Tunable non-enzymatic degradability of N-substituted polyaspartamide main chain by amine protonation and alkyl spacer length in side chains for enhanced messenger RNA transfection efficiency.
Tunable non-enzymatic degradability of N-substituted polyaspartamide main chain by amine protonation and alkyl spacer length in side chains for enhanced messenger RNA transfection efficiency.
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通过胺质子化和侧链烷基间隔长度可调节 N-取代聚天冬酰胺主链的非酶降解性，以增强信使 RNA 转染效率。
DOI：
10.1080/14686996.2019.1569818
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
K. Miyata
中科院分区：
文献类型：
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作者：
M. Naito;Y. Otsu;R. Kamegawa;K. Hayashi;S. Uchida;H. -J. Kim;K. Miyata
聚合体在生理条件下的可降解性是其在生物医学应用中的一个有吸引力的特征，例如核酸的递送。本研究旨在设计具有可调非酶降解性的聚合体。通过侧链上不同长度的烷基间隔剂，制备了一系列含有伯胺的阳离子取代聚天冬酰胺。采用粒径排阻色谱法测定了聚阿斯巴胺衍生物在不同pH条件下的降解率。在生理条件（pH 7.4, 37°C）下，含有2-氨基乙基侧链的聚天冬酰胺（PAsp(AE)）具有相当的可降解性。相比之下，在侧链上具有较长烷基间隔的聚天冬酰胺，即3-氨基丙基（PAsp(AP)）和4-氨基丁基（PAsp(AB)），对降解的抑制作用更强。此外，n -取代多天冬酰胺的降解速率与其侧链上伯胺的去质子化程度呈正相关。因此，我们认为n -取代聚天冬酰胺侧链上的去质子化伯胺可以通过侧链上酰胺氮的活化诱导主链降解。当n取代聚天冬酰胺通过形成多离子复合物（PICs）作为信使RNA （mRNA）递送载体时，可降解PAsp（AE）在培养细胞中的mRNA表达效率显著高于PAsp（AP）和PAsp（AB）。PAsp（AE）的高效率可能是由于细胞内PICs的不稳定，直接导致mRNA的释放。此外，PAsp（AE）的降解大大降低了其细胞毒性。因此，我们的研究强调了一种有用的设计，定义良好的阳离子聚氨基酸具有可调的非酶降解性。
Degradability of polycations under physiological conditions is an attractive feature for their use in biomedical applications, such as the delivery of nucleic acids. This study aims to design polycations with tunable nonenzymatic degradability. A series of cationicN-substituted polyaspartamides were prepared to possess primary amine via various lengths of alkyl spacers in side chains. The degradation rate of each polyaspartamide derivative was determined by size exclusion chromatography under different pH conditions. TheN-substituted polyaspartamide containing a 2-aminoethyl moiety in the side chain (PAsp(AE)) showed considerable degradability under physiological conditions (pH 7.4, 37 °C). In contrast, theN-substituted polyaspartamides bearing a longer alkyl spacer in the side chain, i.e. the 3-aminopropyl (PAsp(AP)) and 4-aminobutyl moieties (PAsp(AB)), more strongly suppressed degradation. Further, a positive correlation was observed between the degradation rate ofN-substituted polyaspartamides and a deprotonation degree of primary amines in their side chains. Therefore, we conclude that the deprotonated primary amine in the side chain ofN-substituted polyaspartamides can induce the degradation of the main chain through the activation of amide nitrogen in the side chain. WhenN-substituted polyaspartamides were utilized as a messenger RNA (mRNA) delivery vehicle via formation of polyion complexes (PICs), degradable PAsp(AE) elicited significantly higher mRNA expression efficiency in cultured cells compared to PAsp(AP) and PAsp(AB). The higher efficiency of PAsp(AE) might be due to the facilitated destabilization of PICs within the cells, directed toward mRNA release. Additionally, degradation of PAsp(AE) considerably reduced its cytotoxicity. Thus, our study highlights a useful design of well-defined cationic poly(amino acid)s with tunable nonenzymatic degradability.