HDL DERIVED CHOLESTEROL UPTAKE BY HEPATOCYTES

肝细胞对 HDL 衍生的胆固醇的摄取

基本信息

批准号：
6184274
负责人：
GREGORY S SHELNESS
金额：
$ 22.66万
依托单位：
WAKE FOREST UNIVERSITY HEALTH SCIENCES
依托单位国家：
美国
项目类别：
财政年份：
1998
资助国家：
美国
起止时间：
1998-07-10 至 2001-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/6184274
关键词：
apolipoprotein E blood lipoprotein metabolism cholesterol enzyme mechanism heparin hepatic lipase high density lipoproteins immunologic assay /test laboratory rabbit laboratory rat lipid transport liver cells proteoglycan receptor receptor binding receptor expression tissue /cell culture

项目摘要

DESCRIPTION: Elevated plasma cholesterol is a well established risk factor for atherosclerosis and coronary artery disease. HDL has been shown to protect against developing atherosclerosis. In lipoprotein metabolism the role of HDL is to transport cholesterol to the liver to be disposed of. Hepatic lipase (HL) is a major determinant of HDL cholesterol levels. The proposed research will be based on recent evidence which shows that HL stimulates direct selective HDL cholesterol ester (CE) uptake by the liver cells. The mechanism of HDL cholesterol ester uptake by the liver cells, and the mechanism by which HL stimulates this uptake, will be studied. The following questions will be addressed: 1) What are the characteristics of HL stimulated direct selective HDL CE uptake? The role of HL will be verified using cells with and without HL. HL knockout hepatocytes and heparin-treated hepatocytes will be used as cells lacking HL. HL antibodies will also be used to block HL action. These experiments will determine if HL action amplifies HDL cholesterol uptake by the liver cell. 2) Is this uptake mediated by the putative HDL receptor, scavenger receptor class B type 1? To study if this uptake mediated by SRB1, antibodies will be used to block this receptor. Experiments where the putative HDL receptor and HL are regulated independently will be carried out to address separately the roles of these factors in HDL CE uptake. 3) Are the cell surface proteoglycans participating in this uptake? The role of cell surface proteoglycans will be addressed by using cells lacking these structures. 4) What is the mechanism of HL-stimulated direct selective HDL CE uptake? It will be determined if lipolytic activity of HL, phospholipid and/or triglyceride hydrolysis, is needed for the stimulation of direct selective HDL cholesterol ester uptake by the liver cells. A hypothesis that HL can have a nonlipolytic role in this pathway will be addressed using inactive mutant HL. These experiments will explore the possibility that HL enhances HDL binding to hepatocyte cell surface resulting in an increase in CE uptake without hydrolyzing HDL lipids.

描述：升高的血浆胆固醇是一个良好的危险因素用于动脉粥样硬化和冠状动脉疾病。 HDL已显示为预防动脉粥样硬化。在脂蛋白代谢中 HDL的作用是将胆固醇运送到肝脏处置。肝脂肪酶（HL）是HDL胆固醇水平的主要决定因素。这拟议的研究将基于最近的证据，表明HL 刺激肝脏的直接选择性HDL胆固醇酯（CE）摄取细胞。肝细胞摄取HDL胆固醇酯的机制， HL刺激这种摄取的机制将被研究。这将解决以下问题：1） HL刺激了直接选择性HDL CE摄取？ HL的角色将是使用有或没有HL的单元格进行了验证。 HL敲除肝细胞和肝素处理的肝细胞将用作缺乏HL的细胞。 HL抗体还将用于阻止HL动作。这些实验将确定是否 HL作用会扩大肝细胞中HDL胆固醇的摄取。 2）是这个推定的HDL受体，清道夫受体B类介导的摄取类型1？为了研究这种摄取是否由SRB1介导，将使用抗体阻止该受体。假定的HDL受体和HL的实验将独立进行监管，以分别解决这些因素在HDL CE摄取中的作用。 3）是细胞表面蛋白聚糖参加了这种摄取？细胞表面的作用使用缺乏这些结构的细胞来解决蛋白聚糖。 4） HL刺激的直接选择性HDL CE摄取的机制是什么？它将确定HL，磷脂和/或需要甘油三酸酯水解，需要刺激直接选择性肝细胞摄取HDL胆固醇酯。 HL可以的假设在此途径中具有非溶解作用，将使用非活动来解决突变HL。这些实验将探讨HL增强的可能性 HDL与肝细胞细胞表面结合，导致CE摄取增加没有水解HDL脂质。