阳离子聚合物基因载体的研究进展

与病毒基因载体相比,非病毒基因载体具有毒性低、免疫原性小、结构改造可实现基因靶向递送、可重复应用等优点。而其中阳离子聚合物能够与基因形成稳定复合物,促进细胞对复合物的内吞,受到越来越广泛的关注。本文主要从修饰方法以及靶向传递等方面介绍了阳离子聚合物在基因传递方面的应用。     

基因治疗的载体系统及应用

目前的基因载体系统可分为病毒载体和非病毒载体。利用病毒载体介导的基因转移 ,以其高转染率和良好靶向性成为肿瘤基因治疗中应用最广泛的方法。非病毒载体由于其非免疫性和易于生产性而逐渐引起学者瞩目。基因治疗是一种用正常基因取代缺陷基因的治疗 ,目前主要用于肿瘤治疗 ,同时在基因治疗造血细胞疾病、心血管疾病、风湿性关节炎方面 ,已在动物试验中取得一定进展。1　基因载体系统本文介绍几种将外源基因引入宿主细胞的转移方法 ,这些方法可使外源基因短期 (数天 )或长期 (数星期或数年 )稳定的表达[1] 。通常可将这些方法分为病毒载…     

非病毒基因递送载体的研究进展

目前,基因药物的递送成为药学研究的热点,基因递送载体主要包括病毒载体和非病毒载体。非病毒基因载体的毒性低,生物相容性好,转染效率高,具有潜在的临床应用价值。本文就靶向递送基因载体、多功能基因载体、同时载基因与化疗药物的载体、智能基因载体和脂质体等非病毒基因递送载体的研究进展做一综述。     

非病毒型载体聚乙烯亚胺在基因递送应用中的研究进展

非病毒型基因载体因具有低毒性、低免疫原性及易制备等诸多优点,近年来成为制备高效低毒型基因递送载体的研究热点。聚乙烯亚胺(PEI)作为典型的非病毒型基因载体以其较好的基因压缩能力及溶酶体逃逸能力引起了广泛关注。本文对基于PEI类基因载体的体内递送过程及所面临的问题(如生物相容性低、细胞毒性、缺乏特异靶向性和目的基因释放不足等)进行了归纳与分析,并总结了相应的改进方案。此外,对基于PEI的智能响应型基因载体(内源性刺激响应型、外源性刺激响应型)的研究进展进行了综述,为开发出更加安全高效的非病毒型基因载体提供参考。     

基因治疗载体的研究进展

参考国内外相关文献，综合介绍逆转录病毒载体、腺病毒载体、痘苗病毒载体、单纯疱疹病毒载体、腺病毒相关病毒载体、艾滋病病毒(HIV)载体和脂质体载体以及氧化铁磁性纳米颗粒等基因治疗载体的研究进展。     

阳离子脂质体用作基因转移载体的研究进展

鉴于阳离子脂质体制备简便、安全无毒、无免疫原性,近年来在基因转移方面得到了广泛应用.为了更好地适用于体内基因治疗,目前正致力于研制高效、稳定、靶向的阳离子脂质体.     

慢病毒———基因转移的潜在新载体

随着对疾病分子机制认识的加深及生物技术的发展,基因治疗已成为治疗感染性疾病、遗传疾病、神经系统疾病以及肿瘤的新焦点。用于基因治疗的载体系统可分为病毒性载体和非病毒性载体两类。目前常用的病毒载体包括逆转录病毒载体、腺病毒载体、腺相关病毒载体、疱疹病毒载体、痘苗病毒载体等,但是这些载体均存在不足之处,严重影响了基因治疗的有效性及安全性。在基因治疗中广泛应用的逆转录病毒载体存在的主要问题,是无法高效转导非分裂期细胞,而腺病毒载体虽然能转导非分裂期细胞,但在体内不能实现目的基因稳定的长期表达,且反复应用容易引起免疫反应。慢病毒载体不但可以感染非分裂期细胞,还具有容纳外源性目的基因片段大、免疫反应小等优点,在基因治疗中具有广泛的应用前景。现以HIV-1为例,就慢病毒载体的生物学特征、慢病毒载体的构建、在基因治疗中的应用以及生物安全性等方面作一综述。     

