三氧化二砷对HepG2细胞表达基因调节作用

目的 应用基因芯片技术，阐明低剂量三氧化二砷作用于肝HepG2细胞之后，无机砷对差异表达基因的调节作用。方法 应用基因表达谱芯片技术，对5μmol／L三氧化二砷诱导的HepG2细胞和以生理盐水处理的相同细胞的mRNA进行差异显示分析，研究三氧化二砷诱导人HepG2细胞后的差异表达基因。结果 HepG2细胞经5μool／L三氧化二砷诱导后。所检测的4096条目的基因中有123条产生差异表达，其中48条基因表达上调，75条基因表达下调。结论 应用基因表达谱芯片成功筛选了低剂量三氧化二砷诱导肝细胞后的差异表达基因，无机砷对肝细胞有双向调节作用。     

二十碳五烯酸对人树突状细胞成熟过程中基因表达谱影响的研究

目的研究二十碳五烯酸(EPA)对人树突状细胞成熟过程中基因表达谱的影响。方法采用GM-CSF及IL-4诱导人外周单核细胞获得非成熟树突状细胞,然后将细胞分为三组处理,A组,维持树突状细胞的未成熟状态;B组,LPS(100ng/ml)作用48h诱导树突状细胞的成熟;C组,经EPA(50μmol/L)预处理24h后再予以LPS(100ng/ml)诱导树突状细胞的成熟。用低通量的cDNA表达谱芯片检测三组细胞基因表达谱的情况。RT-PCR法验证相关差异表达基因的结果。结果在LPS诱导树突状细胞成熟的过程中共有29条基因表达增加,9条基因表达下降。但是经EPA孵育24h后再予以LPS诱导"成熟"的人树突状细胞其基因表达水平发生明显变化,与未经EPA处理的成熟树突状细胞比较,共有15条基因出现差异表达,其中在29条本该上调的基因中有11条基因表达出现下降,1条基因出现上调。在9条本该表达下调的基因中有1条基因出现上调,2条明显下调。RT-PCR验证了其中6条基因的芯片结果。结论 EPA对树突状细胞的成熟过程中多种基因的表达具有明显的抑制作用,其范围涉及细胞因子及抗原提呈分子等不同基因。     

幽门螺杆菌促肝细胞增殖及分子机制的初步研究

目的 研究幽门螺杆菌(Hp)对肝细胞增殖的影响并探讨其分子机制.方法 以不同量的Hp标准株NCTC11637与HepG2肝细胞共培养,CCK-8法检测细胞的增殖情况并确定最佳Hp作用剂量.用Affymetrix人类基因表达谱芯片检测Hp与HepG2共培养对HepG2细胞基因表达谱的影响,并选取5个差异表达基因以半定量RT-PCR技术验证.结果 MOI比值(细菌与细胞个数比)在0.15∶1～0.075∶1时,Hp对HepG2细胞具有明显的促增殖作用；HepG2细胞经MOI比值为0.15∶1 Hp处理后有35个基因转录发生变化:ICAM-1等19个基因上调,SLC38A4等16个基因下调,这些变化基因涉及细胞骨架/基质、DNA结合蛋白及转录因子等；5个基因表达情况与表达谱芯片检测结果完全吻合.结论 一定剂量的幽门螺杆菌可促进肝细胞增殖,这与Hp导致HepG2细胞基因转录调控有关基因的表达变化有关.     

饱和脂肪酸与单不饱和脂肪酸对HepG2细胞自噬和凋亡的影响

目的比较饱和脂肪酸棕榈酸(palmitic acid,PA)和单不饱和脂肪酸油酸(oleic acid,OA)对HepG2细胞凋亡和自噬的影响。方法 PA和OA处理HepG2细胞,CCK-8检测脂肪酸的细胞毒性,caspase-3活性测定检测脂肪酸对细胞凋亡的影响,油红O染色检测细胞内脂质沉积,酶法检测细胞内甘油三酯的含量,Western blot检测自噬相关蛋白LC3-Ⅱ和凋亡相关蛋白caspase-3的表达,实时荧光定量PCR检测相关基因表达。结果 PA和OA都均同时诱导HepG2细胞凋亡与自噬,但PA的影响明显强于OA;PA诱导HepG2细胞自噬相关基因LC3B和VPS38表达、促进脂肪酸β-氧化的PPARα基因mRNA水平升高,但对细胞内脂肪沉积没有明显作用;而OA则导致HepG2细胞内甘油三酯的水平明显增加,但对上述基因表达没有明显影响。结论饱和脂肪酸PA和不饱和脂肪酸OA均能引起HepG2细胞凋亡和自噬,但PA的作用强于OA。     

