基因转染技术的发展与现状

基因转染技术是基因研究中的重要实验手段。探讨了基因转染的兴起和发展,介绍了6种基因转染方法,其中重点对两种新方法——颗粒轰击技术和光诱导的光化学内在基因转染方法进行了介绍,并对各种方法的优势和不足进行了比较,以便研究人员在研究中更好地选择实验方法。介绍了基因转染技术在基因研究中的应用。     

载体与基因转染的研究进展

基因载体是指将基因或其它核酸物质运载到细胞中的工具.其化学本质可以是蛋白质或多肽、核酸、脂类、糖类、其它有机分子或它们的复合物.基因传递系统是基因治疗的重要组成部分,也是目前基因治疗的瓶颈.现有的基因载体包括两类.即病毒载体和非病毒载体.病毒载体转染效率高,但由于其转染具有免疫原性和致突变性限制了它的应用;非病毒载体系统具有低毒、低免疫原性和相对靶向性等优点,是新兴发展起来的基因转移系统.就各种载体的最新研究进展作一综述.     

mRNA-Lipoplex loaded microbubble contrast agents for ultrasound-assisted transfection of dendritic cells

In cancer immunotherapy the immune system should be triggered to specifically recognize and eliminate tumor cells in the patient's body. This could be achieved by loading dendritic cells (DCs) with tumor-associated antigens (TAAs). This can be achieved by transfecting DCs with messenger RNA encoding a tumor-associated antigen. Here we demonstrate transient transfection of dendritic cells by means of mRNA-lipoplexes bound to microbubbles. Microbubble-attached lipoplexes were introduced into the cells by applying ultrasound. Our data demonstrate that ultrasound-mediated delivery of mRNA-complexes led to efficient transfection of DCs. When mRNA encoding luciferase was used, maximal levels of the enzyme activity were detected 8 h after ultrasound application. Upon longer incubation protein expression gradually declined. This treatment did not affect viability of the cells. Intracellular localisation of mRNA-lipoplexes in DCs was determined by flow cytometry using fluorescently labeled lipoplexes. Over 50% of DCs contained fluorescently labeled mRNA-complexes. In the absence of additional maturation signals, transfection of immature DCs with mRNA-lipoplex loaded microbubbles and ultrasound application induced only a minor shift in the expression level of maturation markers (CD40 and CD86). However, in the presence of the activation stimulus (LPS), cells were able to further mature as shown by a significant up-regulation of CD40 expression. Thus, our results demonstrate that mRNA-lipoplex loaded microbubbles can serve as an applicable and safe tool for efficient mRNA-transfection of cultured DCs.     

Dual-role self-assembling nanoplexes for efficient gene transfection and sustained gene delivery

Novel cationic pentablock copolymers with poly(diethylamino ethyl methacrylate) blocks covalently attached to parent triblock Pluronic copolymers have been designed and developed as sustained release non-viral gene delivery vectors. These copolymers electrostatically condense plasmid DNA into nanostructures (nanoplexes) and further self-assemble above critical concentration to form thermoreversible hydrogels at physiological temperatures. Unlike other sustained gene delivery systems of non-ionic copolymers that release naked DNA, hydrogels of pentablock copolymer/DNA nanoplexes dissolve in excess buffers to release DNA compacted inside the nanoplexes. These hydrogels permit aqueous pharmaceutical formulations that do not involve organic solvents and are non-invasively injectable with syringes into localized tissues where they instantly form hydrogels in situ. The hydrogels were found to have better mechanical strength than Pluronic gels. Hydrogels of nanoplexes containing 15wt% copolymer dissolved to release nanoplexes up to 5 days in vitro, compared to rapid release of up to 90% entrapped naked DNA from only Pluronic gels by day 1. The release profile of the nanoplexes from the hydrogels could be modulated by changing the concentration of copolymer or plasmid DNA in the hydrogel formulation. Since DNA is electrostatically bound to copolymer molecules, it does not freely diffuse out of the polymeric network, preventing initial release bursts observed with other such controlled release gels/matrices/microspheres. The released nanoplexes were colloidally stable, preserved the integrity of supercoiled plasmid DNA, and gave good transfection efficiencies in vitro upon dissolution. These novel copolymers, thus, act as both nanoscale gene delivery vectors and macroscale sustained delivery agents, and make a clinically viable long-term sustained gene delivery system.     

