Rational design of soft nanoparticles for non-invasive drug delivery

基因治疗是将编码治疗基因的DNA靶向插入病变细胞或组织的细胞核中，然后表达，是治疗许多疾病和病症的最有前途的新疗法之一。2003年，中国批准了第一个基因治疗产品，Gendicine（基于腺病毒载体），用于头颈癌。2012年7月24日，欧洲药品管理局批准了腺相关病毒（AAV）基因疗法，由uniQure的Glybera，用于治疗脂蛋白脂肪酶缺乏症，一种孤儿疾病。UniQure还在开发GDNF（胶质细胞源性神经营养因子）基因在其AAV-2递送载体中用于治疗帕金森病的用途。目前，超过1300项基因治疗临床试验正在进行中（www.example.com）。尽管取得了巨大进展，但在实现这种治疗模式的全部益处方面仍然存在许多挑战。特别是，为了实现基因治疗的全部益处，有必要开发具有靶向能力、高转染效率和改进的安全性的基因递送载体。目前，病毒是用于DNA递送的最有效的载体，但它们的使用具有许多缺点：高免疫原性和毒性、可被封装的DNA序列的大小的限制以及诱变的可能性。新型的非病毒递送系统不存在这些缺点，并为基因治疗提供了巨大的希望。然而，非病毒系统对于临床应用来说还不够有效和特异。这些系统的结构和功能都需要改进。此外，在靶位点是外部可接近的器官/组织（例如眼睛、皮肤、鼻/阴道/口腔粘膜）的应用中，非侵入性基因治疗方法（例如局部和口服施用）是非常期望的，但由于缺乏有效的递送系统，目前尚不可行。该研究计划将侧重于核酸递送系统设计的基础和应用方面，特别关注质粒DNA和siRNA。在开发新的、更先进的非病毒技术以在体内递送和靶向基因和siRNA的过程中，必须充分理解相互作用的细胞和亚细胞途径。正确和特异性治疗反应的诱导取决于递送系统到达预期靶位点并在那里被激活的"智能"。在这些系统的设计过程中，需要交互过程的可视化和传递效率的量化。基于核酸的治疗剂是特别难以成功递送的分子。这就是为什么目前只有一种方法来管理这些化合物的原因之一：注射。开发非侵入性递送系统，可以在局部施用后通过皮肤、角膜、鼻和阴道粘膜运输药物，可以提供局部无痛靶向基因治疗的方法。此外，局部化方法可以克服口服和肠胃外给药和吸收期间的药物稳定性、注射的局部毒性和刺激性以及由于药物半衰期短而导致的多次给药的相关问题。纳米技术方法在设计和开发用于核酸的局部非侵入性递送和靶向系统中提供了显著的潜力。我们建议开发非侵入性药物输送系统的基础上，复合纳米粒子使用自组装和靶向生物材料，包括磷脂，双子表面活性剂，酰化氨基酸和碳纳米管。

Gene therapy, the targeted insertion of DNA coding for a therapeutic gene into the nuclei of diseased cells or tissues followed by its expression, is one of the most promising new therapies for a host of diseases and conditions. The first gene therapy product, Gendicine (adenoviral vector-based) was approved in China in 2003 for head and neck cancer. On July 24, 2012 the European Medicines Agency approved the adeno-associated viral (AAV) gene therapy, Glybera by uniQure, for lipoprotein lipase deficiency, an orphan disease. uniQure is also developing the use of a GDNF (glial cell derived neurotrophic factor) gene in their AAV-2 delivery vector for the treatment of Parkinson’s disease. Currently >1300 gene therapy clinical trials are in progress (www.clinicaltrials.gov). In spite of the tremendous progress, a number of challenges remain in realizing the full benefit of this treatment mode. In particular, to achieve the full benefit of gene therapy, it is necessary to develop gene delivery vectors with targeting ability, high transfection efficiency and improved safety. Currently, viruses are the most efficient vectors for DNA delivery, but their use has many disadvantages: high immunogenicity and toxicity, limitations in the size of DNA sequences that can be encapsulated, and potential for mutagenesis. Novel non-viral delivery systems do not present these disadvantages and offer tremendous promise for gene therapy. However, non-viral systems are not yet effective and specific enough for clinical applications. Improvements in both the structure and function of these systems are required. Moreover, in applications where the target site is an externally accessible organ/tissue, such as the eye, skin, nasal/vaginal/oral mucosa, a non-invasive approach to gene therapy, such as topical and oral administration, is highly desirable but not presently feasible due to the lack of effective delivery systems. The research program will focus on both the fundamental and applied aspects of delivery system design for nucleic acids, with specific focus on plasmid DNA and siRNA. In the process of developing new, more advanced non-viral technologies to deliver and target genes and siRNA in the body, the cellular and subcellular pathways of interaction must be fully understood. Induction of the correct and specific therapeutic responses is dependent upon the ‘intelligence’ of the delivery system to arrive to the intended target sites and be activated there. During the design of these systems, visualization of the interaction process and the quantification of the delivery efficiency are required. Nucleic acid-based therapeutic agents are especially difficult molecules to deliver successfully. This is one of the reasons why there is currently only one way administer these compounds: by injection. Development of non-invasive delivery systems that can transport drugs through the skin, cornea, nasal and vaginal mucosa after topical administration could provide an approach to target gene therapies locally and painlessly. In addition, the localized approach could overcome problems related to drug stability during oral and parenteral dosing and absorption, local toxicity and irritation from injection, and multiple dosing because of short drug half-lives. Nanotechnological approaches provide significant potential in the design and development of topical non-invasive delivery and targeting systems for nucleic acids. We propose developing non-invasive drug delivery systems based on composite nanoparticles using self-assembling and targetable biomaterials, including phospholipids, gemini surfactants, acylated amino acids and carbon nanotubes.