组织型纤溶酶原激活物重组腺病毒载体的构建及其转染ECV304细胞后对血管内皮细胞生长因子表达的影响

目的 评估外源性组织型纤溶酶原激活物(t-PA)对ECV304细胞中血管内皮细胞生长因子(VEGF)表达的影响.方法 应用细菌内同源重组技术快速构建Adt-PA腺病毒重组质粒,转染不同病毒滴度Adt-PA至ECV304细胞,转染比率(MOI)分别为1∶10、1∶50、1∶100,选取合适MOI值;病毒转染后检测ECV304细胞内t-PA蛋白的表达.然后将培养的ECV304细胞分为二组,在培养液中加入Adt-PA混合培养24 h和48 h分别作为实验组1和实验组2,加入空病毒Ad混合培养48 h作为对照组,比较各组细胞中VEGF mRNA的转录和蛋白表达水平.结果 成功构建了重组腺病毒Adt-PA.当MOI为1∶50时,细胞转染效率为(69.6±21.2)%,且对ECV304细胞增殖具有一定的促进作用;Adt-PA转染ECV304细胞后在72 h内随着时间的延长其蛋白表达量逐渐升高(P<0.01);细胞内VEGFmRNA的转录水平和蛋白表达量在实验组1和2中较对照组均有明显升高(P<0.01).结论 构建的t-PA腺病毒表达载体可有效感染ECV304细胞并可显著增加其VEGF的表达水平.     

MCP-1转染人脐静脉内皮细胞过表达\沉默后相关信号通路研究

【摘要】目的探讨单核细胞趋化蛋白-1（MCP-1）转染人脐静脉内皮细胞过表达/沉默后相关信号通路与深静脉血栓形成的关系。方法培养人脐静脉内皮细胞行免疫荧光、免疫共沉淀检测,构建人MCP-1细胞系过表达/沉默载体,基因表达谱芯片检测人MCP-1细胞系过表达/沉默后转录谱变化并行生物信息技术分析。结果培养人脐静脉内皮细胞;构建人MCP-1过表达/干扰载体MCP-1-pCDH-GFP/ MCP-1-LMP shRNAmir1经病毒转染后感染HUVECs;基因芯片检测发现与正常细胞相比,过表达载体MCP-1-pCDH-GFP转染细胞有18条信号通路下调,7条信号通路上调;干扰载体MCP-1-LMP shRNAmir1转染细胞有60条信号通路下调,15条信号通路上调。结论MCP-1转染人脐静脉内皮细胞后相关信号通路为深静脉血栓疾病分子层面研究提供新的思路,MCP-1可能在深静脉血栓形成发生发展过程中发挥重要作用。     

CD147siRNA对恶性黑色素瘤细胞VEGF及血管内皮细胞体外迁移活性的影响

目的研究CD147siRNA对恶性黑色素瘤细胞株A375中VEGF表达水平和血管内皮细胞体外迁移活性的影响。方法采用半定量RT-PCR法检测转染后A375细胞中VEGF mRNA表达的变化。采用ELISA法检测A375细胞与成纤维细胞共同培养后VEGF表达水平的变化。采用细胞迁移实验检测转染CD147siRNA前后的A375细胞对脐静脉内皮细胞株ECV-304在体外迁移活性的影响。结果转染CD147siRNA后,A375细胞中VEGF的mRNA和蛋白表达水平显著降低,其下调率分别为10.77%（P〈0.05）和38.5%（P〈0.01）。转染CD147siRNA前后的A375细胞与成纤维细胞共同培养后VEGF的表达水平均较单独培养时显著升高,其升高率分别为98.5%（P〈0.01）和159.9%（P〈0.01）。转染CD147siRNA后的A375细胞使ECV-304细胞的体外迁移活性下降44.77%（P〈0.01）。结论 CD147siRNA能有效抑制恶性黑色素瘤细胞株A375中VEGF的表达水平和脐静脉内皮细胞株ECV-304在体外的迁移活性。     

