International Research Fellowship Program: Systematic Design and Evaluation of Synthetic Virus-like Particles for Gene Delivery: Overcoming Barriers for In Vitro

[401542]国际研究奖学金计划使美国科学家和工程师能够到国外进行三到二十四个月的研究。该计划的奖励为联合研究提供了机会，并利用独特或互补的设施、专业知识和国外的实验条件。该奖项将支持Ayesha Ahmad博士与英国伦敦帝国理工学院的Andrew Miller博士进行为期22个月的研究。基因治疗是指通过引入外源DNA，增加、替换或纠正基因，治疗遗传性和后天性疾病的过程。一种可行的载体必须能够包装DNA，将DNA传递到细胞中，并将DNA释放到细胞核中，从而使细胞能够使用其机制来表达治疗性蛋白质。生物方法、化学方法和物理方法目前都在使用，在这一领域的发展中，它们有各种各样的优缺点。本提案的重点是使用化学或合成方法，这些方法因其易于生产，缺乏免疫原性反应，制备方法多变等固有优势而受到广泛关注。尽管它们比基于病毒的基因传递系统有优势，但合成基因传递系统取得的成功有限。尽管合成载体丰富多样，但对基因传递过程中许多不同步骤中发生的相互作用和过程的充分表征和理解仍是缺乏的。在基因传递过程的几个步骤中，已经确定了几种阻碍非病毒载体路径的生物屏障。改进非病毒传递系统的关键是确定合成DNA复合物与这些不同屏障上的细胞之间发生的相互作用。这允许对载体结构和复杂配方进行定向改变和优化，以克服复杂遇到的各种生物障碍和障碍。在帝国理工学院遗传治疗中心，研究人员开发了一种合成的非病毒载体平台系统，称为脂质体：mu:DNA （LMD）。LMD系统是一个围绕？（mu）与腺病毒凝聚核心复合物相关的肽。LMD系统本身并不被认为是一个目的，但它代表了一个坚实的平台，在这个平台上，未来可以构建临床可行的合成非病毒载体系统。LMD是一种由定义明确的化学成分组成的主要工具包构建的具有良好特征、易于理解的转染载体。鉴于这一坚实的基础，下一代LMD系统LMDII现在将以顺序和逻辑的方式开发，通过使用由补充化学成分组成的新二级工具包对这一主要载体进行模块化调整，以供临床准备。提出的研究计划被认为是获得临床可行的非病毒基因治疗载体的唯一系统方法。在开发非病毒基因治疗载体方面，融合新型病毒样纳米颗粒的物理化学-细胞生物学-药物特性的需求至关重要，因此，为临床试验中主要使用的有效但不稳定的病毒载体提供临床可行的替代方案。

0401542AhmadThe International Research Fellowship Program enables U.S. scientists and engineers to conduct three to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a twenty-two-month research fellowship by Dr. Ayesha Ahmad to work with Dr. Andrew Miller at Imperial College in London, United Kingdom.Gene Therapy refers to the process of curing inherited and acquired diseases by adding, replacing, or correcting genes through the introduction of foreign DNA. A viable vector has to be able to, among other things, package the DNA, deliver the DNA to the cell, and release the DNA into the nucleus thereby allowing the cell to use its machinery to express the therapeutic protein. Biological methods, chemical methods, and physical methods, are all currently being used, with their various advantages and disadvantages, in the development of this field. This proposal focuses on using chemical or synthetic methods, which have attracted considerable attention due to their inherent advantages including ease of production, lack of immunogenic response, and variable preparation. Despite their advantages over viral-based gene delivery systems, synthetic gene delivery systems have met with limited success. Although there is an abundance of and variation in synthetic vectors, a full characterization and understanding of the interactions and processes that occur at the many different steps of the gene delivery course is lacking. Several biological barriers have been identified that impede the path of non-viral vectors at several steps in the gene delivery process. The key to improving non-viral delivery systems is to identify the interactions that occur between the synthetic DNA complexes and the cells at these various barriers. This allows directed alteration and optimization of vector structure and complex formulations to overcome the various biological impediments and barriers the complex encounters. At the Imperial College Genetics Therapy Centre, researchers have developed a synthetic non-viral vector platform system known as liposome:mu:DNA (LMD). The LMD system is a ternary LD system built around the ? (mu) peptide associated with the condensed core complex of the adenovirus. LMD systems are not considered an end in themselves but represent a firm platform on which to build clinically viable synthetic non-viral vector systems in the future. LMD represents a well-characterized, well-understood transfection vehicle constructed from a primary tool-kit of well-defined chemical components. Given this firm foundation, the next generation of LMD systems, LMDII, will now be developed in a sequential and logical fashion for clinical readiness by making modular adaptations to this primary vehicle using new secondary tool-kits comprised of supplementary sets of chemical components. The proposed research program is considered the only systematic way to reach a clinically viable non-viral gene therapy vector. The need to merge physicochemical - cellular biology - pharmaceutical characterization of the novel virus-like nanoparticles, is critical in terms of developing non-viral gene therapy vectors, therefore offering clinically viable alternatives to the effective, yet precarious, viral vectors predominantly employed in clinical trials today.