Self-Assembling Polyethylenimine Derivatives Mediate Efficient siRNA Delivery in Mammalian Cells
Self-Assembling Polyethylenimine Derivatives Mediate Efficient siRNA Delivery in Mammalian Cells
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DOI：
10.1002/cbic.200800540
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发表时间：
2008-11-24
期刊：
影响因子：
3.2
通讯作者：
Zuber, Guy
中科院分区：
文献类型：
--
作者：
Creusat, Gaelle;Zuber, Guy
合成的21-22-nt长的RNA双链体（siRNA）可以触发特异性mRNA降解并选择性地控制基因表达，并且正因为如此，它们具有潜在的治疗应用。[1]不幸的是，siRNA靶的细胞内定位和寡核苷酸不能扩散穿过细胞膜需要siRNA缀合或与合成递送载体配制。[2]有趣的是，聚乙烯亚胺（PEI），一种流行的基因转染剂[3]，显示出对癌症基因治疗的希望，[4]似乎对体外siRNA递送无效。[5] PEI的不良性能可能与siRNA阴离子片段的长度有关，其太短而不能与可溶性阳离子聚合物保持静电内聚。因此，siRNA复合物在与细胞表面存在的聚阴离子接触时太容易破裂。[6]我们推断，将水溶性PEI转化为具有自组装性质的分子应该稳定siRNA聚合复合物，从而有利于整体siRNA递送。水溶性聚合物通过引入疏水结构域可以获得新的聚集特性。我们避免使用烷基链，因为烷基链与细胞脂质双层混合后，可能会起到去污剂的作用，导致细胞死亡。我们更倾向于亲水指数降低的天然α-氨基酸，[7]如亮氨酸（L），苯丙氨酸（F），色氨酸（W）和酪氨酸（Y）。事实上，这些氨基酸构成了球状蛋白的核心，并有助于维持蛋白质结构。它们也可以偶联到PEI胺上而不破坏核酸结合性质，因为在反应过程中，阳离子胺取代了反应的胺。
Synthetic 21–22-nt-long RNA duplexes (siRNAs) can trigger specific mRNA degradation and selectively control gene expression, and because of this they have potential therapeutic applications.[1] Unfortunately, the intracellular localization of siRNA targets and the inability of oligonucleotides to diffuse across cellular membranes requires siRNA conjugation or formulation with synthetic delivery vectors.[2] Interestingly, poly-ACHTUNGTRENNUNGethylenimine (PEI), a popular gene transfection agent [3] that showed promise for cancer gene therapy,[4] appears inefficient for siRNA delivery in vitro.[5]The poor performance of PEI could be linked with the length of the siRNA anionic segment, which is too short to maintain electrostatic cohesion with the soluble cationic polymer. Consequently, siRNA polyplexes break apart too readily upon contact with polyanions present at cell surfaces.[6] We reasoned that the transformation of water-soluble PEI into a molecule with self-assembly properties should stabilize siRNA polyplexes and hence favor overall siRNA delivery. A water-soluble polymer could acquire new aggregating properties through the addition of hydrophobic domains. We avoided using alkyl chains, which, by mixing with the cell lipid bilayer, might act as a detergent and cause cell death. Our preference was instead for natural α-amino acids with decreasing hydropathy indices,[7] such as leucine (L), phenylalanine (F), tryptophan (W), and tyrosine (Y). Indeed, these amino acids constitute the cores of globular proteins and help maintain protein structures. They also can be coupled to PEI amines without destroying nucleic acid binding properties, because over the course of the reaction a cationic amine replaces the reacted one.