二十二碳六烯酸对人树突状细胞基因表达谱的影响

目的:研究二十二碳六烯酸(DHA)对人树突状细胞(DCs)成熟过程中基因表达谱的影响. 方法:采用GM-CSF及IL-4诱导人外周血单核细胞获得非成熟DCs,经DHA( 50 μmol/L)孵育24 h后,再予以LPS (100 ng/ml)作用48 h,用cDNA芯片检测人DCs基因表达谱.用RT-PCR法验证相关差异表达基因的结果.分别将未经脂肪酸处理的DCs和硬脂酸(SA)处理的DCs作为对照. 结果:经DHA预处理后,成熟的DCs与未经脂肪酸处理的成熟DCs相比,共有20条基因差异表达 ,约占芯片中基因总数的29.4%.其中18条基因表达下降,2条基因表达增加.在差异表达的基因中,涉及细胞因子、趋化因子(受体)及其抗原呈递相关分子基因等.而采用饱和脂肪酸(SA)处理的DCs的表达谱未见明显变化. 结论:50 μmol/L DHA对DCs成熟过程中的基因表达具有显著的影响 ,涉及到细胞因子、趋化因子(受体)及其抗原呈递相关分子基因的调节.     

磺胺二甲嘧啶对FRTL-5细胞基因表达谱的影响

目的研究磺胺二甲嘧啶对FRTL5细胞基因表达谱的影响,探讨环境甲状腺素干扰物的作用机制。方法指数生长期细胞经20μgml磺胺二甲嘧啶处理24h后,用TRIzol法提取RNA,用9753位点的cDNA芯片检测基因表达情况,实验组和对照组细胞分别用Cy3dCTP和Cy5dCTP标记,计算Cy3和Cy5的比值,找出差异表达基因。结果芯片经扫描分析后,发现表达有差异的基因共有679条占芯片上基因总数的70%,其中395(40%)条基因表达增加,284(30%)条基因表达下降,涉及基因表达调控、细胞周期调控、细胞免疫,细胞代谢等众多事件。结论磺胺二甲嘧啶对FRTL-5细胞的毒性效应,其机制涉及多种基因。     

杀草强诱导人甲状腺Nthy-ori-3-1细胞肿瘤相关基因表达谱变化

目的以人甲状腺Nthy-ori-3-1细胞为受试对象,通过差异性表达谱芯片分析,探索杀草强致人甲状腺肿瘤的相关机制。方法以1~100μg/m L杀草强处理Nthy-ori-3-1细胞24 h后,用MTT法检测其对细胞增殖的影响。以100μg/m L杀草强处理细胞24 h后,做基因表达谱分析,并用GO(Gene Ontology)分析和pathway分析芯片结果,用实时定量PCR验证芯片结果。结果 MTT结果显示,所有检测浓度杀草强对Nthy-ori-3-1细胞增殖均无显著影响。芯片结果显示,有90个基因表达显著变化,55个上调,35个下调;GO分析显示,43个基因与生物过程相关(37个上调,6个下调),42个与分子功能相关(37个上调,5个下调),44个与细胞组分相关(38个上调,6个下调)。Pathway结果显示差异基因共影响45条信号通路,其中10条与肿瘤发生发展密切相关。实时定量PCR验证差异基因表达与芯片结果一致。wnt5b、arnt2和bmp2基因在多条肿瘤相关通路中均有显著变化。结论杀草强可能通过多信号通路导致甲状腺肿瘤,其中wnt5b、arnt2和bmp2等基因可能是其主要靶基因。     

