腺苷通过内质网应激途径诱导HepG2细胞凋亡的研究

目的探讨腺苷(ADO)诱导人类肝癌HepG2细胞凋亡的分子机制。方法将不同浓度的ADO(0～6mmol.L-1)作用于HepG2细胞36h,采用MTT法测定ADO抑制细胞增殖效应。将HepG2细胞暴露于不同浓度的ADO(0～4mmol.L-1)作用36h或2mmol.L-1ADO作用不同时间(0～48h),观察细胞核的形态学改变;观察2mmol.L-1ADO处理12h和24h后细胞周期的变化;观察2mmol.L-1ADO作用前后Caspase-3和CHOP的亚细胞定位的变化;用West-ernblot检测不同浓度ADO作用后HepG2细胞Caspase-3,Caspase-4,CHOP,JNK的蛋白表达变化。结果ADO对HepG2细胞生长有明显的抑制作用,不同浓度ADO(0.5,1,2,4,6mmol.L-1)处理HepG2细胞36h后,与对照组相比,相对细胞存活数分别下降13.48%±0.12%,27.92%±0.25%,35.21%±0.42%,51.46%±0.24%,71.42%±0.58%,呈现剂量依赖性;不同浓度ADO作用36h或2mmol.L-1ADO作用不同时间(0～48h)后,随着ADO浓度的增加或作用时间的延长,HepG2细胞核发生典型核固缩、核碎裂、核分解等凋亡形态学改变;2mmol.L-1ADO作用12h或24h后,细胞周期分析出现亚二倍体峰,提示细胞发生凋亡,对照组、ADD处理12h及24h组细胞凋亡率分别为1.55%±0.12%、10.96%±0.07%和21.04%±0.26%;2mmol.L-1ADO诱导Caspase-3和CHOP表达增加,并从胞质易位进入胞核内;随着ADO浓度的升高,Caspase-4,Caspase-3,CHOP的表达均升高,均呈现剂量依赖性;而JNK的表达则没有变化。结论腺苷诱导HepG2细胞凋亡与内质网应激途径有关。     

细胞凋亡与内质网应激机制

内质网应激介导的细胞凋亡是一种新的凋亡途径,不同于死亡受体信号途径和线粒体途径.短期的内质网应激有保护细胞的作用,但是长期的内质网应激将激活一些凋亡信号分子如CHOP、JNK、Caspase,而诱导细胞凋亡.     

辛伐他汀通过内质网应激途径诱导K562细胞凋亡

探讨内质网应激在辛伐他汀诱导K562细胞凋亡中的作用。采用荧光显微镜观察凋亡细胞的形态变化，AnnexinV-FITC/PI双染法检测细胞凋亡率，激光扫描共聚焦显微镜检测细胞内Ｃa²⁺浓度，RT-PCR检测葡萄糖调节蛋白78(glucose regulated protein 78，GRP78)、钙蛋白酶(calpain)基因mRNA表达水平，Western blotting检测GRP78、 calpain、 caspase-3， -6， -7， -9， -12蛋白水平。结果显示，10、 20、 30 μmol·L^-1辛伐他汀(simvastatin，Sim)作用K562细胞72 h后，细胞出现典型的凋亡形态，凋亡率分别为12.41%、 19.08%和23.41%；细胞内Ca²⁺浓度增加，荧光强度分别为43、54和64；GRP78、calpain基因mRNA表达上调；calpain、 caspase-3， -6， -7， -9， -12蛋白剪切活化、GRP78蛋白表达增强。以上结果表明，内质网作为细胞凋亡的重要途径参与了辛伐他汀诱导K562细胞的凋亡。辛伐他汀将可能被用于临床治疗白血病。     

戊地昔布诱导人食管癌Eca109细胞凋亡的机制研究

目的探讨特异选择性环氧化酶-2(COX-2)抑制剂戊地昔布诱导人食管癌Eca109细胞凋亡及其作用机制。方法流式细胞术检测细胞凋亡和细胞周期分布;电子显微镜进一步检测细胞凋亡;采用乳酸脱氢酶(LDH)试剂盒测定Eca109细胞的LDH含量;流式细胞术检测p-p38MAPK及凋亡基因Fas和FasL蛋白的表达。结果戊地昔布(25~400μmol.L-1)可诱导人食管癌Eca109细胞发生凋亡,,凋亡率由(2.95±0.83)%增加到(48.46±0.73)%;50~400μmol.L-1时增殖指数和S期的细胞比例则明显降低,G0/G1期的细胞比例增加;同时,流式细胞术显示,25μmol.L-1戊地昔布即可上调人食管癌Eca109细胞p-p38MAPK蛋白的表达,并随剂量的增加而增强;50~400μmol.L-1的戊地昔布可上调Eca109细胞Fas及FasL的表达。结论戊地昔布可诱导人Eca109细胞凋亡,其诱导凋亡的机制可能部分是通过激活p-p38MAPK/Fas、FasL途径实现的。     