超声微泡造影剂与眼科基因转染

超声辐照破坏载基因微泡造影剂进行基因转染，为眼科疾病基因治疗提供了一种安全、高效的新技术。对超声微泡介导基因转染的研究已涉及心脏、肝脏、血管等领域，在眼科学方面研究较少，研究主要集中在角膜组织。应进一步研究眼组织细胞的转染情况，优化超声照射参数。超声微泡造影剂有广阔的发展前景，其在眼科基因治疗方面必将发挥巨大的作用。     

磁性纳米颗粒介导基因转染的研究进展

介绍了磁性纳米颗粒介导基因转染的最新研究进展,面临的主要问题以及将来的发展方向.     

超声－微气泡介导的基因转染研究进展

能否成功高效地转染靶基因对于基因治疗的效果具有决定性的影响。微气泡是具有稳定的封装壳,直径为微米量级的小气泡,已作为超声造影剂被广泛应用。微气泡在超声脉冲的作用下可以在靶区释放其携带的基因并使之转染,同时超声脉冲产生的热效应和空化效应能提高转染率。若将微气泡与磁性纳米颗粒结合,还可以进一步提高转染率和转染精度,是一种理想、安全的基因载体。本文综述了由超声－微气泡介导的基因转染在近5年的主要研究成果。对影响转染率的主要因素如微气泡种类、超声辐照条件、基因及受体类型等方面做了详细的论述,并对微气泡介导基因转染过程中的安全性、长效性和差异性等问题进行了讨论。     

A serum-resistant polyamidoamine-based polypeptide dendrimer for gene transfection

A serum tolerant polycation gene vector, G(2) PAMAM-PGlu-G(1) PAMAMs (ALA), was designed, synthesized, characterized and evaluated. A honeycomb-like molecular structure model for mechanistic explanation of ALA was postulated and discussed. Designed as a star-shaped polyamidoamine (PAMAM)-based polypeptide dendrimer through peptide bond linkages, ALA was with non-toxic low generation G(2) PAMAM (G(2)) as its central core, polyglutamate (PGlu)s as its star-shaped backbone branches and G(1) PAMAM (G(1))s as its branch grafts and peripheral terminals. IR, (1)H NMR demonstrated its successful combination. As a gene carrier, ALA exhibited good DNA binding and condensation capacity with particle size (approximately 87 nm for N/P 40, approximately 170 nm for N/P 30) and ζ-potential (approximately 16 mV for N/P 30-40), negligible cytotoxicity, exciting serum tolerant capacity and significant serum-promoted (serum-containing 56.6%>serum-free 32.7%), cell line dependent (Hek 293 > Bel 7402 > Hela), incubation period dependent (38 h > 18 h > 12 h > 9 h > 4 h > 2 h > 1 h) and sustained (peak transfection appeared at 30 h incubation) transfection efficiency. The presence of serum had not only no inhibition on, but also prominent promotion to, the transfection activity of ALA. All above features differentiated ALA clearly from most other serum-inhibitive nonviral gene carriers, and proved ALA the promising and challenging potential efficient gene vector for practical clinical application.     

筛选介导化学合成siRNA转染原代肝癌细胞的最佳试剂

背景：理想的细胞转染试剂应具有高效安全的特点。 目的：筛选能够高效介导化学合成siRNA转染原代肝癌细胞的最佳转染试剂。 方法：应用Lipofectamine RNAiMAX,Lipofectamine 2000和DharmaFECT1转染试剂介导FAM-siRNA和多药耐药基因MDR1siRNA转染原代肝癌细胞,分别于转染6和48 h后应用流式细胞仪和实时荧光定量PCR检测转染效率,然后用MTT法检测3种转染试剂处理原代肝癌细胞24 h后的细胞毒性。 结果与结论：对于Lipofectamine RNAiMAX,Lipofectamine 2000和DharmaFECT1转染试剂介导的FAM-siRNA和MDR1 siRNA转染,流式细胞仪和实时荧光定量PCR仪检测出RNAiMAX转染效率最高(P < 0.05),分别为70.3%和71.5%。MTT法检测结果表明RNAiMAX对原代肝癌细胞没有表现出细胞毒性。结果提示,由于RNAiMAX介导的FAM-siRNA和MDR1 siRNA转染的效率最高,并且对细胞的毒性最小,所以RNAiMAX是最适合介导化学合成siRNA转染原代肝癌细胞的转染试剂。     

