CELLULAR CHOLESTEROL FLUX AND METABOLISM

胆固醇逆向转运（RCT）的第一步将通过询问SR-BI和ABCA 1如何介导细胞和血清组分之间的胆固醇流动来研究。将通过测量ABCA 1或SR-BI阳性和阴性细胞之间脂蛋白通量的差异来探测这些质膜蛋白中的每一种的具体贡献。在与本计划项目中的其他项目的密切互动中，将研究ABCA 1、SR-BI、apo A-I、血清因子、RCT和动脉粥样硬化之间的关系。在特定目标1中，我们将与Rader博士合作，将小鼠血清的通量潜力与通过腺病毒介导的脂质酶和转移蛋白的过表达在体内调节的脂蛋白相关联。在具体目标2中，我们将与Lund-Katz博士和菲利普斯博士合作，在体外操纵胆固醇脂蛋白组成，以更好地衡量单个组分对通量的影响。在特定目标3中，使用在Rader博士的预防心脏病诊所收集的血清，我们将通过血管造影术测试个体的流量与血清组成相关联，以记录动脉粥样硬化的存在/不存在。因此，ABCA 1和SR-BI介导的胆固醇通量将首次与人类病变相关。在具体目标4中，我们将使用THP 1人巨噬细胞泡沫细胞鉴定通过SR-BI或ABCA 1介导胆固醇质量去除的细胞途径和血清组分。 模型这些研究将使用Rader博士实验室提供的小鼠和人血清以及项目2中开发的突变载脂蛋白。在具体目标5中，我们将探索SR-BI和ABCA 1之间的相互作用。我们将表征apo A-t与表达ABCA 1的J774细胞孵育后产生的新生颗粒。将对胆固醇富集/正常J774细胞获得的新生颗粒进行表征，并用于测量与SR-BI表达细胞孵育时的胆固醇通量。相反，将获得、表征SR-BI修饰的HDL并用于测量ABCA 1介导的通量。这些研究结果将为研究新生HDL的形成和HDL的通量提供基础信息。 RCT中的胆固醇。

The first step in reverse cholesterol transport (RCT) will be investigated by asking how SR-BI and ABCA1 mediate cholesterol flux between cells and serum components. The specific contribution of each of these plasma membrane proteins will be probed by measuring the difference in flux to lipoproteins between ABCA1 or SR-BI positive and negative cells, In close interaction with other projects in this Program Project, the relationships between ABCA1, SR-BI, apo A-I, serum factors, RCT and atherosclerosis will be studied. In Specific Aim 1, we will collaborate with Dr. Rader to correlate the flux potential of mouse serum to lipoproteins modulated in vivo by adenovirus-mediated overexpression of lipid enzymes and transfer proteins. In Specific Aim 2, we will collaborate with Drs. Lund-Katz and Phillips to manipulate cholesterol lipoprotein composition in vitro to obtain a better measure of the impact of individual components on flux. In Specific Aim 3, with serum collected in Dr. Rader's Preventive Cardiology Clinic we will correlate flux to serum composition in individuals tested by angiography to document the presence/absence of atheroscterosis. Thus, for the first time, ABCA1-and SR-BI mediated cholesterol flux will be correlated to lesions in humans. In Specific Aim 4, we will identify the cellular pathways and serum components that mediate cholesterol mass removal via either SR-BI or ABCA1 using the THP1 human macrophage foam cell model. These studies will utilize mouse and human sera supplied by Dr. Rader's laboratory and mutant apolipoproteins developed in Project 2. In Specific Aim 5, we will probe the interaction between SR-BI and ABCA1. We will characterize the nascent particles produced upon incubation of apo A-t with J774 cells expressing ABCA1. Nascent particles obtained with both cholesterol-enriched/normal J774 cells will be characterized and used to measure cholesterol flux when incubated with SR-BI-expressing cells. Conversely, SR-BI-modified HDL will be obtained, characterized, and used to measure ABCA1-mediated flux. The results from these studies will provide fundamental information on the formation of nascent HDL and the flux of cholesterol in RCT.