新型非病毒载体聚乙烯亚胺体内应用的研究进展

聚乙烯亚胺是1995年发现的重要的真核细胞基因转染载体，在非病毒载体的研究中处于重要的地位。聚乙烯亚胺体外研究已取得显著的进展，但在体内基因治疗的应用面临着一系列局限。本文综述了非病毒载体聚丙烯亚胺体内应用的障碍和克服办法，包括聚乙烯亚胺-DNA复合物的脂质体包裹或聚乙二醇化修饰等。     

受体介导的靶向基因载体的研究进展

受体介导的基因给药系统是非病毒性载体发展的重点,通过对靶向载体进行结构改造,可以避免DNA/载体复合物与血浆蛋白的相互作用。促进DNA从内吞体的释放和向细胞核的转运,改善体内过程,提高靶向性。     

慢病毒——基因转移的潜在新载体

随着对疾病分子机制认识的加深及生物技术的发展,基因治疗已成为治疗感染性疾病、遗传疾病、神经系统疾病以及肿瘤的新焦点。用于基因治疗的载体系统可分为病毒性载体和非病毒性载体两类。目前常用的病毒载体包括逆转录病毒载体、腺病毒载体、腺相关病毒载体、疱疹病毒载体、痘苗病毒载体等,但是这些载体均存在不足之处,严重影响了基因治疗的有效性及安全性。在基因治疗中广泛应用的逆转录病毒载体存在的主要问题,是无法高效转导非分裂期细胞,而腺病毒载体虽然能转导非分裂期细胞,但在体内不能实现目的基因稳定的长期表达,且反复应用容易引…     

Overcoming the Inflammatory Toxicity of Cationic Gene Vectors

Cationic lipid- and polymer-based vectors are the most extensively studied synthetic gene vectors. These vectors have been widely used in animal models and some have been tested in clinical trials. The clinical progress of these vectors has been slowed by their inflammatory toxicity. This review summarizes the observations, the mechanisms, and various strategies employed to overcome the inflammatory toxicity of cationic gene vectors.     

Vectors for pulmonary gene therapy

The success of gene transfer in preclinical animal models and proof of principle clinical studies has made gene therapy an attractive concept for disease treatment. A variety of diseases affecting the lung are candidates for gene therapy. Delivery of genes to the lungs seems to be straightforward, because of the easy accessibility of epithelial cells via the airways. However, efficient delivery and expression of the therapeutic transgene at levels sufficient to result in phenotypic correction of the diseased state have proven elusive. This review presents a brief summary about current status and future prospects in the development of viral and non-viral strategies for pulmonary gene therapy.     

一种基因治疗和基因免疫表达载体的构建

遗传物质DNA的体内导入为疾病的治疗开辟了一个新的方法，即基因治疗或基因免疫。百为了实现基因在体内的表达，一个高效，安全的真核表达是必不可少的，本研究构建了一个可用于基因治疗或基因免疫的真核表达载体pNCMV，此载体以一个来自巨细胞病毒的立即早期基因启动子作用为调控系列，并且分别引入了用于在原核和真核系统复制的，以及便于筛选的诸多元件，为了验证此载体的有效性，在CMV启动子下游插入了一段编码HBV表面抗原的基因序列，得到一个表达载体PNCMVS2-S，体外转染试验表明了此载体的能够产生具有免疫原性的表面抗原颗粒。     