FasL基因转染对大鼠肥大细胞凋亡的影响

目的：观察FasL基因转染对大鼠肥大细胞凋亡的影响。方法：RT-PCR法扩增大鼠FasL穿膜区和胞外区cDNA，成功构建pcDNA3．1／FasL真核表达质粒，瞬时转染RBL-2H3，RT-PCR、免疫印迹法鉴定FasL在RBL-2H3上的表达，Annexinv流式细胞检测pcDNA3．1／FasL转染RBL-2H3后细胞的凋亡情况。结果：获得FasL穿膜区和胞外区eDNA，构建pcDNA3．1／FasL真核表达质粒，瞬时转染RBL-2H3后在细胞膜和上清均有FasL的存在，瞬时转染RBL-2H3后48小时，细胞发生凋亡。结论：吧大细胞可以通过Fas-FasL途径凋亡，为FasL基因应用于过敏性疾病的治疗提供依据。     

Polysaccharide immunomodulators as therapeutic agents: structural aspects and biologic function

Polysaccharide immunomodulators were first discovered over 40 years ago. Although very few have been rigorously studied, recent reports have revealed the mechanism of action and structure-function attributes of some of these molecules. Certain polysaccharide immunomodulators have been identified that have profound effects in the regulation of immune responses during the progression of infectious diseases, and studies have begun to define structural aspects of these molecules that govern their function and interaction with cells of the host immune system. These polymers can influence innate and cell-mediated immunity through interactions with T cells, monocytes, macrophages, and polymorphonuclear lymphocytes. The ability to modulate the immune response in an appropriate way can enhance the host's immune response to certain infections. In addition, this strategy can be utilized to augment current treatment regimens such as antimicrobial therapy that are becoming less efficacious with the advent of antibiotic resistance. This review focuses on recent studies that illustrate the structural and biologic activities of specific polysaccharide immunomodulators and outlines their potential for clinical use.     

Inkjet-mediated gene transfection into living cells combined with targeted delivery

In this study a novel method of simultaneous gene transfection and cell delivery based on inkjet printing technology is described. Plasmids encoding green fluorescent protein (GFP) were coprinted with living cells (porcine aortic endothelial [PAE] cells) through the ink cartridge nozzles of modified commercial inkjet printers. Agarose gel electrophoresis analysis showed there was no obvious structural alteration or damage to these plasmids after printing. Transfection efficiency of the printed cells, determined by GFP expression, was over 10%, and posttransfection cell viability was over 90%. We showed that printing conditions, such as plasmid concentration, cartridge model, and plasmid size, influenced gene transfection efficiency. Moreover, genetically modified PAE cells were accurately delivered to target sites within a three-dimensional fibrin gel scaffold and expressed GFP in vitro and in vivo when implanted into mice. These results demonstrate that inkjet printing technology is able to simultaneously transfect genes into cells as well as precisely deliver these cell populations to target sites. This technology may facilitate the development of effective cell-based therapies by combining gene therapy with living cells that can be delivered to target sites.     

