具有pH/还原双重响应和荧光特性的靶向型脂质基因载体研究

The most challenging issues for successful application of gene therapy is to develop safe, high efficient and multifunctional vectors. In order to increase the transfection efficiency of non-viral gene vectors, in this project, a series of pH and reduction dual-responsive amino acids cationic lipids are to be synthesized based on pH sensitive histidine and reduction responsive linkage by utilizing the unique stimulus in intracellular environments including slightly acidic environments of endosomes and high concentration of glutathione. To track the gene delivery processes, near-infrared fluorescent group was also introduced into the same lipids. Further, biocompatible hyaluronic acid with good shielding and targeting ability was further used to overcome the poor targeting ability of non-viral gene vector. This research focuses on effective condensation and intelligent release of DNA, fluorescent tracking, reducing cytotoxicity, increasing transfection efficiency, enhancing targeting ability of the title lipids. It is helpful to provide theoretical basis and application prospect for the design and synthesis of safe, efficient, targeted and “visible” gene transfection carriers by studying their structure-activity relationships, transfection process and mechanisms.

安全、高效、多功能化基因载体的构建是基因治疗的关键。为了克服非病毒基因载体转染效率低的问题，本项目研究拟利用细胞内在的生物学刺激（内涵体的弱酸性环境和高浓度谷胱甘肽），基于pH敏感的组氨酸和还原敏感的连接键，构建具有pH/还原双重敏感特性的阳离子脂质基因载体。其次，为了示踪基因的转运过程，向脂质结构中引入近红外疏水荧光团，实现基因的“可视化”传递。再次，为了增强非病毒基因载体的靶向性，利用生物兼容性透明质酸的电荷屏蔽和靶向功能，实现基因的长效循环和靶向传递。本项目拟构建集pH/还原双重响应特征、近红外荧光特性和靶向功能于一体的多功能脂质基因载体。围绕DNA的智能控释、转运示踪、降低毒性、提高转染效率及增强靶向性等核心问题开展系统而深入的研究。通过探讨其作为基因载体的构效关系、转运过程和机理等一系列问题，为设计合成高效、低毒、靶向和“可视”的基因转染载体提供理论基础和应用前景

基因治疗通过调控基因在靶细胞内的表达以治疗疾病，其关键在于发展安全高效的基因载体。为了提高非病毒基因载体的转染效率和阐明基因转运机理，本项目研究以生物兼容性的氨基酸为亲水头部，还原敏感的二硫键为连接键，香豆素、萘二甲酰亚胺和苯并吡喃腈等疏水荧光团为疏水脂质尾部，构建具有刺激响应和荧光特性的多功能化阳离子脂质基因载体。通过系统的DNA相互作用、构效关系和转运机制研究，可为设计合成安全、高效和“可视”的基因转染载体提供理论基础。