TLR4基因小干扰RNA对缺氧复氧诱导BV-2细胞炎症因子分泌的影响

目的 研究Toll样受体4(TLR4)基因小干扰RNA(siRNA)对体外缺氧复氧条件下诱导BV-2细胞分泌TNF-α的抑制作用.方法 小鼠小胶质细胞株BV-2置于六扎培养板培养,随机分为N组(正常培养组)、H组(缺氧复氧组)、T组(缺氧复氧+TLR4-siRNA转染组,转染质粒pEGFP-H1/TLR4-siRNA)、C组(缺氧复氧+对照siRNA转染组,转染含对照序列的质粒pEGFP-H1/对照-siR-NA)和B组(缺氧复氧+空白质粒转染组,转染pEGFP-H1空质粒)共5组.其中H组、T组、C组和B组细胞缺氧培养3 h后复氧培养24 h,运用脂质体转染技术介导质粒转染,流式细胞术检测转染后BV-2细胞EGFP的表达率,RT-PCR方法检测各组BV-2细胞TLR4 mRNA和NF-кB p65 mRNA的表达水平,Western blot方法检测各组BV-2细胞TLR4蛋白表达变化,ELISA方法检测各组上清液中TNF-α含量.采用方差分析进行统计分析.结果 转染后BV-2细胞EGFP的表达率为(67.58±7.16)%;经缺氧复氧处理后,H组、T组、C组和B绀的TLR4 mRNA、NF-кB p65 mRNA、TLR4蛋白水平较N组均明显上调(P＜0.01),各组卜清液TNF-α含量较N组也明显升高(P＜0.01);而T组TLP4 mRNA、NF-кBp65 mRNA、TLR4蛋白表达量和上清液TNF-α含量较H组、C组和B组均明显下凋(P＜0.01);C组和B组分别与H组相比,各项检测指标表达均无明显变化(P＞0.05).结论 针对TLR4 mRNA的小干扰RNA可以有效的抑制缺氧复氧诱导的BV-2细胞的炎症反应.     

阻断RIP2对小鼠巨噬细胞及内毒素血症的影响

目的:阻断RIP2对巨噬细胞产生炎症细胞因子及内毒素血症小鼠的影响。方法:构建小鼠RIP2基因的siRNA质粒,转染细胞后用RT-PCR和Western blot方法检测细胞RIP2的表达;LPS刺激后,用ELISA法测定细胞TNF-α,半定量West- ern blot测定HMGB1的水平。RIP2 siRNA质粒转染小鼠后,予LPS刺激小鼠,观察小鼠死亡率,用Western blot方法检测肝组织RIP2和HMGB1的表达,ELISA法测定血清TNF-α的水平。结果:RIP2 siRNAⅢ号质粒可阻断RIP2的mRNA和蛋白表达。LPS刺激后,阻断RIP2的细胞产生TNF-α、HMGB1减少;体内转染后,阻断RIP2的小鼠生存率较其它组高,肝组织中HMGB1的表达较其他组减少,血清TNF-α水平较其它组低。结论:RIP2 siRNAⅢ号质粒可阻断RIP2的表达,从而减少TNF-α、HMGB1等炎症细胞因子的产生,降低小鼠内毒素血症的死亡率。     

Toll样受体4在四氯化碳致大鼠慢性肝损伤中的作用机制研究

目的:动态观察肝Kupffer细胞(KCs)Toll样受体4(TLR4)mRNA及蛋白在四氯化碳(CCl4)致大鼠慢性肝损伤中的表达及作用.方法:以CCl4诱导慢性肝损伤大鼠模型,于0、4、6、8、10周采集标本,分离肝组织KCs并以逆转录聚合酶链反应检测TLR4mRNA的表达;用基质显色法测定大鼠血清内毒素水平:放射免疫法测定血清肿瘤坏死因子-α(TNF-α)和白细胞介素1-β(IL1-β)水平;TLR4蛋白和核因子kB(NF-kB)蛋白采用免疫组化SP法检测.结果:0周组肝组织TLR4蛋白、KCs,TLR4 mRNA几乎无表达,NF-kB蛋白和炎症积分水平也处于较低水平;4、6、8、10周组肝组织TLR4蛋白、NF-kB蛋白、炎症积分和KCs TLR4 mRNA以及血清内毒素、TNF-α、IL-1β水平明显升高,同0周组比较差异有显著性(P<0.001).NF-kB蛋白、TLR4蛋白、KCs TLR4 mRNA和TNF-α在第10周时较第8周有轻度下降:肝KCs TLR4 mRNA的表达与血浆内毒素水平呈正相关(r=0.845,P<0.001).结论:CCl4诱导的慢性肝损伤中,内毒素可上调KCs TLR4的表达,而TLR4的高表达进一步造成肝脏的损伤.     

