Gene transfer into hematopoietic progenitor cells mediated by an adeno-associated virus vector

We describe here the transduction of murine hematopoietic progenitor cells with the dominant selectable neomycin drug-resistance (Neo) gene using a recombinant adeno-associated virus (AAV) vector. Successful transformation of progenitor cells to drug resistance was determined to be approximately 1.5% by colony formation in the presence of geneticin sulfate (G-418). The value of AAV as an alternative to the retrovirus vector systems is discussed.     

Recombinant adeno-associated virus as delivery vector for gene therapy--a review

Recombinant adeno-associated virus (rAAV) is one of the most promising delivery vectors for gene therapy, due to its nonpathogenic property, nonimmunogenecity to host, and broad cell and tissue tropisms. This article summarizes the biological characteristics of AAV; the procedures to prepare, purify, and characterize the rAAV for gene therapy applications; and some of the clinical trials utilizing rAAV as delivery vehicles. Also discussed are the current efforts to modify rAAV to change its tropism, the application of different promoters to accommodate specific transgene expression, and the strategy to expand its capacity.     

通用型腺病毒伴随病毒载体的构建

目的构建含腺病毒伴随病毒（ＡＡＶ）基因组两端的反向重复序列（ＩＴＲｓ）和表达必须元件如启动子、多克隆位点和ＰｏｌｙＡ信号的通用型载体质粒ｐＡＣＲ－Ｎｅｏ，并获得重组ＡＡＶ（ｒＶＶ／ＡＣＲ－Ｎｅｏ）。方法通过ＤＮＡ重组技术，将ＳＶ４０ＰｏｌｙＡ、Ｎｅｏ基因、ＣＭＶ－ＩＥ启动子和多克隆位点组成表达盒子，取代含ＡＡＶ全基因组质粒ｐＳＳＶ９中ＡＡＶ结构基因部分，构建成质粒ｐＡＣＲ－Ｎｅｏ。用ｐＡＣＲ－Ｎｅｏ转染５型腺病毒（Ａｄ５）感染的重组ＡＡＶ包装细胞系ＡＥ１２０１，能获得重组病毒ｒＡＡＶ／ＡＣＲ－Ｎｅｏ。提取ｒＡＡＶ／ＡＣＲ－Ｎｅｏ感染细胞的染色体，用Ｓｏｕｔｈｅｍ杂交分析重组病毒基因组在感染细胞中的存在情况。结果质粒ｐＡＣＲ－Ｎｅｏ转染包装细胞系后所得ｒＡＡＶ／ＡＣＲ－Ｎｅｏ滴度为４．２×１０５ＣＦＵ／ｍｌ，并且ｒＡＡＶ／ＡＣＲ－Ｎｅｏ能在转导细胞内实现其基因组与细胞染色体的整合。结论成功地构建了通用型ＡＡＶ载体，为今后的ＡＡＶ载体研究、基因治疗和临床应用打下了基础     

腺相关病毒载体pAGX(+)的构建

目的构建腺相关病毒(AAV)载体并进行鉴定,以介导真核细胞的基因传递和表达.方法以基因重组技术构建AAV载体,用Southern杂交、狭缝杂交以及激光共聚焦显微镜等鉴定构建的AAV载体.结果成功地获得了重组AAV表达载体pAGX(+),藉报告基因EYFP鉴定pAGX(+),见pAEYFP经包装的重组AAV储存液的感染滴度达1.39×107TU(transmissionunit)/ml、复制滴度达1.94×1011颗粒/ml.Southern杂交表明EYFP基因获得成功拯救.rAAV/EYFP颗粒成功转导COS7细胞,EYFP获得表达,并整合入COS7细胞基因组,而藉质粒载体pEYFPCMV介导的转移,EYFP未能整合.结论成功地构建了一个AAV载体,并成功地介导了基因的转移、表达和整合.     

Gene transfer into the mouse retina mediated by an adeno-associated viral vector

Gene transfer to photoreceptor cells may provide a means for arresting the retinal degeneration that is characteristic of many inherited causes of blindness, including retinitis pigmentosa (RP). However, transduction of photoreceptors has to date been inefficient, and further limited by toxicity and immune responses directed against vector-specific proteins. An alternative vector system based on adeno- associated virus (AAV) may obviate these problems, and may be useful for transduction of neuronal cells. In this study we have demonstrated successful transduction of all layers of the neuroretina as well as the retinal pigment epithelium (RPE) following subretinal injection of recombinant AAV particles encoding lac Z. Furthermore, the efficiency of transduction of photoreceptors is significantly higher than that achieved with an equivalent adenoviral vector. This is the first report showing that AAV is capable of transducing photoreceptor cells and supports the use of this vector system for gene therapy of retinal diseases such as RP.      