Development of Gene Therapy Vectors: Remaining Challenges

Almost 20 years after the tragic death of a young patient due to an experimental gene therapy trial to treat Ornithine Transcarboxylase deficiency, the FDA approved its first landmark gene therapy drug i.e. Luxturna® to treat inherited blindness, and dozens of gene therapy studies are underway. Whether it is replacing the mutant copies of the gene with the wild type one or editing the mutant one in or ex-vivo to elicit the production of functional proteins, numerous viral and non-viral vectors for delivering the gene payload are being evaluated. While, non-viral vectors avoid or mitigate limiting factors such as immunogenicity and the presence of neutralizing antibodies (NAbs), viral vectors such as recombinant adeno-associated viruses (AAVs) have shown early success as a delivery vehicle, because of the overall safety, target specificity, and long-term stability profile. Nonetheless, multiple challenges during the AAV product development and approval process are still looming. AAV serotypes are continuously being engineered which requires multiple cell-based assays to not only assess the neutralizing antibodies (NAb) seroprevalence but also to develop the in-vitro bio potency assays. Hence, we focus on some critical aspects of the AAVs that determine the path forward for pre-clinical and clinical product development.     

Designer Gene Delivery Vectors: Molecular Engineering and Evolution of Adeno-Associated Viral Vectors for Enhanced Gene Transfer

Gene delivery vectors based on adeno-associated virus (AAV) are highly promising due to several desirable features of this parent virus, including a lack of pathogenicity, efficient infection of dividing and non-dividing cells, and sustained maintenance of the viral genome. However, several problems should be addressed to enhance the utility of AAV vectors, particularly those based on AAV2, the best characterized AAV serotype. First, altering viral tropism would be advantageous for broadening its utility in various tissue or cell types. In response to this need, vector pseudotyping, mosaic capsids, and targeting ligand insertion into the capsid have shown promise for altering AAV specificity. In addition, library selection and directed evolution have recently emerged as promising approaches to modulate AAV tropism despite limited knowledge of viral structure–function relationships. Second, pre-existing immunity to AAV must be addressed for successful clinical application of AAV vectors. “Shielding” polymers, site-directed mutagenesis, and alternative AAV serotypes have shown success in avoiding immune neutralization. Furthermore, directed evolution of the AAV capsid is a high throughput approach that has yielded vectors with substantial resistance to neutralizing antibodies. Molecular engineering and directed evolution of AAV vectors therefore offer promise for generating ‘designer’ gene delivery vectors with enhanced properties.     

Sulfhydryl Based Cationic Surfactants and the Impact of Polyanions on Disulfide Bond Formation: Implications for Gene Transfer Vectors

Compacting plasmid DNA (pDNA) into a small size is a fundamental necessity for the efficient in vivo transfer of nucleic acids to somatic cells. An approach for accomplishing this is to condense pDNA using cationic detergents with sulfhydryl groups, near their critical micelle concentration. In this study, a model surfactant was used to study how the rate of disulfide bond formation relates to environmental factors. It was shown that the thiol detergent had the ability to form a disulfide bond when oxidized and the presence of polyanions was significantly increased. The addition of a reducing agent disrupted the disulfide bonds initially, but this was followed by disulfide bond reformation in a short time period.     

Polyethylenimine Derivatives as Potent Nonviral Vectors for Gene Transfer

The delivery of a functional gene into a tissue can allow the correction of gene defaults or mutations such as those observed in severe hereditary pathologies or in cancer tissues and could lead to gene therapy. To achieve gene transfer, viral vectors are mainly used because of their intrinsic ability to enter the cells and promote expression of the transgene. However, many factors can limit the use of viral vectors, including a heavy laboratory infrastructure, and, in the case of iterative administration, the induction of immune response against viral proteins. Alternative gene transfer technologies based on nonviral vectors have been proposed. Polyethylenimine (PEI) derivatives are polycationic molecules that are able to form stable complexes with plasmidic DNA. PEI/DNA complexes attach to the cell surface, migrate into clumps that enter the cell by endocytosis and are deagregated in an acidic lysosomal compartment and/or enter the nucleus. PEI derivatives can be proposed as linear (22 kDa) or reticulated (25 kDa) molecules that prove efficient for gene transfer in vitro and in vivo. Besides extensive applications of unsubstituted PEI, glycosylated-PEI derivatives were proposed and reported to enhance gene transfer efficiency through decreased size and aggregation of PEI/DNA complexes. Galactosylated-PEI derivatives have been reported to enhance interactions with cell membranes through carbohydrate-binding protein recognition and specifically target PEI/DNA complexes toward biological systems that express galectins. More recently, glucosylated PEI derivatives have been shown to yield higher and longer-lasting transgene expression than unsubstituted-PEI in human head and neck carcinoma tumor cells. In the present paper, a review of in vitro and in vivo properties of PEI-mediated gene transfer experiments is presented. (c) 2002 Prous Science. All rights reserved.     

