Chemical engineering of therapeutic RNAs for extrahepatic delivery

项目摘要 小干扰RNA（siRNA）是一种信息药物，可以设计用于治疗遗传定义的肿瘤。 从而重塑我们对人类医学的态度。siRNA的临床效用取决于 功能性递送至感兴趣的组织和细胞类型，这又由寡核苷酸化学定义。 当化学结构-即，寡核苷酸修饰模式-提供功能性和非功能性的寡核苷酸修饰模式。 优化了向组织的毒性递送，可以快速开发候选药物以治疗其他疾病， 同样的组织受累目前，siRNA的临床应用限于肝脏，其中siRNA的缀合物可以在肝脏中表达。 三价N-乙酰半乳糖胺（GalNAc）部分能够有效递送至肝细胞和治疗剂 一年后，注射一次。 为了将siRNA的效用扩展到肝脏以外的组织，我们必须（i）优化化学修饰模式， 完全稳定siRNA，并且是无毒的，与沉默机制相容;（ii）了解 定义siRNA药代动力学和药效学行为的机制;和（iii）鉴定和 设计新的配体，其能够靶向组织递送和持续的体内功效。我们有 在有机化学、组合化学、寡核苷酸化学、RISC 生物学和siRNA药理学需要解决这些问题。到目前为止，我们已经完全化学鉴定了 显示出最小毒性和免疫原性的稳定的siRNA支架; 支持肝脏、肾脏、心脏、脂肪、肌肉和肺的功能性输送; 动态调节siRNA清除;并合成新的骨架修饰（膦酸酯变体） 其改善siRNA稳定性，并且当置于确定的位置时，增强RISC功效和特异性。 在这些最新进展的基础上，我们提出了四个主要的研究方向，旨在（i）化学 工程化siRNA支架，其能够使任何RNA序列在体内具有完全稳定性和持续功效; (ii)建立膦酸酯变体作为用于调节治疗性RNA性质的新骨架;（iii） 设计并发现将siRNA递送至肝脏以外的组织的新型配体;以及（iv）与网络合作 的专家合作者，以研究新的化学配置的治疗潜力的模型， 未满足医疗需求的疾病。 这些研究的完成将建立siRNA化学结构，使功能性肝外 siRNA的递送，并导致发现了几种具有转化治疗药物的潜力的化合物。 一系列疾病的治疗方法。

Project Summary Small interfering RNAs (siRNAs) are informational drugs that can be designed to treat genetically defined disorders and thereby reshape our approach to human medicine. The clinical utility of siRNAs depends on functional delivery to a tissue and cell type of interest, which is in turn defined by oligonucleotide chemistry. When a chemical architecture—i.e., oligonucleotide modification pattern—that provides functional and non- toxic delivery to a tissue is optimized, candidate drugs can be quickly developed to treat other diseases with the same tissue involvement. Currently, the clinical utility of siRNA is limited to liver, where conjugation of trivalent N-acetylgalactosamine (GalNAc) moiety enables efficient delivery to hepatocytes and therapeutic activity for a year after a single injection. To expand the utility of siRNAs to tissues beyond liver, we must (i) optimize chemical modification patterns that fully stabilize siRNAs and are non-toxic and compatible with the silencing machinery; (ii) understand the mechanisms that define siRNA pharmacokinetic and pharmacodynamic behavior; and (iii) identify and engineer novel ligands that enable targeted tissue delivery and sustained in vivo efficacy. We have the demonstrated expertise in organic chemistry, combinatorial chemistry, oligonucleotide chemistry, RISC biology, and siRNA pharmacology needed to solve these problems. To date, we have identified fully chemically stabilized siRNA scaffolds that exhibit minimal toxicity and immunogenicity; engineered novel conjugates that support functional delivery to liver, kidneys, heart, fat, muscle, and lung; defined chemical approaches to dynamically modulate siRNA clearance; and synthesized novel backbone modifications (phosphonate variants) that improve siRNA stability and, when placed in defined positions, enhance RISC efficacy and specificity. Building on these recent advances, we propose four principal research directions that seek to (i) chemically engineer siRNA scaffolds that enable complete stability and sustained efficacy of any RNA sequence in vivo; (ii) establish phosphonate variants as a new backbone for the modulation of therapeutic RNA properties; (iii) engineer and discover novel ligands that deliver siRNAs to tissues other than liver; and (iv) work with a network of expert collaborators to investigate the therapeutic potential of novel chemical configurations in models of diseases with unmet medical needs. The completion of these studies will establish siRNA chemical architectures that enable functional extrahepatic delivery of siRNAs and lead to the discovery of several compounds with the potential to transform therapeutic approaches for range of diseases.