基因治疗中的核酸药物及非病毒递送载体的研究进展

基因治疗是针对基因异常相关疾病的终极治疗技术,各种具有不同机制的核酸药物的出现为基因治疗带来了更多的可能性。但是,由于存在体内稳定性差、难以高效进入靶细胞等问题,核酸药物需要载体的帮助而进入目标细胞并到达特定的胞内位置,因此,开发安全高效的核酸递送系统是基因治疗的基石。与病毒载体相比,非病毒载体具有更高的安全性,但转染效率较低。随着纳米技术的发展,非病毒载体的效率得到了显著的提升,进入临床研究的数量逐渐增多。本文简要介绍基因治疗中的核酸药物及其递送载体,对非病毒核酸药物递送技术的瓶颈及进展做综合评述。     

非病毒型纳米载体在基因治疗中的研究现状及展望

近 10年来 ,新型非病毒载体在基因治疗中日益受到欢迎。其主要代表为纳米载体 ,具有无毒性及免疫原性的优势 ,已作为高效阳离子载体用于基因转移。体外基因转移实验表明 ,纳米载体的基因转移率高于普通脂质体及其它阳离子多聚体 ,如多聚氮丙啶及聚赖氨酸。本文对纳米载体的结构特点、性能、基因转移机制进行综述 ,并将其在体内外基因转移效率与其它非病毒载体作以比较     

非病毒型载体介导基因转染

基因载体是制约基因转移技术发展的关键。近年来,非病毒载体由于其安全、低毒、低免疫原性等特点而备受青睐。文章以脂质体和聚乙烯亚胺为代表,介绍了非病毒载体的性质、介导转染的机制。随着人们对细胞转染机制了解的深入以及生物材料科学的迅速发展,非病毒型载体将有望实现高效、低毒、靶向特异等特点,从而成为基因治疗中的理想载体。     

非病毒型纳米载体在基因治疗中的研究现状及展望

近10年来，新型非病毒载体在基因治疗中日益受到欢迎。其主要代表为纳米载体，具有无毒性及免疫原性的优势，已作为高效阳离子载体用于基因转移。体外基因转移实验表明，纳米载体的基因转移率高于普通脂质体及其它阳离子多聚体，如多聚氮丙及聚赖氨酸。本对纳米载体的结构特点，性能，基因转移机制进行综述，并将其在体内外基因转移效率与其它非病毒载体作以比较。     

病毒载体介导的基因转移研究进展

实现基因治疗的关键在于目的基因的高效转移并适度表达 ,这将直接影响其治疗效率和安全性。因此探索理想的基因转移技术是基因治疗的一项重要内容 ,目前人们的注意力更多地集中于病毒载体 ,传统的逆转录病毒载体不能转染非分裂细胞 ,且载导容量有限 ,促使人们在寻找改进措施的同时积极研制其它类型的病毒载体 ,本文将阐述这些病毒载体的特性、应用情况及研究进展。     

感染靶向性重组腺相关病毒载体在基因治疗中的研究进展

重组腺相关病毒（rAAV）是一种非常有希望的人体细胞基因治疗载体.它既可以转染分裂细胞又可以转染非分裂细胞.rAAV在宿主体内以定向整合的方式存在.AAV重组体在细胞内能长期稳定地表达,且在体内不引起明显的病理变化,然而它广泛的宿主范围是体内基因治疗的一个缺点,因为它不具备组织特异性或器官局限性转导能力从而难以增加其在基因治疗中的安全性和效率.因此,开发具有组织或器官靶向性的重组腺相关载体是腺相关病毒载体发展的方向.本文就近年来感染靶向性腺相关病毒在基因治疗中的进展作一综述.     

基因治疗中的非病毒载体

添加、修复或替换基因从而达到直接排除病因是基因治疗的目的，也是用于治疗可遗传和获得性疾病的治疗方法。它包括目的基因、载体和靶细胞三个方面，其中载体在整个转染过程中起着关键的作用。非病毒载体是该研究领域的热点之一，虽然转染效率不如病毒载体，但其无毒、无免疫反应、性质可调且制备方便。本文主要就非病毒载体的转染机理及优化策略作一综述。     

感染靶向性重组腺相关病毒载体在基因治疗中的研究进展

重组腺相关病毒(rAAV)是一种非常有希望的人体细胞基因治疗载体.它既可以转染分裂细胞又可以转染非分裂细胞.rAAV在宿主体内以定向整合的方式存在.AAV重组体在细胞内能长期稳定地表达,且在体内不引起明显的病理变化,然而它广泛的宿主范围是体内基因治疗的一个缺点,因为它不具备组织特异性或器官局限性转导能力从而难以增加其在基因治疗中的安全性和效率.因此,开发具有组织或器官靶向性的重组腺相关载体是腺相关病毒载体发展的方向.本文就近年来感染靶向性腺相关病毒在基因治疗中的进展作一综述.     

