Blood-brain barrier P-glycoprotein: a new target for Alzheimer's disease

血脑屏障P-糖蛋白：阿尔茨海默病的新靶点

• 批准号: 8531818
• 负责人: Anika M.S. Hartz
• 金额: $ 29.25万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2014-03-01
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8531818
• 关键词: Affect; Alzheimer' s Disease; Amyloid; Amyloid beta-Protein Precursor; Autopsy; Biological Assay; Blood - brain barrier anatomy; Blood Vessels; Blood capillaries; Brain; Brain Diseases; Cell Line; Clinic; Clinical; Cognition; Data; Deposition; Development; Disease Progression; Duct (organ) structure; Goals; Human; Impaired cognition; Knowledge; Lead; Marketing; Measures; Mediating; Mission; Molecular; Monitor; Mus; National Institute of Neurological Disorders and Stroke; Neurodegenerative Disorders; Outcome; P-Glycoprotein; P-glycoprotein 2; Pathogenesis; Pathology; Patients; Perfusion; Pharmaceutical Preparations; Play; Public Health; Receptor Activation; Research; Research Personnel; Role; Sampling; System; Tail; Testing; Therapeutic; Therapeutic Effect; Transgenic Organisms; Translating; Ubiquitin; Ubiquitination; United States National Institutes of Health; Work; base; capillary; design; effective therapy; feeding; improved; in vivo; inhibitor/antagonist; innovation; mouse model; multicatalytic endopeptidase complex; nervous system disorder; new therapeutic target; novel therapeutics; overexpression; pregnane X receptor; prevent; protein transport; restoration; therapeutic target

DESCRIPTION (provided by applicant): We have a fundamental lack in understanding the mechanism that reduces P-glycoprotein (P-gp) expression and transport activity at the blood-brain barrier in Alzheimer's disease (AD). Lack of this knowledge is a significant clinical problem since it prevents development of an effective therapy to enhance AB clearance from the brain, lower AB brain levels, and thus prevent cognitive decline in AD. The long-term goal of the investigator is to better understand the molecular mechanisms that regulate blood-brain barrier function in neurodegenerative disorders, a goal which may lead to new therapeutic strategies to treat AD. The objectives of this particular application are to identify the mechanism responsible for P-gp reduction in AD, to validate this mechanism as a target to protect P-gp, and to test a novel therapeutic strategy for restoring P-gp. Accomplishing these objectives is expected to reduce A¿ brain levels and improve cognition in AD. Based on preliminary data, the central hypothesis is that A¿ mediates proteasomal degradation of P-gp, that blocking proteasomal degradation protects P-gp, and that restoring P-gp levels through PXR activation reduces A¿ brain burden and improves cognition in mice with AD. The rationale for the proposed research is that identifying the mechanism that reduces brain capillary P-gp and protecting and/or restoring P-gp to improve A¿ brain clearance will potentially provide novel therapeutic targets to lower A¿ brain levels in AD. To accomplish the objectives of this application, we will test our central hypothesis by pursuing the following three specific aims: 1) Identify the mechanism of A¿-mediated P-gp reduction at the blood-brain barrier. 2) Validate the ubiquitin-proteasome system as a target to protect P-gp in an AD mouse model. 3) Develop a therapeutic strategy to reduce cognitive decline in an AD mouse model. In Aim 1, we will inhibit the ubiquitin-proteasome system to identify the steps involved in A¿-mediated P-gp reduction, and determine expression, transport activity, and ubiquitination of P-gp. In Aim 2, we will treat hAPP mice with inhibitors of the ubiquitin-proteasome system, monitor P-gp expression, transport activity, and ubiquitination, and measure A¿ brain levels. We will conduct brain perfusion to assess P-gp activity in vivo and perform tail-flick assays to determine the consequence of changes in P-gp. In Aim 3, we will con- duct a 2-year PCN-feeding study with hAPP mice to assess the long-term therapeutic effect of PXR-mediated P-gp restoration on AB brain levels. P-gp expression and transport activity, A¿ brain load, and cognition will be periodically determined. The proposed research is innovative because it focuses on two independent strategies designed specifically to enhance A¿ clearance from the brain in AD. The proposed research is significant because it holds the promise of two new therapeutic strategies to lower A¿ brain burden and slow progression of AD. The proposed research is translational because drugs for either strategy, inhibition of the ubiquitin- proteasome system and PXR activation, are currently on the market, and both therapeutic strategies could potentially be translated into the clinic for the treatment of AD patients.

描述（由适用提供）：我们根本缺乏理解在阿尔茨海默氏病（AD）中降低P-糖蛋白（P-gp）表达和运输活性的机制。缺乏这种知识是一个重大的临床问题，因为它可以防止开发有效的疗法，从而增强大脑的AB清除率，降低AB的大脑水平，从而防止AD的认知能力下降。研究者的长期目标是更好地了解调节神经退行性疾病中血脑屏障功能功能的分子机制，该目标可能导致新的治疗AD治疗策略。该特定应用的目标是确定负责AD降低P-gp的机制，以验证该机制作为保护P-gp的目标，并测试恢复P-gp的新型治疗策略。实现这些目标有望降低大脑水平并改善AD的认知。基于初步数据，中心假设是A介导P-gp的蛋白酶体降解，即阻断蛋白酶体降解可保护P-gp，并且通过PXR激活恢复P-gp水平可减少脑燃烧并改善AD小鼠的认知。拟议的研究的基本原理是，确定降低脑毛细管P-gp的机制并保护和/或恢复P-gp以改善大脑清除率，将有可能为降低AD中的A脑水平提供新的热目标。为了实现此应用程序的目标，我们将通过追求以下三个特定目的来检验中心假设：1）确定在血脑屏障下降低A介导的P-gp的机制。 2）验证泛素 - 蛋白酶体系统作为保护AD鼠标模型中P-gp的目标。 3）制定一种治疗策略，以减少AD小鼠模型的认知能力下降。在AIM 1中，我们将抑制泛素 - 蛋白酶体系统，以确定介导的P-gp降低的步骤，并确定P-gp的表达，转运活性和泛素化。在AIM 2中，我们将使用泛素 - 蛋白酶体系统的抑制剂，监测P-gp表达，运输活性和泛素化以及测量A脑水平来治疗HAPP小鼠。我们将进行大脑灌注，以评估体内P-gp活性并进行尾流评估，以确定P-gp变化的结果。在AIM 3中，我们将与HAPP小鼠进行一项为期两年的PCN喂养研究，以评估PXR介导的P-gp恢复对AB脑水平的长期治疗作用。 P-gp表达和转运活性，A脑负荷和认知将定期确定。拟议的研究具有创新性，因为它专门针对两种专门设计的独立策略，以增强AD中的大脑清除率。拟议的研究很重要，因为它具有两种新的治疗策略，以降低脑伯恩的脑力并缓慢进展。拟议的研究之所以翻译，是因为任何一种策略的药物，对泛素 - 蛋白酶体系统的抑制和PXR激活，目前都在市场上，并且两种治疗策略都可能被转化为诊所以治疗AD患者。