CELLULAR MECHANISMS OF DRUG TRANSPORT IN CHOROID PLEXUS

脉络丛药物转运的细胞机制

• 批准号: 6138416
• 负责人: KATHLEEN M GIACOMINI
• 金额: $ 16.34万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-01-01 至 2002-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6138416
• 关键词: Xenopus oocyte; basolateral membrane; brain metabolism; brush border membrane; chimeric proteins; choroid plexus; drug metabolism; human tissue; laboratory rat; membrane transport proteins; molecular cloning; neuronal transport; nucleoside analog; protein structure function; purine nucleosides; pyrimidine nucleosides; site directed mutagenesis

Nucleosides (e.g., adenosine) and synthetic nucleoside analogs (e.g., cytosine arabinoside (Ara-C) and 2',3'-dideoxyinosine (ddI)) are being used in the treatment of a wide array of disease states including cancer, viral infections, and cardiac arrhythmias. The overall goal of studies proposed in this competitive renewal application is to identify the structure, function and biological roles of Na+-dependent nucleoside transporters with particular emphasis on the specific transporters in the choroid plexus that are vital in the central nervous system (CNS) disposition and targeting of nucleosides and nucleoside drugs. In recent exciting studies, the first Na+-dependent nucleoside transporters were cloned from rat (rPUR and rPYR) and human (hPUR (cloned in this laboratory) and hPYR) tissues. hPYR and rPYR are pyrimidine-selective whereas hPUR and rPUR are purine- selective. Initial studies suggest that these cloned transporters are present in choroid plexus epithelium and play a role in the CNS targeting of nucleosides and nucleoside analogs. Novel studies performed in this laboratory with chimeric transporters have identified, for the first time, the gross structural domains responsible for the purine and pyrimidine selectivity of rPUR and rPYR. The specific aims of the proposed studies are: (1) To determine the functional characteristics hPUR and hPYR in heterologous expression systems. Particularly, we will investigate the mechanisms of interactions of synthetic nucleoside analogs which are important in the treatment of cancer and viral infections; (2) To determine the functional domains and critical amino acids responsible for purine and pyrimidine substrate recognition in PUR and PYR; and (3) To localize rPUR and rPYR to the brush border or basolateral membrane of the choroid plexus. Briefly, we will perform functional studies in a mammalian expression system. Site-directed mutagenesis, construction of chimeric transporters together with molecular modeling will be used to determine the critical amino acids responsible for substrate selectivity in the transporters. Studies with antibodies will localize the transporters in choroid plexus epithelium. These studies will greatly advance our understanding of the molecular mechanisms involved in nucleoside transport and the structural elements of nucleoside transporters critical in purine and pyrimidine discrimination. The information gained is important in drug design and targeting to the CNS.

核苷（例如腺苷）和合成核苷类似物（例如， 胞嘧啶阿拉伯糖苷（ARA-C）和2'，3'-二维氨酸（DDI）正在 用于治疗多种疾病状态 癌症，病毒感染和心律不齐。 总体目标 在此竞争更新应用中提出的研究是确定 Na+依赖性核苷的结构，功能和生物学作用 转运蛋白特别强调特定转运蛋白 在中枢神经系统（CNS）中至关重要的脉络丛 核苷和核苷药物的处置和靶向。 在 最近的令人兴奋的研究，第一个Na+依赖性核苷转运蛋白 从大鼠（rpur和rpyr）和人类（HPUR（在此中克隆） 实验室）和HPYR）组织。 HPYR和RPYR是嘧啶选择性的 而HPUR和RPUR是嘌呤的选择性。 最初的研究表明 这些克隆的转运蛋白存在于脉络丛上皮中 并在核苷和核苷的CNS靶向中起作用 类似物。 用嵌合在该实验室进行的新型研究 转运蛋白首次确定了总体结构 负责RPUR的嘌呤和嘧啶选择性的域 和rpyr。 拟议研究的具体目的是：（1） 确定异源的功能特征HPUR和HPYR 表达系统。特别是，我们将研究 合成核苷类似物的相互作用在 治疗癌症和病毒感染； （2）确定 功能域和关键氨基酸负责嘌呤和 PUR和PYR中的嘧啶底物识别； （3）本地化 rpur和rpyr到脉络的刷子边框或基底外侧膜 丛。 简而言之，我们将在哺乳动物中进行功能研究 表达系统。 定向诱变，嵌合的构造 转运蛋白与分子建模将用于确定 负责底物选择性的关键氨基酸 运输商。 使用抗体的研究将定位转运蛋白 在脉络丛上皮中。 这些研究将大大推动我们的 了解核苷涉及的分子机制 转运和核苷转运蛋白的结构元素 对嘌呤和嘧啶歧视至关重要。 信息 获得在药物设计中很重要，并且针对中枢神经系统很重要。