靶向TNF-α基因shRNA干扰片段的筛选和重组体的构建

本研究利用RNA干扰技术，筛选出可以高效、特异性抑制肿瘤坏死因子-α（TNF-α）表达的小发夹状RNA（shRNA）片段，设计并构建重组质粒，进行序列分析，为探索TNF-α相关疾病的基因治疗提供新途径。取原代培养小鼠腹腔巨噬细胞，置于15％ DMEM中，调细胞浓度为2×10^7／L，接种于6孔板，3ml／well；细胞用脂多糖（LPS）激活，ELISA法测不同时间培养上清中TNF—α的浓度；将针对TNF-α基因的5段shRNA干扰片段的表达框经PCR扩增、纯化后，与转染试剂混合转染入巨噬细胞，细胞用LPS激活24小时后用ELISA法测培养上清中TNF-α的浓度，RT—PCR法测细胞TNF-α mRNA的表达；将最有效抑制TNF-α表达的干扰片段插入质粒载体，转化Ecoli DH5α感受态菌株，提取质粒，进行测序分析。结果表明：LPS刺激巨噬细胞24小时后，细胞分泌TNF—α达高峰；转染了干扰序列1的细胞培养上清中TNF—α浓度与对照组相比下降最明显（P〈0．05），达59．46％，TNF—α mRNA的表达被抑制了61．2％；将干扰序列1DNA序列克隆到载体上，经测序鉴定确实为所需序列。结论：成功筛选出靶向TNF-α基因的shRNA干扰片段并构建重组质粒，可进一步利用克隆所得到的shRNA干扰TNF-α mRNA的表达，为TNF—α相关疾病的基因治疗提供新手段。     

TLR4基因的shRNA对内毒素刺激下RAW264.7细胞TLR2表达的影响及机制

目的 观察针对Toll样受体4的发夹结构RNA(short hairpin RNA,shRNA)对内毒素刺激后小鼠巨噬细胞系RAW264.7细胞Toll样受体2表达的影响,并探讨其机制.方法 将携带增强型绿色荧光蛋白(EGFP)及shRNA克隆位点的质粒pEGFP/TLR4-siRNA,运用脂质体Lipofectamine2000转染至小鼠巨噬细胞系RAW264.7.转染24 h后予新霉素(G418)筛选获取稳定转染细胞株.然后将细胞分为三组:空白组(Blank group),未转染细胞LPS刺激组(LPS group)和稳定转染细胞LPS刺激组(LPS-TLR4-siRNA group),采用荧光定量PCR及流式细胞学方法检测各组细胞TLR2 mRNA和蛋白的表达,Western blot检测NF-κB p65的表达,同时用ELISA方法检测细胞分泌的TNF-α水平的变化.结果 将pEGFP/TLR4-siRNA转染至RAW264.7细胞后,增强型荧光蛋白的表达为(45.25±9.23)%.LPS-TLR4-siRNA组细胞的TLR2mRNA及蛋白的表达均明显低于LPS组(P＜0.05),同时NF-κB p65表达下调及分泌TNF-α的水平下降(P＜0.01).结论 针对TLR4 mRNA的shRNA能降低LPS刺激下的RAW204.7细胞TLB2的表达.     

