ARL15升高载脂蛋白B100导致动脉粥样硬化的机制研究

Hypercholesterolemia is a major risk factor for atherosclerotic disease. ARL15 is a G protein in the ADP ribosylation family, which is one of the possible genes associated with the disorder of lipid metabolism and atherosclerosis detected by GWAS. Our previous study confirmed for the first time that ARL15 overexpression in mouse liver leads to hypercholesterolemia through upregulated of ApoB100 protein in liver and peripheral blood; and in hepatocytes cultured in vitro,ARL15 knockdown can decrease ApoB100 protein secretion,without change of gene expression.It is speculated that ARL15 may take an important role in regulation of ApoB100 protein degradation and secretion, but the accurate mechanisms are not clear. The project intends to explore the molecular mechanism of ARL15 function by overexpression of ARL15 in vitro and applying specific blocker of G protein and ADP ribosylation; to determine the key pathway of ARL15 regulation of ApoB100 degradation by detecting the ApoB100 vesicle trafficking during secretion; and to prove that ARL15 gene knockdown can decrease cholesterol level and atherosclerosis in ApoE deficient mice hypercholesterolemia and atherosclerosis model in vivo. This study will help further understand the molecular mechanism of the degradation of ApoB100 with the regulation of ARL15, and provide new targets and ideas for the prevention and treatment of lipid metabolism disorder and atherosclerosis.

高胆固醇血症是动脉粥样硬化疾病的主要危险因素。ARL15是二磷酸核糖基化家族中的G蛋白之一，我们的前期研究证实，ARL15在小鼠肝脏中过表达通过升高ApoB100蛋白水平导致高胆固醇血症，并在体外肝细胞实验中发现，敲低ARL15能够降低细胞内ApoB100蛋白的表达及分泌，而其mRNA水平表达并未见改变，推测ARL15可能通过调控ApoB100蛋白的降解来起作用，具体机制未明。本项目拟通过过表达ARL15，经特异性阻断G蛋白活性及核糖基化作用，初步探寻ARL15作用的分子机制；通过检测ApoB100分泌及降解的囊泡转运情况，确定ARL15调控ApoB100降解的关键途径；并通过RNA干扰的方法证明体内ARL15敲低对ApoE缺陷性小鼠动脉粥样硬化的作用。该研究有助于深入认识ARL15调控ApoB100的降解导致高胆固醇血症的分子机制，为脂代谢紊乱及动脉粥样硬化的防治提供新的的靶点和思路。