腺苷体外对人肝癌HepG2细胞凋亡的诱导作用及其作用机制

目的研究腺苷及其代谢途径对人肝癌HepG2细胞凋亡的诱导作用及其机制。方法将腺苷2.0mmol.L-1作用于HepG2细胞24和48h,采用流式细胞术(FCM)测定细胞周期及凋亡率;观察腺苷膜转运体抑制剂双嘧达莫、腺苷脱氨酶抑制剂红-9-(2-羟基-3-壬烷基)腺嘌呤(EHNA)和腺苷激酶抑制剂5′-氨基5′-脱氧腺苷(AMDA)对腺苷抑制细胞存活的影响,应用MTT法测定细胞存活率;应用Western蛋白印迹法检测P53和Bcl-2蛋白的表达。结果腺苷与HepG2细胞作用24和48h,HepG2细胞出现特征性的亚二倍体凋亡峰,细胞凋亡百分率分别由对照组的(1.2±0.4)%和(4.1±1.6)%增加到(24.3±4.8)%和(38.6±7.4)%,细胞周期阻滞于G0/G1期。腺苷与HepG2细胞作用24h明显抑制细胞存活,P53表达明显增强,Bcl-2表达降低。预先分别给予双嘧达莫,AMDA和AMDA+双嘧达莫处理后,各处理组HepG2细胞存活率较腺苷组升高,细胞凋亡百分率和P53表达降低,Bcl-2表达无明显变化;EHNA预处理组细胞存活率、细胞凋亡百分率、P53和Bcl-2表达与腺苷组比较均无明显变化。结论腺苷可诱导HepG2细胞凋亡,腺苷在胞内可能通过腺苷激酶而不是通过转氨酶的代谢途径参与诱导细胞凋亡的过程。腺苷对HepG2细胞凋亡的诱导作用还可能与其增加P53蛋白表达有关。     

辣椒素经内质网应激反应途径诱导K562/ADM耐药细胞凋亡

目的：研究辣椒素（capsaicin）是否经内质网途径诱导耐药性白血病K562/ADM细胞凋亡。方法：以耐药性白血病K562/ADM细胞为靶细胞,采用MTT比色法测定细胞增殖活性;细胞形态学和AnnexinV/PI双染色法检测细胞凋亡,电镜观察凋亡细胞内质网形态结构变化;实时定量RT-PCR检测GRP78mRNA的表达;Western blot法检测GRP78蛋白的表达。结果：不同浓度的辣椒素显著抑制K562/ADM细胞的增殖活性,20、50μmol/L辣椒素诱导后K562/ADM细胞出现典型的凋亡形态学改变,细胞凋亡率明显增高,分别为39.67%和41.78%。辣椒素诱导凋亡过程中,K562/ADM细胞出现内质网明显扩张和脱颗粒现象,GRP78mRNA的表达增高,GRP78蛋白的表达量分别增高1.5和2.2倍,随时间延长有所降低。结论：辣椒素可能通过内质网应激反应性途径诱导K562/ADM细胞发生凋亡。     

丹皮酚体内外抗人食管癌Eca-109细胞增殖及诱导凋亡的作用

目的研究丹皮酚(paeonol,Pae)在体内外对人食管癌细胞Eca-109的抑瘤作用及其对细胞凋亡的影响。方法采用噻唑蓝(MTT)体外试验法和灌胃给药体内抗肿瘤试验。光镜及电镜观察各组的肿瘤组织的形态学变化。应用末端脱氧核苷酸转移酶介导的缺口末端标记(TUNEL)法测定细胞凋亡指数。结果丹皮酚在体外对Eca-109细胞有明显的细胞毒作用,半数抑制浓度(IC50)为0.342mmol·L-1;体内灌胃给予丹皮酚25、50、100和200mg·kg-1对裸鼠移植人食管癌Eca-109的抑制率分别为10.67%、23.54%、27.91%和34.46%;顺铂5mg·kg-1组抑瘤率为58.71%;丹皮酚在100mg·kg-1剂量下与顺铂5mg·kg-1联合用药抑制率为77.91%。光镜下用药组可见较多凋亡的肿瘤细胞。透射电镜下可见肿瘤细胞核染色质浓缩边聚、胞质浓缩、核碎裂以及凋亡小体形成等典型的凋亡表现。用药组凋亡指数较对照组明显增加。结论丹皮酚在体内外具有抑制人食管癌Eca-109细胞增殖及诱导其凋亡作用。     

