Department of Metabolic Disorders, Amgen, Inc., Thousand Oaks, CA 91320, USA.
J Lipid Res. 2012 Apr;53(4):643-52. doi: 10.1194/jlr.M020438. Epub 2012 Jan 27.
The aim of this study is to investigate the capability of an apoA-I mimetic with multiple amphipathic helices to form HDL-like particles in vitro and in vivo. To generate multivalent helices and to track the peptide mimetic, we have constructed a peptibody by fusing two tandem repeats of 4F peptide to the C terminus of a murine IgG Fc fragment. The resultant peptidbody, mFc-2X4F, dose-dependently promoted cholesterol efflux in vitro, and the efflux potency was superior to monomeric 4F peptide. Like apoA-I, mFc-2X4F stabilized ABCA1 in J774A.1 and THP1 cells. The peptibody formed larger HDL particles when incubated with cultured cells compared with those by apoA-I. Interestingly, when administered to mice, mFc-2X4F increased both pre-β and α-1 HDL subfractions. The lipid-bound mFc-2X4F was mostly in the α-1 migrating subfraction. Most importantly, mFc-2X4F and apoA-I were found to coexist in the same HDL particles formed in vivo. These data suggest that the apoA-I mimetic peptibody is capable of mimicking apoA-I to generate HDL particles. The peptibody and apoA-I may work cooperatively to generate larger HDL particles in vivo, either at the cholesterol efflux stage and/or via fusion of HDL particles that were generated by the peptibody and apoA-I individually.
本研究旨在探究具有多个两亲性螺旋的载脂蛋白 A-I 模拟物在体外和体内形成高密度脂蛋白（HDL）样颗粒的能力。为了产生多价螺旋并追踪肽模拟物，我们通过将 4F 肽的两个串联重复序列融合到鼠 IgG Fc 片段的 C 末端构建了一个肽结合物。所得的肽结合物 mFc-2X4F 可剂量依赖性地促进体外胆固醇流出，其流出效力优于单体 4F 肽。与载脂蛋白 A-I 一样，mFc-2X4F 稳定了 J774A.1 和 THP1 细胞中的 ABCA1。与载脂蛋白 A-I 相比，该肽结合物与培养细胞孵育时形成的 HDL 颗粒更大。有趣的是，当给予小鼠时，mFc-2X4F 增加了前-β和α-1 HDL 亚组分。与脂质结合的 mFc-2X4F 主要位于α-1 迁移亚组分中。最重要的是，发现 mFc-2X4F 和载脂蛋白 A-I 共同存在于体内形成的相同 HDL 颗粒中。这些数据表明，载脂蛋白 A-I 模拟肽结合物能够模拟载脂蛋白 A-I 生成 HDL 颗粒。肽结合物和载脂蛋白 A-I 可能在体内以胆固醇流出阶段和/或通过融合由肽结合物和载脂蛋白 A-I 分别生成的 HDL 颗粒的方式协同作用生成更大的 HDL 颗粒。
