化学修饰对反义寡核苷酸稳定性及抗流感病毒活性的影响

为了探讨 Ａ Ｓ Ｏ Ｄ Ｎ 化学修饰形式与 Ａ Ｓ Ｏ Ｄ Ｎ 稳定性,体外细胞毒性以及抗流感病毒活性之间的关系,合成了 ７ 种不同化学修饰形式的 Ａ Ｓ Ｏ Ｄ Ｎ：硫代 Ａ Ｓ Ｏ Ｄ Ｎ 及其 ３′端分别磷酸化和胆固醇修饰;３′与 ５′端硫代,中间为天然结构的混合骨架 Ａ Ｓ Ｏ Ｄ Ｎ;天然结构 Ａ Ｓ Ｏ Ｄ Ｎ 及其 ３′端分别磷酸化和胆固醇修饰等．测定了 ７ 种修饰体在小鼠血清, Ｍ Ｄ Ｃ Ｋ 细胞裂解液,含 ２％ 胎牛血清的 Ｄ Ｍ Ｅ Ｍ培养液以及水中的稳定性,体外细胞毒性和在细胞水平抗流感病毒活性．结果表明,混合骨架 Ａ Ｓ Ｏ Ｄ Ｎ,硫代 Ａ Ｓ Ｏ Ｄ Ｎ 及其 ３′端接磷酸和胆固醇的修饰形式在小鼠血清, Ｍ Ｄ Ｃ Ｋ 细胞裂解液与含２％ 胎牛血清的 Ｄ Ｍ Ｅ Ｍ 培养液中稳定性相对较高,作用 ２４～４８ ｈ 仅混合骨架 Ａ Ｓ Ｏ Ｄ Ｎ 与硫代 Ａ Ｓ Ｏ Ｄ Ｎ 发生部分降解;天然结构 Ａ Ｓ Ｏ Ｄ Ｎ 及其 ３′端接磷酸和胆固醇修饰体在 ２４ ｈ 内大部分降解．所有 Ａ Ｓ Ｏ Ｄ Ｎ 修饰体在水中具有很高稳定性,４８ ｈ 内未见降解作用．７ 种 Ａ Ｓ Ｏ Ｄ Ｎ 修饰形式在 Ｍ Ｄ Ｃ Ｋ 细胞中未表现明显的细胞毒性．硫代 Ａ Ｓ Ｏ Ｄ Ｎ 及其 ３′端接磷酸和胆     

硫代反义寡核苷酸在细胞培养内抗甲型流感病毒活性

为了研究抗流感病毒特异性反义核酸药物,针对Ａ型流感病毒基因组３＇和５＇端保守序列,设计并合成了４条硫代寡核苷酸（ＯＤＮ）：３＇端反义ＯＤＮ（ＩＶ３＾＃）与３＇端正义ＯＤＮ（ＩＶ３Ｓ）,５＇端反义ＯＤＮ（ＩＶ４＾＃）与５＇端正交ＯＤＮ（ＩＶ４Ｓ）。以流感病毒血凝滴度和致细胞病变作用为指标,测定了ＯＤＮｓ在ＭＤＣＫ细胞中对Ａ型流感病毒Ａ／京防／８６－１（Ｈ１Ｎ１）复制的影响。结果表明,与流感病毒基因组     