Feasibility of gene therapy in Gaucher disease using an adeno-associated virus vector

Gaucher disease, one of the common lysosomal storage disorders, is caused by a deficiency of glucocerebrosidase (GC). We investigated gene transfer using recombinant adeno-associated viral (rAAV) vectors containing human GC cDNA driven by the human elongation factor 1- promoter. This rAAV vector mediated efficient expression of human GC in human Gaucher fibroblasts. GC activities were increased from 2.8 to 3.4 times in normal fibroblast and from 1.9 to 4.6 times in Gaucher fibroblasts, and these increases in GC activity were maintained over 20 weeks. Intravenous administration of vectors via the hepatic portal vein and tail vein of wild-type mice resulted in efficient transduction into the tissues. GC activities of the liver, spleen, and lung in transduced mice were increased significantly up to two fold at 6 weeks after transduction. Significantly increased GC activities persisted over 20 weeks. Therefore, rAAV vector-mediated gene transfer may provide a therapeutic approach for the treatment of Gaucher disease.     

AAV-GDNF/TH双基因载体的构建及表达

目的 探讨构建于同一个重组腺相关病毒(rAAV)载体上的酪氨酸羟化酶(TH)基因和胶质细胞源性神经营养因子(GDNF)基因是否能够同时表达.方法 应用反转录聚合酶链反应(RT-PCR)检测双基因在HEK293包装细胞中的转录;通过免疫细胞化学荧光染色和免疫组织化学染色技术分别检测双基因在体外培养大鼠骨髓基质细胞(BMSCs)和大鼠脑中的表达.结果 在HEK293包装细胞和BMSCs中分别同时检测到了GDNF和TH基因RNA和蛋白的表达.对照LacZ在HEK293包装细胞和骨髓基质细胞中的表达率分别为50%和15%.大鼠脑组织切片中注射AAV-GDNF/TH病毒的部位与注射PBS的对侧相比无论是GDNF还是TH的表达均显著增加(P＜0.01).结论 构建于同一个rAAV载体上的TH基因和GDNF基因体内体外都能够同时表达,此结果为PD的基因治疗提供了新的依据.     

Purification method for the avian adeno-associated virus

Avian adeno-associated virus (AAAV) pre-purified by Uvasol extraction, one discontinuous and two CsCl equilibrium density gradients, was still considerably contaminated with avian adenovirus (CELO strain). Four different approaches were investigated in attempts to improve the elimination of the contaminating CELO virus. The contaminations were assayed by double immunodiffusion and indirect immunofluorescence. The immunoprecipitation of CELO virus with antiserum and protein A-Sepharose is the most effective method of obtaining purified AAAV free of CELO virus.     

Pim-1基因重组腺相关病毒2载体的构建及感染大鼠视网膜

目的构建携带大鼠原癌基因Pim-1的重组腺相关病毒2载体(rAAV2-Pim-1),检测其体内感染大鼠视网膜的细胞类型及目的基因Pim-1在视网膜中的表达。方法 p AOV-CAGMINI-EGFP-2A-MCS-3FLAG载体及Pim-1基因PCR产物用Nhel酶切,琼脂糖凝胶电泳鉴定后回收载体及目的基因DNA并连接转化,鉴定质粒阳性克隆及测序。rAAV2-Pim-1表达质粒p AOV-CAGMINI-EGFP-2A-Pim-1-3FLAG及包装质粒p AAV-RC和辅助质粒p Helper,通过Lipofectamine 2000共转染293细胞,纯化获得高滴度的rAAV2-Pim-1。大鼠玻璃体注射rAAV2-Pim-1,用免疫荧光组织化学检测其感染视网膜的细胞类型;用Real-time PCR和Western blotting检测Pim-1在视网膜中的表达。结果rAAV2-Pim-1质粒构建成功并且核苷酸序列比对正确;质粒转染293细胞后出现绿色荧光;包装出的病毒浓缩滴度为5.7×1015vg/L。rAAV2-Pim-1组体内感染视网膜神经节细胞(RGCs)达71%,并感染少量无长突细胞,几乎不感染星形胶质细胞;Pim-1 mRNA和蛋白在视网膜中的表达约为rAAV2-EGFP组的6.61倍和2.29倍。结论成功构建rAAV2-Pim-1病毒载体,并在感染后的大鼠视网膜RGCs中过表达Pim-1。     

Effect of a viral rep gene on transformation of cells by an adeno-associated virus vector

Adeno-associated virus (AAV) vectors readily express the gene for geneticin-resistance under control of the AAV p40 promoter when chromosomally integrated at low copy number in mammalian cells. We show that a truncated AAV rep gene, transcribed from the p5 and p19 promoters, mediates a negative effect on expression of geneticin-resistance in human 293 cells and a positive effect in HeLa cells. Also, we describe a novel phenotype for a mutant expressing the p19 rep gene alone which has a negative effect in 293 cells but no positive effect in HeLa cells.     

