Gene delivery mediated by synthetic oligopeptide

质粒DNA已知与多种阳离子肽和脂质形成复合物，已被探索作为哺乳动物细胞中DNA转染的可能载体。我们合成了由9个氨基酸残基组成的寡肽，包括赖氨酸(K)、色氨酸(W)和半胱氨酸(C)，以及它们对称的二硫键二聚体作为可能的载体。pDNA (pGL3)/寡肽复合物对HeLa S3的转染效率一般较差，但细胞毒性较小。由胆固醇衍生物（DMB-Chol）和二油基磷脂酰乙醇胺（DOPE）组成的含有阳离子脂质体的DNA/寡肽/脂质体三元体系的有效基因表达量（10^8-10^9水平，RLU/min/mg蛋白）比相应的pDNA/寡肽复合物高10^4-10^5倍。在10%血清存在的情况下，三元复合物维持在10^7水平。溴化乙啶的排除研究表明，三元配合物对pDNA的亲和力远高于相应的pDNA/寡肽配合物。质粒对dna i降解的敏感性表明，三元配合物受到很好的保护，不受消化的影响。人工合成的寡肽在阳离子脂质体介导的dope转染中具有潜在的增强作用。这些发现对成功的体内转染具有启示意义。

Plasmid DNA is known to form complexes with a variety of cationic peptides and lipids, which have been explored as possible carriers for DNA transfection in mammalian cells. We synthesized, oligopeptides consisting of nine amino acid residues including lysine (K) tryptophan (W), and cysteine (C), and also their symmetrical dimmers with a disulfide bond as possible carriers. The pDNA (pGL3)/oligopeptide complexes generally showed poor transfection efficiencies but little cytotoxicity for HeLa S3. The ternary system of DNA/oligopeptide/liposome containing cationic liposome formulated from the cholesterol derivative (DMB-Chol) and dioleylphosphatidylethanolamine (DOPE) showed 10^4-10^5 fold greater effective gene expression (10^8-10^9 level, RLU/min/mg protein) than those of the corresponding pDNA/oligopeptide complexes. In the presence of 10% serum, the ternary complexes were maintained at 10^7 level. The ethidium bromide exclusion studies showed the ternary complexes have much greater affinity to pDNA than the corresponding pDNA/oligopeptide complexes. Plasmid sensitivity against DnaseI degradation showed that the ternary complexes were well protected from the digestion. Synthetic oligopeptides are active as potential enhancers for DOPE-containing cationic liposome-mediated transfection. These findings have implications for successful in vivo transfection.