TLR4基因小干扰RNA对缺氧复氧诱导肾小管上皮细胞凋亡的影响

目的研究Toll样受体4(TLR4)基因小干扰RNA(siRNA)对体外缺氧复氧条件下诱导肾小管上皮细胞分泌TNF-α的抑制作用。方法 Wistar大鼠原代肾小管上皮细胞(PTECs)置于六孔培养板培养,随机分为A组(正常培养组)、B组(缺氧复氧+TLR4-siRNA转染组)、C组(缺氧复氧组)、D组(缺氧复氧+对照siRNA转染组)共4组。其中B组、C组和D组细胞缺氧3h,随后复氧24h,RT-PCR方法和Westernb lot检测TLR4 mRNA和蛋白表达情况;流式细胞仪检测细胞凋亡情况,ELISA方法检测各组上清液中TNF-α含量。结果经缺氧复氧处理后,B组、C组和D组的TLR4 mRNA、蛋白水平较A组均显著上调(P<0.01),各组上清液TNF-α含量较A组也显著升高(P<0.01):而B组TLR4 mRNA、TLR4蛋白表达量和上清液TNF-α含量较C组和D组均显著下调(P<0.01);D组与C组相比,各项检测指标表达无显著变化(P>0.05)。结论针对TLR4 mRNA的siR-NA可以有效地抑制缺氧复氧诱导的肾小管上皮细胞的凋亡和炎症反应。     

氨溴索对急性肺损伤的保护作用

目的 通过建立急性肺损伤大鼠模型和体外肺泡巨噬细胞培养体系,观察急性肺损伤中,肺泡巨噬细胞在氨溴索干预前后细胞因子表达的情况,探讨氨溴索可能的肺损伤保护机制.方法 一、体内实验:大鼠24只,随机分成3组,每组8只:(1)正常对照组;(2)急性肺损伤组:采用腹腔注射酵母悬液方法复制大鼠急性肺损伤模型;(3)氨溴索治疗组:建立ALI大鼠模型后用氨溴索干预.观察指标主要有:肺部病理学改变、测量大鼠肺系数、血氧分压,肺泡巨噬细胞TNF-α、IL-10、IL-24 mRNA的表达则采用通过逆转录-聚合酶链式反应(RT-PCR)技术检测.二、体外实验:收集肺泡巨噬细胞后分3组:(1)正常对照组:肺泡巨噬细胞中加无菌生理盐水;(2)LPS组:予LPS 10 mg/L刺激肺泡巨噬细胞;(3)LPS+氨溴索组:予LPS10 mg/L和氨溴索180 μmol/L刺激肺泡巨噬细胞.分别于刺激前(0 h),刺激后(6、12、24 h)留取细胞.通过RT-PCR技术检测肺泡巨噬细胞TNF-α、IL-10、IL-24 mRNA的表达变化.结果 氨溴索治疗组在病理改变,肺系数,动脉血氧分压等各项指标均优于急性肺损伤组,氨溴索干预治疗组,TNF-α、IL-10、IL-24 mRNA表达水平均明显下降,与急性肺损伤组比较差异有统计学意义(P＜0.05),但仍高于正常对照组.体外实验也得出了相同的结论.结论 氨溴索可抑制急性肺损伤或LPS刺激的肺泡巨噬细胞TNF=α、IL-10、IL-24细胞因子mRNA的表达水平.     

白介素-10对内毒素诱导肺泡巨噬细胞核因子-κB活化及肿瘤坏死因子释放的调节

目的 探讨白介素-10对内毒素(LPS)诱导肺泡巨噬细胞核因子-κB(NF-κB)活化及肿瘤坏死因子α(TNF-α)基因表达的调节,为临床运用白介素-10提供理论依据。方法 用支气管肺泡灌洗法收集肺泡巨噬细胞(PAM)进行培养,分正常对照组、LPS组、IL-10＋LPS组。用凝胶电泳迁移率改变分析(EMSA)法和ELISA法分别检测核提取物中NF-κB活性和细胞培养上清中TNF-α含量。结果 LPS组NF-κB活性和TNF-α含量在刺激后0.5～4h明显高于正常对照组;IL-10＋LPS组NF-κB活性和TNF-α含量均显著低于LPS组。结论 LPS诱导PAM的NF-κB活化,导致TNF-α基因表达增强;白介素-10可抑制NF-κB活化而减少TNF-α的释放。     

