大鼠心肌细胞自噬H9C2/GFP-LC3稳定株的构建

目的:在大鼠心肌细胞H9C2(2-1)中建立表达绿色荧光蛋白融合微管相关蛋白3(GFP-LC3)的稳定细胞株,为研究心肌细胞自噬提供合适的细胞模型。方法:将表达增强的绿色荧光蛋白融合微管相关蛋白3的质粒(pEGFP-LC3)瞬时转染人胚肾-293T细胞(HEK-293T),通过荧光观察和免疫印迹对质粒进行鉴定;将质粒用同样的方法转染H9C2(2-1)细胞,G418筛选出稳定表达GFP-LC3的细胞株,通过观察荧光和免疫印迹检测GFP-LC3在H9C2中的表达;稳定细胞株在缺氧1 h复氧0、6、12、48 h和60 h的模型中,荧光显微镜观察GFP在细胞质中的表达,免疫印迹检测内源性LC3的变化;确定荧光及内源性LC3的高表达时相,用3-甲基腺嘌呤(3MA)进行自噬抑制后观察荧光及内源性LC3蛋白表达情况。结果:荧光观察和免疫印迹检测到GFP-LC3在H9C2中的表达,成功建立了表达GFP-LC3的H9C2稳定株;筛选出荧光及内源性LC3的高表达时相为缺氧1 h复氧48 h,在此模型中,GFP-LC3在细胞质中聚集成点状,内源性LC3表达显著升高,细胞经3MA处理后点状聚集减少,内源性LC3表达减弱。结论:成功建立了过表达GFP-LC3的H9C2稳定株,该细胞株为研究心肌细胞自噬奠定了基础。     

重组IL-12对人乳腺癌细胞自噬的研究

目的 探讨重组人IL-12（rIL-12）对乳腺癌细胞自噬的影响。方法 两株乳腺癌细胞（MDA-MB-231和MCF7）分别用rIL-12处理,经免疫蛋白印迹技术和细胞免疫荧光技术检测其自噬微管相关蛋白轻链3（LC3）的变化,以观察自噬情况;另外,用透射电镜观察rIL-12处理乳腺癌细胞前后自噬小体的变化。分别用胰岛素样生长因子1（IGF-1）激活磷脂酰肌醇-3激酶/蛋白激酶B（PI3K/Akt）通路,再加入rIL-12处理后,蛋白免疫印迹法检测相关通路蛋白PI3K/Akt, 哺乳动物雷帕霉素靶点（TOR）磷酸化变化及LC3的表达。结果 与空白组相比,rIL-12组细胞的自噬标志蛋白LC3表达增高,差异有统计学意义（P＜0.05）,且增加程度呈时间和浓度依赖性;荧光显微镜观察自噬体形成的结果显示,与空白组相比,rIL-12处理组的细胞核周点状聚集的绿色荧光增多;使用电镜观察到rIL-12处理组明显有自噬小体形成。与rIL-12组相比,IGF-1+rIL-12组的LC3Ⅱ表达减少,差异有统计学意义（P＜0.05）。结论 rIL-12可以激活乳腺癌细胞自噬,并通过抑制PI3K/Akt信号通路的机制,促进自噬标志蛋白LC3,特别是LC3Ⅱ的表达。     

UVRAG 调控金黄色葡萄球菌诱导的细胞自噬及其细菌的胞内存活

目的:探究紫外线抵抗相关基因(UVRAG)对金黄色葡萄球菌(SA)诱导HeLa细胞自噬及胞内菌存活的影响。方法:通过SA刺激HeLa细胞建立体外感染模型,分别用UVRAG小干扰RNA(siRNA)及pCI-neo-HA-hUVRAG质粒转染HeLa细胞。Western blot法检测自噬相关蛋白LC3B、p62及UVRAG的表达水平。用EGFP-LC3质粒及pCI-neo-HA-hUVRAG质粒共转染HeLa细胞后SA感染细胞,激光共聚焦显微镜观察EGFP-LC3的点状聚集。分别用UVRAG siRNA及pCI-neo-HA-hUVRAG质粒转染HeLa细胞后SA感染细胞,平板计数法计算胞内SA数量。结果:SA感染HeLa细胞能够引起自噬水平升高以及UVRAG的表达升高,UVRAG siRNA能够抑制LC3Ⅱ的表达,促进p62的表达。过表达UVRAG能够促进LC3Ⅱ的表达,抑制p62的表达。过表达UVRAG使EGFP-LC3的点状聚集增多,并且抑制胞内菌的存活,UVRAG siRNA促进胞内菌的复制。结论:SA感染宿主细胞诱导UVRAG表达的增加可以增强自噬水平并且抑制胞内菌的存活。     

