血清高密度脂蛋白(HDL)与动脉硬化疾病发生呈负相关,HDL具有抗动脉硬化保护血管的功能。HDL有两种主要载脂蛋白即apoA-I和apoA-II,和apoA-I相比,apoA-II的生理功能以及在脂质代谢异常和动脉硬化的发生中的作用目前还没有阐明。本项研究的目的是(1)利用TALEN靶向基因敲除敲入技术，首先开发研制apoA-II基因敲入家兔模型;(2)研究apoA-II基因敲入家兔在正常饮食条件下的脂质代谢特点;(3)利用体外细胞培养和分子生物学手段研究含有不同apoA-I和apoA-II的HDL功能特性;(4)研究高脂饮食诱导情况下apoA-II基因敲入家兔的动脉硬化的特性;(5)利用LDL受体缺失WHHL家兔,研究apoA-II对冠状动脉斑块的形成及心肌梗死的发生的影响。以此揭示HDL的抗动脉硬化分子机制,为将来开发以apoA-II为靶点的治疗动脉硬化新方法提供理论依据。

Plasma levels of high density lipoproteins (HDL) are inversely associated with risk of atherosclerosis. HDL protects vascular functions by its anti-atherogenic actions. HDL particles contain two major apolipoproteins (apo): apoA-I and apoA-II. Compared with apoA-I, pathophysiological roles of apoA-II in vivo is not fully understood. This is mainly due to lack of appropriate animal models because mouse metabolic system along with mouse apoA-II structures is quite different from those of humans. Rabbits are one of the best animal models for the study of lipid metabolism and atherosclerosis because they are sensitive to a cholesterol diet. In addition, rabbits are naturally deficient in apoA-II gene therefore, rabbit HDLs contain only apoA-I without apoA-II. The purpose of this project is to elucidate the functional roles of apoA-II on lipid metabolism and atherosclerosis. For this undertaking, we will first (1)generate apoA-II gene knock-in (KI) rabbits in which human apoA-II gene is introduced into rabbit apoA-I gene locus using TALEN technology;(2)then, we will characterize the lipid and lipoprotein metabolism in apoA-II KI rabbits compared with wild-type rabbits on a chow diet;(3)we will examine these apoA-II KI rabbits in terms of their susceptibility to cholesterol diet-induced atherosclerosis; and(4)coronary plaque stability and myocardial infarction in the setting of LDL receptor deficiency using WHHL rabbits, (5)we will also investigate the molecular mechanisms such as cholesterol efflux, anti-inflammatory properties, anti-oxidization using isolated HDLs from apoA-II KI and wild-type rabbits. This is the first study to examine apoA-II pathophysiological functions in lipoprotein metabolism using apoA-II KI rabbit models and our results will not only provide a novel insight into understanding apoA-II molecular mechanisms in atherosclerosis but also explore the possibility of using apoA-II as a therapeutic strategy for treatment of atherosclerosis.