tRNA-包埋核酶在HepG2细胞中的抗HBV活性

已知 ｔ Ｒ Ｎ Ａ 包埋核酶比裸露核酶在胎牛血清和 Ｈｅｐ Ｇ２ 细胞抽提液中有较高的稳定性 构建了 ｈ Ｃ Ｍ Ｖ 启动子驱动下的抗 Ｈ Ｂ Ｖ（ａｄｒ 亚型）的 ｔ Ｒ Ｎ Ａ 包埋核酶基因质粒,与携带 Ｈ Ｂ Ｖ 基因的ｐ１２Ⅱ质粒共转染 Ｈｅｐ Ｇ２ 细胞,用 Ｇ４１８ 筛选抗性细胞 分析稳定表达细胞中的 Ｈ Ｂ Ｖ Ｒ Ｎ Ａ, Ｈ Ｂ Ｖ 抗原合成和新生 Ｄ Ｎ Ａ 合成,表明ｔ Ｒ Ｎ Ａ 包埋核酶比裸露核酶有较高的抑制 Ｈ Ｂ Ｖ 活性．ｔ Ｒ Ｎ Ａ 包埋核酶和裸露核酶分别使靶 Ｒ Ｎ Ａ 减少 ８２％ ～８７％ 和 ７５％ ～８１％ ,抗原减少 ７３％ ～８０％ 和７０％ ～７４％ 以及新生 Ｄ Ｎ Ａ 减少 ７４％ ～７６％ 和 ６７％ ～７１％ 结果指出,核酶,特别是 ｔ Ｒ Ｎ Ａ 包埋核酶,对 Ｈｅｐ Ｇ２ 细胞中 Ｈ Ｂ Ｖ 表达和复制有明显抑制作用,可能作为 Ｈ Ｂ Ｖ 基因治疗的手段之一      

SA脂质体介导DNA转染细胞的进一步研究

ＳＡ脂质体可高效介导ＤＮＡ转染ＣＶ－１细胞,本文进步研究表明,ＳＡ脂质体还可介导ＤＮＡ高效瞬时和稳定地转染ＣＨＯ和ＣＯＳ细胞。ＳＡ脂质体和ＤＮＡ形成复合物可保护ＤＡＮ不被核酸内切酶和ＤＮａｓｅＩ降解。荧光标记和细胞松驰素Ｂ抑制实验分别表明,ＳＡ脂质体易被细胞吸附,主要通过内吞传送ＤＮＡ进入细胞,而Ｌｉｐｏｆｅｃｔｉｎ主要通过融合传送ＤＮＡ进细胞。     

人脑源性神经营养因子cDNA在COS7细胞中的表达及活性研究

本文从质粒Ｍ１３ｍｐ１８－ｈＢＤＮＦ中酶切回收人脑源性神经营养因子（ｈＢＤＮＦ）全长基因,构建真核表达载体ｐＣＭＶ４－ｈＢＤＮＦ。利用脂质体的方法转染ＣＯＳ７细胞,对转染后的ＣＯＳ７细胞提取ＲＮＡ进行狭缝杂交分析和免疫细胞化学反应,分别从转录及翻译水平上检测ＢＤＮＦ基因在ＣＯＳ７细胞中的表达。实验还证实在ＣＯＳ７细胞中表达的ｈＢＤＮＦ蛋白可分泌至胞外并可促进中脑黑质细胞的发育和生长,具有良好的生物学活性。     

应用放射性自显影技术检测外源DNA与鸡精子的结合

应用放射性自显影技术检测外源ＤＮＡ与鸡精子的结合ＤＥＴＥＣＴＩＮＧＡＳＳＯＣＩＡＴＩＯＮＯＦＥＸＯＧＥＮＯＵＳＤＮＡＷＩＴＨＣＨＩＣＫＥＮＳＰＥＲＭＵＳＩＮＧＡＵＴＯＲＡＤＩＯＧＲＡＰＨＹ关键词鸡，精子，脂质体，ＤＮＡ与精子的结合ＫｅｙｗｏｒｄｓＣｈ...     

反义寡核苷酸对丙型肝炎病毒调控基因表达的体外抑制活性研究

为探讨反义寡核苷酸对丙型肝炎病毒的抑制活性,研究和开发新型抗ＨＣＶ药物。采用ＨＣＶ５’ＮＣＲ调控荧光素酶基因的稳定表达细胞株ＨｅｐＧ２．９７０６,评价了３条针对ＨＣＶ调控基因的ＡＳＯＤＮ,即ＨＣＶ３６３,ＨＣＶ３４９及ＨＣＶ２７９。将Ｌｉｐｏｆｅｃｔｉｎ包封的ＡＳＯＤＮ与ＨｅｐＧ２．９７０６细胞株每天作用５小时,连续３天后检测荧光素酶活性。     