柯萨奇病毒B3通过caspase依赖途径诱导HeLa细胞凋亡

目的 评价柯萨奇病毒B3（CVB3）致HeLa细胞死亡的方式及分子机制。方法 用CVB3作用于HeLa细胞,在不同时间收集细胞,通过相差显微镜、电子显微镜、流式细胞仪以及分子生物学手段,HeLa细胞的病变及caspase-3基因mRNA和蛋白质的表达。结果 CVB3作用于HeLa细胞后,细胞很快发生变性和坏死,24h后较多细胞凋亡;caspase基因在病毒作用早期即被活化,表现在caspase-3 mRNA在病毒作用后6h内,迅速增高达峰值。在24h内,又降至接近病毒作用前的水平。caspase-3蛋白表达在42h内逐渐增高。结论CVB3可诱导HeLa细胞发生坏死和凋亡两种反应,坏死早于凋亡,细胞凋亡与caspase-3的表达密切相关。     

雷公藤甲素通过ERK通路诱导肺癌A549细胞自噬

目的:研究雷公藤甲素(tripchlorolide,TP)对肺癌A549细胞活力及自噬的影响,并初步探讨其作用机制。方法:应用TP作用于肺癌A549细胞后,MTT法检测细胞活力;吖啶橙染色(AO)法在荧光显微镜下观察细胞自噬状态;GFP-LC3质粒转染实验观察细胞胞质中绿色点状聚集的自噬小体;Western blot法检测自噬相关蛋白LC3-Ⅱ的表达情况及有关的信号通路ERK蛋白水平的变化。结果:TP可以显著抑制肺癌A549细胞的增殖(P0.05),并呈一定的剂量-时间依赖关系。TP作用于肺癌A549细胞48 h后,细胞内酸性滤泡染成亮红色荧光比例增多。GFP-LC3转染实验结果显示在100 nmol/L TP处理后,细胞胞质中出现绿色点状聚集的自噬小体,而正常培养组极少细胞有自噬小体形成;同时转染GFP-control质粒的细胞在100 nmol/L TP处理及正常培养条件下均未观察到点状聚集的自噬小体产生。TP作用于肺癌A549细胞48 h后,与对照组相比,100 nmol/L TP组LC3-Ⅱ蛋白表达水平显著升高(P0.01),同时p-ERK/ERK蛋白水平也显著升高(P0.01);与100 nmol/L TP组相比,TP+3-MA组LC3-Ⅱ蛋白表达水平显著下降(P0.01),同时p-ERK/ERK蛋白水平也显著下降(P0.01)。结论:TP可显著抑制肺癌A549细胞活力并诱导细胞发生自噬,这种作用可能与影响ERK的磷酸化有关。     

鸟苷结合蛋白1对柯萨奇病毒B3及乙型肝炎病毒体外介导的不同作用

目的构建人鸟苷结合蛋白1（hGBP-1）真核表达质粒，观察hGBP-1体外对柯萨奇病毒B3（CVB3）和乙型肝炎病毒（HBV）的抑制作用。方法长链RT-PCR扩增全长hGBP-1编码区基因，克隆到pCR2．1TA克隆载体，再亚克隆到pcDNA3．1（-）真核表达载体。体外转染HepG2细胞和Hela细胞，Western blot检测hGBP-1的表达。然后分别观察转染细胞中hGBP-1对HBV体外复制子pHBV1．3和CVB3的抑制作用。ELISA检测共转染HepG2细胞培养L清HBsAg、HBeAg水平；Southern blot检测细胞HBVDNA复制中间体。TCID50试验检测Hela细胞培养物中CVB3感染量。结果成功构建hGBP-1真核表达质粒，能在HepG2细胞和HeLa细胞进行高效表达。该质粒与pHBV1．3共转染HepG2细胞，不能抑制HBV复制，HBsAg、HBeAg及HBV DNA复制中间体水平与对照相比都无明显变化。转染质粒在HeLa细胞上对CVB3复制有明显的抑制作用，CVB3感染量显著降低，尤其在低剂量病毒攻击时能完全抑制CVB3复制。结论hGBP-1可能在IFN介导的抗CVB3中起重要作用，但不能抑制HBV的复制。     

