美国宾夕法尼亚大学Michael J. Mitchell团队报道了，多臂辅助设计树突样可降解的可电离脂质促进了mRNA向脾脏的系统性传递。相关研究成果于2025年1月1日发表于国际一流学术期刊《美国化学会杂志》。

脂质纳米粒（LNPs）已成为信使RNA（mRNA）在全身给药后递送到肝细胞，和肌肉注射后递送到抗原呈递细胞的关键载体。然而，如果不掺入靶向配体，如抗体、肽或小分子，实现向非肝细胞的全身mRNA递送仍然具有挑战性。

受梳状聚合物结构的启发，研究人员利用多臂辅助设计，通过改变胺头和多臂尾的结构，构建了270个树状可降解可电离脂质库，以实现最佳的mRNA递送。经过体外高通量筛选，鉴定出一系列具有高转染效率的顶部树枝状LNPs。与缺乏树枝状结构的可电离脂质类似物相比，这些树枝状可电离脂质在体内促进了更多的mRNA递送到脾脏。

冠状蛋白LNP颗粒的蛋白质组学分析显示，关键蛋白质簇增强，表明潜在的内源性靶向脾脏。18-2-9b2是一种类似铅树枝的LNP制剂，进一步用于包封Cre mRNA，并在脾脏巨噬细胞中表现出优异的基因组修饰，在Ai14小鼠模型中优于亲脾MC3/18PA LNP。

此外，在静脉注射Spic-GFP转基因模型中，18-2-9b2 LNP封装的治疗性BTB结构域和CNC同源物1（BACH1）mRNA在脾红髓巨噬细胞（RPM）中表现出BACH1的高效表达和随后的Spic下调。

研究结果强调了树枝状LNPs促进RNA递送到脾脏巨噬细胞的潜力，可能为一系列mRNA LNP治疗应用开辟了途径，包括再生医学、蛋白质替代和基因编辑疗法。

附：英文原文

Title: Multiarm-Assisted Design of Dendron-like Degradable Ionizable Lipids Facilitates Systemic mRNA Delivery to the Spleen

Author: Lulu Xue, Xinhong Xiong, Gan Zhao, William Molina-Arocho, Rohan Palanki, Zebin Xiao, Xuexiang Han, Il-Chul Yoon, Christian G. Figueroa-Espada, Junchao Xu, Ningqiang Gong, Qiangqiang Shi, Qinyuan Chen, Mohamad-Gabriel Alameh, Andrew E. Vaughan, Malay Haldar, Karin Wang, Drew Weissman, Michael J. Mitchell

Issue&Volume: January 1, 2025

Abstract: Lipid nanoparticles (LNPs) have emerged as pivotal vehicles for messenger RNA (mRNA) delivery to hepatocytes upon systemic administration and to antigen-presenting cells following intramuscular injection. However, achieving systemic mRNA delivery to non-hepatocytes remains challenging without the incorporation of targeting ligands such as antibodies, peptides, or small molecules. Inspired by comb-like polymeric architecture, here we utilized a multiarm-assisted design to construct a library of 270 dendron-like degradable ionizable lipids by altering the structures of amine heads and multiarmed tails for optimal mRNA delivery. Following in vitro high-throughput screening, a series of top-dendron-like LNPs with high transfection efficacy were identified. These dendron-like ionizable lipids facilitated greater mRNA delivery to the spleen in vivo compared to ionizable lipid analogs lacking dendron-like structure. Proteomic analysis of corona-LNP pellets showed enhancement of key protein clusters, suggesting potential endogenous targeting to the spleen. A lead dendron-like LNP formulation, 18–2–9b2, was further used to encapsulate Cre mRNA and demonstrated excellent genome modification in splenic macrophages, outperforming a spleen-tropic MC3/18PA LNP in the Ai14 mice model. Moreover, 18–2–9b2 LNP encapsulating therapeutic BTB domain and CNC homologue 1 (BACH1) mRNA exhibited proficient BACH1 expression and subsequent Spic downregulation in splenic red pulp macrophages (RPM) in a Spic-GFP transgene model upon intravenous administration. These results underscore the potential of dendron-like LNPs to facilitatem RNA delivery to splenic macrophages, potentially opening avenues for a range of mRNA-LNP therapeutic applications, including regenerative medicine, protein replacement, and gene editing therapies.

DOI: 10.1021/jacs.4c10265

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c10265