重组腺相关病毒载体介导的LacZ基因转染骨胳肌途径的研究

目的研究重组腺相关病毒载体(recombinantadeno-associatedvirusvector,rAAV)介导的β-半乳糖苷酶的结构基因LacZ,构建的rAAVLacZ病毒经不同途径给药后骨骼肌的转染效率、表达持续时间,为rAAV载体介导的目的基因对Duchenne肌营养不良的基因治疗探索合适的给药途径。方法采用报告基因LacZ、包装质粒PXX2、腺病毒成份辅助质粒PXX6三质粒共转染293细胞,包装重组腺相关病毒载体介导的rAAVLacZ,将rAAVLacZ局部腓肠肌肌肉注射转染至C57/BL6鼠骨胳肌,分别于单点注射后2个月、5个月取肌肉切片X-Gal染色。采用经股动脉注射rAAVLacZ观察LacZ基因在后肢骨骼肌的转染表达。结果(1)C57/BL6鼠局部肌注rAAVLacZ后,2个月和5个月时,均呈LacZ基因阳性表达,5个月时无表达减低。(2)经股动脉注射rAAVLacZ,C57/BL6小鼠后肢骨骼肌的肌膜及血管壁平滑肌LacZ基因广泛转染。结论重组腺相关病毒载体介导的报告基因LacZ可在C57/BL6鼠骨胳肌中高效持续表达5个月以上,经股动脉转染是有希望的下肢肌肉转染途径,此工作为神经肌肉遗传病,尤其是Duchenne肌营养不良基因治疗的进一步研究奠定了基础。     

A minimal genome simian foamy virus type 1 vector system with efficient gene transfer

Foamy viruses have several inherent features for the opportunity to develop efficient and versatile vectors for gene therapy. We have constructed a series of vectors and helper plasmids based on simian foamy virus type 1 (SFV-1) to establish the minimum vector genome required for efficient gene transduction. To characterize the efficiency of gene transduction by these vectors, the green fluorescent protein (GFP) coding sequence is linked to the human cytomegalovirus immediate gene promoter. Several deletion analyses of SFV-1 vectors revealed that the minimum genome with efficient GFP transduction contained the 5' untranslated region extending to the first 637 nucleotides of the gag gene, a 596 nucleotides of pol sequence from position 3137-3733, the 3' pol region at position 5200-5693, the 3' end polypurine tract, and the 3' LTR. An additional 1131 nucleotides can be removed from the 3' end LTR without affecting the efficiency of vector transduction. SFV-1 vector can therefore accommodate a minimum 8930 base-size heterologous DNA fragment. Furthermore, the efficiency of SFV-1 vector transduction was analyzed using different packaging plasmids. GFP transduction with packaging plasmid that contained the 5' R-U5 region of the LTR was compared with helper plasmids that had deletions in this region except for 22 nucleotides (positions 21-41), the first 61, 77, or 140 nucleotides of the R of the LTR. Transduction efficiencies were significantly reduced with the deletion mutations implicating that for optimum SFV-1 vector productions a packaging construct that includes the 5' R-U5 is required.     

晚期糖化终产物受体反义 RNA 腺相关病毒载体的构建及在肾脏系膜细胞中表达

目的 构建晚期糖化终产物受体(RAGE)反义RNA腺相关病毒载体,并在大鼠肾脏系膜细胞中表达. 方法 构建腺相关病毒介导的RAGE反义RNA载体,3个质粒共转染293细胞,获得病毒原液,感染大鼠肾脏系膜细胞,流式细胞术、RT-PCR、ELISA检测重组病毒感染的细胞RAGE的表达和分泌细胞外基质的情况.结果 经酶切鉴定、序列分析显示RAGE基因片段正确完整反向插入pAAV-MCS.利用293细胞包装获得病毒原液的滴度为8.7×107VP/mL.感染重组病毒的细胞与正常细胞比较RAGE表达被抑制(48.2±6.1)%,分泌Ⅳ型胶原(ColⅣ)水平明显下降(P＜0.05).结论 成功构建具有抑制功能的RAGE反义RNA腺相关病毒载体,为进一步研究RAGE的作用机制,以及基因治疗RAGE相关疾病提供一个重要工具.     

