Department of Natural Resources and Environmental Studies, National Dong Hwa University, Hualien, Taiwan.
PLoS One. 2013 May 28;8(5):e64205. doi: 10.1371/journal.pone.0064205. Print 2013.
Cell-penetrating peptides (CPPs) comprised of basic amino residues are able to cross cytoplasmic membranes and are able to deliver biologically active molecules inside cells. However, CPP/cargo entrapment in endosome limits biomedical utility as cargoes are destroyed in the acidic environment. In this study, we demonstrate protein transduction of a novel CPP comprised of an INF7 fusion peptide and nona-arginine (designated IR9). IR9 noncovalently interacts with quantum dots (QDs) and DNAs to form stable IR9/QD and IR9/DNA complexes which are capable of entering human A549 cells. Zeta-potentials were a better predictor of transduction efficiency than gel shift analysis, emphasizing the importance of electrostatic interactions of CPP/cargo complexes with plasma membranes. Mechanistic studies revealed that IR9, IR9/QD and IR9/DNA complexes may enter cells by endocytosis. Further, IR9, IR9/QD and IR9/DNA complexes were not cytotoxic at concentrations below 30, 5 and 20.1 µM, respectively. Without labor intensive production of fusion proteins from prokaryotes, these results indicate that IR9 could be a safe carrier of genes and drugs in biomedical applications.
细胞穿透肽（CPPs）由碱性氨基酸组成，能够穿过细胞质膜，并将生物活性分子递送到细胞内。然而，CPP/货物被内体捕获限制了其在生物医学中的应用，因为货物在酸性环境中被破坏。在这项研究中，我们展示了一种由 INF7 融合肽和九聚精氨酸（命名为 IR9）组成的新型 CPP 的蛋白转导。IR9 与量子点（QDs）和 DNA 非共价相互作用，形成稳定的 IR9/QD 和 IR9/DNA 复合物，能够进入人 A549 细胞。Zeta 电位比凝胶迁移分析更能预测转导效率，这强调了 CPP/货物复合物与质膜之间静电相互作用的重要性。机制研究表明，IR9、IR9/QD 和 IR9/DNA 复合物可能通过内吞作用进入细胞。此外，在低于 30、5 和 20.1 µM 的浓度下，IR9、IR9/QD 和 IR9/DNA 复合物均无细胞毒性。无需从原核生物费力地生产融合蛋白，这些结果表明，IR9 可能是生物医学应用中基因和药物的安全载体。