雄激素对人前列腺细胞中鸟氨酸脱羧酶基因表达的调节作用

 为探讨雄激素对人前列腺中鸟氨酸脱羧酶（ Ｏ Ｄ Ｃ）基因表达的调节作用,以研究雄激素诱导前列腺良性增生的分子机理,分离培养了人胎儿前列腺间质细胞,以 Ｍ Ｔ Ｔ 法测定不同浓度 Ｄ Ｈ Ｔ对细胞的促增殖作用;以最适浓度的 Ｄ Ｈ Ｔ（１ ０００ μｇ／ Ｌ）刺激该细胞,分别于 ０,３,６,１２,２４,３０ ｈ 提取总 Ｒ Ｎ Ａ,用斑点杂交及 Ｎｏｒｔｈｅｒｎ ｂｌｏｔ 法分析测定各组细胞中 Ｏ Ｄ Ｃ ｍ Ｒ Ｎ Ａ 的丰度,并对杂交膜进行薄层扫描定量．结果显示：（１） Ｄ Ｈ Ｔ 对前列腺间质细胞的增殖呈双相调节作用,即在低浓度时随着 Ｄ Ｈ Ｔ 浓度的增加,对该细胞的促增殖作用增强,１ ０００ μｇ／ Ｌ时刺激活性最强,高浓度 Ｄ Ｈ Ｔ 对该细胞的刺激作用降低．（２）斑点杂交显示,在 １ ０００ μｇ／ Ｌ Ｄ Ｈ Ｔ 刺激细胞后 ６ ｈ 时, Ｏ Ｄ Ｃ ｍ Ｒ Ｎ Ａ开始明显升高,２４ ｈ 达高峰（约为 ０ ｈ 的 ４８ 倍）,至 ３０ ｈ 有所降低．（３） Ｎｏｒｔｈｅｒｎ ｂｌｏｔ 结果显示,人胎儿前列腺间质细胞中有两种 Ｏ Ｄ Ｃ ｍ Ｒ Ｎ Ａ,分别为 ２０ ｋｂ 和 ２６ ｋｂ,经扫描定量结果显示：１ ０００μｇ／ Ｌ Ｄ Ｈ Ｔ 对两种 Ｏ Ｄ Ｃ ｍ Ｒ Ｎ Ａ     

癫痫大鼠大脑皮质及海马神经元NOS的变化

给大白鼠侧脑室注射马桑内酯（Ｃｏｒｉａｒｉａ Ｌａｃｔｏｎｅ, ＣＬ）（１７５×１０－ ２ｍ ｏｌ／Ｌ２μｌ）后可诱发癫痫,用ＮＡＤＰＨｄ 组织化学方法观察大脑皮质及海马ＮＯＳ阳性神经元的变化, 结果： 大脑皮质ＮＯＳ阳性神经元数目逐渐增加, 至２ｈ 达高峰, 与生理盐水组相比差异具有非常显著性意义（Ｐ＜ ００１）, 随着ＣＬ作用时间延长ＮＯＳ反应由弱变强;海马区ＮＯＳ阳性神经元２ｈ 时才出现染色明显加深。对体外培养的大脑皮质及海马神经元用ＣＬ （２５×１０－ ５ｍ ｏｌ／Ｌ） 作用１／２ｈ、１ｈ、２ｈ、４ｈ 后ＮＯＳ阳性神经元均未见明显增加。     

人淀粉样前体蛋白基因C端在SH-SY5Y细胞系中的稳定表达及其对细胞生长发育的影响

淀粉样前体蛋白（ＡＰＰ）是阿尔茨海默氏病（ＡＤ）病因学中重要的分子,但其正常的生理功能尚不清楚．为了研究细胞内过量产生其各种片段对细胞生理机能的影响．将人ＡＰＰ６９５ｃＤＮＡ中编码Ｃ端１０５个氨基酸残基的ＤＮＡ片段重组到真核表达载体ｐＤＯＲｎｅｏ中形成重组质粒ｐＤＯＲ－ｎｅｏ－ＣＴ．然后用脂质体将其转染到人神经母细胞瘤细胞ＳＨ－ＳＹ５Ｙ中．用８００μｇ／ｍｌＧ４１８筛选获得了在ｍＲＮＡ和蛋白质水平均表达相应片段的稳定细胞系．ＭＴＴ和ＬＤＨ分析表明,ＡＰＰＣ端的表达未能对ＳＨ－ＳＹ５Ｙ细胞产生明显的毒性作用．     

