Department of Biosystems and Biomaterials Science and Engineering, College of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea.
J Control Release. 2011 May 30;152(1):110-9. doi: 10.1016/j.jconrel.2011.02.013. Epub 2011 Feb 23.
Bioreducible cationic polymers (p(DAH(a)-R/API(b))s) composed of different ratios (a:b=2:1, 1:1, 1:2) between arginine-grafted diaminohexane (DAH-R) (cell penetrating functionality) and 1-(3-aminopropyl) imidazole (API) (endosome buffering functionality) monomers were synthesized by Michael reaction of N,N'-cystaminebisacrylamide (CBA) with them, in order to study the effect of endosome buffering moiety on arginine-grafted bioreducible polymeric gene carriers. Several experiments displayed a distinct correlation between monomer composition ratios of p(DAH-R/API)s and the polymer features. Increased endosome buffering capacities proportional to API portions was evaluated for p(DAH-R/API)s due to the imidazole group (pKa=6) of API. Increased portions of API non-ionized at physiological pH and resultant decrease of arginine residues also reduced cytotoxicities of the polymers due to less interaction of cellular compartments with less positively charged polymers but decreased pDNA condensing abilities, Zeta-potential values, cellular uptakes of polyplexes, and finally transfection efficiencies as well. Thus, the predominance of arginine residues over endosome buffering moieties was revealed regarding efficient gene delivery for p(DAH-R/API)s. From transfection results with chloroquine or nigericin, it can be deduced that the endosomal escape of p(DAH-R/API) polyplexes occurs by direct endosome membrane penetration of arginine moieties as well as endosome buffering of the polymers after cellular uptake, which emphasizes the importance of arginine moieties for polymeric gene delivery systems.
由精氨酸接枝二氨基己烷（DAH-R）（细胞穿透功能）和 1-(3-氨基丙基)咪唑（API）（内涵体缓冲功能）单体以不同比例（a:b=2:1、1:1、1:2）组成的生物还原阳离子聚合物（p(DAH(a)-R/API(b))s）通过 N,N'-胱胺双丙烯酰胺（CBA）与它们的迈克尔反应合成，以研究内涵体缓冲部分对精氨酸接枝生物还原聚合物基因载体的影响。几项实验显示了 p(DAH-R/API)s 的单体组成比例与聚合物特性之间存在明显的相关性。由于 API 的咪唑基团（pKa=6），p(DAH-R/API)s 的内涵体缓冲能力与 API 部分成正比增加。由于生理 pH 下未离解的 API 部分增加，以及带正电荷的聚合物与带负电荷的细胞区室相互作用减少，导致精氨酸残基减少，聚合物的细胞毒性降低，但 pDNA 凝聚能力、Zeta 电位值、多聚物的细胞摄取量以及最终的转染效率降低。因此，对于 p(DAH-R/API)s 而言，有效基因传递中精氨酸残基的优势超过了内涵体缓冲部分。通过氯喹或尼可霉素的转染结果可以推断，p(DAH-R/API) 聚合物的内涵体逃逸是通过精氨酸部分直接穿透内涵体膜以及细胞摄取后聚合物的内涵体缓冲作用发生的，这强调了精氨酸部分对于聚合物基因传递系统的重要性。
