Karmali Priya P, Kumar Valluripalli V, Chaudhuri Arabinda
Division of Lipid Science and Technology, Indian Institute of Chemical Technology, Hyderabad-500 007, India.
J Med Chem. 2004 Apr 8;47(8):2123-32. doi: 10.1021/jm030541+.
Structure-activity investigation including design, syntheses, and evaluation of relative in vitro gene delivery efficacies of a novel series of cationic amphiphiles (1-10) containing mono-, di-, and trilysine headgroups are described in CHO, COS-1, and HepG2 cells. Several interesting and rather unexpected transfection profiles were observed. In general, lipid 1 with the myristyl tail used in combination with DOPE as colipid exhibited superior transfection properties compared to (a) the monolysinated analogues with longer hydrocarbon tails (lipids 2-4), (b) the dilysine (lipids 5-7) and the trilysine headgroup analogues (lipids 8-10), and (c) commercially available LipofectAmine with multiple positive charges in its polar region. As a preliminary estimate of the relative DNA-compacting efficacies of these new lysinated cationic lipids, the hydrodynamic diameters of representative lipoplexes were measured using dynamic laser light scattering technique. Our lipoplex size data are consistent with the notion that covalent grafting of an increasing number of positively charged functional groups in the headgroup region of cationic lipids need not necessarily result in more compacted lipoplexes. Both gel retardation and DNase I sensitivity assays indicated similar lipid/DNA binding interactions for all the novel mono-, di-, and trilysinated cationic lipids. MTT-assay-based cell viability results clearly demonstrate that the overall lower transfection properties of trilysine analogues (8-10) compared to their mono- (1-4) and dilysinated (5-7) counterparts are unlikely to originate from differential toxicity related effects. Taken together, the present findings support the notion that caution needs to be exercised in ensuring enhanced gene delivery efficacies of cationic lipids through covalent grafting of multiple lysine functionalities in the headgroup region.
本文描述了一系列新型阳离子两亲物（1 - 10）的结构 - 活性研究，这些阳离子两亲物包含单、二和三赖氨酸头基，在CHO、COS - 1和HepG2细胞中进行了设计、合成以及相关体外基因传递效率的评估。观察到了一些有趣且相当意外的转染情况。总体而言，带有肉豆蔻酰尾的脂质1与DOPE作为共脂质联合使用时，与以下情况相比表现出优异的转染特性：（a）具有更长烃链尾的单赖氨酸类似物（脂质2 - 4）；（b）二赖氨酸（脂质5 - 7）和三赖氨酸头基类似物（脂质8 - 10）；以及（c）在其极性区域带有多个正电荷的市售LipofectAmine。作为对这些新型赖氨酸化阳离子脂质相对DNA压缩效率的初步估计，使用动态激光光散射技术测量了代表性脂质体的流体动力学直径。我们的脂质体大小数据与以下观点一致：在阳离子脂质头基区域共价接枝越来越多的带正电荷官能团不一定会导致形成更紧密的脂质体。凝胶阻滞和DNase I敏感性分析表明，所有新型单、二和三赖氨酸化阳离子脂质具有相似的脂质/DNA结合相互作用。基于MTT分析的细胞活力结果清楚地表明，与单赖氨酸（1 - 4）和二赖氨酸（5 - 7）类似物相比，三赖氨酸类似物（8 - 10）总体较低的转染特性不太可能源于不同的毒性相关效应。综上所述, 目前的研究结果支持这样一种观点，即在通过在头基区域共价接枝多个赖氨酸官能团来确保阳离子脂质增强基因传递效率时需要谨慎行事。