酒精诱导嗜铬细胞瘤细胞自噬及其与P62作用的关系

目的 采用不同浓度酒精作用于大鼠嗜铬细胞瘤（PC12）细胞,观察细胞自噬发生及其与P62变化的关系。 方法 用四甲基偶氮唑盐比色法（MTT）观察酒精对PC12细胞生存率的影响;间接免疫荧光法检测细胞自噬标志性蛋白LC3和P62的变化;高内涵活细胞成像系统检测细胞LC3荧光强度;透射电镜检测细胞自噬的超微结构;Western blotting方法检测P62蛋白量的表达。 结果 50～800mmol/L浓度酒精对PC12细胞的增殖有显著的抑制作用,呈浓度依赖性。酒精致PC12细胞自噬标志性蛋白LC3在细胞核周围密度增高,并与P62形成点状聚集共定位,其中在200mmol/L浓度酒精作用2h,PC12细胞LC3自噬荧光强度最高;透射电镜也观察到酒精作用的PC12细胞质中自噬体和自噬溶酶体。Western blotting结果显示,不同浓度酒精处理PC12细胞2h,P62蛋白表达量显著增加 (P<0.01);用200mmol/L浓度酒精处理PC12细胞,P62蛋白表达在2h达到最高值。 结论 酒精诱导PC12细胞的自噬作用,P62蛋白参与自噬调控过程。     

3-甲基腺嘌呤对顺铂诱导HeLa细胞凋亡的影响

目的 采用自噬特异性抑制剂3-甲基腺嘌呤(3-MA)抑制自噬,观察其对顺铂(DDP)诱导HeLa细胞凋亡的影响,探讨自噬在DDP诱导人宫颈癌HeLa细胞凋亡中的作用.方法 用四甲基偶氮唑盐比色法(MTT)观察3-MA对DDP抑制HeLa细胞生长情况的影响;倒置相差显微镜观察细胞形态变化;间接免疫荧光法检测自噬标志蛋白LC3和p62的变化;Hoechst荧光染色检测细胞凋亡.结果 MTT法显示,3-MA与DDP联合应用导致HeLa细胞生长抑制率增加;光镜结果显示,3-MA与DDP联合应用加剧了HeLa细胞收缩变圆,促进死亡;间接免疫荧光法检测到3-MA与DDP联合应用减弱了DDP诱导的HeLa细胞LC3聚集及其与p62的共定位;Hoechst荧光染色检测到3-MA与DDP联合应用增加HeLa细胞凋亡率.结论 3-MA抑制自噬能够促进DDP诱导HeLa细胞发生凋亡.     

紫草素通过PI3K/Akt/mTOR信号通路诱导人宫颈癌HeLa细胞凋亡和自噬

目的:观察紫草素(shikonin)对人宫颈癌HeLa细胞凋亡(apoptosis)和自噬(autophagy)的影响,并初步探讨PI3K/Akt/mTOR信号通路在其中的可能作用。方法:以紫草素作用于HeLa细胞后,采用CCK-8检测细胞活力;Annexin V/PI双染法检测细胞凋亡;GFP-LC3质粒转染HeLa细胞后观察自噬小体;紫草素分别与自噬抑制剂3-甲基腺嘌呤(3-methyladenine,3-MA)和凋亡抑制剂Z-DEVD-FMK共同作用后,Western blot分析检测细胞内自噬和凋亡相关蛋白微管相关蛋白1轻链3 (LC3)和cleaved caspase-3表达的变化,并检测PI3K/Akt/mTOR信号通路中磷酸化PI3K(p-PI3K)、磷酸化Akt(p-Akt)和磷酸化mTOR(p-mTOR)蛋白表达的变化。结果:紫草素显著抑制HeLa细胞活力(P0.05)。与对照组比较,紫草素可诱导HeLa细胞凋亡(P0.05)。GFP-LC3质粒转染分析结果显示,HeLa细胞经紫草素作用后,细胞质中出现绿色点状聚集的自噬小体,而对照组细胞中极少观察到点状聚集的自噬小体形成。与紫草素组比较,紫草素+3-MA组中LC3-II/LC3-I显著降低,而cleaved caspase-3表达显著升高(P0.05);与紫草素组比较,紫草素+Z-DEVD-FMK组LC3-II/LC3-I显著升高,而cleaved caspase-3表达显著降低(P0.05)。与对照组比较,紫草素可使p-PI3K、p-Akt和p-mTOR表达明显降低(P0.05)。结论:论紫草素能诱导HeLa细胞凋亡和自噬,且其凋亡及自噬具有协同作用,其机制可能与抑制PI3K/Akt/mTOR信号通路有关。     