阳性脂质体介导反义寡聚核苷酸转染HeLa细胞的效果研究

采用FITC标记的未经修饰的和经过修饰的两种19-mer反义寡聚核苷酸序列(ODN19和S-ODN19)作为转染物质,用流式细胞技术(FCM)研究比较几种常用阳性脂质体介导的寡聚核苷酸转染HeLa细胞的效果及适宜的转染时间。未经化学修饰的ODN19转染结果显示,LipofectAmine和DM-RIE-C增强转染的作用相对较强,而其他两种脂质体的作用并不明显。对于经过修饰的S-ODN19转染而言,四种阳性脂质体均具有增强S-ODN19转染作用,但以LipofectAmine的效果最为明显,其转染效果(FITC均值为5203.11)为无脂质体介导对照的数十倍。四种阳性脂质体的增强转染作用排序为:LipofectAmine>FuGENE6>Lipofectin>DM-RIR-C。另外,在用FuGENE6介导寡聚核苷酸转染时,采用4小时转染时间可获较好转染效果。     

反义寡核苷酸体外抗流感病毒活性

为了获得具有抗流感病毒活性的反义寡核苷酸,针对A型流感病毒基因组3′和5′端保守序列,设计并合成了多条硫代寡核苷酸(ODN)：3′端反义ODN(IV3#)与3′端正义ODN(IV3S);5′端反义ODN(IV4#)与5′端正义ODN(IV4S)以及由5′和3′端正义/反义保守序列组成的复合序列ODN(IV6#和IV7#)。测定了PSODN的体外细胞毒性和在MDCK细胞中对流感病毒复制的影响。结果表明：(1)PSODN浓度高达50μmol/L时对MDCK细胞末表现有毒性作用;(2)与流感病毒基因组5′端互补的ODN IV4#以及由5′和3′端保守序列构成的IV6#ODN和IV7#ODN均具有较高的抗病毒活性;如IV4#ODN浓度为1μmol/L时对流感病毒A/京防/861(H1N1)抑制率近50%,浓度为10μmol/L或更高时抑制率超过70%,且IV4#抑制病毒活性呈现明显的序列和剂量依赖性;(3)IV4#ODN不仅对A型流感病毒H1N1亚型有抑制作用,对H3N2亚型也表现较高的抑制活性;(4)病毒感染复数(MOI)对IV4#ODN抗病毒活性有一定影响,当MOI较低时,IV4#ODN表现的剂量效应关系更加明显。抗流感病毒反义寡核苷核IV4#ODN的发现为进一步研究流感新型药物奠定了实验基础。〖HTH〗关键词〖HTSS〗：流感病毒, 反义寡核苷酸, 体外细胞毒性, 抗病毒活性, 感染复数     

Sendai virus induced leakage of liposomes containing gangliosides

Sendai virus induced liposome leakage has been studied by using liposomes containing a self-quenching fluorescent dye, calcein. The liposomes used in this study were prepared by a freeze and thaw method and were composed of phosphatidylcholine, phosphatidylserine, and phosphatidylethanolamine (1:2.60:1.48 molar ratio) as well as various amounts of gangliosides and cholesterol. The leakage rate was calculated from the fluorescence increment as the entrapped calcein leaked out of the liposomal compartment and was diluted into the media. It was shown that the target liposome leakage was virus dose dependent. Trypsin-treated Sendai virus in which the F protein had been quantitatively removed did not induce liposome leakage, indicating that the leakage was a direct result of F-protein interaction with the target bilayer membrane. The activation energy of this process was approximately 12 kcal/mol below 17 degrees C and approximately 25 kcal/mol above 17 degrees C. Gangliosides GM1, GD1a, and GT1b could serve as viral receptor under appropriate conditions. Liposome leakage showed a bell-shaped curve dependence on the concentration of ganglioside in the liposomes. No leakage was observed if the ganglioside content was too low or too high. Inclusion of cholesterol in the liposome bilayer suppressed the leakage rate of liposomes containing GD1a. It is speculated that the liposome leakage is a consequence of fusion between Sendai virus and liposomes.     

