The LXR agonist GW3965 increases apoA-I protein levels in the central nervous system independent of ABCA1
- 作者：Sophie Stukas ; Sharon May ; Anna Wilkinson ; Jeniffer Chan ; James Donkin ; Cheryl L. Wellington ; Cheryl@cmmt.ubc.ca
- 关键词：Apo-A-I ; apoE ; ABCA1 ; LXR ; Brain lipid metabolism
- 刊名：Biochimica et Biophysica Acta (BBA)/Molecular and Cell Biology of Lipids
- 出版年：2012
- 期刊代码：18_13881981
- 类别：bio
- 出版时间：March, 2012
- 卷：1821
- 期：3
- 页码：536-546
- 文件大小：992 K
摘要
Lipoprotein metabolism in the central nervous system (CNS) is based on high-density lipoprotein-like particles that use apoE as their predominant apolipoprotein rather than apoA-I. Although apoA-I is not expressed in astrocytes and microglia, which produce CNS apoE, apoA-I is reported to be expressed in porcine brain capillary endothelial cells and also crosses the blood-brain barrier (BBB). These mechanisms allow apoA-I to reach concentrations in cerebrospinal fluid (CSF) that are approximately 0.5%of its plasma levels. Recently, apoA-I has been shown to enhance cognitive function and reduce cerebrovascular amyloid deposition in Alzheimer's Disease (AD) mice, raising questions about the regulation and function of apoA-I in the CNS. Peripheral apoA-I metabolism is highly influenced by ABCA1, but less is known about how ABCA1 regulates CNS apoA-I. We report that ABCA1 deficiency leads to greater retention of apoA-I in the CNS than in the periphery. Additionally, treatment of symptomatic AD mice with GW3965, an LXR agonist that stimulates ABCA1 expression, increases apoA-I more dramatically in the CNS compared to the periphery. Furthermore, GW3965-mediated up-regulation of CNS apoA-I is independent of ABCA1. Our results suggest that apoA-I may be regulated by distinct mechanisms on either side of the BBB and that apoA-I may serve to integrate peripheral and CNS lipid metabolism. This article is part of a Special Issue entitled Advances in High Density Lipoprotein Formation and Metabolism: A Tribute to John F. Oram (1945-2010).