人参皂苷Rc、Re、Rf和Rg1对药物代谢酶CYP1A1活性诱导作用研究

目的研究人参皂苷Rc、Re、Rf和Rg1能否激活h AhR受体信号通路诱导CYP1A1基因及蛋白表达。方法利用前期实验室构建的p GL4.17-CYP1A1报告基因质粒、pc DNA3.1-h AhR表达质粒与pRL-TK内参质粒共转染Hep G2细胞,检测人参皂苷Rc、Re、Rf和Rg1对AhR的转录激活效应;并利用Real-time PCR及Western blot技术对人参皂苷Rc、Re、Rf和Rg1的不同浓度、不同时间处理组进行mRNA及蛋白的检测。结果报告基因模型检测结果显示,人参皂苷Rc、Re、Rf和Rg1对AhR具有转录激活作用,其中人参皂苷Re与Rf对AhR转录激活效应明显;同时不同浓度人参皂苷Rc、Re、Rf和Rg1均能上调CYP1A1 mRNA与蛋白表达水平。结论人参皂苷Rc、Re、Rf和Rg1可以诱导CYP1A1mRNA与蛋白质水平的表达,这种诱导作用可能与上述皂苷成分激活AhR并提高其对CYP1A1的转录活性有关。     

SDF-1α促进原代培养大鼠星形胶质细胞增殖的作用

目的研究间质细胞来源因子-1α(stromal cell-derived factor-1α,SDF-1α)对原代培养大鼠星形胶质细胞增殖的作用及其可能机制。方法以不同浓度的重组人SDF-1α作用于星形胶质细胞后,用细胞计数法和溴化去氧尿苷参入法检测细胞增殖;钙离子荧光探针检测细胞内钙离子浓度;Western blot法检测细胞外调节蛋白激酶(extracellular regulated protein kinase,ERK)1/2磷酸化水平;流式细胞仪检测细胞周期;定量RT-PCR法检测Cyclin A2和Cyclin B1的mRNA表达。结果不同浓度的SDF-1α(10-40 nmol·L-1)作用48 h可明显地促进星形胶质细胞的增殖。SDF-1α(20 nmol·L-1)处理可增加细胞内钙离子浓度,提高ERK1/2磷酸化水平;而且可促使细胞由G0期进入DNA合成期(S期)和有丝分裂期(M期),上调Cyclin A2和Cyclin B1的mRNA表达。结论 SDF-1α可明显诱导离体培养大鼠星形胶质细胞增殖,其机制可能是促进钙离子内流,磷酸化ERK1/2,上调Cyclin表达而促进细胞进入DNA合成期和分裂期。     

D-聚甘酯对血管内皮细胞损伤的保护作用

目的 用 H_2O_2(200μmol·L~(-1))诱导人脐静脉内皮细胞株ECV304氧化损伤,研究D-聚甘酯(DPS)对血管内皮细胞损伤的保护作用。方法 噻唑蓝(MTT)比色法检测细胞活性,采用试剂盒测定细胞内脂质过氧化产物丙二醛(MDA)含量、培养液中乳酸脱氢酶(LDH)和超氧化物歧化酶(SOD)活性。同时采用流式细胞仪检测损伤后细胞内Ca~(2+)含量,并观察DPS对H_2O_2导致的内皮细胞内钙离子浓度的影响和细胞凋亡的作用。结果DPS 0.1,1,10μg·L~(-1)对损伤后ECV304具有促进增殖作用。DPS 0.1,1μg·L~(-1)使细胞培养液中SOD水平升高并降低细胞内MDA含量,4个剂量的DPS均能使细胞培养液中LDH释放减少。流式细胞术检测结果显示DPS能降低H_2O_2导致的细胞内Ca~(2+)含量的升高,并抑制细胞凋亡。结论 DPS具有保护H_2O_2致血管内皮细胞损伤的作用,其机理可能与其抗脂质过氧化作用,降低损伤后细胞内Ca~(2+)含量并抑制细胞凋亡有关。     