PEG化壳聚糖质粒纳米粒的制备及其转染的研究

目的:制备壳聚糖纳米粒并构建聚乙二醇(PEG)化壳聚糖质粒纳米粒,研究其对大鼠主动脉内皮细胞的转染能力及细胞毒性.方法:采用离子交联法制备壳聚糖纳米粒,应用喷金扫描电子显微镜检测壳聚糖纳米粒粒径的分布与形态;通过静电吸附作用连接上pGenesil-1质粒(报告基岗);对壳聚糖质粒纳米粒进行PEG化的修饰;应用PEG化壳聚糖质粒纳米粒转染大鼠主动脉内皮细胞;采用噻唑蓝(MTT)法测定壳聚糖纳米粒对细胞的毒性作用.结果:喷金扫描电镜检测显示壳聚糖纳米粒呈均匀分散的球形颗粒,平均直径为5 nm;PEG化壳聚糖质粒纳米粒能转染大鼠主动脉内皮细胞;MTT结果显示壳聚糖纳米粒对细胞无毒性作用;壳聚糖质粒纳米粒对内皮细胞的转染效率为26%,PEG修饰壳聚糖质粒纳米粒转染细胞,转染率为63.4%.结论:对壳聚糖质粒纳米粒进行化学修饰不仅能提高其转染效率,且对细胞无毒性作用.     

PEG化壳聚糖质粒纳米粒的制备及其转染的研究

目的:制备壳聚糖纳米粒并构建聚乙二醇(PEG)化壳聚糖质粒纳米粒,研究其对大鼠主动脉内皮细胞的转染能力及细胞毒性.方法:采用离子交联法制备壳聚糖纳米粒,应用喷金扫描电子显微镜检测壳聚糖纳米粒粒径的分布与形态;通过静电吸附作用连接上pGenesil-1质粒(报告基岗);对壳聚糖质粒纳米粒进行PEG化的修饰;应用PEG化壳聚糖质粒纳米粒转染大鼠主动脉内皮细胞;采用噻唑蓝(MTT)法测定壳聚糖纳米粒对细胞的毒性作用.结果:喷金扫描电镜检测显示壳聚糖纳米粒呈均匀分散的球形颗粒,平均直径为5 nm;PEG化壳聚糖质粒纳米粒能转染大鼠主动脉内皮细胞;MTT结果显示壳聚糖纳米粒对细胞无毒性作用;壳聚糖质粒纳米粒对内皮细胞的转染效率为26%,PEG修饰壳聚糖质粒纳米粒转染细胞,转染率为63.4%.结论:对壳聚糖质粒纳米粒进行化学修饰不仅能提高其转染效率,且对细胞无毒性作用.     

转染isl1基因促进骨髓间充质干细胞向心肌样细胞分化

目的: Isli蛋白在心脏发生和多能心脏祖细胞分化调节中发挥着重要作用, 本文旨在探寻转染 isl1 基因是否能提高骨髓间充质干细胞(BMSCs)向心肌样细胞分化的能力。方法: 利用携带 isl1 基因的慢病毒(LVS- isl1)感染人骨髓间充质干细胞, 通过Puromycin筛选获得稳定细胞株,并对其进行RT-PCR和Western blotting鉴定。以共培养为基础, 用real-time PCR、Western blotting以及免疫荧光法检测Isl1蛋白的心肌诱导能力。结果: RT-PCR和Western blotting表明成功获得稳定细胞株BMSC- isl1, real time-PCR结果显示BMSC- isl1组较之BMSCs组和BMSC-vehicle组GATA 结合蛋白4、NK2转录因子5、肌细胞增强因子2C和兰尼碱受体2的表达量分别提高了2.3、2.7、2.6和3.2倍;Western blotting以及免疫荧光法结果均提示BMSC- isl1 组内心肌肌钙蛋白T、心肌肌钙蛋白I和α-辅肌动蛋白的表达均比BMSCs组和BMSC-vehicle组要高。结论: 转染isl基因的BMSCs不仅可以稳定表达Isli蛋白, 而且在微环境共培养条件下, 可以提高BMSCs向心肌细胞分化的能力。     

