Cell-penetrating peptide adaptors for intracellular cargo delivery

项目摘要 代表重要治疗线索的生物分子通常会失败，因为它们无法到达目标， 通常是因为不能穿过细胞膜并到达适当的亚细胞目的地。细胞- 穿透肽（CPPs）长期以来对克服这些缺陷具有很大的希望。它们能够 介导与它们偶联的分子穿透质膜，允许递送 “货物”到细胞内部，这是一种潜在的变革性平台技术，可以实现一系列特定的 应用.然而，CPP治疗剂的开发一直令人失望，因为传统的CPP- 货物分子大部分保持被捕获在内体中而不是到达细胞质。最大的技术 CPP治疗剂开发的障碍是不能从核内体逃逸-我们的技术解决了这个问题 问题.我们的创新方法是使用高亲和力但可逆的非共价偶联来连接货物 到CPP。我们的原型CPP-接头融合蛋白，TAT-CaM，由细胞穿透 部分来自HIV转录反式激活因子和人钙调蛋白。TAT-CaM结合CaM结合位点（CBS） 含有在钙存在下具有nM亲和力但在钙不存在下可忽略不计的货物。因为哺乳动物 细胞通常维持低的静息钙浓度，一旦钙转运蛋白从CPP-接头上解离， 在细胞内，释放货物到细胞质或其他亚细胞目的地。 这个R15区域更新应用程序描述了努力阐明机制，动力学和其他基本 CPP生物学问题，设计下一代适配器和货物的改进，并开发方法， 使用它们来有效地运送用于研究和治疗目的的货物。这些努力的成功将 验证了我们的策略是一种适用于递送包括核酸在内的广泛大分子的工具， 酸，可能使新一代创新疗法和研究工具的发展。

PROJECT SUMMARY Biomolecules that represent important therapeutic leads often fail because they cannot reach their targets, commonly because of inability to cross cell membranes and reach appropriate subcellular destinations. Cell- penetrating peptides (CPPs) have long held great promise for overcoming these failures. They are capable of mediating penetration of the plasma membrane by molecules to which they are coupled, allowing delivery of ‘cargos’ to cell interiors, a potentially transformative platform technology that can enable an array of specific applications. Nevertheless, development of CPP therapeutics has been disappointing because traditional CPP- cargo molecules largely remain trapped in endosomes rather than reach the cytoplasm. The largest technical hurdle to development of CPP therapeutics is failure to escape from endosomes – our technology solves this problem. Our innovative approach is the use of high affinity but reversible noncovalent coupling to attach cargos to CPPs. Our prototype CPP-adaptor fusion protein, TAT-Calmodulin (TAT-CaM), consists of the cell penetrating moiety from HIV transactivator of transcription and human calmodulin. TAT-CaM binds CaM binding-site (CBS) containing cargos with nM affinity in the presence of calcium but negligibly in its absence. Because mammalian cells typically maintain low resting concentrations of calcium, cargos dissociate from the CPP-adaptor once inside the cell, releasing cargo to the cytoplasm or other subcellular destination. This R15 AREA renewal application describes efforts to elucidate the mechanisms, kinetics and other basic issues of CPP biology, engineer next-generation improvements in adaptors and cargos and develop methods to use them to efficiently deliver cargos for research and therapeutic purposes. Success in these endeavors will validate that our strategy is an adaptable tool for delivery of a wide array of macromolecules including nucleic acids, potentially enabling the development of a new generation of innovative therapeutics and research tools.