Koike Tomonari, Koike Yui, Yang Dongshan, Guo Yanhong, Rom Oren, Song Jun, Xu Jie, Chen Yajie, Wang Yanli, Zhu Tianqing, Garcia-Barrio Minerva T, Fan Jianglin, Chen Y Eugene, Zhang Jifeng
Center for Advanced Models for Translational Sciences and Therapeutics, Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, MI, USA; Department of Molecular Pathology, Faculty of Medicine, Graduate School of Medical Sciences, University of Yamanashi, Yamanashi, Japan.
Center for Advanced Models for Translational Sciences and Therapeutics, Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, MI, USA.
Atherosclerosis. 2021 Jan;316:32-40. doi: 10.1016/j.atherosclerosis.2020.11.028. Epub 2020 Nov 28.
Apolipoprotein A-II (apoAII) is the second major apolipoprotein of the high-density lipoprotein (HDL) particle, after apoAI. Unlike apoAI, the biological and physiological functions of apoAII are unclear. We aimed to gain insight into the specific roles of apoAII in lipoprotein metabolism and atherosclerosis using a novel rabbit model.
Wild-type (WT) rabbits are naturally deficient in apoAII, thus their HDL contains only apoAI. Using TALEN technology, we replaced the endogenous apoAI in rabbits through knock-in (KI) of human apoAII. The newly generated apoAII KI rabbits were used to study the specific function of apoAII, independent of apoAI.
ApoAII KI rabbits expressed exclusively apoAII without apoAI, as confirmed by RT-PCR and Western blotting. On a standard diet, the KI rabbits exhibited lower plasma triglycerides (TG, 52%, p < 0.01) due to accelerated clearance of TG-rich particles and higher lipoprotein lipase activity than the WT littermates. ApoAII KI rabbits also had higher plasma HDL-C (28%, p < 0.05) and their HDL was rich in apoE, apoAIV, and apoAV. When fed a cholesterol-rich diet for 16 weeks, apoAII KI rabbits were resistant to diet-induced hypertriglyceridemia and developed significantly less aortic atherosclerosis compared to WT rabbits. HDL isolated from rabbits with apoAII KI had similar cholesterol efflux capacity and anti-inflammatory effects as HDL isolated from the WT rabbits.
ApoAII KI rabbits developed less atherosclerosis than WT rabbits, possibly through increased plasma HDL-C, reduced TG and atherogenic lipoproteins. These results suggest that apoAII may serve as a potential target for the treatment of atherosclerosis.
载脂蛋白A-II（apoAII）是高密度脂蛋白（HDL）颗粒中仅次于载脂蛋白AI（apoAI）的第二大主要载脂蛋白。与apoAI不同，apoAII的生物学和生理功能尚不清楚。我们旨在使用一种新型兔模型深入了解apoAII在脂蛋白代谢和动脉粥样硬化中的具体作用。
野生型（WT）兔天然缺乏apoAII，因此它们的HDL仅含有apoAI。利用转录激活样效应因子核酸酶（TALEN）技术，我们通过敲入（KI）人apoAII替代了兔体内的内源性apoAI。新生成的apoAII KI兔用于研究独立于apoAI的apoAII的特定功能。
通过逆转录-聚合酶链反应（RT-PCR）和蛋白质免疫印迹法证实，apoAII KI兔仅表达apoAII而不表达apoAI。在标准饮食下，由于富含甘油三酯（TG）颗粒的清除加速以及脂蛋白脂肪酶活性高于野生型同窝仔兔，KI兔的血浆TG水平较低（降低52%，p < 0.01）。apoAII KI兔的血浆高密度脂蛋白胆固醇（HDL-C）也较高（升高28%，p < 0.05），并且它们的HDL富含载脂蛋白E（apoE）、载脂蛋白A-IV（apoAIV）和载脂蛋白A-V（apoAV）。在喂食富含胆固醇的饮食16周后，与野生型兔相比，apoAII KI兔对饮食诱导的高甘油三酯血症具有抗性，并且主动脉粥样硬化的发展明显较少。从apoAII KI兔分离的HDL与从野生型兔分离的HDL具有相似的胆固醇流出能力和抗炎作用。
apoAII KI兔的动脉粥样硬化发展程度低于野生型兔，可能是通过增加血浆HDL-C、降低TG和致动脉粥样硬化脂蛋白实现的。这些结果表明，apoAII可能是治疗动脉粥样硬化的潜在靶点。