CVB3-VP1 siRNA对CVB3复制的抑制作用

目的：观察柯萨奇B组病毒3型衣壳蛋白1（CVB3-VP1）特征性小干扰RNA（small interfering RNA,siRNA）对CVB3复制及VP1蛋白表达的抑制作用.方法：根据CVB3VP1基因的序列及其结构特征,设计并用化学方法合成小于扰RNA（siRNA）.以CVB3感染HeLa细胞,通过脂质体介导以siRNA转染HeLa细胞.48 h后,观察细胞病变的程度,用TCID5o法测定病毒滴度,免疫荧光法测定CVB3-VP1蛋白的表达,RT-PCR法检测CVB3-RNA的水平.结果：化学合成的4对针对CVB3-VP1的siRNA,发现其中有两对（VP1-1、VP1-2）对CVB3的复制具有明显的抑制作用,同时VP1蛋白的表达明显减少;细胞病变的程度也明显减轻.结论：CVB3-VP1siRNA可有效地抑制CVB3在HeLa细胞中的复制及表达VP1.     

柯萨奇病毒B3感染HeLa细胞后Bax和Bim的表达*

 目的：观察HeLa细胞感染柯萨奇病毒B3 (CVB3)后Bax和Bim mRNA和蛋白的表达。方法：将HeLa细胞分为未予以CVB3感染的对照组和予以CVB3感染的病毒组,取3 h、6 h、9 h、12 h和24 h 的细胞,采用RT-PCR和Western blotting分别检测Bax和Bim mRNA和蛋白的表达。结果：Bax和Bim　mRNA在对照组和病毒组HeLa细胞中均有表达,在病毒组和对照组中Bax和Bim mRNA的表达在各自组内均无显著差异（P＞0.05）,但在24 h Bax和Bim在病毒组mRNA的表达低于对照组（P＜0.05）。Bax和Bim蛋白表达在对照组中各时点均有表达,但无显著差异（P＞0.05）。病毒组Bax蛋白在24 h表达下降,差异有统计学意义（P＜0.05）,且病毒组表达明显低于对照组（P＜0.05）;Bim蛋白的表达随感染时间延长而下降（P＜0.05）,9 h、12 h和24 h表达病毒组低于对照组（P＜0.05）。结论:Bax和Bim在CVB3感染诱导的HeLa细胞凋亡早期发挥作用。     

卵巢上皮-间质肿瘤中B7-H3、B7-H4的表达及临床病理意义

目的探讨B7-H3、B7-H4在卵巢上皮-间质肿瘤中的表达及其临床病理意义。方法用RT-PCR技术及免疫组化PV9000两步法研究86例卵巢恶性上皮-间质肿瘤(恶性组),40例卵巢交界性上皮-间质肿瘤(交界组)和40例卵巢良性上皮-间质肿瘤(良性组)B7-H3与B7-H4mRNA及蛋白表达情况,并结合临床病理参数进行分析。结果 B7-H3、B7-H4mRNA在3组卵巢肿瘤组织中均有表达,且各自的3组卵巢肿瘤组织的mRNA光密度值差异均有统计学意义(P<0.05);B7-H3与B7-H4蛋白在恶性组中均呈细胞质和(或)细胞膜表达,其中B7-H3阳性率为81.4%(70/86),明显高于交界组22.5%(9/40)和良性组5.0%(2/40)的表达,差异有统计学意义(P<0.05);B7-H4阳性率为77.9%(67/86),明显高于交界组35.0%(14/40)和良性组5.0%(2/40)的表达,差异有统计学意义(P<0.05)。恶性组的卵巢癌组织中B7-H3蛋白在非黏液性卵巢癌中较黏液性卵巢癌高表达,差异有显著性(P<0.01),与临床分期、病理分级、患者年龄、腹水细胞学和淋巴结转移差异均无统计学意义(P>0.05)。B7-H4蛋白表达与组织病理学类型、临床分期、病理分级、患者年龄、腹水细胞学和淋巴结转移差异均无统计学意义(P>0.05)。结论 B7-H3与B7-H4在卵巢恶性上皮-间质肿瘤表达提示其可能与肿瘤的发生、发展有关,可为卵巢恶性肿瘤的诊断及治疗提供新的依据。     

