Structural Transition of Lipopolysaccharide and Reduction in the Biological Activity by Amphiphilic Lipid with Cationic Amino Acid
作者:Wenjing Li、Shinichi Mochizuki、Kazuo Sakurai
DOI:10.1246/bcsj.20120353
日期:2013.5.15
Lipopolysaccharide (LPS), the endotoxin of Gram-negative bacteria, is a strong elicitor in the immune system by interacting with lipopolysaccharide-binding protein and CD14 with high specificity. The removal of LPS contamination in protein drug products expressed by bacteria is essential in pharmaceutical products for human use. Although polymyxin B (PMB)-immobilized columns are mainly used for removal of LPS, there are some problems, such as high production cost, and the toxicity of ligands. We synthesized aromatic lipids bearing lysine or arginine at the headgroup. These lipids form a complex with LPS through electrostatic interaction between cationic amino acids and phosphate groups in the lipid A backbone. The resultant complexes induce the structural transition of LPS from a cylindrical structure to a vesicle. Addition of amino-lipid/LPS complexes to RAW264.7 cells, a macrophage-like cell line, decrease the LPS activity. The efficiencies are higher than commonly used cationic compounds, such as dioleoyltrimethylammoniumpropane (DOTAP) and PMB. These results show that amphiphilic lipids with cationic amino acids can be used for deactivation of LPS.
脂多糖(LPS)是革兰氏阴性细菌的内毒素,通过与脂多糖结合蛋白和 CD14 的高特异性相互作用,成为免疫系统的强诱导剂。清除细菌表达的蛋白质药物产品中的 LPS 污染对人类使用的药物产品至关重要。虽然多粘菌素 B(PMB)固定化柱主要用于去除 LPS,但存在生产成本高、配体毒性大等问题。我们合成了头基含有赖氨酸或精氨酸的芳香族脂质。这些脂质通过阳离子氨基酸和脂质 A 骨架上的磷酸基团之间的静电作用与 LPS 形成复合物。由此产生的复合物促使 LPS 从圆柱结构转变为囊泡结构。向 RAW264.7 细胞(一种类似巨噬细胞的细胞系)中添加氨基脂质/LPS 复合物可降低 LPS 活性。其效率高于常用的阳离子化合物,如二油酰三甲基铵丙烷(DOTAP)和 PMB。这些结果表明,含有阳离子氨基酸的两性脂类可用于 LPS 的去活化。