Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta, Canada T6G2N8.
ACS Appl Mater Interfaces. 2009 Apr;1(4):841-8. doi: 10.1021/am8002445.
Poly(L-lysine) (PLL) is a commonly used polymer for nonviral gene delivery. However, the polymer exhibits significant toxicity and is not very effective for transgene expression. To enhance the gene delivery efficiency of the polymer, we imparted an amphiphilic property to PLL by substituting approximately 10% of epsilon-NH2 with several endogenous lipids of variable chain lengths (lipid carbon chain ranging from 8 to 18). Lipid-modified PLL with high molecular weight (approximately 25 vs 4 kDa) was found to be more effective in delivering plasmid DNA intracellularly in clinically relevant bone marrow stromal cells (BMSC). For lipid-substituted 25 kDa PLL, a correlation between the extent of lipid substitution and the plasmid DNA delivery efficiency was obtained. Additionally, transgene expression by BMSC significantly increased (20-25%) when amphiphilic PLLs were used for plasmid delivery as compared to native PLL and the commercial transfection agent Lipofectamine-2000. The transfection efficiency of the polymers was positively correlated with the extent of lipid substitution. The amphiphilic polymers were able to modify the cells up to 7 days after transfection, after which the expression was decreased to background levels within 1 week. We conclude that lipid-substituted PLL can be used effectively as a nonviral carrier for DNA, and the extent of lipid substitution was an important determinant of gene delivery.
聚赖氨酸（PLL）是一种常用于非病毒基因传递的聚合物。然而，该聚合物表现出显著的毒性，对于转基因表达并不十分有效。为了提高聚合物的基因传递效率，我们通过用几种不同链长的内源性脂质（脂质碳链长度从 8 到 18）替代 PLL 中的约 10%的 ε-NH2，赋予 PLL 两亲性。发现高分子量的脂质修饰 PLL（约 25 kDa 与 4 kDa）在临床相关的骨髓基质细胞（BMSC）中更有效地将质粒 DNA 递送至细胞内。对于脂质取代的 25 kDa PLL，获得了脂质取代程度与质粒 DNA 传递效率之间的相关性。此外，与天然 PLL 和商业转染试剂 Lipofectamine-2000 相比，当使用两亲性 PLL 进行质粒传递时，BMSC 的转基因表达显著增加（20-25%）。聚合物的转染效率与脂质取代的程度呈正相关。两亲性聚合物能够在转染后 7 天内修饰细胞，此后在 1 周内表达降至背景水平。我们得出结论，脂质取代的 PLL 可以有效地用作 DNA 的非病毒载体，脂质取代的程度是基因传递的重要决定因素。