NT4-Apoptin-HA2-TAT融合基因重组腺相关病毒的构建及鉴定

目的:构建编码融合基因NT4-Apoptin-HA2-TAT的重组腺相关病毒表达载体.方法:利用限制性内切酶切相应载体后将Apoptin和HA2-TAT连入pUC19/NT4质粒, 再将融合基因NT4-Apoptin-HA2-TAT亚克隆至腺相关病毒的穿梭质粒内, 与辅助质粒pAAV/Ad、 腺病毒质粒pFG140共同转染HEK-293细胞, 通过同源重组获得NT4-Apoptin-HA2-TAT重组腺相关病毒载体, 收集病毒上清, Dot blot法测定其滴度.MTT比色法观察NT4-Apoptin-HA2-TAT重组腺相关病毒表达载体, 对HepG2细胞存活率的影响.结果:经酶切及测序证实克隆出NT4-Apoptin-HA2-TAT融合基因; 得到高滴度的(3.14×1015 pfu/L)重组腺相关病毒表达载体.NT4-Apoptin-HA2-TAT重组腺相关病毒表达载体, 对HepG2细胞有强烈的诱导凋亡作用, 与对照组比较, 处理组细胞的存活率明显降低.结论:通过分子克隆体外重组技术成功制备了NT4-Apoptin-HA2-TAT重组腺相关病毒载体, 为下一步的Apoptin应用于基因治疗奠定了基础.     

腺病毒伴随病毒表达载体表达人乳头瘤病毒18型E6E7基因构建及其转化作用的鉴定

目的：探讨人乳头瘤病毒（HPV）的E6E7基因在细胞恶性转化中所起的作用。方法：将人乳头瘤病毒（HPV）的E6E7基因克隆至腺病毒伴随病毒表达载体中，通过包装的重组病毒感染，将E6E7基因导入并整合到永生293细胞的基因组中。结果：本研究成功地构建了HPV18 E6E7 AAV病毒并感染了永生293细胞，PCR／Southern杂交分析表明E6E7基因在转化细胞293TL中确有表达，转化细胞293TC和293TL具有明显的转化表型，和亲本293细胞相比，生长速度快，接触抑制消失，集落形成率提高20倍，且集落明显增大，形成时间短。结论：成功地构建了HPV18 E6E7 AAV病毒，HPV18 E6E7基因引起永生化人上皮细胞293的恶性转化。此病毒可用于感染正常上皮细胞，研究其致癌机制。     

Gene therapy using adeno-associated virus vectors

SUMMARY: The unique life cycle of adeno-associated virus (AAV) and its ability to infect both nondividing and dividing cells with persistent expression have made it an attractive vector. An additional attractive feature of the wild-type virus is the lack of apparent pathogenicity. Gene transfer studies using AAV have shown significant progress at the level of animal models; clinical trials have been noteworthy with respect to the safety of AAV vectors. No proven efficacy has been observed, although in some instances, there have been promising observations. In this review, topics in AAV biology are supplemented with a section on AAV clinical trials with emphasis on the need for a deeper understanding of AAV biology and the development of efficient AAV vectors. In addition, several novel approaches and recent findings that promise to expand AAV's utility are discussed, especially in the context of combining gene therapy ex vivo with new advances in stem or progenitor cell biology.     

Neuronal-specific and nerve growth factor-inducible expression directed by the preprotachykinin-A promoter delivered by an adeno-associated virus vector

The ability to manipulate the expression of genes within neurons provides unique opportunities to study the role of individual gene products in nervous system function. Virus vectors are a potentially rapid tool for the experimental manipulation of gene expression in the mammalian nervous system. However, a block to the use of virus vector systems in neurobiology is often the lack of cell-specific expression of the gene within the nervous system, and the immune and inflammatory responses to both the virus vector and the delivered gene. We have generated an adeno-associated virus vector that exploits the restricted expression pattern of the rat preprotachykinin-A promoter to support reporter gene expression. We demonstrate that this virus has a neuronal-specific expression pattern. Moreover, it is shown for the first time that the proximal rat preprotachykinin-A promoter is nerve growth factor inducible. This virus will be a useful tool to (i) modify neuronal phenotype by expressing therapeutic molecules or antisense nucleic acid and (ii) dissect the signal transduction pathways that regulate promoter function in vivo.