Kim Jin Bum, Lee Yeong Mi, Ryu Jooyeon, Lee Eunji, Kim Won Jong, Keum Gyochang, Bang Eun-Kyoung
Center for Neuro-Medicine, Brain Science Institute, Korea Institute of Science and Technology , 5 Hwarang-ro 14-gil, Seongbuk-gu, Seoul 02792, Republic of Korea.
Center for Self-Assembly and Complexity, Institute for Basic Science (IBS), and Department of Chemistry, Pohang University of Science and Technology , 77 Cheongam-ro, Nam-gu, Pohang 37673, Republic of Korea.
Bioconjug Chem. 2016 Aug 17;27(8):1850-6. doi: 10.1021/acs.bioconjchem.6b00260. Epub 2016 Jul 14.
In this study, we developed coordinative amphiphiles for use as novel siRNA transporters. As a modification of a conventional cationic lipid structure, we replaced the cationic head with zinc(II)-dipicolylamine complex (Zn/DPA) as a phosphate-directing group, and used various membrane-directing groups in the place of the hydrophobic tails. These simple amphiphiles are readily synthesized and easy to modify. The Zn/DPA head groups bind to the phosphate backbones of siRNAs, and to our surprise, they prevented the enzymatic degradation of siRNAs by RNase A. Interestingly, the Zn/DPA head itself exhibited moderate transfection efficiency, and its combination with a membrane-directing group-oleoyl (CA1), pyrenebutyryl (CA2), or biotin (CA3)-enhanced the delivery efficiency without imparting significant cytotoxicity. Notably, the uptake pathway was tunable depending on the nature of the membrane-directing group. CA1 delivered siRNAs mainly through caveolae-mediated endocytosis, and CA2 through clathrin- and caveolin-independent endocytosis; CA3 recruited siRNAs specifically into biotin receptor-positive HepG2 cells through receptor-mediated endocytosis. Thus, it appears possible to develop tunable siRNA transporters simply by changing the membrane-directing parts. These are the first examples of amphiphilic siRNA transporters accompanying coordinative interactions between the amphiphiles and siRNAs.
在本研究中，我们开发了用作新型小干扰RNA（siRNA）转运体的协同性两亲分子。作为对传统阳离子脂质结构的一种修饰，我们用锌（II）-二吡啶甲胺配合物（Zn/DPA）作为磷酸引导基团取代了阳离子头部，并使用各种膜引导基团取代疏水尾部。这些简单的两亲分子易于合成且易于修饰。Zn/DPA头部基团与siRNA的磷酸主链结合，而且令我们惊讶的是，它们能防止siRNA被核糖核酸酶A酶解。有趣的是，Zn/DPA头部自身表现出适度的转染效率，并且它与膜引导基团——油酰基（CA1）、芘丁酰基（CA2）或生物素（CA3）——的组合提高了递送效率，同时不会产生明显的细胞毒性。值得注意的是，摄取途径可根据膜引导基团的性质进行调节。CA1主要通过小窝介导的内吞作用递送siRNA，CA2通过网格蛋白和小窝蛋白非依赖性内吞作用递送；CA3通过受体介导的内吞作用将siRNA特异性地募集到生物素受体阳性的肝癌细胞系（HepG2）细胞中。因此，似乎仅通过改变膜引导部分就有可能开发出可调节的siRNA转运体。这些是两亲性siRNA转运体伴随两亲分子与siRNA之间协同相互作用的首个实例。