双环醇对组成型雄甾烷受体和孕烷X受体介导的CYP3A4和CYP286转录的调控

目的：构建pGL4．17-CYP3A4启动子嵌合报告基因表达载体,研究双环醇是否通过活化组成型雄甾烷受体（Constitutive Androstane Receptor,CAR）和孕烷X受体（pregnane Xreceptor．PXR）影响CYP3A4及CYP286的转录。方法：以提取的人肝组织基因组DNA为模板,应用RT-PCR技术,扩增获得CYP3A4启动子的近端启动序列（-362／＋53）和远端调控序列（-7836／-7208）,并连接到pGEM-T载体,测序正确后将目的基因片段先后插入至pGL4．17报告基因表达载体。将hPXR、hCAR表达载体分别与CYP3A4及CYP286报告载体共转染HepG2细胞,利用双荧光素酶报告基因系统检测CYP3A4及CYP286均具有启动活性后,双环醇分别与转染hPXR和CYP3A4、hCAR和CYP3A4、hCAR和CYP286的HepG2细胞温孵24h后,收获细胞并裂解,检测活性以分析双环醇对CYP3A4及CYP286的转录调节途径。结果：获得pGL4．17-CYP3A4启动子嵌合报告基因表达载体,经酶切鉴定及核酸序列测定证实该报告基因表达载体构建成功。双环醇主要通过活化CAR受体途径,调控CYP3A4和CYP286的转录,而PXR受体途径较少参与。     

CHO-hm_1R工程细胞株的建立及乙酰胆碱对其细胞内钙离子浓度的影响

目的　获得表达人毒蕈碱样乙酰胆碱Ⅰ型受体(hm1 R)的工程细胞株 (CHO hm1 R)并鉴定表达受体是否具有相应的功能活性。方法　以健康人基因组DNA为模板 ,PCR扩增hm1 R之cDNA ,并构建pcDNA3 .1 (+) hm1 R表达载体 ,转染CHO K1 细胞获得CHO hm1 R工程细胞株 ,将不同浓度的乙酰胆碱作用于细胞 ,以Fura 2为荧光探针检测细胞内钙离子浓度变化 ;同时 ,观察阿托品预处理对乙酰胆碱作用的影响。结果　成功得到CHO hm1 R工程细胞株 ;乙酰胆碱 1 0 ,1 0 0 μmol·L-1 均可增高细胞内钙离子浓度 ,此反应可被阿托品 50 0 μmol·L-1 完全阻断。结论　CHO hm1 R工程细胞株可以用于hm1 R配基的检测 ,为建立相关孤儿G蛋白偶联受体的研究体系提供借鉴     

漏芦对大鼠原代肝细胞细胞色素P4501A1酶活性及其mRNA表达的影响

目的研究漏芦对细胞色素P450A1酶活性及其mRNA水平的影响。方法以大鼠原代肝细胞为研究对象,实验组分别加入不同浓度(15.6,31.2,62.4 mg/ml)药物处理48小时,用氨基比林N-脱甲基酶(aminopyrence N-demethylase,ADM)活性反映CYP1A1酶活性;采用逆转录聚合酶链反应(RT-PCR)测定药物作用前后酶基因mRNA表达的相对水平变化。结果漏芦作用后,CYP1A1酶活性及相应mRNA的表达呈浓度依赖性抑制。药物在15.6,31.2,62.4 mg/ml对CYP1A1酶活性的抑制率分别为18.1%,46.9%,55.1%;对CYP1A1mRNA表达水平的抑制率分别为14.8%,18.1%,31.0%。结论漏芦浓度依赖性抑制CYP1A1酶活性,在转录水平下调大鼠肝细胞CYP1A1的表达。     

转染血管生成素1对胃癌细胞在低氧环境下整合素β1表达的影响

目的 探讨低氧环境下血管生成素1(Ang-1)对人胃癌细胞中整合素β1的影响.方法 利用腺病毒作为载体将已构建成功含Ang-1基因的重组腺病毒(Ad-Ang-1)瞬时转染人胃癌细胞株BGC-823,利用低氧诱导剂氯化钴进行低氧干预低氧转染(D)组,以单纯转染(B)组及单纯低氧干预(C)组作为对照,以未转染未行低氧干预的正常细胞作为空白对照(A)组,利用半定量RT-PCR,免疫细胞化学和Western blot方法对4组细胞中整合素β1的mRNA和蛋白表达水平进行分析.结果 D纽整合素β1的mRNA及蛋白表达明显高于A、B、C组(P<0.05).结论 低氧环境下转染Ang-1能够明显提高人胃癌细胞BGC-823中整合素β1 mRNA及蛋白的表达,表明低氧环境下Ang-1促进肿瘤细胞的侵袭转移.     