姜黄素诱导食管癌Eca-109细胞凋亡机制的研究

目的观察姜黄素诱导食管癌Eca-109细胞凋亡,并初步探讨其作用机制。方法通过CCK-8法检测不同浓度、不同时间点作用于Eca-109细胞的增殖抑制率。应用Caspase 3活性检测试剂盒检测胱天蛋白酶3活性。流式细胞技术检测细胞早期凋亡。免疫细胞化学法检测凋亡相关基因Bax和Bcl-2的表达情况。结果随浓度增加时间延长各组生长抑制率有明显增高,且呈剂量浓度依赖性,组间差异有显著性(P<0.01)。胱天蛋白酶3活性检测发现:姜黄素20μmol·L-1,40μmol·L-1作用24 h后OD值与对照组比较,差异具有统计学意义(P<0.05)。流式细胞术检测到姜黄素作用后,细胞凋亡率明显升高。免疫细胞化学染色显示,随着姜黄素浓度的增高和作用时间的增长,Bcl-2蛋白表达减弱,Bax蛋白表达增强。结论姜黄素可能是通过诱导胱天蛋白酶3表达活性增高,上调促凋亡基因Bax及下调抗凋亡基因Bcl-2的表达,诱导Eca-109发生凋亡。     

细胞外ATP和腺苷及其受体与细胞凋亡

细胞外ATP(ATPo)和腺苷是细胞内外重要的信号分子,对包括肿瘤细胞在内的多种组织细胞具有细胞毒和诱导凋亡的作用。腺苷及其受体诱导细胞凋亡的机制主要涉及腺苷酸环化酶(AC)、cAMP、Ca2+等。ATP的诱导细胞凋亡作用与多个嘌呤受体有关,包括P2X1、P2X2、P2X7、P2Y1、P2Y2等,进一步的作用机制可能涉及FasL/FasR死亡受体、T细胞受体(TCR)、bcl-2和bax的基因调控等。     

Cantharidin-induced LO2 cell autophagy and apoptosis via endoplasmic reticulum stress pathway in vitro

Cantharidin (CTD), an important active compound derived from the traditional Chinese medicine Mylabris (also called Banmao), has been used in the treatment of diseases such as tumors and dermatosis. However, Mylabris has been shown to induce hepatotoxicity in clinical practice and animal experiments, limiting its use. Further, a detailed mechanism underlying CTD-induced hepatotoxicity has not been determined. In the present study, we aimed to explore the effect of endoplasmic reticulum stress (ERS), autophagy, and apoptosis on CTD-induced hepatotoxicity. We found that CTD could inhibit the proliferation of LO2 cells; increase alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, and malondialdehyde levels; and reduce glutathione peroxidase and superoxide dismutase activities. Western blotting showed that low concentrations of CTD induced the expressions of ERS-related proteins [GRP78, ATF4, PERK, p-PERK, XBP1–1 s, and CHOP], but high concentrations of CTD inhibited their expressions. Furthermore, high concentrations of CTD activated autophagy (LC3, Beclin-1, Atg3, Atg4A, Atg4B, and Atg7), induced the expressions of apoptotic proteins (Bax/Bcl-2 and caspase-3), and increased LO2 toxicity. Taken together, these results indicated that CTD can induce LO2 cytotoxicity by inhibiting ERS and inducing autophagy and apoptosis, which provides a scientific basis for CTD-induced hepatotoxicity.     

Nickel oxide nanoparticles induce hepatocyte apoptosis via activating endoplasmic reticulum stress pathways in rats

