CHOROID PLEXUS AND A BETA/APOLIPOPROTEIN CNS HOMEOSTASIS

淀粉样β蛋白(Abeta)在血管中枢组织中的沉积 脉络丛(CP)发生在正常衰老过程中，并被 阿尔茨海默病(AD)。最近的研究表明， 血脑屏障(BBB)与脑脊液(CSF)清除 调节中枢神经系统内Abeta的浓度。CP具有重要的 在调节脑脊液和脑脊液中几种蛋白质水平的作用 大脑，并清除脑脊液中的废物和潜在的细胞毒性 用于大脑的物质。CP在Abeta中枢神经系统内稳态中的作用主要是 未知。我们在豚鼠体内的初步数据表明， 糖蛋白330和可能的一些低密度的其他成员 脂蛋白受体家族参与CP上皮内化 与载脂蛋白(Apo)J和E4络合的无脂Abeta/1-40， 分别进行了分析。磷脂载脂蛋白E3和载脂蛋白E4的CP摄取是 与其各自的破旧设备相比，高达4.5倍 单体。循环中游离的Abeta/1-40不能通过 血液-脑脊液屏障，与其快速运输出 脑脊液，CP上皮显著积聚中枢神经系统来源的Abeta 软脑膜血管显著摄取。初步尝试 血脑脊液屏障体外转运模型的建立 从培养的人CP上皮细胞构建的证实 人CP上皮不对称Abeta转胞反应一致 与活体数据进行比较。我们建议使用活体血管脑/CP和 豚鼠脑室-脑池灌流及其体外转运 正常人和AD患者血脑脊液屏障模型的建立及检测 CP通过调节Abeta中枢神经系统稳态的假说 控制脑脊液和脑内的转运 脂结合的apoJ和不同的apoE亚型游离和络合到 阿贝塔。我们将在体内测定基底侧方CP的摄取、代谢和 循环载脂蛋白J、E_2、E_3和E_3跨血脑脊液屏障转运 E4，脱脂，加脂，游离，与Abeta络合(目标1)，以及 脑脊液的清除率，脑脊液顶端的摄取和 软脑膜和实质微血管的隔离(目标2)。在……里面 目标3和4我们将研究CP上皮基底侧至根尖和 心尖-基底外侧Abeta/载脂蛋白结合、内吞作用和 采用人体体外模型进行细胞穿透。不同的角色 脂蛋白和Abeta受体将被定义。这些研究将 为理解Cp参与的功能提供分子基础 调节脑脊液和中枢神经系统Abeta水平以减少其中枢神经系统损害 积聚致病。

Deposition of amyloid beta peptide (Abeta) in vascular CNS tissues and the choroid plexus (CP) occurs during normal aging and is accelerated by Alzheimer's disease (AD). Recent studies suggest major roles for the blood-brain barrier (BBB) and the cerebrospinal fluid (CSF) clearance in regulating the concentrations of Abeta in the CNS. The CP has important functions in regulating the levels of several proteins in the CSF and brain, and in cleansing the CSF of waste and potentially cytotoxic substances for brain. The role of CP in Abeta CNS homeostasis is largely unknown. Our preliminary in vivo data in guinea pigs indicate that glycoprotein 330 and possibly some other members of the low density lipoprotein receptor family participate in CP epithelial internalization of lipid-free Abeta/1-40 complexed to apolipoproteins (apo) J and E4, respectively. The CP uptake of blood-borne lipidated apoE3 and apoE4 was up to 4.5-fold greater compared to their respective dilapidated monomers. Circulating unbound free Abeta/1-40 is prevented from crossing the blood-CSF barrier, in contrast to its rapid transport out of the CSF, remarkable accumulation of CNS-derived Abeta by the CP epithelium and significant uptake by leptomeningeal vessels. Preliminary attempts to develop an in vitro transport model of the blood-CSF barrier constructed from cultured human CP epithelial cells confirmed asymmetrical Abeta transcytosis across human CP epithelium consistent with in vivo data. We propose to use in vivo vascular brain/CP and ventriculo-cisternal perfusions in guinea-pigs and an in vitro transport model of human blood-CSF barrier from control and AD subjects to test the hypothesis that the CP regulates Abeta CNS homeostasis by controlling transport in and out of the CSF and brain of lipid-free and lipid-bound apoJ and different apoE isoforms free and complexed to Abeta. We will determine in vivo basolateral CP uptake, metabolism and transport across the blood-CSF barrier of circulating apoJ, E2, E3 and E4, delipidated, lipidated, free and complexed to Abeta (aim 1), and their clearance from the CSF, uptake at the apical side of the CP and sequestration by leptomeningeal and parenchymal microvessels (aim 2). In aims 3 and 4 we will study the CP epithelial basolateral-to-apical and apical-to-basolateral Abeta/apolipoprotein binding, endocytosis and transcytosis using human in vitro model. The role of different lipoprotein and Abeta receptors will be defined. The studies will provide the molecular basis to understand the CP functions involved in the regulation of the CSF and CNS levels of Abeta to minimize its CNS accumulation and pathogenic effects.