Myosin light-chain kinase inhibitor, 1-(5-chlornaphthalene-1-sulfonyl)-1H-hexahydro-1,4-diazepine (ML-9), inhibits catecholamine secretion from adrenal chromaffin cells by inhibiting Ca2+ uptake into the cells

For determination of whether myosin light-chain kinase (MLCK) is involved in the secretory mechanism of adrenal chromaffin cells, the effect of a preferential inhibitor of the enzyme, 1-(5-chlornaphthalene-1-sulfonyl)-1H-hexahydro-1,4-diazepine (ML-9), on catecholamine secretion from cultured bovine adrenal chromaffin cells was studied. ML-9 did not affect basal catecholamine secretion, but inhibited catecholamine secretion stimulated by acetylcholine, high K+, veratridine or palytoxin. At similar concentrations to those inhibiting the secretion of catecholamine, ML-9 also inhibited increased [45Ca]2+ uptake by the cells induced by these stimulants. However, it did not inhibit catecholamine secretion induced by the Ca2+ ionophore A23187. Moreover, it did not affect catecholamine secretion from digitonin-permeabilized cells induced by a micromolar Ca2+ concentration in the presence of Mg ATP. These results indicate that ML-9 inhibits catecholamine secretion from adrenal chromaffin cells by inhibiting the transmembrane Ca2+ uptake mechanism, but not by inhibiting the intracellular Ca2+-dependent mechanism. The possible role of MLCK in stimulus-secretion coupling in adrenal chromaffin cells is discussed.     

PPARγ overexpression regulates cholesterol metabolism in human L02 hepatocytes

Peroxisome proliferator-activator receptor (PPAR) γ is a nuclear hormone receptor that regulates glucose homeostasis, lipid metabolism, and adipocyte function. It has been shown that activation of PPARγ can reduce the incidence of gallstone. Herein we aimed to clarify the role of PPARγ in the reduction of gallstones. The plasmid containing the coding sequence of PPARγ was constructed and transfected in the human liver cell line (L02 cells). Western blot and RT-PCR were used to detect hydroxyl-methyl-glutaryl-CoA reductase (HMGCR), sterol regulatory element-binding proteins 2 (SREBP2), 7α-hydroxylase (CYP7A1), adenosine triphosphate-binding cassette (ABC) sterol transporters G5 and G8 (ABCG5, ABCG8) and liver X receptor α (LXRα). The Amplex Red cholesterol assay kit was used to detect the intracellular or extracellular cholesterol level. Our data showed that PPARγ overexpression caused significant decreases in both extracellular and intracellular cholesterol in the L02 cells. The further studies indicated PPARγ overexpression substantially decreased expression of HMGCR and SREBP-2, increased expression of CYP7A1, ABCG5, ABCG8 and LXRα. These results indicated that upregulation of PPARγ may reduce cholesterol levels through multiple-pathways including HMGCR/SREBP2-mediated biosynthesis, CYP7A1-mediated transformation, and ABCG5/ABCG8-mediated efflux. We thus suggest that PPARγ might have beneficial effects for cholesterol gallstones diseases.     

豆腐果苷对人孕烷X受体介导的CYP3A4和MDR1的转录调节作用

目的:建立和验证人孕烷X受体(human pregnant X receptor,hPXR)介导的CYP3A4、MDR1药物诱导剂的体外筛选体系,考察豆腐果苷对hPXR介导的CYP3A4、MDR1的转录调节作用。方法:利用构建的双荧光素酶报告基因系统,将表达载体和报告载体共转染HepG2细胞,以10μmol/L利福平为阳性对照,用不同浓度(0.004、0.04、0.4μmol/L)豆腐果苷处理48h后裂解细胞进行双荧光素酶活性检测。结果:不同浓度的豆腐果苷均不能通过激活hPXR来介导CYP3A4和MDR1表达上调,各浓度处理组的双荧光素酶比活性值与DMSO溶媒组差异无统计学意义(P>0.05)。结论:成功构建了hPXR介导的CYP3A4和MDR1药物诱导剂的体外筛选体系,并发现豆腐果苷不能通过激活hPXR介导CYP3A4和MDR1的表达上调。     

