An albumin-mediated cholesterol design-based strategy for tuning siRNA pharmacokinetics and gene silencing

作者：Bienk Konrad; Hvam Michael Lykke; Pakula Malgorzata Maria; Dagnaes Hansen Frederik; Wengel Jesper; Malle Birgitte Molholm; Kragh Hansen Ulrich; Cameron Jason; Bukrinski Jens Thostrup; Howard Kenneth A^*

来源：Journal of Controlled Release, 2016, 232: 143-151.

DOI：10.1016/j.jconrel.2016.04.013

• Albumin
• Drug delivery
• siRNA
• Biodistribution
• Half-life extension
• Factor VII

Major challenges for the clinical translation of small interfering RNA (siRNA) include overcoming the poor plasma half-life, site-specific delivery and modulation of gene silencing. In this work, we exploit the intrinsic transport properties of human serum albumin to tune the blood circulatory half-life, hepatic accumulation and gene silencing; based on the number of siRNA cholesteryl modifications. We demonstrate by a gel shift assay a strong and specific affinity of recombinant human serum albumin (rHSA) towards cholesteryl-modified siRNA (K-d > 1 x 10(-7) M) dependent on number of modifications. The rHSA/siRNA complex exhibited reduced nuclease degradation and reduced induction of TNF-alpha production by human peripheral blood mononuclear cells. The increased solubility of heavily cholesteryl modified siRNA in the presence of rHSA facilitated duplex annealing and consequent interaction that allowed in vivo studies using multiple cholesteryl modifications. A structural-activity-based screen of in vitro EGFP-silencing was used to select optimal siRNA designs containing cholesteryl modifications within the sense strand that were used for in vivo studies. We demonstrate plasma half-life extension in NMRI mice from t(1/2) 12 min (naked) to t(1/2) 45 min (single cholesteryl) and t(1/2) 71 min (double cholesteryl) using fluorescent live bioimaging. The biodistribution showed increased accumulation in the liver for the double cholesteryl modified siRNA that correlated with an increase in hepatic Factor VII gene silencing of 28% (rHSA/siRNA) compared to 4% (naked siRNA) 6 days post-injection. This work presents a novel albumin-mediated cholesteryl design-based strategy for tuning pharmacokinetics and systemic gene silencing.

• 出版日期2016-6-28