Department of Pharmacology and Pharmacy, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong SAR.
Institute of Pharmaceutical Science, School of Cancer & Pharmaceutical Science, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, United Kingdom.
Mol Pharm. 2021 Jun 7;18(6):2218-2232. doi: 10.1021/acs.molpharmaceut.0c01242. Epub 2021 May 20.
Pulmonary delivery of small interfering RNA (siRNA) is a promising therapeutic strategy for treating various respiratory diseases but an effective carrier for the delivery of siRNA into the cells of the lungs and a robust gene-silencing effect is still lacking. Previously, we reported that the KL4 peptide, a synthetic cationic peptide with a repeating KLLLL sequence, can mediate effective siRNA transfection in lung epithelial cells but its high hydrophobic leucine content, and hence poor water solubility, limits its application as a delivery vector. Here, we show that the covalent attachment of monodisperse poly(ethylene glycol) (PEG) improves the solubility of KL4 and the uptake of its complex with siRNA into lung epithelial cells, such that very robust silencing is produced. All PEGylated KL4 peptides, with PEG length varying between 6 and 24 monomers, could bind and form nanosized complexes with siRNA, but the interaction between siRNA and peptides became weaker as the PEG chain length increased. All PEGylated KL4 peptides exhibited satisfactory siRNA transfection efficiency on three human lung epithelial cell lines, including A549 cells, Calu-3 cells, and BEAS-2B cells. The PEGKL4 peptide, which contains 12 monomers of PEG, was optimal for siRNA delivery and also demonstrated a low risk of inflammatory response and toxicity following pulmonary administration.
肺部递送小干扰 RNA（siRNA）是治疗各种呼吸道疾病的有前途的治疗策略，但仍然缺乏将 siRNA 有效递送到肺部细胞中的有效载体和强大的基因沉默效果。以前，我们报道了 KL4 肽，一种具有重复 KLLLL 序列的合成阳离子肽，可以介导肺上皮细胞中有效的 siRNA 转染，但由于其高疏水性亮氨酸含量，因此水溶性差，限制了其作为递药载体的应用。在这里，我们表明单分散聚乙二醇（PEG）的共价连接可提高 KL4 的溶解度及其与 siRNA 的复合物被肺上皮细胞摄取的能力，从而产生非常强的沉默效果。所有 PEG 化 KL4 肽，PEG 长度在 6 到 24 个单体之间，都可以与 siRNA 结合并形成纳米大小的复合物，但随着 PEG 链长的增加，siRNA 与肽之间的相互作用变弱。所有 PEG 化 KL4 肽在三种人肺上皮细胞系（包括 A549 细胞、Calu-3 细胞和 BEAS-2B 细胞）上均表现出令人满意的 siRNA 转染效率。含有 12 个单体 PEG 的 PEGKL4 肽是 siRNA 递送的最佳选择，并且在肺部给药后也显示出低炎症反应和毒性风险。