杀草强对人甲状腺Nthy-ori-3-1细胞全基因表达谱的影响

目的研究杀草强对人甲状腺Nthy-ori-3-1细胞全基因表达谱的影响。方法以100μg/ml杀草强处理Nthy-ori-3-1细胞24 h后,进行全基因表达谱分析,采用实时定量PCR验证芯片结果,并用GO分析和pathway分析芯片结果。结果实时定量PCR验证差异基因表达与芯片结果一致。GO和pathway分析结果显示共检测了41 001个基因,按P0.005和FC≤0.5或FC≥2的标准筛选,共有20个差异基因涉及44条通路。Agt、cd70、bmp2、arnt2和wint5b基因出现在多条信号通路中。结论杀草强主要影响Nthy-ori-3细胞肿瘤发生相关基因,即上调cd70和wint5b基因表达及下调bmp2和arnt2基因表达,可能是其导致甲状腺肿瘤的机制之一。     

体外铅染毒对人膀胱细胞基因表达谱的影响

目的研究体外培养的人胚胎膀胱组织来源细胞(humanbladder,HB)在铅暴露不同时间和浓度下的基因表达差异,以探讨铅毒性的作用机制。方法分别使用100、200μg/ml乙酸铅溶液暴露体外培养的HB细胞(浓度为2×103个/ml)8、24h,设置空白对照,提取RNA,进行cDNA基因表达谱芯片实验。芯片扫描结果经归一化处理,设定Ratio值0.5或≥2为表达有差异基因。结果铅暴露HB细胞导致差异表达的基因共有2406个,其中,在铅暴露不同时间(8、24h)、不同浓度(100、200μg/ml)皆上调的有45个基因,皆下调的有40个基因。结论基因表达因铅暴露的时间和浓度变化而发生改变;差异表达基因的功能与信号传导、细胞代谢密切相关,也与疾病发生发展相关;可以通过分析基因表达谱改变,探悉铅暴露导致机体损伤的原因和致病机制。     

甲基纳曲酮对肝癌HepG2的VEGF的mRNA表达的抑制作用

目的:观察甲基纳曲酮对肝癌HepG2细胞VEGF的m RNA的影响。方法:分别将含0.01μmol甲基纳曲酮(低剂量组)、0.05μmol(中剂量组)、0.1μmol(高剂量组)培养基与肝癌HepG2细胞共孵72h,以等体积生理盐水处理组设立空白对照组。应用RT-PCR检测肝癌HepG2细胞中VEGF基因表达水平。结果:RT-PCR显示,甲基纳曲酮高剂量处理组作用72h的胞VEGF在m RNA水平表达均较对照组下调,低浓度组、中浓度组、高浓度组分别为0.75±0.03、0.58±0.05、0.47±0.04,各组均与对照组相比具有显著性差异(F=107.9,p=0.000),且具有时间依赖关系。结论:甲基纳曲酮能够下调肝癌HepG2细胞VEGF在m RNA的表达。     

Epigallocatechin gallate changes mRNA expression level of genes involved in cholesterol metabolism in hepatocytes

Catechins, compounds derived from green tea, have been shown to improve cholesterol metabolism in animal studies, but the molecular mechanisms underlying this function have not been fully understood. We performed DNA microarray analysis in order to clarify the effects of epigallocatechin gallate (EGCG), the dominant catechin in green tea, on cholesterol metabolism in HepG2 hepatocytes. This revealed that the expression levels of several genes related to cholesterol metabolism, including the LDL receptor, were changed by EGCG treatment. Using a real-time PCR technique, we confirmed that EGCG treatment up-regulated mRNA expression level of the LDL receptor. Moreover, EGCG decreased extracellular apoB levels. These findings indicated that EGCG improves cholesterol metabolism through the up-regulation of LDL receptor and also reduces extracellular apoB levels.     