Regulation of cytochrome P-450 (CYP) 1B1 in mouse Hepa-1 variant cell lines: A possible role for aryl hydrocarbon receptor nuclear translocator (ARNT) as a suppressor of CYP1B1 gene expression

Cytochrome P-450 (CYP) 1B1 expression in mouse hepatoma (Hepa-1) wild-type (WT) cells was compared with responses in Hepa-1 variants LA1 and LA2, which, respectively, exhibit low aryl hydrocarbon receptor (AhR) level and defective AhR nuclear translocator (ARNT) protein. 10T1/2 mouse embryo fibroblasts express predominantly CYP1B1 and at a 100 times higher level than in Hepa-1 cells, whereas they express about 300-fold lower CYP1A1 than Hepa-1 cells. The expression of CYP1B1 in WT and LA1 variant, although at a much lower level, follows that of CYP1A1, reflecting their common regulation through the AhR. The LA2 (ARNT-defective) cells showed a major difference between CYP1B1 and CYP1A1 expression. Although CYP1A1 mRNA levels in LA2 were extremely low and unresponsive to 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD), basal CYP1B1 mRNA and protein were expressed at levels similar to those seen in TCDD-induced WT. The elevated basal CYP1B1 mRNA in LA2 cells decreased by 50% after transient transfection of ARNT cDNA, in parallel with substantial restoration of CYP1A1 induction. This implicates ARNT as a suppressor of CYP1B1 basal expression in Hepa cells. In transient CYP1B1-luciferase constructs in LA2 cells, ARNT shows stimulatory effects in the enhancer region but an inhibitory effect on the proximal promoter. Two CYP1B1 enhancer elements [xenobiotic-responsive element (XRE) 1/2 and XRE4] formed TCDD-unresponsive complexes of similar mobility to TCDD-stimulated AhR-ARNT complex with XRE5. However, because these two complexes were formed to the same extent in LA2 as in WT cells, they cannot be due to ARNT or contribute to ARNT-regulated suppression.     

Orai1-STIM1 formed store-operated Ca2+ channels (SOCs) as the molecular components needed for Pb2+ entry in living cells

Heavy metal lead (Pb2+) is a pollutant and causes severe toxicity when present in human tissues especially the nervous system. Recent reviews have suggested that Pb2+ can target Ca2+-related proteins within neurons and that Ca2+ channels might be a candidate for Pb2+ entry. This study's main aim was to identify the functional entry pathway of Pb2+ into living cells. We firstly characterized the endogenous expression of Orai1 and STIM1 mRNA together with the level of thapsigargin (TG) stimulated capacitative Ca2+ entry in PC12 and HeLa cells; this was done by RT-PCR and time-lapse Ca2+ imaging microscopy, respectively. Our data supported Orai1 and STIM1 as contributing to store-operated Ca2+ channel (SOC) basal activity. Secondly, using the indo-1 quenching method with the SOC blocker 2-APB, we observed that Pb2+ was able to enter cells directly through unactivated SOCs without TG pretreatment. Thirdly, we further demonstrated that co-expression of Orai1 and STIM1 differentially enhanced SOC functional activity (4-fold with PC12 and 5-fold with HeLa cells) and Pb2+ entry (5- to 7-fold with PC12 and 2-fold with HeLa cells). Furthermore, after a 1 h of Pb2+ exposure, the depolarization- and histamine-induced Ca2+ responses were significantly decreased in both PC12 and HeLa cells in a dose-dependent manner. This result indicated that the decreased Ca2+ responses were, in part, due to Pb2+ entry. In summary, our results suggest that SOCs are responsible for Pb2+ permeation and that the Orai1-STIM1 protein complex formed by functional SOCs is one of the molecular components involved in Pb2+ entry.     