大鼠过氧化物酶体增生因子活化受体α基因重组腺病毒载体及在乳鼠心肌细胞中的表达☆

背景:过氧化物酶体增生因子活化受体α是调节心脏脂肪酸氧化的重要核转录因子,利用基因工程技术构建其重组腺病毒载体对研究心脏能量代谢障碍机制具有重要意义. 目的:构建大鼠过氧化物酶体增生因子活化受体α基因重组腺病毒载体,评价其在原代培养的乳鼠心肌细胞中的表达效率. 方法:采用RT-PCR法自SD大鼠肝脏扩增过氧化物酶体增生因子活化受体α基因,将其克隆至带有增强型绿色荧光蛋白的穿梭质粒载体pAd-Track-CMV.线性化重组穿梭质粒载体并转化入含有腺病毒骨架质粒pAd-Easy-1的感受态大肠杆菌BJ5183构建重组腺病毒载体质粒.用脂质体将线性化的重组腺病毒载体质粒转染于人胚肾293细胞以包装、扩增,纯化病毒后计算滴度.用纯化的重组腺病毒转染心肌细胞,荧光显微镜观察转染效率;荧光定量PCR、免疫印迹法检测细胞过氧化物酶体增生因子活化受体α mRNA、蛋白表达. 结果与结论:成功构建携带大鼠过氧化物酶体增生因子活化受体α基因的重组腺病毒载体,病毒滴度为3.5×1011 pfu/L.重组腺病毒转染心肌细胞的效率达90%以上,被转染细胞目的基因mRNA、蛋白表达显著增高.该载体的成功构建为研究过氧化物酶体增生因子活化受体α基因在心肌能量代谢障碍中的作用奠定基础.     

白细胞介素-10对内毒素诱导急性肺损伤大鼠炎症因子的影响

目的研究白细胞介素-10(IL-10)对内毒素诱导急性肺损伤(ALI)大鼠肺组织炎症因子mRNA表达的影响,探讨IL-10对急性肺损伤的保护作用。方法24只SD大鼠随机分为3组:对照组,实验组,治疗组。实验组于尾静脉注射内毒素,治疗组注射内毒素和IL10,对照组注射生理盐水。测定各组肺组织肿瘤坏死因子-α(TNF-α)、白介素-1β(IL-1β)和白介素-6(IL-6)mRNA表达和血浆TNF-α、IL-1β和IL-6水平,观察各组大鼠肺组织的病理改变。结果TNF-α、IL-1β和IL6mRNA的表达:实验组、治疗组高于对照组,P<0.01;实验组高于治疗组,P<0.05。血浆TNF-α、IL1-β、IL-6:实验组高于治疗组对照组,P<0.05。肺组织病理改变:治疗组明显轻于实验组。结论IL10能抑制内毒素诱导ALI大鼠肺组织中TNF-α、IL-1β和IL6mRNA的表达,降低血浆炎症因子水平,减轻肺组织的病理损害,能起到治疗ALI的作用。     