Evolution of the spatial distribution of MAP1B phosphorylation sites in vertebrate neurons

The microtubule-associated protein MAP1B has important roles in neural development, particularly in migrating and differentiating neurons. MAP1B is phosphorylated by glycogen synthase kinase 3β (GSK-3β) at a site that requires prior phosphorylation by another kinase four amino acid residues downstream of the GSK-3β site, a so-called primed site, and at non-primed sites that have no such requirement. In developing mammalian neurons, MAP1B phosphorylated by GSK-3β at primed and non-primed sites is distributed in spatially distinct patterns. Non-primed GSK-3β-phosphorylated MAP1B sites are only expressed in axons and are present in the form of a gradient that is highest distally, towards the growth cone. In contrast, primed GSK-3β-phosphorylated MAP1B sites are present throughout the neuron including the somato-dendritic compartment and uniformly throughout the axon. To examine the function of these two sites, we explored the evolutionary conservation of the spatial distribution of GSK-3β primed and non-primed sites on MAP1B in vertebrate neurons. We immunostained spinal cord sections from embryonic or newly hatched representatives of all of the main vertebrate groups using phospho-specific antibodies to GSK-3β primed and non-primed sites on MAP1B. This revealed a remarkable evolutionary conservation of the distribution of primed and non-primed GSK-3β-phosphorylated MAP1B sites in developing vertebrate neurons. By analysing amino acid sequences of MAP1B we found that non-primed GSK-3β sites are more highly conserved than primed sites throughout the vertebrates, suggesting that the latter evolved later. Finally, distinct distribution patterns of GSK-3β primed and non-primed sites on MAP1B were preserved in cultured rat embryonic cortical neurons, opening up the possibility of studying the two sites in vitro.     

A fluorescence resonance energy transfer-based fluorometer assay for screening anti-coxsackievirus B3 compounds

In view of the need to develop a simple and rapid method to screen for antiviral therapeutic agents, a fluorescence resonance energy transfer (FRET)-based reporter system consisting of engineered mammalian cells expressing a cyan fluorescent protein-yellow fluorescent protein (CFP-YFP) pair linked by a short peptide containing the cleavage site of viral protease 2A (2A^pro) was developed. By detecting the 2A^pro produced early during the virus infection cycle, the CFP-YFP pair effectively identifies infectious coxsackievirus B3 (CVB3), a picornavirus that causes viral myocarditis in humans. The reporter system was used to screen a library of 2000 drugs and natural products for potential antiviral compounds. The reporter cells were treated with the test compounds, challenged with CVB3, and then examined using a fluorometer at 24 h post-infection. Sixty-four compounds, mostly therapeutic drugs, antimicrobial compounds and compounds with unknown functions, caused at least 50% inhibition of 2A^pro activity. Three known antiviral compounds, cosmosiin, ribavirin and baicalein, were also identified in the screening. The developed method is an effective strategy for rapid screening, and identifies compounds that inhibit CVB3 2A^pro. This method should be a valuable aid in the antiviral drug discovery effort.     