Nickel oxide nanoparticles (nano NiO) could induce hepatocyte apoptosis, while its potential mechanisms are unclear. This study aimed to explore the role of endoplasmic reticulum (ER) stress pathways in hepatocyte apoptosis induced by nano NiO. Male Wistar rats were administrated with nano NiO (0.015, 0.06, and 0.24 mg/kg b.w.) and micro NiO (0.24 mg/kg b.w.) by intratracheal instillation twice a week for 6 weeks. We measured the hepatocyte apoptosis levels by TdT‐mediated dUTP nick‐end labeling (TUNEL) staining, ER stress related gene and protein expression levels in rat liver. The results showed that the TUNEL positive cells increased after exposure nano NiO, hinting hepatocyte apoptosis. The up‐regulated gene and protein levels of 78 kD glucose regulated protein and CCAAT/enhancer binding protein homologous protein suggested that nano NiO triggered ER stress. Nano NiO exposure contributed to the increased protein contents of inositol‐requiring enzyme 1 (IRE‐1)α, p‐IRE‐1α, X box protein‐1S, pancreatic ER kinase (PERK), p‐PERK, eukaryotic initiation factor‐2 alpha (eIF‐2α), p‐eIF‐2α, caspase‐12, ?9, and ?3, implicating that nano NiO can activate the pathways of ER stress‐mediated apoptosis. These findings indicate that the ER stress pathways may play an important role in hepatocyte apoptosis induced by nano NiO.     

Nickel sulfate induced apoptosis via activating ROS‐dependent mitochondria and endoplasmic reticulum stress pathways in rat Leydig cells

Nickel can induce apoptosis of testicular Leydig cells in mice, whereas the mechanisms remain unclear. In this study, we investigated the role of nickel‐induced reactive oxygen species (ROS) generation in mitochondria and endoplasmic reticulum stress (ERS) mediated apoptosis pathways in rat Leydig cells. Fluorescent DCF and Annexin‐V FITC/PI staining were performed to measure the production of ROS and apoptosis in Leydig cells. RT‐qPCR and Western blot were conducted to analyze the key genes and proteins involved in mitochondria and ERS apoptotic pathways. The results showed that nickel sulfate induced ROS generation, consequently resulted in nucleolus deformation and apoptosis in testicular Leydig cells, which were then attenuated by ROS inhibitors of N‐acetylcysteine (NAC) and 2,2,6,6‐tetramethyl‐1‐piperidinyloxy (TEMPO). Nickel sulfate‐triggered Leydig cells apoptosis via mitochondria and ERS pathways was characterized by the upregulated mRNA and proteins expression of Bak, cytochrome c, caspase 9, caspase 3, GRP78, GADD153, and caspase 12, which were inhibited by NAC and TEMPO respectively. The findings indicated that nickel‐induced ROS generation was involved in apoptosis via mitochondria and ERS pathways in rat Leydig cells.     

Atrazine induces endoplasmic reticulum stress‐mediated apoptosis of T lymphocytes via the caspase‐8‐dependent pathway

Atrazine (ATR) is one of the most commonly applied broad‐spectrum herbicides. Although ATR is well known to be a biologically hazardous molecule with potential toxicity in the immune system, the molecular mechanisms responsible for ATR‐induced immunotoxicity remain unclear. In this study, we found that the immunotoxic properties of ATR were mediated through the induction of apoptotic changes in T lymphocytes. Mice exposed to ATR for 4 weeks exhibited a significant decrease in the number of spleen CD3⁺ T lymphocytes, while CD19⁺ B lymphocytes and nonlymphoid cells were unaffected. ATR exposure also led to inhibition of cell growth and induction of apoptosis in human Jurkat T‐cells. Importantly, ATR triggered the activation of caspase‐3 and the cleavage of caspase‐8 and PARP, whereas it did not affect the release of cytochrome c from the mitochondria in Jurkat T‐cells. In addition, ATR activated the unfolded protein response signaling pathway, as indicated by eIF2α phosphorylation and CHOP induction. Our results demonstrate that ATR elicited an immunotoxic effect by inducing ER stress‐induced apoptosis in T‐cells, therefore providing evidence for the molecular mechanism by which ATR induces dysregulation of the immune system. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 998–1008, 2016.     

活性氧与内质网应激

内质网(endoplasmic reticulum,ER)是细胞加工蛋白质和贮存Ca2+的主要场所,对应激极为敏感,其功能紊乱时出现错误折叠与未折叠蛋白在腔内聚集以及Ca2+平衡紊乱的状态,称为内质网应激(endoplasmic reticulum stress,ERS)。活性氧(reactive oxygen species,ROS)作为第二信使,在细胞生物学功能的调节中起着重要作用。细胞内氧化还原状态的改变促进了ROS的产生和凋亡诱导因子的激活,致使细胞凋亡的同时又加剧了细胞内氧化还原状态的改变。研究发现细胞内氧化还原水平的改变在ERS介导的细胞凋亡过程中承担重要的角色,推测ROS可能是ERS介导的凋亡通路的上游信号分子,该文就ROS与ERS之间的关系作一综述。     