超声及超声微泡联合shRNA质粒对survivin基因的沉默效应

目的:研究超声及超声微泡联合短发夹状RNA(shRNA)干扰技术对宫颈癌细胞(Hela)survivin基因的沉默效应.方法:构建3个靶向survivin基因的shRNA真核表达质粒(pSIREN/S1/S2/S3)和无关序列质粒(pSIREN/con),对培养的Hela细胞行超声及超声微泡联合处理(US+SO)或脂质体转染,以空白细胞组、单纯超声辐照组、pSIREN/S1组、超声辐照+pSIREN/S1组为对照,应用蛋白质印迹和RT-PCR检测survivin蛋白表达及mRNA转录水平的变化.结果:酶切、测序分析证实重组质粒构建成功.RT-PCR和蛋白质印迹法表明,3种pSIREN/S均可抑制Hela细胞内survivin mRNA和蛋白质的表达(P＜0.05),而pSIREN/con无此作用,以pSIREN/S3的抑制效果最显著(P＜0.05);US+SO组的mRNA和蛋白表达水平的抑制率分别为(87.04±1.80)%和(85.94±1.02)%,均显著高于其他各组(P＜0.05).结论:survivin可将作为宫颈癌基因治疗的理想靶标,超声及超声微泡联合shRNA干扰技术可显著沉默靶基因survivin的表达.     

PEG化壳聚糖质粒纳米粒的制备及其转染的研究

目的:制备壳聚糖纳米粒并构建聚乙二醇(PEG)化壳聚糖质粒纳米粒,研究其对大鼠主动脉内皮细胞的转染能力及细胞毒性.方法:采用离子交联法制备壳聚糖纳米粒,应用喷金扫描电子显微镜检测壳聚糖纳米粒粒径的分布与形态;通过静电吸附作用连接上pGenesil-1质粒(报告基岗);对壳聚糖质粒纳米粒进行PEG化的修饰;应用PEG化壳聚糖质粒纳米粒转染大鼠主动脉内皮细胞;采用噻唑蓝(MTT)法测定壳聚糖纳米粒对细胞的毒性作用.结果:喷金扫描电镜检测显示壳聚糖纳米粒呈均匀分散的球形颗粒,平均直径为5 nm;PEG化壳聚糖质粒纳米粒能转染大鼠主动脉内皮细胞;MTT结果显示壳聚糖纳米粒对细胞无毒性作用;壳聚糖质粒纳米粒对内皮细胞的转染效率为26%,PEG修饰壳聚糖质粒纳米粒转染细胞,转染率为63.4%.结论:对壳聚糖质粒纳米粒进行化学修饰不仅能提高其转染效率,且对细胞无毒性作用.     

PEG化壳聚糖质粒纳米粒的制备及其转染的研究

目的:制备壳聚糖纳米粒并构建聚乙二醇(PEG)化壳聚糖质粒纳米粒,研究其对大鼠主动脉内皮细胞的转染能力及细胞毒性.方法:采用离子交联法制备壳聚糖纳米粒,应用喷金扫描电子显微镜检测壳聚糖纳米粒粒径的分布与形态;通过静电吸附作用连接上pGenesil-1质粒(报告基岗);对壳聚糖质粒纳米粒进行PEG化的修饰;应用PEG化壳聚糖质粒纳米粒转染大鼠主动脉内皮细胞;采用噻唑蓝(MTT)法测定壳聚糖纳米粒对细胞的毒性作用.结果:喷金扫描电镜检测显示壳聚糖纳米粒呈均匀分散的球形颗粒,平均直径为5 nm;PEG化壳聚糖质粒纳米粒能转染大鼠主动脉内皮细胞;MTT结果显示壳聚糖纳米粒对细胞无毒性作用;壳聚糖质粒纳米粒对内皮细胞的转染效率为26%,PEG修饰壳聚糖质粒纳米粒转染细胞,转染率为63.4%.结论:对壳聚糖质粒纳米粒进行化学修饰不仅能提高其转染效率,且对细胞无毒性作用.     

基因转染法建立小鼠胸腺基质细胞系

利用基因转染方法使细胞获得不死性，快速建立小鼠胸腺基质细胞（ＭＴＳＣ）系。用含有多瘤病毒ｍＴ基因的重组质粒Ｚｉｐ－ｍＴ以脂质体介导法转染初代培养的ＭＴＳＣ，经过８００μｇ／ｍｌ的Ｇ４１８筛选，得到５个ＭＴＳＣ克隆。Ｓｏｕｔｈｅｒｎ杂交分析表明所得细胞克隆的染色体中整合有ｍＴ基因，说明ｍＴ基因的整合是导致细胞转化的原因。基因转染建系比常规建系所需时间大大缩短，仅需２个月。