Inhibition of 12-O-tetradecanoylphorbol-13-acetate-induced inflammatory skin edema and ornithine decarboxylase activity by theaflavin-3,3'-digallate in mouse

Among black tea polyphenols, theaflavins were generally considered to be the most effective in cancer chemoprevention. In this study, we examined the inhibitory effects of black tea polyphenols, including theaflavin (TF-1), a mixture (TF-2) of theaflavin-3-gallate and theaflavin-3'-gallate, theaflavin-3,3'-digallate (TF-3), and the green tea polyphenol (-)-epigallocatechin-3-gallate (EGCG) on 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced edema and ornithine decarboxylase (ODC) activity. Topical application of these polyphenols onto the mouse resulted in inhibition of TPA-induced ear edema and skin epidermal ODC activity. The inhibitory order was as follows: TF-3 > TF-2 approximately equal to EGCG > TF-1. Western and Northern blots indicated that TF-3 significantly reduced the protein and mRNA levels of ODC in TPA-treated mouse skin and NIH 3T3 cells, whereas EGCG showed less activity. EGCG and TF-3 were able to inhibit the ODC enzyme activity in vitro. Furthermore, TF-3 also significantly reduced the basal promoter activity of the ODC gene in NIH 3T3 cells that were transiently transfected with ODC reporter plasmid. These results suggested that TF-3 was a potential inhibitor of ODC activity and TPA-induced edema and might be effective in cancer chemoprevention.     

应用基因芯片技术筛选转染NOR1基因后HepG2细胞差异表达基因

目的研究转染NOR1基因后肝癌细胞系HepG2基因表达谱的改变。方法应用脂质体介导的转染方法将pcDNA3.1( )/NOR1真核表达载体和pcDNA3.1( )空白载体分别转染入肝癌细胞系HepG2,再分别提取转染pcD-NA3.1( )/NOR1和空载体pcDNA3.1( )的HepG2细胞总RNA,应用基因芯片技术进行芯片分析。结果芯片分析结果显示差异表达基因中上调的基因有59个,下调的基因有103个,这些差异基因的功能涉及多个方面。结论应用基因芯片技术成功筛选了NOR1基因转染细胞后差异表达基因,为阐明NOR1基因与肝癌发生发展的关系提供了实验依据。     

茶多酚和茶色素对人肝癌细胞株HepG2细胞凋亡的影响

目的利用人肝癌细胞株HepG2探讨茶多酚和茶色素对细胞凋亡的影响。方法5×105个孔HepG2接种于6孔培养板中,于指数生长期加入50mgL和100mgL茶多酚和茶色素,48h后消化细胞,制成细胞悬液。用琼脂糖凝胶电泳检测DNALADDER的形成,Westernblot方法检测细胞凋亡蛋白Bcl2和Bax的表达。结果茶多酚和茶色素诱导了明显的DNALADDER的出现,Westernblot分析发现茶多酚和茶色素显著抑制了Bcl2表达,诱导了Bax蛋白表达。结论诱导细胞凋亡是茶预防肿瘤的一个重要机制。     

Epigallocatechin gallate supplementation alleviates diabetes in rodents

As the prevalence of type 2 diabetes mellitus is increasing at an alarming rate, effective nutritional and exercise strategies for the prevention of this disease are required. Specific dietary components with antidiabetic efficacy could be one aspect of these strategies. This study investigated the antidiabetic effects of the most abundant green tea catechin, epigallocatechin gallate (EGCG, TEAVIGO), in rodent models of type 2 diabetes mellitus and H4IIE rat hepatoma cells. We assessed glucose and insulin tolerance in db/db mice and ZDF rats after they ingested EGCG. Using gene microarray and real-time quantitative RT-PCR we investigated the effect of EGCG on gene expression in H4IIE rat hepatoma cells as well as in liver and adipose tissue of db/db mice. EGCG improved oral glucose tolerance and blood glucose in food-deprived rats in a dose-dependent manner. Plasma concentrations of triacylglycerol were reduced and glucose-stimulated insulin secretion was enhanced. In H4IIE cells, EGCG downregulated genes involved in gluconeogenesis and the synthesis of fatty acids, triacylgycerol, and cholesterol. EGCG decreased the mRNA expression of phosphoenolpyruvate carboxykinase in H4IIE cells as well as in liver and adipose tissue of db/db mice. Glucokinase mRNA expression was upregulated in the liver of db/db mice in a dose-dependent manner. This study shows that EGCG beneficially modifies glucose and lipid metabolism in H4IIE cells and markedly enhances glucose tolerance in diabetic rodents. Dietary supplementation with EGCG could potentially contribute to nutritional strategies for the prevention and treatment of type 2 diabetes mellitus.     