Toxicogenomics of Non-viral Vectors for Gene Therapy: A Microarray Study of Lipofectin- and Oligofectamine-induced Gene Expression Changes in Human Epithelial Cells

Of the non-viral vectors, cationic lipid (CL) formulations are the most widely studied for the delivery of genes, antisense oligonucleotides and gene silencing nucleic acids such as small interfering RNAs. However, little is known about the impact of these delivery systems on global gene expression in target cells. In an attempt to study the geno-compatibility of CL formulations in target cells, we have used microarrays to examine the effect of Lipofectin and Oligofectamine on the gene expression profiles of human A431 epithelial cells. Using the manufacturer's recommended CL concentrations routinely used for gene delivery, cDNA microarray expression profiling revealed marked changes in the expression of several genes for both Lipofectin- and Oligofectamine-treated cells. Data from the 200 spot arrays housing 160 different genes indicated that Lipofectin or Oligofectamine treatment of A431 cells resulted in more than 2-fold altered expression of 10 and 27 genes, respectively. The downstream functional consequences of CL-induced gene expression alterations led to an increased tendency of cells to enter early apoptosis as assessed by annexin V-FITC flow cytometry analyses. This effect was greater for Oligofectamine than Lipofectin. Observed gene expression changes were not sufficient to induce any significant DNA damage as assessed by single cell gel electrophoresis (COMET) assay. These data highlight the fact that inadvertent gene expression changes can be induced by the delivery formulation alone and that these may, ultimately, have important safety implications for the use of these non-viral vectors in gene-based therapies. Also, the induced non-target gene changes should be taken into consideration in gene therapy or gene silencing experiments using CL formulations where they may potentially mask or interfere with the desired genotype and/or phenotype end-points.     

Gene medicine: A new field of molecular medicine

Gene therapy has emerged as a new concept of therapeutic strategies to treat diseases which do not respond to the conventional therapies. The principle of gene therapy is to introduce genetic materials into patient cells to produce therapeutic proteins in these cells. Gene therapy is now at the stage where a number of dinical trials have been carried out to patients with gene-deficiency disease or cancer. Genetic materials for gene therapy are generally composed of gene expression system and gene delivery system. For the dinical application of gene therapy in a way which conventional drugs are used, researches have been focused on the design of gene delivery system which can offer high transfection efficiency with minimal toxicity. Currently, viral delivery systems generally provide higher transfection efficiency compared with non-viral delivery systems while non-viral delivery systems are less toxic, less immunogenic and manufacturable in large scale compared with viral systems. Recently, novel strategies towards the design of new non-viral delivery system, combination of viral and non-viral delivery systems and targeted delivery system have been extensively studied. The continued effort in this area will lead us to develop gene medicine as 'gene as a drug' in the near future.     

基因多态性对地高辛代谢影响的研究进展

地高辛作为临床上治疗充血性心力衰竭的经典药物,因其作用持久、价格低廉且不容易产生耐药现象,广泛地用于各种急慢性心功能不全、室上性心动过速、心房扑动及心房颤动等疾病的治疗。因地高辛的治疗浓度接近中毒浓度,如何在其狭窄的治疗窗内提高疗效,保证安全有效地应用地高辛,一直是临床亟待解决的问题。近年来,对地高辛的药物基因组学研究发现,某些基因位点的多态性可影响地高辛的药物代谢及作用,从而部分解释了患者对地高辛有效剂量的个体差异。本文就近年来涉及的地高辛药物基因组学研究进行综述,以期为地高辛的个体化用药提供参考。