用于基因治疗的病毒样颗粒的构建及其应用研究进展

基因治疗的关键问题是找到安全有效的基因转运载体.目前,基因治疗中常用的病毒载体和非病毒载体均存在一定程度的缺点,从而限制了基因治疗的发展.病毒样颗粒(virus-like par-ticles,VLPs)是缺乏病毒基因组.而仅由一种或几种病毒衣壳蛋白自我组装而成的不具有复制能力的颗粒,所以其可弥补上述载体的不足而成为具有应用前景的新型基因转运载体.本文拟对用于基因治疗的VLPs构建方法及应用研究进展作一综述.     

非病毒转基因载体的研究进展

高效的转基因载体是基因释放系统的核心。非病毒转基因载体具有低免疫原性和易制备等特性。本就近年来非病毒转基因载体的发展作一综述。     

Progress in developing cationic vectors for non-viral systemic gene therapy against cancer

Initially, gene therapy was viewed as an approach for treating hereditary diseases, but its potential role in the treatment of acquired diseases such as cancer is now widely recognized. The understanding of the molecular mechanisms involved in cancer and the development of nucleic acid delivery systems are two concepts that have led to this development. Systemic gene delivery systems are needed for therapeutic application to cells inaccessible by percutaneous injection and for multi-located tumor sites, i.e. metastases. Non-viral vectors based on the use of cationic lipids or polymers appear to have promising potential, given the problems of safety encountered with viral vectors. Using these non-viral vectors, the current challenge is to obtain a similarly effective transfection to viral ones. Based on the advantages and disadvantages of existing vectors and on the hurdles encountered with these carriers, the aim of this review is to describe the "perfect vector" for systemic gene therapy against cancer.     

Laboratory formulated magnetic nanoparticles for enhancement of viral gene expression in suspension cell line

One factor critical to successful gene therapy is the development of efficient delivery systems. Although advances in gene transfer technology including viral and non-viral vectors have been made, an ideal vector system has not yet been constructed. Due to the growing concerns over the toxicity and immunogenicity of viral DNA delivery systems, DNA delivery via improve viral routes has become more desirable and advantageous. The ideal improve viral DNA delivery system should be a synthetic materials plus viral vectors. The materials should also be biocompatible, efficient, and modular so that it is tunable to various applications in both research and clinical settings. The successful steps towards this improve viral DNA delivery system is demonstrated: a magnetofection system mediated by modified cationic chitosan-coated iron oxide nanoparticles. Dense colloidal cationic iron oxide nanoparticles serve as an uptake-enhancing component by physical concentration at the cell surface in presence of external magnetic fields; enhanced viral gene expression (3-100-fold) due to the particles is seen as compared to virus vector alone with little virus dose.     

Progress in cationic lipid-mediated gene transfection: a series of bio-inspired lipids as an example

Over the last several years, various gene delivery systems have been developed for gene therapy applications. Although viral vector-based gene therapy has led to the greatest achievements in animal and human studies, synthetic non-viral vectors have also been developed as they offer several advantages over viral systems, including lower immunogenicity and greater nucleic acid packaging capacity. Nevertheless, the transfection efficiency of the current non-viral gene carriers still needs to be improved, especially as regards direct in vivo transfection. In particular, cationic lipid/nucleic acid complexes (termed lipoplexes) have been the subject of intensive investigation with a view to optimize their performance and to better understand their mechanisms of action, and consequently to design new approaches to overcome the critical barriers of cationic liposome-mediated gene delivery. A possible strategy may rely on considering the membrane constituents and properties of the vast variety of living organisms as a source of inspiration for the design of biocompatible, non-toxic and effective novel artificial liposomal systems. Thus, the present forward-looking review provides an overview of the progress already made during the last years in the field of cationic lipid-mediated gene transfection and also focuses on a series of novel bio-inspired lipids for both in vitro and in vivo gene transfection.     