Eosinophilia in transgenic mice expressing interleukin 5

Experiments in vitro suggest that although interleukin 5 (IL-5) stimulates the late stages of eosinophil differentiation, other cytokines are required for the generation of eosinophil progenitor cells. In this study transgenic mice constitutively expressing the IL-5 gene were established using a genomic fragment of the IL-5 gene coupled to the dominant control region from the gene encoding human CD2. Four independent eosinophilic transgenic lines have thus far been established, two of which with 8 and 49 transgene copies, are described in detail. These mice appeared macroscopically normal apart from splenomegaly. Eosinophils were at least 65- and 265-fold higher in blood from transgenics, relative to normal littermates, and approximately two- or sevenfold more numerous relative to blood from mice infected with the helminth Mesocestoides corti. Much more modest increases in blood neutrophil, lymphocyte, and monocyte numbers were noted in transgenics, relative to normal littermates (less than threefold). Thus IL-5 in vivo is relatively specific for the eosinophil lineage. Large numbers of eosinophils were present in spleen, bone marrow, and peritoneal exudate, and were highest in the line with the greatest transgene copy number. Eosinophilia was also noted in histological sections of transgenic lungs, Peyer's patches, mesenteric lymph nodes, and gut lamina propria but not in other tissues examined. IL-5 was detected in the sera of transgenics at levels comparable to those seen in sera from parasite-infected animals. IL-3 and granulocyte/macrophage colony-stimulating factor (GM-CSF) were not found. IL-5 mRNA was detected in transgenic thymus, Peyer's patches, and superficial lymph nodes, but not in heart, liver, brain, or skeletal muscle or in any tissues from nontransgenics. Bone marrow from transgenic mice was rich in IL-5-dependent eosinophil precursors. These data indicate that induction of the IL-5 gene is sufficient for production of eosinophilia, and that IL-5 can induce the full pathway of eosinophil differentiation. IL-5 may therefore not be restricted in action to the later stages of eosinophil differentiation, as suggested by earlier in vitro studies.     

Cells expressing Ia antigens in the avian thymus

The various cell types expressing Ia antigens in the chick and quail thymus have been studied by means of monoclonal antibodies (mAb) prepared by using chick and quail thymic adherent cells (macrophages and dendritic cells) as immunogens. Three reagents were selected by the following criteria: (a) they react with a surface determinant carried by thymic adherent cells and bursal lymphocytes, (b) they can be used to immunoprecipitate from spleen cell membrane extracts molecular entities of an apparent molecular weight close to 55,000, which can be fractionated into monomers at approximately 30,000 mol wt in dissociating conditions. Among these three reagents, two are strictly species specific, i.e., they recognize either chick (TaPl) or quail (TaCl) Ia determinants, whereas the third, TaC2, recognizes both chick and quail Ia molecules. Chimeric thymuses in which the epithelioconnective stroma is derived from the quail thymic primordium and the whole hemopoietic cell population (lymphocytes and accessory cells) are of chick origin were constructed as previously described by our group (20). The different mAb were applied on normal (quail and chick) and chimeric thymuses. It appears that the thymus is divided into two compartments in terms of the nature of cells expressing Ia: the cortex, in which class II antigens are exclusively expressed by endodermal epithelial cells, and the medulla, where the majority of nonlymphoid cells are Ia-positive cells of hemopoietic origin. A few epithelial cells only are present in the thymic medulla. They are closely intricated with the sessile Ia-positive cells, whose precursors penetrate the thymus along with the lymphocyte progenitors and which are renewed in the course of thymic development. In contrast, the epithelial reticulum, expressing Ia both in the cortex and medulla, contributes a stable thymic component. During early thymic ontogeny, the hemopoietic cells expressed detectable levels of Ia antigen before the epithelial cell network.     

Improved production of adenovirus vectors expressing apoptotic transgenes

Adenovirus vectors expressing gene products that can induce apoptosis have potential utility in gene therapy applications ranging from the treatment of proliferative diseases to transplantation. However, adenovirus vectors carrying proapoptotic gene products are difficult to produce, as the apoptotic environment is not conducive to adenovirus gene expression and replication. Production of AdFasL/G, an adenovirus vector that expresses high levels of Fas ligand, was severely reduced in the 293 packaging cell line. Increased yields of AdFasL/G were achieved by inclusion of peptide-based caspase inhibitors in the growth medium. However, use of these inhibitors for large-scale production would be difficult and expensive. A screen for gene products that increase the yield of AdFasL/G in 293 cells revealed that the poxvirus serpin CrmA and the adenovirus 14.7K product were able to increase virus yields significantly. Apoptosis induced by AdFasL/G was attenuated in 293CrmA cell lines and virus titers were increased dramatically. However, serial passage of AdFasL/G on 293CrmA cells resulted in the generation of replication-competent adenovirus. To resolve this problem, the CrmA gene was introduced into AE25 cells, an E1-complementing cell line that has limited sequence identity with the vectors. AdFasL/G titers were increased 100-fold on AE25CrmA cells relative to the AE25 cells and RCA contamination was not detectable. In addition, adenovirus vectors that express FADD, caspase 8, and Fas/APO1 were produced efficiently in AE25CrmA and 293CrmA.     

