Role of ABCA7 in iNKT development and function and its impact on atherosclerosis

描述（由申请人提供）：心血管疾病是北美成年人的单一最大杀手，目前针对动脉粥样硬化的治疗方法以他汀类药物为代表。不变的自然杀伤T（iNKT）细胞，具有先天性和适应性免疫应答特征的T淋巴细胞，已被证明是动脉粥样硬化进展的关键参与者。ABCA 7是一种三磷酸腺苷结合盒转运蛋白，已显示在免疫细胞中响应于他汀类药物而上调。研究表明，他汀类药物治疗通过调节ABCA 7直接参与宿主防御系统的调节。他汀类药物在动脉粥样硬化中的有益作用部分归因于其免疫调节功能。我们认为他汀类药物作用于iNKT细胞中ABCA 7的表达，ABCA 7的这种改变会导致iNKT细胞群的发育和功能异常，这对动脉粥样硬化的发展/进展有直接影响。我们将首先详细研究ABCA 7在iNKT细胞功能和发育中的作用，因为我们有初步数据表明ABCA 7的缺乏对iNKT的发育和功能产生负面影响。我们的第一个具体目标是检验ABCA 7调节胸腺细胞中CD 1d功能改变iNKT细胞胸腺发育进程的假设。我们将研究ABCA 7基因敲除DP胸腺细胞在体外的功能能力，并在体内通过混合骨髓嵌合体的产生。我们还将利用混合骨髓嵌合体来测试ABCA 7在细胞内在效应中对iNKT的作用。第二个具体目标将检验ABCA 7调节外周抗原呈递细胞中的CD 1d功能，影响iNKT活化的假设。这将通过使用共聚焦显微镜来完成，我们将分析ABCA 7敲除CD 11 c+细胞中的CD 1d定位和脂质抗原运输。具体目标三将测试他汀类药物施用是否引起ABCA 7介导的iNKT细胞功能的变化，最终影响动脉粥样硬化的发展。我们将ABCA7.ldlr双敲除和ldlr敲除iNKT细胞过继转移至ldlr.Jalpha18双敲除受体中，转移前接受或不接受他汀类药物治疗，用于动脉粥样硬化研究。

DESCRIPTION (provided by applicant): Cardiovascular disease is the single largest killer of adults in North America with current therapeutics against atherosclerosis represented by drugs known as statins. Invariant Natural Killer T (iNKT) cells, T lymphocytes with qualities characterized by both innate and adaptive immune responses, have been demonstrated as key players in the progression of atherosclerosis. ABCA7, an adenosine triphosphate binding cassette transporter, has been shown to be upregulated in immune cells in response to statins. Studies have shown direct involvement of statin treatment in the regulation of the host defense system through the modulation of ABCA7. The beneficial effects of statins in atherosclerosis have been partly attributed to their immunomodulating functions. We propose that statins act on ABCA7 expression in iNKT cells, and that this alteration in ABCA7 brings about developmental and functional aberrancies in the iNKT population, which has a direct effect on the development/progression of atherosclerosis. We will first examine in detail the role ABCA7 plays in iNKT cell function and development as we have preliminary data that suggests the absence of ABCA7 negatively impacts iNKT development and function. Our first specific aim will test the hypothesis that ABCA7 modulates CD1d function in thymocytes altering the thymic developmental progression of iNKT cells. We will examine the functional capabilities of ABCA7 knockout DP thymocytes in vitro, and in vivo through the generation of mixed bone marrow chimeras. We will utilize the mixed bone marrow chimeras to also test the role of ABCA7 on iNKT in a cell intrinsic effect. The second specific aim will test the hypothesis that ABCA7 modulates CD1d function in peripheral antigen presenting cells, impacting iNKT activation. This will be done through the use of confocal microscopy where we will analyze CD1d localization and lipid antigen trafficking in ABCA7 knockout CD11c+ cells. Specific aim three will test whether statin administration causes ABCA7-mediated changes in iNKT cell function ultimately effecting the development of atherosclerosis. We will perform adoptive transfers of ABCA7.ldlr double knockout and ldlr knockout iNKT cells, with or without statin treatment prior to transfer, into ldlr.Jalpha18 double knockout recipients for atherosclerosis studies.