National Engineering Research Center for Biomaterials, Sichuan University, No. 29, Wangjiang Road, Chengdu 610064, P. R. China.
J Mater Chem B. 2019 Feb 14;7(6):915-926. doi: 10.1039/c8tb02650e. Epub 2018 Dec 12.
Disulfide modified lipopeptide assemblies with an arginine-rich dendritic periphery provide a promising platform for effective gene transfer. Dendritic arginine peptides that mimic the cell-penetrating peptides of a virus envelope are vital for complexation, interaction with physical barriers, and final gene release. Here, we report three lipopeptides with different-generation dendritic peripheries (RLS, RLS and RLS), each of which contains a dioleoyl-l-lysinate hydrophobic tail. Such molecules were proven to self-assemble in aqueous solution with different morphologies, sizes, and surface zeta potentials. RLS and RLS assemblies showed spherical and spindle shapes with zeta potentials of 27.2 and 32.8 mV, respectively. They exhibited complete condensation of pDNA at a low N/P ratio, while RLS assemblies displayed a fiber pattern with a relatively low electric potential of 10.9 mV with poor DNA binding ability. In a cellular viability experiment, RLS and RLS have no significant cytotoxicity even at high dosage, while RLS showed conspicuous toxicity. As a gene vector, RLS presented high gene transfection efficiency either in the presence or the absence of serum, which was 58.7% greater than liposome 2000 and PEI in the condition of 10% fetal bovine serum for HeLa cells. While RLS showed good results just without serum and RLS was unserviceable in all situations. Moreover, molecular dynamic simulation was exploited to analyze the kinestate of the signal molecule and the interactions of multiple molecules, which could assist us in better understanding the experimental phenomena. The simulation results indicated that the RLS molecule has better flexibility, which was favorable for interaction with the cell membrane. And it could generate tight integration in self-assembly while RLS and RLS assemblies have a large molecular interval, which led to a controllable release of cargos for RLS in a reductive environment. In summary, the generation of the dendrimer in lipopeptides is vital for the gene transfer effect. For optimization, it is necessary to study the structure-function relationship, and molecular dynamic simulation is an effective strategy for screening the molecular structure and even for predicting experimental results.
具有精氨酸丰富树突状外围的二硫键修饰的脂肽组装体为有效基因转移提供了有前途的平台。模拟病毒包膜穿透肽的树突状精氨酸肽对于复合物的形成、与物理屏障的相互作用以及最终的基因释放至关重要。在这里，我们报告了三种具有不同代树突状外围的脂肽（RLS、RLS 和 RLS），它们都含有二油酰基-l-赖氨酸疏水性尾部。事实证明，这些分子可以在水溶液中自组装成具有不同形态、大小和表面 zeta 电位的结构。RLS 和 RLS 组装体分别呈现出球形和纺锤形，zeta 电位分别为 27.2 和 32.8 mV。它们在低 N/P 比下完全浓缩了 pDNA，而 RLS 组装体则显示出纤维图案，zeta 电位相对较低（10.9 mV），与 DNA 的结合能力较差。在细胞活力实验中，即使在高剂量下，RLS 和 RLS 也没有明显的细胞毒性，而 RLS 则表现出明显的毒性。作为基因载体，RLS 在存在或不存在血清的情况下均表现出较高的基因转染效率，在含 10%胎牛血清的情况下，HeLa 细胞的基因转染效率比脂质体 2000 和 PEI 分别高 58.7%。而 RLS 在没有血清的情况下表现良好，RLS 在所有情况下都无法使用。此外，还利用分子动力学模拟分析了信号分子的运动状态和多个分子的相互作用，这有助于我们更好地理解实验现象。模拟结果表明，RLS 分子具有更好的柔韧性，有利于与细胞膜相互作用。而且，它可以在自组装过程中产生紧密的整合，而 RLS 和 RLS 组装体具有较大的分子间隔，这导致 RLS 在还原环境中能够可控地释放货物。总之，脂肽中二硫键修饰的树突状的产生对于基因转移效果至关重要。为了进行优化，有必要研究结构-功能关系，而分子动力学模拟是筛选分子结构甚至预测实验结果的有效策略。
