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

描述(申请人提供)：心血管疾病是北美成年人的最大杀手，目前以他汀类药物为代表的抗动脉粥样硬化药物。不变自然杀伤T细胞(INKT)是一种具有先天免疫反应和获得性免疫反应的T淋巴细胞，已被证明在动脉粥样硬化的发展过程中起关键作用。ABCA7是一种三磷酸腺苷结合盒转运蛋白，已被证明在免疫细胞中对他汀类药物有上调作用。研究表明，他汀类药物通过调节ABCA7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ABCA7的表达，ABCA7的这种改变导致了iNKT群体的发育和功能异常，这对动脉粥样硬化的发生发展有直接的影响。我们将首先详细研究ABCA7在iNKT细胞功能和发育中的作用，因为我们有初步数据表明，ABCA7的缺失对iNKT的发育和功能产生了负面影响。我们的第一个特定目标将测试ABCA7调节胸腺细胞CD1d功能改变iNKT细胞胸腺发育进程的假设。我们将在体外和体内通过产生混合骨髓嵌合体来检测ABCA7基因敲除的DP胸腺细胞的功能能力。我们将利用混合的骨髓嵌合体来测试ABCA7在细胞内在效应中对iNKT的作用。第二个特定目标将检验ABCA7调节外周抗原提呈细胞中CD1d功能，影响iNKT激活的假设。这将通过使用共聚焦显微镜来完成，我们将在其中分析ABCA7基因敲除的CD11c+细胞中CD1d的定位和脂类抗原的运输。具体目标三将测试他汀类药物是否会导致ABCA7介导的iNKT细胞功能变化，最终影响动脉粥样硬化的发展。我们将进行ABCA7.ldlr双基因敲除和LDLR基因敲除iNKT细胞的过继转移，在转移前进行或不经他汀类药物治疗，转移到ldlr.Jalpha18双基因敲除受体中，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.