Ligation of the T cell co-stimulatory receptor CD28 activates the serine-threonine protein kinase protein kinase B

The intracellular signaling pathways activated upon ligation of the co-stimulatory receptor CD28 remain relatively ill-defined, although CD28 ligation does result in the strong association with, and activation of, phosphatidylinositol (PI) 3-kinase. The downstream effector targets of the CD28-activated PI 3-kinase-dependent signaling pathway remain poorly defined, but recent evidence from other systems has shown that Akt/protein kinase B (PKB) is a major target of PI 3-kinase and have indicated that a major function of PKB is the regulation of cell survival events. Given the strong coupling of CD28 to PI 3-kinase and the known protective effects of both CD28 and PI 3-kinase against apoptosis in different cell models, we investigated the effects of CD28 on PKB activation. We demonstrate that ligation of CD28 by either anti-CD28 monoclonal antibodies or the natural ligand B7.1, results in the marked activation of PKB in both the leukemic T cell line Jurkat and freshly isolated human peripheral blood-derived normal T lymphocytes. Our data suggest therefore, that PKB may be an important intracellular signal involved in CD28 signal transduction and demonstrate CD28 coupling to downstream elements of a signaling cascade known to promote cell survival.     

Plaque formation by B cell colonies

Three techniques for separating free antigen from antigen-antibody complexes have been applied to radioimmunoassay of myelin basic protein: cold ethanol precipitation of complexes, dextran-coated charcoal precipitation of free antigen, and second antibody precipitation of complexes. After optimization of the incubation and separation steps, the 3 methods were evaluated for precision and accuracy when applied to both spinal fluid and brain tissue homogenates. For determinations in brain tissue all 3 methods showed the same precision and gave largely the same values, though the ethanol method gave slightly lower levels. For spinal fluid the ethanol and dextran-charcoal methods gave the same values, but the double antibody method gave values only 1/3 as high. With spinal fluid, the precision of the dextran-charcoal method was poor compared with that of the other two. The double antibody method proved to be the method of choice for brain tissue samples, when the results of the incubation and separation steps, and the precision and accuracy of the determinations were taken into account. However, for an unknown reason values for spinal fluid were too low by this method. Therefore the ethanol precipitation method is recommended for spinal fluid samples and the double antibody method for brain tissue samples.     

RIPK3 mRNA level acts as a diagnostic biomarker in hepatitis B virus-associated hepatocellular carcinoma

HBV-associated hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide, and non-invasive early detection of HBV-associated HCC requires to be improved. To determine the alteration and clinical relevance of necroptosis and its key regulator receptor-interacting protein kinase 3 (RIPK3) in HBV-associated HCC, we detected the mRNA level of RIPK3 in peripheral blood mononuclear cells (PBMCs) and analyzed its correlation with clinical parameters. Here, we demonstrate that the expression of RIPK3 is elevated in patients with HBV-associated HCC compared to patients with chronic hepatitis B (CHB) and patients with HBV-related liver cirrhosis (LC). The mRNA level of RIPK3 is positively correlated with the severity of clinical manifestations and TNM stages. Moreover, the serum levels of RIPK3-asssocited cytokines are altered in consistent with the change of RIPK3 expression. The diagnostic accuracy of RIPK3 mRNA level is comparable to AFP test in discriminating HBV-associated HCC from LC and is better than AFP test in discriminating HBV-associated HCC from CHB. The combination of RIPK3 mRNA level and AFP test significantly improves the diagnosis of HBV-associated HCC. These data suggest that RIPK3 mRNA level is a biomarker in the onset and progression of HBV-associated HCC and may provide novel diagnostic strategies combined with the AFP test.     

LH3, a "homologue" of the mastadenoviral E1B 55-kDa protein is a structural protein of atadenoviruses

Ovine adenovirus serotype 7 (OAdV), the prototype atadenovirus, has gene homologues for most mastadenovirus structural proteins but lacks proteins V and IX. Instead, OAdV has structural proteins of 32 and 42 kDa although the gene encoding the latter had not previously been identified. The presently reported studies of OAdV virions have now identified a minor structural polypeptide of approximately 40 kDa as the product of the L1 52/55-kDa gene and, more surprisingly, shown that the 42-kDa protein is encoded by LH3. This gene product was previously thought to be a homologue of mastadenovirus E1B 55 kDa, which is a multi-functional, non-structural protein that cooperates with E1A in cell transformation. The lack of transforming activity previously demonstrated for OAdV combined with a structural role for the LH3 product indicates that the protein has a different function in atadenoviruses. We discuss the abundance and likely core location of LH3 in the virion and the possible derivation of the E1B 55-kDa gene from the LH3 gene.