THE STRUCTURAL BASIS OF AGONIST TRANSPORT BY THE MULTIPLE DRUG RESISTANCE TRANSPO

描述(申请人提供)：缺乏药物对血脑屏障(BBB)的渗透是治疗中枢神经系统(CNS)疾病和开发中枢神经系统药物的一个巨大障碍。大量的血脑屏障穿透被一种称为人类多药耐药1(MDR1)转运蛋白的外排转运蛋白阻断。这种转运蛋白通过核苷酸结合域(NbD)上的ATP水解和构象变化，将一系列化学和结构上不同的化合物从血脑屏障内的上皮细胞排出到血流中。二苯丙胺衍生物、吗啡生物碱和三聚氰胺代表了三种化学类别的中枢神经系统激动剂，尽管它们的分子结构相似，但在同一化学类别内，它们的MDR1外排速率和转运特性存在很大差异。虽然已经有许多研究，但激动剂的分子结构和转运速率之间的关系仍有待澄清。这项拟议的工作将检验中心假设，即激动剂MDR1的转运速率由膜的胞外侧(血侧)附近的药物结合(接近Y953)控制，而不与NBD直接相互作用。该提案分为两个特定的目的：1)表征激动剂与人MDR1的相互作用，确定它们对ATP水解酶的影响，并建立它们与高表达人MDR1的MDCK细胞的转运速率；2)定位激动剂与人MDR1的结合部位。创新的核磁共振和计算方法将被用来探索激动剂和人类MDR1之间的相互作用。这些技术将为用人类多药耐药基因筛选广泛的治疗药物打开大门。了解分子结构和转运速率之间的关系也将填补我们对转运蛋白了解的重大空白，并导致新的神经疗法，加速中枢神经系统药物的开发，提高现有中枢神经系统药物的有效性。

DESCRIPTION (provided by applicant): Lack of drug penetration through the blood-brain barrier (BBB) represents a formidable hurdle to treatment of central nervous system (CNS) diseases and the development of CNS drugs. A significant amount of BBB penetration is blocked by an efflux transporter called the human multiple drug resistance 1 (MDR1) transporter. This transporter effluxes a wide range of chemically and structurally diverse compounds from epithelial cells within the BBB to the blood stream by ATP hydrolysis at nucleotide binding domains (NBDs) and conformational changes. Diphenylpropylamine derivatives, morphine alkaloids and triptans represent three chemical classes of CNS agonists that show large differences in their MDR1 efflux rates and transport properties within a chemical class, despite the similarities in their molecular structures. Although there have been numerous studies, the relationship between the agonist's molecular structure and transport rates remains to be clarified. The proposed work will test the central hypothesis that the agonist MDR1 transport rate is controlled by drug binding near the extracellular side (blood-side) of the membrane (near Y953) and without direct interaction with the NBDs. The proposal was divided into two specific aims: 1) to characterize the interaction of agonists with human MDR1, to determine their effect on ATP hydrolysis and to establish their transport rates with MDCK cells overexpressing human MDR1 and 2) to locate the agonist binding sites on human MDR1. Innovative NMR and computational methods will be used to explore the interaction between agonists and human MDR1. These technologies will open the door to screening a wide range of therapeutics with human MDR1. Understanding the relationship between molecular structure and transport rates will also fill significant gaps in our understanding of the transporter as wellas lead to novel neurotherapeutics, acceleration of CNS drug development and improvements in the effectiveness of current CNS drugs.