应用拟人化基因敲除仓鼠模型研究ATP结合盒转运体A1在冠心病中的作用

ATP-binding cassette transporter A1 (ABCA1) is an integral cell membrane protein that plays important roles in cholesterol reverse transport and the initial step of high-density lipoprotein (HDL) biogenesis. ABCA1 mutations in human can reduce plasma HDL levels and increase the risk for coronary heart disease (CHD). Interestingly, genetic knockout of ABCA1 in mice reduces plasma HDL levels, but does not promote atherosclerotic lesions and CHD. Therefore, human-like animal models must be applied to clarify the relations of ABCA1 mutation and CHD. Hamster is widely used in the research of metabolic disease due to the human-like characteristics in lipid metabolism and atherosclerosis susceptibility. The founders of ABCA1 knockout hamster have been generated by our team and our collaborator, who had setup the coronary heart disease model in LDL receptor knockout hamsters. We found that the plasma HDL level was significantly reduced and triglyceride level was increased in ABCA1 homozygous group compared with wild type hamsters. Based on the preliminary data, we will try to establish the human-like ABCA1 knockout small animal model. To clarify the advantage of hamsters to study ABCA1 mutation, systemically comparison of the phenotype will be conducted between mouse and hamster in ABCA1 knockout background. Moreover, the ABCA1/LDLR double-knockout hamsters will be generated to obtain a human-like model for studying the role of ABCA1 on the development of coronary heart disease and the underlying mechanisms. The implementation of this project will be able to clear ABCA1 role on the pathogenesis of coronary heart disease, and provide theoretical basis for clinical intervention.

三磷酸腺苷结合盒转运体A1(ABCA1)在胆固醇逆转运和高密度脂蛋白(HDL)生成的起始步骤中起重要作用。人类ABCA1基因突变导致血浆HDL水平降低，冠心病风险增加六倍，而小鼠ABCA1缺陷模型不能发生冠心病，必须应用拟人化动物模型，才能明确ABCA1突变和冠心病发生的问题。仓鼠是脂代谢及动脉粥样硬化易感性与人类高度近似的动物。我们在成功构建了可诱发冠心病的LDLR敲除仓鼠模型的基础上，制备了ABCA1敲除仓鼠。初步结果显示，纯合子血浆HDL水平显著降低，甘油三酯升高，与ABCA1功能丧失患者相似。本项目拟以此为基础，建立模拟人类ABCA1基因突变疾病的小动物模型。我们将系统比较仓鼠与小鼠ABCA1敲除模型的表型差异，确认仓鼠的优势；并通过与LDLR敲除仓鼠杂交建立冠心病模型，分析ABCA1对冠心病发生发展的影响及机制，为阐明ABCA1在冠心病发病中的作用和干预的可能性提供依据。

三磷酸腺苷结合盒转运体A1(ABCA1)在胆固醇逆转运和高密度脂蛋白(HDL)生成的起始步骤中起重要作用。人类ABCA1基因突变导致血浆HDL水平降低，冠心病风险增加六倍，而小鼠ABCA1缺陷模型不能发生冠心病，必须应用拟人化动物模型，才能明确ABCA1突变和冠心病发生的问题。仓鼠是脂代谢及动脉粥样硬化易感性与人类高度近似的动物。我们在成功构建了可诱发冠心病的LDLR敲除仓鼠模型的基础上，制备了ABCA1敲除仓鼠。初步结果显示，纯合子血浆HDL水平显著降低，甘油三酯升高，与ABCA1功能丧失患者相似。本项目建立了模拟人类ABCA1基因突变疾病的小动物模型，系统分析了ABCA1-/-仓鼠的表型，确认了仓鼠的优势；并通过肝脏特异性过表达PCSK9建立了冠心病小动物模型，为小动物模型的推广应用及阐明ABCA1在冠心病发病中的作用和干预的可能性提供了依据。