Key Laboratory of Optical Field Manipulation & Center for Optoelectronics Materials and Devices of Zhejiang Province, Department of Physics , Zhejiang Sci-Tech University , Hangzhou 310018 , China.
J Phys Chem B. 2019 Mar 28;123(12):2636-2644. doi: 10.1021/acs.jpcb.8b10483. Epub 2019 Mar 14.
Complementary to endocytosis, cell-penetrating peptides (CPPs) at high concentrations can penetrate the cell membrane in a direct way, which further makes CPPs popular candidates for delivering therapeutic or diagnostic agents. Although featured as rapid uptake, the translocation efficiency and potential toxicity of the direct penetration are usually affected by cargoes, which is still unclear. Here, using coarse-grained molecular dynamics simulations, we show that the polyarginine (R) peptides penetrate the membrane through a water pore in the membrane, and the transmembrane efficiency is improved by conjugating to small nanoparticles (NPs) with proper linkers. It can be attributed to both the extension of the lifetime of the water pore by the NPs and outward diffusion of negative lipids in the asymmetry membrane, which induces the surrounding R-NP conjugates to the water pore before it is closed. The translocation efficiency is closely related to the length of the linkers, and it gets the maximum value when the length of the linkers is around half of the membrane thickness. Overlong linkers not only decrease the transmembrane efficiency because of the blockage of NPs in the water pore but may also cause cytotoxicity because of the unclosed water pore. The results provide insights into the internalization of CPPs and facilitate the design of CPP and drug conjugates with high efficiency and low toxicity.
细胞穿透肽（CPPs）在高浓度时可以通过直接穿透细胞膜，这使得 CPPs 成为递呈治疗或诊断试剂的理想候选者。尽管 CPPs 具有快速摄取的特点，但直接穿透的转位效率和潜在毒性通常会受到载体的影响，这一点仍不清楚。在这里，我们使用粗粒化分子动力学模拟表明，多聚精氨酸（R）肽通过膜中的水孔穿透膜，并且通过与具有适当连接子的小纳米颗粒（NPs）缀合来提高跨膜效率。这归因于 NPs 延长了水孔的寿命，以及不对称膜中带负电荷的脂质向外扩散，这使得周围的 R-NP 缀合物在水孔关闭之前进入水孔。转位效率与连接子的长度密切相关，当连接子的长度约为膜厚度的一半时，转位效率达到最大值。过长的连接子不仅会因为 NPs 阻塞水孔而降低跨膜效率，而且还可能因为水孔未关闭而导致细胞毒性。该结果为 CPP 的内化提供了深入的了解，并有助于设计具有高效低毒性的 CPP 和药物缀合物。