Cancer gene therapy by adenovirus-mediated gene transfer

Cancer arises as a direct result of genetic mutations. It therefore stands to reason that cancer should be well suited for the correction through gene therapy. Recent advances in the understanding of the molecular pathogenesis of cancer and the rapid development of recombinant DNA technology have made cancer gene therapy feasible in the clinical setting. The current efforts for cancer gene therapy mainly focus on immunogene therapy, chemogene therapy, restoration of tumor suppressor gene function, and oncolytic virus therapy. Central to all these therapies is the development of efficient vectors for gene delivery--this remains a work in progress. These vectors can be classified as viral and non-viral vectors. This paper will concentrate on viral vectors because of their practical advantages over non-viral vectors. Of the viral vectors, by far the most important are the human adenoviruses as is reflected by the enormous data and literature accumulated by studies relating to animal tumor models and clinical trials. In this review, we examine the recent progress in adenovirus-mediated cancer gene therapy with regard to cytokine gene, tumor suppressor gene, chemogene, and oncolytic adenovirus. We also discuss the current limitations of the adenoviral vector system and how they may be circumvented in future developments relating to targeted gene delivery.     

Non-viral delivery of RNA interference targeting cancer cells in cancer gene therapy

RNA interference (RNAi) is a collection of small RNA-directed mechanisms that result in sequence-specific inhibition of gene expression. RNAi delivery has demonstrated promising efficacy in the treatment of genetic disorders in cancer. Although viral vectors are currently the most efficient systems for gene therapy, potent immunogenicity, mutagenesis, and the biohazards of viral vectors remain their major risks. Various non-viral delivery vectors have been developed to provide a safer approach for gene delivery, including polymers, peptides, liposomes, and nanoparticles. However, some concerns and challenges of these non-viral gene delivery approaches remain to be overcome. In this review, we summarize the recent progress in the development of non-viral systems delivering RNAi and the currently available preclinical and clinical data, and discuss the challenges and future directions in cancer therapy.     

Modified montmorillonite as vector for gene delivery

Currently, gene delivery systems can be divided into two parts: viral or non-viral vectors. In general, viral vectors have a higher efficiency on gene delivery. However, they may sometimes provoke mutagenesis and carcinogenesis once re-activating in human body. Lots of non-viral vectors have been developed that tried to solve the problems happened on viral vectors. Unfortunately, most of non-viral vectors showed relatively lower transfection rate. The aim of this study is to develop a non-viral vector for gene delivery system. Montmorillonite (MMT) is one of clay minerals that consist of hydrated aluminum with Si-O tetrahedrons on the bottom of the layer and Al-O(OH)2 octahedrons on the top. The inter-layer space is about 12 A. The room is not enough to accommodate DNA for gene delivery. In the study, the cationic hexadecyltrimethylammonium (HDTMA) will be intercalated into the interlayer of MMT as a layer expander to expand the layer space for DNA accommodation. The optimal condition for the preparation of DNA-HDTMA-MMT is as follows: 1 mg of 1.5CEC HDTMA-MMT was prepared under pH value of 10.7 and with soaking time for 2 h. The DNA molecules can be protected from nuclease degradation, which can be proven by the electrophoresis analysis. DNA was successfully transfected into the nucleus of human dermal fibroblast and expressed enhanced green fluorescent protein (EGFP) gene with green fluorescence emission. The HDTMA-MMT has a great potential as a vector for gene delivery in the future.     

纳米基因载体的研究进展

由于使用病毒载体难以避免机体对病毒微粒的免疫反应和由病毒介导的随机整合或野生型病毒重整等潜在危害,因此应用纳米技术进行新型非病毒基因载体的研究发展迅速。本文就纳米微粒应用于基因载体的研究作一综述。     

Polysaccharide gene transfection agents

Gene delivery is a promising technique that involves in vitro or in vivo introduction of exogenous genes into cells for experimental and therapeutic purposes. Successful gene delivery depends on the development of effective and safe delivery vectors. Two main delivery systems, viral and non-viral gene carriers, are currently deployed for gene therapy. While most current gene therapy clinical trials are based on viral approaches, non-viral gene medicines have also emerged as potentially safe and effective for the treatment of a wide variety of genetic and acquired diseases. Non-viral technologies consist of plasmid-based expression systems containing a gene associated with the synthetic gene delivery vector. Polysaccharides compile a large family of heterogenic sequences of monomers with various applications and several advantages as gene delivery agents. This chapter, compiles the recent progress in polysaccharide based gene delivery, it also provides an overview and recent developments of polysaccharide employed for in vitro and in vivo delivery of therapeutically important nucleotides, e.g. plasmid DNA and small interfering RNA.