Macrophage activation for microbicidal activity against Leishmania major: inhibition of lymphokine activation by phosphatidylcholine-phosphatidylserine liposomes

Resident peritoneal macrophages from untreated mice develop microbicidal activity against amastigotes of the protozoan parasite Leishmania tropica (current nomenclature = Leishmania major) after in vitro exposure to LK from antigen-stimulated leukocyte culture fluids. This LK-induced macrophage microbicidal activity was completely abrogated by addition of 7:3 phosphatidylcholine: phosphatidylserine liposomes. Liposome inhibition was not due to direct toxic effects against the parasite or macrophage effector cell; factors in LK that induce macrophage microbicidal activity were not adsorbed or destroyed by liposome treatment. Other phagocytic particles, such as latex beads, had no effect on microbicidal activity. Moreover, liposome inhibition of activated macrophage effector function was relatively selective: LK-induced macrophage tumoricidal activity was not affected by liposome treatment. Liposome inhibition was dependent upon liposome dose (5 nmoles/culture) and time of addition of leishmania-infected, LK-treated macrophage cultures. Addition of liposomes through the initial 8 hr of culture completely inhibited LK-induced macrophage microbicidal activity; liposomes added after 16 hr had no effect. Similarly, microbicidal activity by macrophages activated in vivo by BCG or Corynebacterium parvum was not affected by liposome treatment. Liposome treatment also did not affect the increased resistance to infection induced in macrophages by LK. These data suggest that liposomes interfere with one or more early events in the induction of activated macrophages (macrophage-LK interaction) and not with the cytotoxic mechanism itself (parasite-macrophage interaction). These studies add to the growing body of data that implicate cell lipid in regulatory events controlling macrophage effector function.     

Stable target-sensitive immunoliposomes.

Interaction of immunoliposomes composed of dioleoylphosphatidylethanolamine (DOPE) (80%), dioleoylphosphatidic acid (DOPA) (20%), and a small amount of specific antibody with Herpes Simplex virus (HSV) were studied by detecting the immune-dependent lysis of liposomes. DOPA was used as the principal stabilizer of the immunoliposomes. Antibodies conjugated with N-glutarylphosphatidylethanolamine or oxidized GM1 served as the target-specific ligands of immunoliposomes. These immunoliposomes (d = 160-180 nm) were stable for at least one month when stored at 4 degrees C. However, they undergo a rapid aggregation and lysis reaction in the presence of a membrane-bound target such as intact HSV virions. We have also employed epitope peptide-containing liposomes (target liposomes) to mimic the virus and showed that the immunoliposomes could be aggregated and lysed by the target liposomes in an antigen-dependent manner. Immunoliposome lysis could be accelerated by increasing the incubation temperature to 60-70 degrees C. No immunoliposome lysis was observed if the target liposomes were absent, indicating the prolonged stability of the immunoliposomes. Liposome lysis was always accompanied by liposome aggregation. However, the aggregation-induced liposome destabilization is unique to the HII phase-forming lipids such as DOPE. DOPC-containing immunoliposomes did not lyse despite the fact that massive liposome aggregation had taken place.     

Synthesis of S-linked NeuAc-α(2-6)-di-LacNAc bearing liposomes for H1N1 influenza virus inhibition assays

S-NeuAc-α(2-6)-di-LacNAc (5) was efficiently synthesized by a [2+2] followed by a [1+4] glycosylation, and later conjugated with 1,2-dilauroyl-sn-glycero-3-phosphoethanolamine (DLPE) to form both single-layer and multi-layer homogeneous liposomes in the presence of dipalmitoyl phosphatidylcholine (DPPC) and cholesterol. These liposomes were found to be weak inhibitors in both the influenza virus entry assay and the hemagglutination inhibition assay. The single layer liposome was found to more efficiently interfere with the entry of the H1N1 influenza virus into MDCK cells than the multilayer liposome containing 5.     

