Abstract：
Although small-interfering RNAs (siRNAs) are specific silencers for numerous disease-related genes, their clinical applications still require safe and effective means of delivery into target cells. Highly efficient lipid nanoparticles (LNPs) are developed for siRNA delivery, showcasing the advantages of novel pH-responsive lipoamino xenopeptide (XP) carriers. These sequence-defined XPs are assembled by branched lysine linkages between cationizable polar succinoyl tetraethylene pentamine (Stp) units and apolar lipoamino fatty acids (LAFs) at various ratios into bundle or U-shape topologies. Formulation of siRNA-LNPs using LAF4-Stp1 XPs as ionizable compounds led to robust cellular uptake, high endosomal escape, and successful in vitro gene silencing activity at an extremely low (150 picogram) siRNA dose. Of significance is the functional in vivo endothelium tropism of siRNA-LNPs with bundle LAF4-Stp1 XP after intravenous injection into mice, demonstrated by superior knockdown of liver sinusoidal endothelial cell (LSEC)-derived factor VIII (FVIII) and moderate silencing of hepatocyte-derived FVII compared to DLin-MC3-DMA-based LNPs. Optimizing lipid composition following click-modification of siRNA-LNPs with ligand c(RGDfK) efficiently silenced vascular endothelial growth factor receptor-2 (VEGFR-2) in tumor endothelial cells (TECs). The findings shed light on the role of ionizable XPs in the LNP in vivo cell-type functional targeting, laying the groundwork for future therapeutic applications.
摘要：
尽管小干扰RNA（siRNA）是许多疾病相关基因的特异性沉默，它们的临床应用仍然需要安全有效的方式递送到靶细胞中。高效脂质纳米颗粒（LNPs）被开发用于siRNA递送，展示了新型pH响应性脂氨基异肽（XP）载体的优势。这些序列定义的XPs通过可阳离子化的极性琥珀酰四亚乙基五胺（Stp）单元和非极性脂氨基脂肪酸（LAF）之间的支链赖氨酸键以各种比例组装成束或U形拓扑结构。使用LAF4-Stp1XPs作为可电离化合物的siRNA-LNPs的制剂导致强大的细胞摄取，高度内体逃逸，和在极低（150皮克）siRNA剂量下成功的体外基因沉默活性。意义重大的是在静脉注射入小鼠后，具有LAF4-Stp1XP束的siRNA-LNP在体内的功能内皮嗜性，与基于DLin-MC3-DMA的LNP相比，肝窦内皮细胞（LSEC）衍生因子VIII（FVIII）的高敲低和肝细胞衍生FVII的中度沉默证明。在用配体c(RGDfK)点击修饰siRNA-LNP后优化脂质组成有效沉默肿瘤内皮细胞(TECs)中的血管内皮生长因子受体-2(VEGFR-2)。这些发现揭示了可电离的XPs在LNP体内细胞型功能靶向中的作用，为未来的治疗应用奠定基础。