日本血吸虫丝氨酸蛋白酶抑制剂的克隆与表达

目的获得日本血吸虫丝氨酸蛋白酶抑制剂的原核表达蛋白。方法根据GenBank中日本血吸虫丝氨酸蛋白酶抑制剂的序列设计引物,以cDNA为模板聚合酶链反应(PCR)扩增该基因,将其亚克隆入原核表达载体pET28a中,异丙基硫代半乳糖苷(IPTG)诱导表达重组蛋白。结果成功克隆了具有完整开放阅读框的日本血吸虫丝氨酸蛋白酶抑制剂重组质粒,获得相对分子质量约44×103的目的蛋白。结论成功地克隆表达了丝氨酸蛋白酶抑制剂,为进一步研究该蛋白的特性、功能及免疫保护作用奠定了基础。     

携带DREAM基因小分子干扰RNA重组质粒的构建

背景：DREAM是一种多功能蛋白，在细胞中不同位置与不同靶蛋白结合，体外细胞培养和动物实验均证明DREAM参与了许多疾病的发病机制。目的：构建携带DREAM基因的小分子干扰RNA重组质粒。方法：设计并合成shRNA对应的两条互补的寡核苷酸链，pDC316-EGFP—U6质粒经BamH I 和 HindIII双酶切与退火后的寡核苷酸连接，转化感受态coliDH5a，获得阳性克隆进行PCR和测序鉴定。结果与结论：经PCR、酶切及测序证实，重组质粒pDC316-EGFP．DREAM-shRNA-U6片段大小为473bp，其中插入的片断序列和位点与预期完全一致，说明pDC316．EGFPDREAM．shRNA-U6重组质粒构建成功。     

Tumor-targeted Salmonella expressing cytosine deaminase as an anticancer agent

The study was designed to evaluate whether TAPET-CD, an attenuated strain of Salmonella typhimurium expressing Escherichia coli cytosine deaminase (CD), was capable of converting nontoxic 5-fluorocytosine (5-FC) to the active antitumor agent 5-fluorouracil (5-FU). The antitumor effect of TAPET-CD plus 5-FC against subcutaneously implanted colon tumors was also evaluated. TAPET-CD was given to tumor-bearing mice by a single bolus intravenous administration followed with 5-FC by intraperitoneal administration. TAPET-CD accumulated in tumors at levels 1000-fold higher than that in normal tissues and high levels of 5-FU were detected in tumors in mice treated with both TAPET-CD and 5-FC. No 5-FU could be detected in normal tissues. Inhibition of tumor growth was observed in mice treated with either TAPET-CD alone or TAPET-CD in combination with 5-FC (TAPET-CD/5-FC), but not with 5-FC alone. TAPET-CD/5-FC inhibited tumor growth by 88%-96%, compared to TAPET-CD alone, which inhibited tumor growth by 38%-79%. These data suggest that tumor-targeting Salmonella could be used to deliver prodrug-converting enzyme selectively to tumors and produced anti-tumor effects when the corresponding prodrug was also given.     

Oncolytic adenoviruses expressing interleukin: a novel antitumour approach

Importance of the field: Viral oncolysis, or virotherapy, is an emerging strategy for the treatment of cancer based on tumor cell killing by virus infection and replication. Oncolytic adenoviruses have shown promise in clinical trials, which demonstrated proof-of-concept for tumor-selective virus replication and a favorable safety profile.

Areas covered in this review: We provide an overview of specifications for a novel antitumour approach by oncolytic adenoviruses expressing interleukin and discuss recent progresses in this field.

What the reader will gain: Creating an armed therapeutic viral platform, where the lytic property of viral infection coupled to virus-mediated interleukin delivery, may enhance the potential of virus-based therapeutics.

Take home message: Oncolytic adenoviruses expressing interleukin may be a novel approach for tumour treatment. Combining advances in oncolytic adenoviruses with interleukin will open new avenues for treatment of human tumour.