五味子乙素通过ROS介导内质网应激诱导人乳腺癌MDA-MB-231细胞凋亡的研究

目的 研究五味子乙素对人乳腺癌MDA-MB-231细胞凋亡的影响及其作用机制。方法 用细胞计数试剂(CCK-8)检测不同浓度五味子乙素对MDA-MB-231细胞存活率的影响;五味子乙素（10、20、40 μmol/L）作用 MDA-MB-231 细胞 24 h,分别用Annexin V-FITC/PI检测细胞凋亡情况;用DCFA-DA荧光探针检测细胞内活性氧（ROS）水平;用Western blot法检测细胞凋亡及内质网应激相关蛋白（Bcl-2、Bax、CHOP、GPR78、PERK、p-PERK、p-eIF2α、eIF2）的表达。结果 与空白组比较,随着五味子乙素浓度增大,细胞存活率明显降低,其IC₅₀为19.16 μmol/L;与对照组比较,五味子乙素（10、20、40 μmol/L）均能抑制细胞克隆形成(P<0.05),且呈剂量依赖;五味子乙素（10、20、40 μmol/L）均可诱导细胞凋亡（P<0.05）,使抗凋亡蛋白BCL-2的表达显著降低,促凋亡蛋白Bax的表达显著升高(P<0.05);五味子乙素（10、20、40 μmol/L）显著升高细胞内ROS水平(P<0.05),且呈剂量依赖;五味子乙素（10、20、40 μmol/L）能够激发内质网应激,使内质网应激相关蛋白CHOP、GPR78、p-eIF2α表达增多(P<0.05),且呈剂量依赖。结论 五味子乙素可能通过ROS介导内质网应激诱导MDA-MB-231细胞凋亡。     

内质网应激与心房颤动研究进展

心房颤动（AF）是临床常见的持续性心律失常,是卒中和心力衰竭的独立危险因素,然而其具体发病机制尚不完全清楚。内质网是调控蛋白质合成、细胞内Ca2+浓度、氧化应激水平、诱导细胞凋亡信号通路的主要细胞器,在心律失常发生和发展中的作用日益受到重视。多种致病因素可导致内质网应激（ERS）,其主要通过未折叠蛋白反应（UPR）来恢复内质网稳态。ERS的过度激活可导致心房肌细胞Ca2+超载、氧化应激失衡和细胞凋亡,在AF的发病机制中发挥重要作用。本文对ERS和AF研究进展进行了综述。     

Zonisamide,an antiepileptic drug,alleviates diabetic cardiomyopathy by inhibiting endoplasmic reticulum stress

Endoplasmic reticulum stress(ER stress)plays a key role in the development of cardiac hypertrophy and diabetic cardiomyopathy(DCM).Zonisamide(ZNS)was originally developed as an antiepileptic drug.Studies have shown that ZNS suppresses ER stress-induced neuronal cell damage in the experimental models of Parkinson’s disease.Herein,we investigated whether ZNS improved DCM by attenuating ER stress-induced apoptosis.C57BL/6J mice were fed with high-fat diet(HFD)and intraperitoneally injected with low-dose streptozotocin(STZ)to induce type 2 diabetes mellitus(T2DM),and then treated with ZNS(40 mg·kg^?1·d^?1,i.g.)for 16 weeks.We showed that ZNS administration slightly ameliorated the blood glucose levels,but significantly alleviated diabetes-induced cardiac dysfunction and hypertrophy.Furthermore,ZNS administration significantly inhibited the Bax and caspase-3 activity,upregulated Bcl-2 activity,and decreased the proportion of TUNEL-positive cells in heart tissues.We analyzed the hallmarks of ER stress in heart tissues,and revealed that ZNS administration significantly decreased the protein levels of GRP78,XBP-1s,ATF6,PERK,ATF4,and CHOP,and elevated Hrd1 protein.In high glucose(HG)-treated primary cardiomyocytes,application of ZNS(3μM)significantly alleviated HG-induced cardiomyocyte hypertrophy and apoptosis.ZNS application also suppressed activated ER stress in HG-treated cardiomyocytes.Moreover,preapplication of the specific ER stress inducer tunicamycin(10 ng/mL)eliminated the protective effects of ZNS against HG-induced cardiac hypertrophy and ER stress-mediated apoptosis.Our findings suggest that ZNS improves the cardiac diastolic function in diabetic mice and prevents T2DM-induced cardiac hypertrophy by attenuating ER stress-mediated apoptosis.