Godinho Bruno M D C, Knox Emily G, Hildebrand Samuel, Gilbert James W, Echeverria Dimas, Kennedy Zachary, Haraszti Reka A, Ferguson Chantal M, Coles Andrew H, Biscans Annabelle, Caiazzi Jillian, Alterman Julia F, Hassler Matthew R, Khvorova Anastasia
RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA, USA.
Mol Ther Nucleic Acids. 2022 Jun 13;29:116-132. doi: 10.1016/j.omtn.2022.06.005. eCollection 2022 Sep 13.
Effective systemic delivery of small interfering RNAs (siRNAs) to tissues other than liver remains a challenge. siRNAs are small (∼15 kDa) and therefore rapidly cleared by the kidneys, resulting in limited blood residence times and tissue exposure. Current strategies to improve the unfavorable pharmacokinetic (PK) properties of siRNAs rely on enhancing binding to serum proteins through extensive phosphorothioate modifications or by conjugation of targeting ligands. Here, we describe an alternative strategy for enhancing blood and tissue PK based on dynamic modulation of the overall size of the siRNA. We engineered a high-affinity universal oligonucleotide anchor conjugated to a high-molecular-weight moiety, which binds to the 3' end of the guide strand of an asymmetric siRNA. Data showed a strong correlation between the size of the PK-modifying anchor and clearance kinetics. Large 40-kDa PK-modifying anchors reduced renal clearance by ∼23-fold and improved tissue exposure area under the curve (AUC) by ∼26-fold, resulting in increased extrahepatic tissue retention (∼3- to 5-fold). Furthermore, PK-modifying oligonucleotide anchors allowed for straightforward and versatile modulation of blood residence times and biodistribution of a panel of chemically distinct ligands. The effects were more pronounced for conjugates with low lipophilicity (e.g., N-Acetylgalactosamine [GalNAc]), where significant improvement in uptake by hepatocytes and dose-dependent silencing in the liver was observed.
将小干扰RNA（siRNA）有效地全身递送至肝脏以外的组织仍然是一项挑战。siRNA分子量较小（约15 kDa），因此会迅速被肾脏清除，导致血液停留时间和组织暴露受限。目前改善siRNA不良药代动力学（PK）特性的策略依赖于通过广泛的硫代磷酸酯修饰或与靶向配体偶联来增强与血清蛋白的结合。在此，我们描述了一种基于动态调节siRNA整体大小来增强血液和组织PK的替代策略。我们设计了一种与高分子量部分偶联的高亲和力通用寡核苷酸锚定物，它可与不对称siRNA引导链的3'端结合。数据显示PK修饰锚定物的大小与清除动力学之间存在很强的相关性。40 kDa的大型PK修饰锚定物使肾脏清除率降低了约23倍，并使组织曲线下暴露面积（AUC）提高了约26倍，从而使肝外组织滞留增加（约3至5倍）。此外，PK修饰寡核苷酸锚定物能够直接且通用地调节一系列化学性质不同的配体的血液停留时间和生物分布。对于亲脂性较低的偶联物（例如N - 乙酰半乳糖胺[GalNAc]），这种效果更为明显，在这些偶联物中观察到肝细胞摄取有显著改善以及肝脏中存在剂量依赖性沉默。
