Sun Yun-Xia, Zeng Xuan, Meng Qing-Fei, Zhang Xian-Zheng, Cheng Si-Xue, Zhuo Ren-Xi
Key Laboratory of Biomedical Polymers, Ministry of Education and Department of Chemistry, Wuhan University, Wuhan 430072, PR China.
Biomaterials. 2008 Nov;29(32):4356-65. doi: 10.1016/j.biomaterials.2008.07.045. Epub 2008 Aug 20.
Arginine-glycine-aspartic acid (RGD) ligand is often chemically attached to polycation vector to improve the transfection efficiency. However, the chemical reaction may reduce or even inactivate the biological activities of peptides. In order to retain the targeting ability and biological activities, the RGD peptide was noncovalently introduced into polycations as gene delivery systems. In this paper, the tripeptide sequence RGD was added to disulfide-containing polyethyleneimine (SS-PEI)/DNA binary complexes to evaluate the influence of RGD addition for the particle size, zeta potential, morphology, and transfection efficiency. GelRed was used as a molecular probe to show the effect of RGD addition on the cellular uptake of complexes. In vitro transfection experiments showed that SS-PEI exhibited comparable transfection efficiency, but lower cytotoxicity in comparison with 25kDa PEI. The transfection efficiency of complexes with RGD in HeLa cells was reduced statistically significantly with the increasing content of RGD peptide, but that in 293T cells was not altered significantly with the increasing content of RGD peptide. The reduced transfection efficiency of SS-PEI/DNA complexes with RGD in HeLa cells was attributed to the targeted binding interactions between the surplus RGD and the alpha(nu)beta(3) and alpha(nu)beta(5) integrins in HeLa cells, which would prevent the binding between RGD in complexes and integrin receptor on the surface of cells as well as nonspecific endocytosis of SS-PEI/DNA complexes mediated by proteoglycan in HeLa cells.
精氨酸 - 甘氨酸 - 天冬氨酸（RGD）配体通常通过化学方法连接到聚阳离子载体上，以提高转染效率。然而，化学反应可能会降低甚至使肽的生物活性失活。为了保留靶向能力和生物活性，RGD肽以非共价方式被引入聚阳离子作为基因递送系统。在本文中，将三肽序列RGD添加到含二硫键的聚乙烯亚胺（SS - PEI）/DNA二元复合物中，以评估添加RGD对粒径、zeta电位、形态和转染效率的影响。使用GelRed作为分子探针来显示添加RGD对复合物细胞摄取的影响。体外转染实验表明，与25kDa聚乙烯亚胺相比，SS - PEI表现出相当的转染效率，但细胞毒性较低。随着RGD肽含量的增加，HeLa细胞中含RGD的复合物的转染效率在统计学上显著降低，但在293T细胞中，随着RGD肽含量的增加，转染效率没有明显改变。HeLa细胞中含RGD的SS - PEI/DNA复合物转染效率降低归因于多余的RGD与HeLa细胞中的α（ν）β（3）和α（ν）β（5）整合素之间的靶向结合相互作用，这会阻止复合物中的RGD与细胞表面的整合素受体结合，以及HeLa细胞中蛋白聚糖介导的SS - PEI/DNA复合物的非特异性内吞作用。
