的TTF1-NP组4种细胞生长抑制率升高(P<0.05或P<0.01),且呈一定的浓度和时间依赖关系。细胞凋亡检测,与阴性对照组比较,TTF1-NP实验组随药物浓度增加其细胞凋亡率逐渐上升(P<0.05或P<0.01);内质网应激关键蛋白GRP78和caspase-4 随着TTF1-NP浓度增加,表达水平逐渐升高(P<0.05或P<0.01)。4-PBA有效抑制GRP78和caspase-4表达,与TTF1-NP组比较差异有统计学意义(P<0.05或P<0.01)。 结论: TTF1-NP可诱导人肝癌 HepG-2 细胞凋亡;内质网应激途径是 TTF1-NP 诱导人肝癌 HepG-2 细胞凋亡的主要作用机制之一。