JNK inhibitor SP600125 is a partial agonist of human aryl hydrocarbon receptor and induces CYP1A1 and CYP1A2 genes in primary human hepatocytes

SP600125, a specific inhibitor of c-Jun-N-Terminal kinase (JNK), was reported as a ligand and antagonist of aryl hydrocarbon receptor (AhR) [Joiakim A, Mathieu PA, Palermo C, Gasiewicz TA, Reiners Jr JJ. The Jun N terminal kinase inhibitor SP600125 is a ligand and antagonist of the aryl hydrocarbon receptor. Drug Metab Dispos 2003;31(11):1279-82]. Here we show that SP600125 is not an antagonist but a partial agonist of human AhR. SP600125 significantly induced CYP1A1 and CYP1A2 mRNAs in primary human hepatocytes and CYP1A1 mRNA in human hepatoma cells HepG2. This effect was abolished by resveratrol, an antagonist of AhR. Consistent with the recent report, SP600125 dose-dependently inhibited CYP1A1 and CYP1A2 genes induction by a prototype AhR ligand 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in human hepatocytes. Moreover, SP600125 displayed typical behavior of a partial agonist in HepG2 cells transiently transfected with a reporter plasmid containing two inverted repeats of the dioxin responsive element or with a plasmid containing 5'-flanking region of human CYP1A1 gene. SP600125 transactivated the reporter plasmids with EC(50) of 0.005 and 1.89 microM, respectively. On the other hand, TCDD-dependent transactivation of the reporter plasmids was inhibited by SP600125 with IC(50) values of 1.54 and 2.63 microM, respectively. We also tested, whether the effects of SP600125 are due to metabolism. Using liquid chromatography/mass spectrometry approach, we observed formation of two minor monohydroxylated metabolites of SP600125 in human hepatocytes, human liver microsomes but not in HepG2 cells. These data imply that biotransformation is not responsible for the effects of SP600125 on AhR signaling. In conclusion, we demonstrate that SP600125 is a partial agonist of human AhR, which induces CYP1A genes.     

CYP1A2低表达增强何首乌水提物及其相关单体成分肝细胞毒性的研究

目的建立CYP1A2低表达人正常肝细胞株,探究何首乌水提物(PMR)及其相关单体成分的肝细胞毒性与CYP1A2低表达的关系。方法运用RNA干扰技术构建稳定转染shCYP1A2的2种人正常肝细胞系L02、HepaRG,RT-qPCR验证干扰效果;PMR及其相关单体成分:二苯乙烯苷(2,3,5,4’-tetrahydroxystilbene-2-O-β-D-glucoside,TSG)、大黄素-8-O-β-D-葡萄糖苷(emodin-8-O-β-D-glucopyranoside,EG)、没食子酸(gallic acid,GA)、大黄素(emodin,EM)、大黄素甲醚(physcion,PH)、芦荟大黄素(aloe-emodin,AE)、大黄酸(rhein,RH)作用CYP1A2敲低的L02及HepaRG细胞48 h,MTT检测细胞活力。结果成功构建了稳定转染shCYP1A2的2种人正常肝细胞系,L02-shCYP1A2、HepaRG-shCYP1A2与相应空质粒对照组相比,CYP1A2 mRNA表达分别下降了59.81%(L02-shCYP1A2)和66.60%(HepaRG-shCYP1A2)。1.5~3 mg/mL PMR作用CYP1A2敲低的L02-shCYP1A2细胞48 h,细胞毒性显著增加(P<0.01);2.5~3 mg/mL PMR作用CYP1A2敲低的HepaRG-shCYP1A2细胞48 h,细胞毒性显著增加(P<0.05、P<0.01);40~120μmol/L GA作用CYP1A2敲低的L02-shCYP1A2及HepaRGshCYP1A2细胞48 h,细胞毒性显著增加(P<0.01、P<0.01);AE作用CYP1A2敲低的HepaRG-shCYP1A2细胞48 h,细胞毒性显著增加(P<0.01)。结论CYP1A2低表达显著增加PMR的肝细胞毒性,推测GA和AE可能为相关的增毒成分。