Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan.
Bioorg Med Chem Lett. 2011 Oct 1;21(19):5688-91. doi: 10.1016/j.bmcl.2011.08.030. Epub 2011 Aug 11.
Cell-penetrating peptides (CPPs) are useful tools for the delivery of hydrophilic bioactive molecules, such as peptides, proteins, and oligonucleotides, across the cell membrane. To realize the delivery of therapeutic macromolecules by CPPs, the CPPs are required to show resistance to protease and no cytotoxicity. In order to produce potent non-toxic and protease-resistant CPPs with high cellular uptake, we designed an amphipathic helix peptide using α-aminoisobutyric acid (Aib, U) and named it MAP(Aib). In the MAP(Aib) molecule, five Aib residues are aligned on the hydrophobic face of the helix and five lysine (K) residues are aligned on the hydrophilic face. MAP(Aib) showed potent resistance to trypsin and pronase compared with MAP, an amphipathic helix peptide formed by usual amino acids. Fluorescein-labeled MAP(Aib) efficiently traversed the A549 cell membrane, diffusing into the cytoplasm and slightly into the nucleus without exerting any cytotoxicity. In contrast, MAP was poorly taken up by the cell. These results indicate that the incorporation of Aib residues into CPPs markedly improves cellular uptake and MAP(Aib) may be a useful tool for the delivery of hydrophilic macromolecules.
细胞穿透肽 (CPPs) 是将亲水性生物活性分子（如肽、蛋白质和寡核苷酸）递送到细胞膜内的有用工具。为了实现 CPP 介导的治疗性大分子的递药，CPP 需要表现出对蛋白酶的抗性和无细胞毒性。为了产生具有高效细胞摄取能力的、无毒且抗蛋白酶的强效 CPP，我们使用α-氨基异丁酸 (Aib，U) 设计了一种两亲性螺旋肽，并将其命名为 MAP(Aib)。在 MAP(Aib)分子中，五个 Aib 残基排列在疏水螺旋面，五个赖氨酸 (K) 残基排列在亲水螺旋面。与由常规氨基酸组成的两亲性螺旋肽 MAP 相比，MAP(Aib)对胰蛋白酶和糜蛋白酶具有更强的抗性。荧光素标记的 MAP(Aib)能够有效地穿过 A549 细胞膜，扩散到细胞质中，并且稍微进入细胞核，而没有任何细胞毒性。相比之下，MAP 则很少被细胞摄取。这些结果表明，将 Aib 残基掺入 CPP 中可显著提高细胞摄取效率，MAP(Aib)可能是递亲水大分子的有用工具。