Green tea,black tea,and epigallocatechin modify body composition,improve glucose tolerance,and differentially alter metabolic gene expression in rats fed a high-fat diet

The mechanisms of how tea and epigallocatechin-3-gallate (EGCG) lower body fat are not completely understood. This study investigated long-term administration of green tea (GT), black tea (BT), or isolated EGCG (1 mg/kg per day) on body composition, glucose tolerance, and gene expression related to energy metabolism and lipid homeostasis; it was hypothesized that all treatments would improve the indicators of metabolic syndrome. Rats were fed a 15% fat diet for 6 months from 4 weeks of age and were supplied GT, BT, EGCG, or water. GT and BT reduced body fat, whereas GT and EGCG increased lean mass. At 16 weeks GT, BT, and EGCG improved glucose tolerance. In the liver, GT and BT increased the expression of genes involved in fatty acid synthesis (SREBP-1c, FAS, MCD, ACC) and oxidation (PPAR-α, CPT-1, ACO); however, EGCG had no effect. In perirenal fat, genes that mediate adipocyte differentiation were suppressed by GT (Pref-1, C/EBP-β, and PPAR-γ) and BT (C/EBP-β), while decreasing LPL, HSL, and UCP-2 expression; EGCG increased expression of UCP-2 and PPAR-γ genes. Liver triacylglycerol content was unchanged. The results suggest that GT and BT suppressed adipocyte differentiation and fatty acid uptake into adipose tissue, while increasing fat synthesis and oxidation by the liver, without inducing hepatic fat accumulation. In contrast, EGCG increased markers of thermogenesis and differentiation in adipose tissue, while having no effect on liver or muscle tissues at this dose. These results show novel and separate mechanisms by which tea and EGCG may improve glucose tolerance and support a role for these compounds in obesity prevention.     

三种食物多酚对化学诱导DM大鼠糖脂代谢的影响

目的探讨膳食多酚[绿原酸、表没食子儿茶素没食子酸酯(EGCG)、槲皮素]对链脲佐菌素(STZ)诱导的糖尿病大鼠血糖、血脂、肝脏中葡萄糖-6-磷酸酶(G-6-pase)和骨胳肌组织中葡萄糖转运体4(GLUT4)表达的影响。方法单次腹腔注射链脲佐菌素(STZ,35 mg/kg)结合高脂饮食建立糖尿病大鼠模型,将成模大鼠分成5组[糖尿病模型组(DM)、糖尿病模型+二甲双胍组(S)、糖尿病模型+绿原酸组(CA)、糖尿病模型+EGCG组(E)、糖尿病模型+槲皮素组(Q)],另设正常对照组(NC),分别灌喂二甲双胍、绿原酸、EGCG和槲皮素4w后,测定其糖耐量、空腹胰岛素、甘油三酯、胆固醇、G-6-pase和GLUT4 mRNA的表达。结果绿原酸、EGCG、槲皮素均表现出改善STZ诱导的糖尿病大鼠血糖、甘油三酯(TG)和胆固醇(TC)的含量,并能改善糖尿病模型大鼠的胰岛素敏感性,抑制肝脏G-6-pase mRNA的表达,且提高了骨胳肌GLUT4 mRNA的表达,其中以绿原酸效果最佳。仅仅其糖耐量改善弱于槲皮素作用,但均弱于阳性对照组二甲双胍的作用。结论绿原酸、EGCG、槲皮素均能有效改善STZ诱导的SD糖尿病大鼠的糖代射、脂代射、胰岛素敏感生及肝脏G-6-pase mRNA和骨胳肌GLUT4 mRNA的表达,绿原酸的效果最佳。[营养学报,2012,34(6):572-575,581]