Architecture of a nascent viral fusion pore

Enveloped viruses use specialized protein machinery to fuse the viral membrane with that of the host cell during cell invasion. In influenza virus, hundreds of copies of the haemagglutinin (HA) fusion glycoprotein project from the virus surface. Despite intensive study of HA and its fusion activity, the protein's modus operandi in manipulating viral and target membranes to catalyse their fusion is poorly understood. Here, the three‐dimensional architecture of influenza virus–liposome complexes at pH 5.5 was investigated by electron cryo‐tomography. Tomographic reconstructions show that early stages of membrane remodeling take place in a target membrane‐centric manner, progressing from punctate dimples, to the formation of a pinched liposomal funnel that may impinge on the apparently unperturbed viral envelope. The results suggest that the M1 matrix layer serves as an endoskeleton for the virus and a foundation for HA during membrane fusion. Fluorescence spectroscopy monitoring fusion between liposomes and virions shows that leakage of liposome contents takes place more rapidly than lipid mixing at pH 5.5. The relation of ‘leaky’ fusion to the observed prefusion structures is discussed.     

FLT-1启动子在血管内皮细胞中特异生物活性的检测及其意义

目的:构建带有组织特异性FLT-1启动子的真核表达载体,检测其在转染的人脐静脉内皮细胞（HUVEC）中对荧光素酶报告基因表达的驱动能力。方法：采用PCR扩增FLT-1启动子,插入到pGL3-Basic-luc载体中,构建携带FLT-1启动子的真核表达载体pGL3-FLT-Basic-luc,经脂质体法转染HUVEC、HepG2、NIH3T3和HEK293细胞,于转染48h后采用双荧光报告系统检测荧光素酶表达活性。 结果:酶切及测序证实构建的pGL3-FLT-Basic-luc载体中含有序列正确的FLT-1基因启动子,双荧光报告系统检测显示,转染的HUVEC细胞其荧光素酶活性明显高于HEK293细胞（P<0.01）,而转染的HepG2和NIH3T3细胞中未检测出荧光素酶表达。结论:克隆的FLT-1启动子具有较高的血管内皮特异性转录活性,可作为血管疾病靶向基因治疗的启动子来源。图     

Fusion of influenza virus with cardiolipin liposomes at low pH: mass action analysis of kinetics and extent

The kinetics and extent of low pH induced fusion between influenza virus and large unilamellar cardiolipin liposomes were investigated with an assay for lipid mixing based on fluorescence resonance energy transfer. The results were analyzed in terms of a mass action kinetic model, which views the overall fusion reaction as a sequence of a second-order process of virus-liposome adhesion or aggregation followed by the first-order fusion reaction itself. The fluorescence development during the course of the fusion process was calculated by numerical integration, employing separate rate constants for the initial aggregation step and for the subsequent fusion reaction. Analytical solutions were found for several limiting cases. Deaggregation of virus--liposome aggregates was explicitly taken into account but was found to be a minor effect under the conditions studied. The calculations gave good simulations and predictions for the kinetics and extent of fusion at different virus/liposome concentrations and ratios. At pH 5.0 and 37 degrees C, very high rate constants for aggregation and fusion were obtained, and essentially all of the virus particles were involved in the fusion process. Experiments at different virus/liposome ratios showed that fusion products may consist of a single virus particle and several liposomes but not of a single liposome and several virus particles. At pH 6.0, the rate constant for aggregation was the same as at pH 5.0, but the rate constant of fusion was about 5-fold lower, and only 25-40% of the virus particles were capable of fusing with the liposomes. The analytical procedure presented enables elucidation of the crucial role of the composition of target membrane vesicles in the initial adhesion and subsequent fusion of the virus at various pH values.